Anatomy

I am Your Dog’s Tongue

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Almost everybody is familiar with a dog’s tongue, whether it’s hanging out of the mouth of a dog on a hot summer day or being used to vigorously lick the owner in a greeting, this organ is sure to play a conspicuous role in a dog’s life and the life of the people living with the dog. Yet, there are so many things to discover about a dog’s tongue such as the tasks a dog’s tongue is responsible for, the various anatomical parts of the tongue, the number of taste buds populating it and much, much more! So today, let’s have the dog’s tongue do the talking and tell us his fascinating story.

dog panting tongueIntroducing Your Dog’s Tongue

Hello, it’s your dog’s tongue talking! Yes, just for today I have been granted the ability to speak and I am honored to be on stage to talk about myself. I am sure you are already familiar with me, I’m that familiar muscular organ that is often seen hanging out from your dog’s mouth when he is hot or tired as after romping in the yard. I am usually kept nicely moist with doggy saliva and my color is normally pink, but in the dog world, there always seems to be some exception. Wanna know something really cool? The chow chow dog breed boasts a fascinating blue tongue that is out of this world!

People are often surprised when they learn that I am an organ, but since I am more than just tissue and am composed by bundles of muscles that are richly supplied with nerves and blood vessels, I think I deserve to keep this “title.” Wanna learn a bit about my anatomy? Well, my upper surface is known as “dorsum” and that groove you see in the center that divides me into two symmetrical halves is called the median sulcus. I am attached to the back of your dog’s mouth by the hyoid bone. While among humans, I mostly aid with chewing, swallowing and talking, in dogs, I carry out some other interesting functions.

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I House the Taste Budsdog watermelon eating

Ever wondered why your dog spits out those bitter pills with a disgusting look on his face? Well, I am home of the taste buds, special sensory organs that are scattered throughout my surface. Dogs are estimated to have about 1,700 taste buds, which is a mere number considering that on average, humans have about 10,000! Each taste bud is equipped with special taste receptor cells responsible for transmitting messages to the dog’s brain such as what he should or should not eat. It’s a known fact that dogs are capable of discerning between salt, sweet, sour and bitter.  You see, generally, in nature, most bad bitter flavors, are a warning sign that an animal has likely encountered something that can be harmful or even poisonous, explains Stanley Coren.So no wonder why Rover spits out those nasty tasting pills!

But hey, here’s a dirty little secret: you can fool my taste buds by wrapping up those pills in a piece of low-sodium hot-dog or piece of cheese (ask your vet first as some medications don’t agree with cheese). If your dog is a smarty pants and still detects the pill, you can trick him by giving him a series of cheese or hot dog pieces without the pill in a row and then in the midst of all of these you can give the one with the pill. Chances are, your dog will be so eagerly eating, he won’t hardly even notice!

dog hotI am a Radiator

On top of allowing Rover to enjoy tasty meals and avoid the potentially harmful ones, I also play a big role in helping him cool down. You see, when your dog pants, he’s not just hanging me out to look silly. Dogs are not able to sweat in the same people do, so it’s my turn to take matters into my own hands. Since I am moistened by saliva produced by four pairs of salivary glands, when Rover sticks me out as he breathes heavily (like 300-400 breaths a minute!) I act like a radiator. Basically, along with the rest of the dog’s mouth and upper respiratory tract, I allow moisture to evaporate with the end result of cooling him down during those dog days of summer. Now, don’t I deserve a nice pat on my back?

I Work as a Ladle

Dogs don’t have the manual dexterity necessary to grab a cup full of water, bring it to the mouth and pour it down, so they rely on me when it’s time to drink. When dogs stick me out to get a drink of water, I curl up backwards and work as a ladle, collecting water and quickly bringing it in to the dog’s mouth. The dog then quickly bites down and then rinses and repeats the whole cycle until his thirst is finally quenched. So if you think your dog is messy drinker, don’t blame him, rather, blame me instead as my backward curl can cause some splashes! Now, watch me below to have a better idea on exactly what I do. Quite fascinating, huh?

 

Did you know? Other than detecting sweet, bitter, sour and salt, a dog’s taste buds are  even capable of tasting water, something quite surprising, isn’t it! Now you know why your dog has a potty mouth. Read more about this here: Dogs have taste buds for water. 

mother dogI am a Cleaning Device

When you get  need to clean a wound, you can just walk to your medicine cabinet and grab some bandages and a disinfectant, while dogs are left with nothing more than their mouths. This is where I can come handy. Dogs may use me as cleaning device to remove dirt or debris from a wound, and while I am at it, I can even disinfect it a bit too.  My tongue is kept humid with saliva, and that saliva is thought to contain some beneficial compounds capable of destroying the cell walls of  gram-positive bacteria. But as with almost everything in life, moderation is key. Dogs can sometimes get too carried away with licking, and if they sue me too much, my abrasive surface can cause more harm than good. The result can be a moist, raw area, basically, what vets call an “acral lick granuloma.” This is why Rover is sometimes better off wearing that  big satellite dish, also know as the “cone of shame.”

“Pets can get obsessed with licking to the detriment of healthy skin. There’s also a lot of bad bacteria in a pet’s mouth, so as with so many good things in life, licking is an activity best done in moderation.”~ Dr. Patty Khuly

Did you know? I also play a role in keeping a batch of newborn puppies clean and happy. Mother dog uses me to vigorously lick the pups clean and improve their circulation as they take their first gasps of air. Mother dogs also uses me to stimulate the pups to potty, something day-old pups cannot do yer on their own!

I Allow “Dog Talk”dog lip licking

In humans, I play a main role in allowing speech and proper pronunciation, but in dogs I can also “speak volumes,” but this time we’re talking about body language. Those tongue flicks your dog does every now and then may look casual, but there’s likely more to it if you pay attention to the context in which they’re happening. Patricia McConnell in her book ” For the Love of a Dog: Understanding Emotion in You and Your Best Friend” explains that those fast tongue flicks can be a sign of low level anxiety or an appeasement signal. So watch what’s going on when you see me in action. It could be your dog is nervous at the vet’s often, not comfortable with a pal he just met at the dog park or nervous about being pat on the head.

If you notice your best friend doing this, take notice of when it happens and then try to find ways to make your dog more comfortable in the future. Consider though that all tongue flicks in dogs don’t always stem from uneasiness or anxiety. You may also see me in action when your dog greets you walking towards you with the head lowered and tongue flicking as a friendly way to solicit attention. And of course, you’re likely familiar with me being used as a greeting tool when your dog submerges you with all those wet “doggy kisses”  when you first come home. 

Dogs like to lick our faces, a behavior that is disturbing for many dog owners and particularly non-dog owners. Yet, this behavior is a demonstration of friendliness, an attempt at pacifying us and themselves, a hand (though not literally) reaching for peace. It’s a compliment a dog gives you, “I like you, you can be my friend.” ~Roger Abrantes

dog sniffI Help With Smells

Have you ever seen your dog chatter his teeth when he sniffs something interesting and perhaps even foam at the mouth? When dogs do this, they are basically gathering large scent molecules and with my help they are able to send them towards their incisiva papilla a behavior known as tonguing. These scent molecules then reach the dog’s vomeronasal organ and finally the dog’s brain possibly eliciting a behavior response such as marking over the sniffed area. Interesting stuff, huh?

 

When Things Go Wrongwhen to see vet

You don’t hear about me much when it comes to medical diseases and conditions. Even though I am made of muscles, you never hear about me getting sore or a sprain as other muscles do. Something though that dog owners notice a lot is that I bleed a whole lot when I get accidentally cut. A bleeding tongue in dogs indeed can be quite scary at times! Using some ice on the area or offering a bowl of ice, cold water can help in such a case, suggests veterinarian Dr. Christian K. Keeping the dog calm and relaxed is also important as any increase in blood pressure can increase my bleeding. Of course, see your vet if the bleeding is pretty significant! Also, if I start bleeding for no reason, it’s important to see the vet, as there may be some bleeding lump, blister, ulcer or wart hiding somewhere in the dog’s mouth that needs to be checked out.

When I sustain any type of injury such as a bug bite, burn or cut, your dog will usually let yo know by drooling, smacking his lips a lot and sometimes being reluctant to eat. Glossitis is the term used for when I get inflamed and swollen and this can be triggered by several things such as a foreign body (think a burr or grass awn working its way into me), an allergic reaction, a fungal or bacterial infection or exposure to something toxic. Sometimes, immune diseases such as lupus, kidney disease and cancer can cause this too. At times, swelling right under me can be a ranula, a blocked salivary gland that causes saliva to collect under the tongue, explains veterinarian Dr. Kara. And yes, Hanging Tongue Syndrome is not what you see in those world’s ugliest dogs competitions, it’s actually a real medical problem. In this condition, trauma to the dog’s jaw or head can lead to nerve dysfunction which causes affected dogs to carry me abnormally.

As with checking a dog’s gums colors, my color can also be an indicator of health or trouble. I am normally pink in color (except some exceptions such as blue tongues in chow chows and dogs with spotted tongues ) so if you see me turn pale, red, bluish or a yellow/brown tint, please see your vet right away as this can be a sign of a dog not getting enough oxygen as seen in heart and respiratory diseases and internal bleeding, decreased profusion (less oxygen moving through body) or liver problems (jaundice) among other possible causes.

So I hope you enjoyed learning more about me today! As you can see, I can do a lot of talking! I won’t bite my tongue in saying that I play many important roles in your dog’s life, so make sure to take good care of me and keep an eye for signs of trouble. Your dog and I will thank you!

Best regards,

Your Dog’s TongueDog Pawprint

Disclaimer: this article is not meant to be used as a substitute for professional veterinary advice. If you notice any abnormalities in your dog’s tongue, please see your vet for proper diagnosis and treatment.

 

References:

  • Krönert, H.; Pleschka, K. (January 1976). “Lingual blood flow and its hypothalamic control in the dog during panting”. Pflügers Archiv European Journal of Physiology. 367
  • For the Love of a Dog: Understanding Emotion in You and Your Best Friend, by Patricia McConnell, Ph.D Ballantine Books; 1 Reprint edition (July 22, 2009)
  • American Physical Society’s Division of Fluid Dynamics. “Fluid dynamics explain what happens when dogs drink water.” ScienceDaily. ScienceDaily, 25 November 2014.
  • Gart, Sean, et al. “Dogs lap using acceleration-driven open pumping.”Proceedings of the National Academy of Sciences 112.52 (2015): 15798-15802.
  • Psychology Today, How Good Is Your Dog’s Sense of Taste?, by Stanley Coren, retrieved from the Wed on March 4th, 2016.
  •  Ethology Institute Institute Cambridge, Why Do Dogs Like to Lick Our Faces?, by Roger Abrantes, retrieved from the Web on March 4th, 2016.
  • Just Answer, Dog has cut on tongue, bleeding steadily, retrieved from the web on August 22, 2016

 

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I am Your Dog’s Pupil

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The saying “the eyes are the window to the soul” has a medical application as well. From a medical perspective we should also say “the eyes are the window to our health” considering the many notions we can deduce from simply looking into the eyes of another person or an animal. Because most dog eyes are brown, looking into the pupil may be a bit challenging at times, but it’s good to get acquainted with  how those pupils look like normally so that we can identify signs of trouble promptly and refer to our veterinarians. So today, let’s learn more about a dog’s pupil, what it does, how it works and things to watch for.

dog pupilIntroducing Your Dog’s Pupil

Hello, it’s your dog’s pupil talking! Yes, to simply put it, I am that black circle that you find in the middle of your dog’s eye. Well, to tell you the truth, I am not really black. That’s just an optical illusion!

In reality, I am a black hole and appear black because I am an opening that allows light to enter your dog’s eye and the inside of the eye is generally dark. I can be of different shapes and sizes based on the species you are looking at. For instance, in goats and horses, I am oval, in cats I am a thin vertical slit, but in dogs and humans I tend to be round.

I am an Adjustable Opening

For sake of comparison, you can compare your dog’s eyes to a camera that takes pictures of the world and sends those images to your dog’s brain through the optic nerve. When it comes to me though, you can think of me as an adjustable opening. The iris (the colored part of the eye) acts as a camera’s shutter and basically regulates how much light should enter and reach me. The amount of light that reaches me therefore elicits the iris to change my size. When it’s dark, the iris muscle contracts so to enlarge me so to allow more light into the dog’s eye so he can see. When it’s bright instead, the iris muscle expands so to constrict me so to allow less light into the dog’s eye. My size is therefore controlled by two groups of smooth muscles of the dog’s iris: the iris sphincter muscle and the iris dilator muscle. These two muscle basically work in opposition. Pretty neat no?

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Did you know? The technical term for when I constrict is “miosis” (allowing less light in) whereas, the technical term for when I dilate is “mydriasis” (allowing more light in).

I Act as An “Eye-Opener”scared dog

On top of shrinking and dilating in response to light, I also react to certain stimuli and situations. For instance, if the dog sees something scary, I may dilate too. There’s yet no proof to back up why I do so, but experts theorize that it’s part of a survival tactic.

Basically, I dilate so to allow more light to enter the eyes so that the dog’s brain can process information quicker when every second counts. I therefore act as an “eye-opener” so to say, so to help the dog take in more visual information about his surroundings in such a critical time.

According to Scientific American, the autonomic nervous system responsible for the fight and flight response is what triggers me to dilate when under stress, whereas the parasympathetic system, responsible for “rest and digest” functions, causes me to constrict.

dog pawing eyesWhen Things Go Wrong

When I am working properly, I will dilate and constrict based on the amount of light entering the eyes, but when things go wrong I may stop from properly responding to light. In some cases, I might not look good from the get-go and you can notice abnormalities in my size. This is one of the main reasons why veterinarians often check a dog’s eyes as part of the physical exam and check my dilation or constriction in different lighting situations as a diagnostic tool.

Anisocoria, is the medical term for when the pupil in a dog’s eye is different from the other. Basically, in this case, I am bigger in one eye compared to the other. According to veterinary ophthalmologist Caryn E. Plummer, anisocoria may be indicative of some type of ocular or neurological disorder. However, not always this is detectable from onset; it may be necessary to shine a light in the dog’s eyes and watch how I respond both in bright and dim lights. This should be done by a vet, or even better, a veterinary ophthalmologist specially trained in evaluating eyes.  Just consider that there are many conditions that may cause anisocoria in dogs such as an eye injury, inflammation somewhere within the eye, Horner’s syndrome, glaucoma, uveitis, exposure to toxins, head concussions and even cancer. Also, a very important important piece of information needed is uncovering which pupil is the abnormal one. Is it the dilated one or the constricted one?

“If anisocoria occurs suddenly, you should consider this an emergency situation and seek veterinary care immediately to lessen the chance that your dog’s vision will be permanently affected.”~ Dr. Cheryl Yuill, VCA Animal Hospital

Sometimes, I  may also appear dilated in both eyes. When I no longer constrict in response to light this is often a sign that the dog’s eyes are no longer capable of recognizing light on the back of the eye causing blindness. Several conditions can cause this, such as blood clotting problems, infections, high blood pressure or a mass around the area of the optic nerve, explains Dr. Christian K.

Other times, I may appear dilated in both eyes. Dog owners describe their dogs as having “pin-point’ pupils. This can be due to exposure to chemicals such as pesticides, exposure to certain medications such as opioid drugs or benzodiazepines, or  traumatic brain injury affecting the front of the brain stem, explains veterinarian Dr. Altman.

In some cases abnormalities in my shape can be due to congenital eye problems affecting me or the surrounding iris such as persistent pupillary membranes in dogs, coloboma, iris hypoplasia, sunburst pupils

As seen, I am very important when it comes to your dog’s vision and by looking at me, vets can even sort out medical problems. If you notice anything odd with me and the surrounding eye, please see your vet sooner than later. A “wait and see” approach could cost your dog’s vision and even affect his health, so keep an “eye” on me and report changes to your vet promptly! Yours truly,

Your Dog’s PupilDog Pawprint

Disclaimer: this article is not meant to be used as a substitute for professional veterinary advice. If your dog has signs of eye problems, please see your vet promptly to protect your dog’s vision.

 

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I am Your Dog’s Radial Nerve

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Just as in people, the dog’s body is innervated by several branches of  nerves that relay information from the brain and spinal cord to several parts of the body and organs. There are several nerves originating from the dog’s spinal cord which branch off into several ramifications made of individual nerves that supply the dog’s front legs. The radial nerve in particular, is a nerve that can be predisposed to several problems such as dogs having trouble moving their front legs and possibly developing muscle wasting. This is another good reason to see the vet when a dog starts limping for no obvious reason.

dog radial nerveIntroducing the Dog’s Radial Nerve

Hello, it’s your dog’s radial nerve talking! Before introducing myself, I want to give out a little lesson in canine anatomy so that you can better understand my role. You see, just like you, your dog is blessed with a nervous system that’s composed by the brain and spinal cord. The brain is your dog’s command central, while the spinal cord, and its associated nerves, work as a pathway for all those messages being relayed from the dog’s  brain to his body and vice versa.

Your dog’s brachial plexus is a network of of cervical (neck) and thoracic (thorax) nerves originating from the spinal cord and then branching off into singular nerves that reach the dog’s front legs.

The brachial plexus is composed by three nerves: me (the radial nerve) and my neighboring median nerve and ulnar nerve. I basically, innervate your dog’s front legs  from the elbow all the way down to your’s dog’s wrist and toes. I  don’t want to sound like I am bragging, but I am basically, the biggest nerve of your dog’s front leg. Can you guess how I got my name? I am known as radial nerve for the simple fact that I run right by your dog’s radius bone, the main weight-supporting bone of your dog’s forelimb.

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I Help With Movement and Sensation

Not many people are aware of me, but I sure do a whole lot to help your dog move about all day. I provide motor innervation to your dog’s muscles in the front leg allowing your dog to romp around every time he wants to and also provide sensory innervation to the skin, in particular to the upper-outside surface of the dog’s front leg and the upper surface of the dog’s paw. When all goes well with me and I am all in one piece, your dog is capable of moving around, having reflexes and feeling sensations. Problems start though when something goes wrong with me.

Did you know? Dogs tend to carry the majority of their weight in the front legs. If we were to look at proportions when it comes to weight distribution in dogs, we could expect 60 percent of weight to be carried in the front legs and the remaining 40 percent in the back legs.

When Things Go Wrong dog pain goes away at the vet

As with other body parts, I can be prone to traumatic injury such as seen with a fall or car accident. I am one of the most common areas to be subjected to nerve injuries. If the impact is strong enough or if the dog’s foreleg is hyperextended away from the body, it may cause the nervous tissue of the brachial plexus to stretch and even forcibly detach from the spinal cord (what is known as brachial plexus avulsion), which affects my functionality just like an electric cord that is fraying or splitting in half.

When this happens, affected dogs may suffer from weakness and loss of muscle use and sensation below the elbow which can lead to toe dragging when walking and since the elbow can’t be extended inability to bear weight. The use of special boots or socks may be needed in dogs with radial nerve injury to prevent injury to their paws.

In some other cases, a tumor such as a nerve sheath tumor or a tumor of neighboring tissue (fibrosarcoma, myosarcoma), on or around the brachial plexus, can affect me leading to problems with the dog’s forelimbs. As soon as dog owners notice any problems such as loss of sensation, weakness or paralysis, it’s important to see veterinary care immediately because muscle mass can be lost quite quickly considering that us nerves time time to regenerate. Seeing a veterinarian specializing in neurology is recommended. Physical therapy using passive range of motion exercises is important so to provide blood flow to the dog’s muscles preventing them from atrophying.

Unfortunately, when us nerves sustain an injury either because of trauma or presence of a tumor, we take quite a while to heal. Need a general idea? Consider that according to Pet Education, nerve fibers generally heal at the rate of 1 mm a day (that’s about 1 inch per month!). Prognosis depends on the extent of injury affecting me. I might lose function temporarily recovering within a few days or I might take weeks or even months to recover and in severe cases  I may sometimes never recover. In the meanwhile as I start to repair myself, I can cause a pins and needles sensation (paraesthesia) that dogs may find hard to accept. Affected dogs may therefore lick and chew on the affected leg, and since they cannot feel pain, if not monitored, they may cause substantial damage.

“Nerve injuries are very mysterious. It can be very difficult to predict if function will return after injury.”~ Dr. Foster and Smith

As seen, I am an important nerve that allows your dog to move and feel sensations. Without me, dogs would not be able to walk and use their front legs to bear weight. So make sure you keep your dog safe and off the roads, so to prevent me from getting injured, and if you notice any problems with your dog’s front legs, please see your vet promptly, that means sooner than later as time is of the essence with these type of injuries. I hoped this helped understand me better!

Best regards,

Your Dog’s Radial NerveDog Pawprint

 

References:

  • Pet Education, Radial Nerve Paralysis in Dogs and Cats, retrieved from the web on August 8th, 2016
  • Dr Fosters and Smith, Dog Neurological Disorders: Radial Nerve Paralysis, retrieved from the web on August 8th, 2016

Photo Credits:

Anterior view of right brachial plexus. Illustration. Modified by Mattopaedia on 02-Jan-2006 from the 1918 Edition of Gray’s Anatomy. Public Domain

 

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I am Your Dog’s Iliopsoas Muscle

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Like many other cursorial animals, dogs are equipped with powerful muscles which allows them to move about and sprint into action. The muscles in the hips allow dogs to perform everyday activities such as walking and running. In particular, the dog’s iliopsoas muscles which comprise the psoas major and the iliacus muscle play a major role in getting that hip to flex nicely. Indeed, these muscles are often referred to as the most powerful flexors of the thigh at the hip joint. So today, let’s get more acquainted with these muscles, learning how they work and the signs of something potentially going wrong.

dog iliacus muscleIntroducing Your Dog’s Iliopsoas Muscle

Hello, it’s your dog’s iliopsoas muscle talking! Yes, I know, my name is quite hard to pronounce, well here is a tip: just try to say “e-leo-soas” that should be somewhat better! For sake of easiness, you can even call me a “hip flexor” muscle, courtesy of my duty.  I am found along the dog’s lower spine and groin area and then go down and connect to the inside portion of the dog’s thigh bone. To be more precise, I am comprised of a group of two muscles: the psoas major and the iliacus muscles,  Ilio +psoas get it? Hence my name .

I Allow Movement

What do I do? Of course, I don’t just sit around doing nothing all day, actually, to the contrary I am very useful. You must thank me if your dog is able to move his hind limb up toward his abdomen and forward. I help accomplish this movement by externally rotating and flexing your dog’s hip joint. At the same time, I also work as a stabilizer of the dog’s hip joint and vertebral column. Yup, I am a useful dude, indeed!

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dog agility role of tailWhen Things go Wrong

As with other other muscles, I  can be prone to excessive stretching and tearing. I can get injured when a dog slips or falls with his legs splayed out (such as on an icy surface or a slippery floor) or when dogs run a whole lot on uneven terrain or jump out of a car or over obstacles.

I am not very known for being a location of common injuries (perhaps because I am often misdiagnosed), but dogs involved in sports like  agility or fly ball are the poster child for this condition. Sometimes, I may get injured secondarily such as when dogs are affected by some other orthopedic problem (think, cruciate ligament rupture) or neurological condition that causes them to tense up in the groin area in hopes of compensating or protecting the injury.

“A possible cause of an iliopsoas strain might be repeated jumping with extreme extension of the hind limbs (active eccentric muscle contraction).”~ Dr. Sherman O. Canapp, DVM, Diplomate ACVS

agilitySigns of  Iliopsoas Strain in Dogs

Owners of performance dogs may know something is amiss when their dogs don’t perform well as before. For instance, their dogs may be knocking down obstacle bars more or they may appear hesitant in weaving in and out poles or they may run more slowly.

Once at the vet, affected dogs may show signs of pain such as during their physical exam when their hips are extended and rotated inwardly. Pressing on the muscle may also cause a pain response.

Since I am responsible for allowing dogs to move their leg up and forward, in a dog with an iliopsoas strain, you will often see a shortened stride, and possibly, a circular outward movement of the leg to avoid the pain. This is most visible at a trot. When I am the troublemaker, dogs may try to avoid bearing weight on the affected hip so their weight will be mostly distributed on the uninjured side.

Getting me back in top shape is not easy. Affected dogs will need loads of rest. In acute injuries, vets may try to reduce my spasms by prescribing muscle relaxers and medications to reduce pain and inflammation.

Rehabilitation therapy may include acupuncture, laser therapy, passive range of motion exercises followed by, a few weeks later, active range of motion exercises meant to strengthen me. This may include stepping over cavaletti poles and wobble board exercises. According to veterinarian Sherman O Canapp, having the affected dog slowly walk up and down a steep hill (20 to 40 degrees in incline) for 100 feet three to five times can further help strengthen me and my neighboring muscles.

I hope this article has helped you understand me better!  If your dog has an injury in his back leg and it’s not getting any better or if it appears to be a medical mystery, don’t forget about me! Consult with a veterinarian specializing in orthopedics and sport injuries, and he or she may be able to spot the problem and your dog should hopefully be soon on the mend!

Respectfully yours,

Your Dog’s Iliopsoas MuscleDog Pawprint

Disclaimer: this article is not meant to be used as a substitute for professional veterinary advice. If your dog is having problems with his leg, please see your vet for appropriate diagnosis and treatment.

 

References:

  • Blue Pearl Vet, Iliopsoas Muscle Tears, retrieved from the web on August 1st, 2016
  • Clean Run, Iliopsoas Strain Revisited, retrieved from the web on August 1st, 2016
  • DVM360, Hind limb sprains and strains (Proceedings), retrieved from the web on August 1st, 2016
  • Veterinary Orthopedic Sports Medicine Group, Non-responsive Hind-limb Lameness in Agility Dogs: Iliopsoas Strains, retrieved from the web on August 1st, 2016
  • Compend Contin Educ Vet. 2013 May;35(5):E2.Iliopsoas muscle injury in dogs. Cabon Q1, Bolliger C.

Photo Credits:

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I am Your Dog’s Vagus Nerve

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The vagus nerve is a part of the dog not many people are likely to hear about, but it’s a very important bundle of nerves that carries many different functions. It’s one of the twelve nerves that emerge directly from the brain, and as such, it’s responsible for relaying information between the dog’s brain and other body parts. Like a good captain of a ship, the dog’s vagus nerve controls a vast range of crucial functions, so let’s discover today more about where this powerful nerve bundle is located, how it works and the variety of things that may go wrong when there’s some sort of malfunction going on.

vagal nerveIntroducing Your Dog’s Vagus Nerve

Hello, it’s your dog’s vagus nerve talking! I am a nerve that emerges from the brain and travels down your dog’s neck, close to the carotid artery and jugular vein. While technically there are two of us, one on the left and one on the right, doctors tend to usually refer to me as being one. I am the longest and most complex of your dog’s cranial nerves (nerves that stem from the skull) and if you look at the etymology of my name you can learn more about me.

The term “vagal” derives from the Latin word “vagus ” which literally  means “wandering.” Yes, I wander like a vagabond providing two-way communication of nerve impulses back and forth from the brain stem to the lowest viscera of your dog’s abdomen touching the heart and other major organs along the way. As mentioned, I work like a good captain and my job encompasses overseeing your dog’s parasympathetic nervous system. Because I have multiple branches that travel to so many organs, I accomplish many functions.

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I Control The Heart Rate heart

I am responsible for regulating your dog’s heart rate. Being the captain of the parasympathetic system, also known as the “rest and digest system,” (basically the total opposite of the sympathetic nervous system which is ‘fight of flight’), it’s my job to slow down the heart rate. I do so by triggering the release of a substance known as acetylcholine which helps slow down the pulse courtesy of electrical impulses sent to the sinoatrial node of the heart. Back in the old days, Otto Loewi, a German-born pharmacologist, referred to acetylcoline as “Vagusstoff” in honor of me.

“The sympathetic nervous system is geared to rev you up like the gas pedal in an automobile – it thrives on adrenaline and cortisol and is part of the fight-or-flight response. The parasympathetic nervous system is the polar opposite. The vagus nerve is command central for the function of your parasympathetic nervous system. It is geared to slow you down like the brakes on your car and uses neurotransmitters like acetylcholine and GABA to literally lower heart rate, blood pressure, and help your heart and organs slow down. “~Christopher Bergland

back massageI Help with Breathing

Interestingly, my nerves associated with respiration, cause the heart rate to increase with inspiration and decrease with expiration. For those anxious people out there, taking deep breaths followed by a long and slow exhale can calm them down as this stimulates me to biologically release vagusstuff with the associated pleasant consequence of lowering the heart rate and blood pressure. Relaxation is sure to follow as cortisol levels are reduced.

Sure, you can’t really teach dogs to say “Ommm” and take deep breaths and exhale, but if you perform a calming activity such as giving your dog a massage, chances are, you can help me release acetylcholine so your dog’s heart rate and breathing can lower. Veterinarian Narda G. Robinson and Shelly Sheets, a Canine Massage Specialist, explain in the book “Canine Medical Massage: Techniques and Clinical Applications” that moderate-pressure massage primarily works on the dog’s parasympathic nervous system, (and that includes the vagal nerve pathways) slowing the heart rate, lowering blood pressure and reducing cortisol levels.

“Dogs probably like their ears rubbed because neurologically speaking, gentle massage in these areas are relaxing. The vagus nerve serves a large part of the midportion of the ear, and stimulating this nerve is calming because it controls vegetative, restorative functions. This calming effect also counteracts the fight and flight response associated with the sympathetic nervous system.  ~ Marty Becker, D.V.M., Gina Spadafori

I am Responsible for Motilitydog eating

One of my interesting roles is my ability to “read’ and interpret the microbiome of your dog’s gut. Basically, I check whether there are any pathogenic organisms in the gut. If I detect something alarming, I will modulate the inflammatory response. Too much inflammation is not a good thing!

Also, I play a role in motility. I basically work like a walkie-talkie, relaying information from the gut to the brain. When your dog feels hungry from the sensation of his stomach being empty and he looks up at you in hope for a tasty morsel, you must thank me for relaying that message.

I am also behind general motility, orchestrating the muscles in your dog’s stomach telling them when to contract and push food into the neighboring small intestine. Now, off it goes!

I Do a Whole Lot!

There are many more important functions I play a role in, so here is a quick run down of others things I do. In the gallbladder, I help release bile, in the liver and pancreas, I help control the balance of glucose, in the kidneys, I help excrete sodium so to lower blood pressure, in the eyes, I help promote excretion of tears, in the tongue I help with taste and production of saliva and much more.

Interestingly, in the last years, I have been researched a lot. Researchers have discovered that that the neurotransmitter acetylcholine I release not only helps with relaxation, but also plays a role in learning, memory and reducing inflammation. Activation of me has also be linked with production of new cells and even repair of organs. According to Pet Education, researchers at the North Carolina State University College of Veterinary Medicine have been studying using a pacemaker-like device to stimulate me, which can turn helpful to control seizures in epileptic dogs.

dog pain goes away at the vetWhen Things Go Wrong

While I can be a great captain when I have everything under control, when things backfire, I can quickly turn from a loyal comrade on deck into a major saboteur. Yeah, you really don’t want anything to go wrong with me; with all the tasks I perform, you may expect problems anywhere along my route from the brain to all those important organs. While stimulating me may lead to relaxation, over-stimulation can lead to problems.

At the esophagus level, several vagal receptors detect the presence of food and liquid so that the dog can swallow and the esophagus contracts. When things go wrong though and dogs start suffering from megaesophagus, defects in my vagal afferent innervation or abnormalities of the muscles of the esophagus are often to blame.

While not too common in animals as in people, dogs can sometimes faint when I am stimulated. This is often referred to as “vasovagal syncope.”  Basically, when my vagal nerves of the pharynx are overstimulated, I can trigger a lower heart rate and a drop in blood pressure. This can happen when dogs eat too fast, bark, cough or vomit. According to veterinarian Henry Green III, in small dogs suffering from heart problems, I can cause fainting when the heart rate is very low (bradycardia) and it’s then following by bouts of high heart rate (tachycardia). Also, a high vagal tone which happens when my impulses produce an inhibition in the heart beat, can cause what’s known as first-degree heart block.

As seen, I really accomplish a whole lot! Just consider that anywhere between 80 and 90 percent of my nerve fibers are dedicated to relaying important information pertaining the state of your dog’s viscera to your brain. Connect the brain to your dog’s pharynx, larynx, esophagus, ears, tongue, gut, heart, liver, pancreas, gallbladder, kidney, ureter, spleen and lungs. I guess I can say that I am largely responsible for your dog’s mind and body connection.  I hope this article has helped you understand the vagus nerve better! Oh, and I am also found in humans, so chance are today you learned even something new about yourself too!

Respectfully yours,

Your dog’s vagus nerveDog Pawprint

 

References:

  1. Pavlov, V.A., and K.J. Tracey. 2005. The cholinergic anti-inflammatory pathway. Brain Behav Immun 19 (6):493-99.
  2. 1999 “Use of ocular compression to induce vagal stimulation and aid in controlling seizures in seven dogs.”
    Speciale, J. and J. E. Stahlbrodt (1999). J Am Vet Med Assoc 214(5): 663-5.
  3. *Zabara J. Inhibition of experimental seizures in canines by repetitive vagal nerve stimulation. Epilepsia 1992;33:1005-1012.
  4. Why Do Dogs Drink Out of the Toilet?: 101 of the Most Perplexing Questions …By Marty Becker, D.V.M., Gina Spadafori, HCI (September 15, 2006)
  5. Canine Medical Massage: Techniques and Clinical Applications, By Narda G. Robinson, DO, DVM, MS, FAAMA, Shelley Sheets, BA, CMT, CAMT, AAHA Press (February 3, 2015)

Photo Credits:

  • Plan of upper portions of glossopharyngeal, vagus, and accessory nerves, Henry Vandyke Carter – Henry Gray, public domain
  • My Favorite Pet Sitter, Chester loves a back scratch, Flickr Creative Commons, CC BY 2.0

 

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I am Your Dog’s Neurons

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Many people are intimidated by neuroscience because they believe it is something really complicated, but it all sums up to making it easy to understand. Today, we will be taking a close look to a dog’s neurons, how they work and the many tasks they accomplish. Turns out dogs and people share similar nervous systems, so by learning more about neurons, we also learn a bit more about ourselves and how our nervous system functions. So let’s see what a dog’s neurons have to say, how they work and how they help us accomplish the many things we do in life.

Introducing Your Dog’s NeuronsNEuron dog

Hello, it’s your dogs’ neurons talking! While your dog’s body is made of many cells, cells that are part of the nervous system are known as “neurons” so to distinguish us from the average cells. We are the longest cells of the body, sometimes reaching great lengths (like when going from the spinal cord all the way to your dog’s skin or lower leg).

Like other cells, we are surrounded by a cell membrane, we have a nucleus, cytoplasm, mitochondria and other organelles. What mostly distinguishes us from other cells though is what we do. There are different types of us: Sensory neurons responsible for your dog’s senses such as touch, sound and scent, motor neurons specialized for muscle contractions and movement and interneurons specialize in connecting  neurons with other neurons sharing the same region of the brain or spinal cord.

synapsysWe Convey Messages

We are responsible for carrying messages. We are electrically excitable, and we use this electrical energy to receive and transmit information. We have dendrites and axons to help carry out the task. Imagine your dog’s brain as a telephone switch-board receiving and delivering messages. Our dendrites are on the receiving end and take incoming calls (mostly local calls), while our axons take care of the outgoing calls, including the long distance ones. Like telephone poles, electricity travels on wires from one pole to another until it reaches its destination. The gaps between one pole and another can be compared to the gaps known as a ‘synapses.’ In the same fashion a telephone switchboard allows a big number of callers to talk to one another simultaneously, a neuron is able to communicate with other neurons courtesy of these synapses. Instead of telephone numbers though, us neurons rely on chemicals known as neurotransmitters to ensure that all messages reach their destination.

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What messages do we relay? Well, just think that just now, as you are reading this sentence, your brain and nervous system is working. As you are reading, nerve cells in your eyes are relaying the information from your eyes to the brain. While dogs don’t read, they perform many other actions. Everything a dog sees, hears or touches, turns into electrical signals moving between the brain and body. For instance, when your dog is stepping on a thorn, a message is sent from his paw to his brain. Thanks to us neurons, your dog will sense pain and will lift his foot off the ground before he risks getting it injured any further. And we do work fast! Just think that the message reaches his brain within a few thousandths of a second! It is ultimately thanks to messages traveling from one neuron to the next that your dog can move his muscles, joints and other body parts.

idea tipDid you know? There are chances that dogs may be also gifted with “mirror neurons” special neurons capable of “firing in patterns that mimic others’ actions,” explains Adám Miklósi, a leading expert on canine behavior.

When Things go Wrong

While we are known for doing amazing work, sometimes if the incoming or outgoing calls are plugged wrongly or there are problems with the switchboard, there will be chaos and problems in our ability to communicate. When dogs develop health problems, it’s important to verify whether the problem is local or whether it may derive from a breakdown in our communication.

For example, the lower motor neurons are found by the spinal cord and innervate directly into the dog’s skeletal muscles. These neurons are known for innervating the dog’s front and back legs. When vets examine a dog’s legs, they may want to rule out any problems with our communications. During their neurological examination vets will therefore look for signs such as absence of a reflex, weakness (paresis) or paralysis (plegia) which denote some of spinal injury interfering with our communication. In the picture on the left, a neurologic deficit related to the spinal cord, causes this dog to fail to detect that the paw is not positioned correctly. In a dog with a healthy nervous system instead, he will quickly correct it. Unfortunately because we are such specialized cells, some of us cannot divide and create new cells as other cells do. As a result, it’s more challenging to recover from a brain or spinal cord injury compared to other injuries.

As seen, we do a whole lot! Actually, your life and your dog’s life depend on us. It is thanks to us that your dog feels emotions and sensations. It is thanks to us that your dog makes decisions. You must basically thank us for every action your dog makes, whether, mental or physical, conscious or reflexive. We are the working unit or your dog’s brain designed to relay information to other nerve cells, muscle, or gland cells. So every time your dog moves, reacts or thinks, give us a though and thank us for existing!

Yours truly

Your Dog’s Neurons.Dog Pawprint

idea tipDid you know? According to Live Science,  cats’ brains account for about 0.9 percent of their body mass, while dogs’ brains make up 1.2 percent. According to scientists though, a bigger brain doesn’t necessarily mean smarter; rather, the number of neurons may be more accurate. Considering that cats have 300 million neurons while dogs have 160 million, this may suggests cats are smarter than dogs, but dog lovers hold your horses: There are yet not enough studies on feline smarts to prove that.

 

References:

  • Live Science, Are Cats Smarter Than Dogs? retrieved from the web on July 18th, 2016.
  • Scientific American, Do Dogs Have Mirror Neurons? retrieved from the web on July 18th, 2016.
  • DVM360, The tetraparetic dog: The upper motor neuron, the lower motor neuron, and the in-between (Proceedings), retrieved from the web on July 18th, 2016.

Photo credits:

 

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Five Fascinating Facts About Dog Whiskers

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Want some fascinating facts about dog whiskers? Well, let’s start with an obvious one: dog owners don’t really pay much attention to them, and sometimes they even cut them off as if they really don’t serve any purpose, but those facial hairs are actually important for several different reasons! You might think that dog whiskers aren’t as fascinating as cat whiskers, but when it comes to canines, those whiskers still play many important roles that we often take for granted. So today, let’s discover five fascinating facts about dog whiskers that will explain why dogs have whiskers in the first place and why you should think twice before trimming dog whiskers.

dog face1) Dog Whiskers Work Like Antennas

Whiskers are unlike any other hairs found on your dog’s body; they are thicker, longer and sprout from a hair follicle that’s highly innervated by an abundance of sensory nerves responsible for helping your dog navigate the world around him.

Also known as “vibrissae,” whiskers tend to work in an antenna-like function.

Basically, when anything in your dog’s environment happens to rub against your dog’s whiskers, the whiskers vibrate, stimulating special nerves found in the hair follicles which in turn provide feedback about the surrounding environment, explains veterinarian Dr. Mary Fuller.  For a good reason the word vibrissae, comes from the ancient Latin word “vibrio” which means “to vibrate!”

dog tipDid you know? Out of all the areas the brain invests in registering tactile information, 40 percent is dedicated to the dog’s facial area, explains Stanley Coren.

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2) Dog Whiskers Have Different Nameswhisker

“Tell me where your dog’s whiskers are and I will give you their name based on their location.”

Yes, dog whiskers have different names which can sometimes sound a tad bit technical, but they are sure interesting to discover. Let’s start with the most popular ones, those long, horizontal ones sprouting from the dog’s muzzle which sit comfortably on top of Rover’s upper lip. These whiskers are known as “mystacial whiskers” and that’s because they somewhat resemble a mustache.

If we travel towards the end of the dog’s cheek we’ll find  instead the “genal whiskers,” while if we take a peek under the dog’s chin we may stumble on a mole-like spot that houses a little set of whiskers known as “interramal tufts.”  And what about those whiskers above the dog’s eyes? Those are known as “supraorbital whiskers.” Fascinating stuff, huh?

 

dog whisker under chin3) Dog Whiskers Help with Blind Spots

Cars and trucks aren’t the only ones to have blind spots, turns out dogs have blind spots too. If you ever wondered why your dog doesn’t see that treat that’s right under his nose, it’s either because its color doesn’t stand out in the background as dogs don’t see colors like we do, or because it’s located right within the dog’s blind spot.

While mystacial whiskers provide dogs with information about what’s on their left and what’s on their right right, especially in low-light conditions, his interramal tuft on the chin informs him about what’s found right under his head.

This feature comes handy when he needs to determine how close or far is muzzle is from his food or water bowl or how close his head is from the ground when he’s out and sniffing. Those hairs also turn helpful when he’s digging to his heart’s content and sticks his head in a hole or tunnel.

 

4) Dog Whiskers Have A Protective Function

fingers

On top of providing information about a dog’s surroundings so the dog can navigate safely, whiskers also fulfill an important protective role.

In particular, the whiskers above a dog’s eyes, the “supraorbital whiskers,” function as an extension of the dog’s eyelashes. Basically, they protect the dog’s eyes from any harm by triggering a reflexive blinking action.

This reflex must have played an important evolutionary advantage considering how important a dog’s eyes were in their past when hunting for their dinner or preventing themselves from becoming dinner for other predators.

Still as today, those whiskers can help prevent the eyes from being poked and injured by objects in the dog’s environment.

You might have stumbled on this reflex at some time or another when trying to place eye drops in your dog’s eyes or when upon petting your dog’s head you inadvertently tapped those hairs causing your dog’s eye on the same side of the face to blink.

 

DOG FUR5) Dog Whiskers Tend to Grow Back

“Help! I cut my dog’s whiskers while grooming her, will they grow back?” This is something that many dog owners may be concerned about. No big worries though, groomers tend to cut those dog whiskers at times to attain a neater look of the outline of the jaw.

Whether your groomer cut them off when trimming your dog’s facial hairs or you accidentally cut your dog’s whiskers while shaving her, the good news is that, yes, they will grow back.

In the meanwhile though, there are chances your dog may feel a bit odd and he may need a bit of time to adjust how he navigates around his surroundings, explains veterinarian Roger L. Welton.

 

 

References:

  • Psychology Today, Why do dogs have whiskers? Retrieved from the web on July 15th, 2016
  • Vet Street, What’s the deal with whiskers? Retrieved from the web on July 15th, 2016

 

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I am Your Dog’s Esophagus

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A dog’s esophagus is similar in many ways to the human esophagus. After all, it’s just a tube connecting the mouth to the stomach. However, don’t think of this tube as something very simple, the esophagus is quite a sophisticated piece of machinery considering how much it’s used on a daily basis. As other structures of the dog’s body, the esophagus can also be prone to some problems which are quite similar to certain conditions occurring in humans. So today, let’s get more acquainted with the dog’s esophagus, what it looks like, how it functions and things that may go wrong.

Introducing Your Dog’s Esophagusdog esopha

Hello, it’s your dog’s esophagus talking! As mentioned, I am  a muscular tube-like structure. You see, when your dog eats, food travels from his mouth, to the pharynx and then though me all the way down to his stomach. For this reason, I am also called “food pipe.”

I am nicely lined with moist pink tissue called mucosa and I have two two muscular sphincters one at the top and one at the bottom.

My upper esophageal sphincter is made of a bundle of muscles (cricopharyngeal muscle) which open when food is swallowed and close the esophagus when food is not being swallowed, while my lower esophageal sphincter  is made of a bundle of muscles which open to allow food to reach the stomach and close to prevent your dog’s stomach acids from making their way back up.

My main goal is to deliver food to your dog’s stomach.

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esophagussI Deliver Food

When you think of me as a simple tube that transports food from point A to point B, think again. First of all, I have to make sure that the food your dog eats is delivered to the right pipe. Yes, because failure to do so means your dog will choke as “food goes down the wrong pipe. ” You see, when your dog swallows, about 30 different muscles spring into action in a split second. As in humans, when food travels down, there are only two pipe options, me the esophagus (food pipe) and my neighbor, the larynx, which leads to the trachea (wind pipe) and the lungs.

When your dog swallows correctly, food travels down me and reaches the stomach, courtesy of the epiglottis which tilts backwards closing off access to the larynx and preventing food from entering the “wrong pipe,” that is, the trachea. At the same time the epiglottis closes, my upper esophageal sphincter relaxes and opens up allowing the bolus of chewed food to reach me. Then, a series of muscles work together to move the bolus of food towards the stomach. This all occurs courtesy of my muscles which move in a wave-like fashion which is referred to as “peristalsis.” Now, my lower sphincter relaxes and opens up allowing entry to the dog’s stomach. Of course, this is what happens when all goes well. Below you will see what happens instead when things go wrong.

 Going Down the Wrong Pipecough

While the epiglottis and I work hard in preventing food from entering the wrong pipe, sometimes things beyond our control may happen. If we think of it, it’s not very easy for us and for dogs to breath in air and swallow food at the same time.

If a dog eats too fast or doesn’t pay attention to swallowing carefully, a particle of food may end up being aspirated into the trachea. Yes, this is what really happens when food goes down the wrong pipe!

Luckily, your dog’s coughing reflex will kick in and soon things will go back to normal. The cough reflex is so effective in clearing the airway that sometimes your dog may cough and you’ll see a piece of kibble flying out of his mouth (and your dog will happily pick it up and ingest it again, yay, jackpot!)

Even though dogs may not choke too often, it’s not a bad idea to learn how to do the Heimlich maneuver on dogs too.

Cricopharyngeal Achalasia

Remember how I mentioned how my cricopharyngeal muscle opens when food is around and closes when it’s not? Well, sometimes this muscle may not relax and open up enough to allow the passage of food. Generally, according to Merck Veterinary Manual this is due to an inherited defect, meaning that it’s passed down genetically, but in some instances, this condition can occur in adult dogs without a history of being predisposed to it genetically. This neuromuscular disorder may cause dogs to have a hard time swallowing solid foods and liquids and may lead to complications such as gagging, regurgitation and even aspiration pneumonia, where food or liquids are accidentally inhaled into the lungs. Fortunately, this condition can be treated through corrective surgery.

bailey chairEnlarged Esophagus 

Sometimes, there are problems with my muscles responsible for producing those important wave-like motions that allow delivery of food from me to your dog’s stomach. When this happens I stretch and lose muscle tone and dogs develop what is known as “megaesophagus.”  This translates into the poor affected dogs having quite a hard time. With the food having a hard time reaching the stomach, it lingers by me and decays or is eventually regurgitated. Unlike vomiting, when a dog regurgitates, food will come out passively with little effort and will appear as if just chewed up. Often, repeated regurgitation in dogs is a tell-take sign of this condition. A risk associated with megaesophagus is aspiration pneumonia which may occur when food sits too long around me and it’s accidentally inhaled by the dog’s lungs. To prevent this from happening, dog owners may feed small portions and keep their dogs in a sitting position for around 10 minutes using what’s known as a Bailey chair for megaesophagus. My lack of muscle motion can sometimes be due to an underlying condition known myasthenia gravis, a neuromuscular disease causing weakness in various parts of the dog’s body.

 Inflammation of the Esophagusvet

Sometimes, I may get inflamed and dogs may develop a condition known as esophagitis. This can happen when I am exposed to to stomach acids or the dog ingests some foreign object that causes me trauma. I can also sometimes get inflamed from ingestion of certain drugs. If this ever happens, your vet will treat your dog based on the underlying cause. For example, if stomach acids were making me irritated, medications meant to reduce stomach acid may help. Your vet may also recommend feeding several meals throughout the day. In severe cases though, a stomach tube which bypasses me, may be needed to provide the dog nutrition.

Narrowing Esophagus

Sometimes I can become narrow after some sort of trauma, exposure to toxins or repeated inflammation and reflux of stomach acids. When this happens, affected dogs may regurgitate, drool and have problems swallowing and pain. In this case, I may need intervention so that I can be stretched out through some sort of balloon-shaped catheter that widens me or some other type of surgery.

Foreign Items in Esophagus

Some dogs will eat the oddest things, and it’s not that unusual for things to get stuck in my narrow passages. Fish hooks, pieces of rawhide, toys and other objects sometimes get stuck in me causing a an esophageal blockage. Since food sometimes cannot make it past me, affected dogs will drool, gag, swallow repeatedly and regurgitate. It’s important to see the vet  sooner than later as things can get worse later on. Once at the vet, the vet may retrieve the object using an endoscope with an extension meant to grasp it and remove it.

As seen, I do a whole lot but I can also get into trouble as well.  Thankfully, cancer will rarely affect me. According to Pet Cancer Center, cancer of the esophagus accounts for less than 0.5% of all cancer affecting dogs. However, it’s important to see your vet as soon as you notice any signs of problems with me such as trouble swallowing and regurgitation. Your vet can check me out using an endoscope which entails the insertion of a flexible tube that has a small camera that allows him to visualize what may be going on. So please don’t forget about me and keep me in mind every time your dog effortlessly swallows those tasty treats!

Respectfully yours,

Your dog’s esophagusDog Pawprint

 

Did you know? In dogs, the esophageal muscles are entirely striated (which means they are under voluntary control) so that they can voluntary regurgitate to feed their young.

Disclaimer: this article is not meant to be used as a substitute for professional veterinary advice. If you suspect your dog is suffering from some form of esophageal problem, please wee your vet for proper diagnosis and treatment.

 

References:

  • Hume, C. Edward Stevens, Ian D. (2005). Comparative physiology of the vertebrate digestive system (1st pbk. ed.). Cambridge: Cambridge University Press. p. 15.
  • Merck Veterinary Manual, Disorders of the Esophagus in Dogs, retrieved from the web on July 11th, 2016.
  • Wikipedia, Esophagus, retrieved from the web on July 11th, 2016.

Photo Credits:

  • Flickr, Creative Commons, Eric M, Yip Begging CCBY.2.0
  • A vet examines a dog in New York, Archivist1174 – Own work, Photo of New York State Assemblyman Dr. Stephen M. “Steve” Katz at the Bronx Veterinary Center.CC BY-SA 3.0
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Eight Interesting Facts About Dog Nails

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You notice your dog’s nails when it’s time to trim them, and whether your dog dreads those pedicures or not, you may have never really given those nails much thought other than when they’re making a clicking sound when your dog walks. Dog nails though are more than just sharp protrusion from your dog’s paws. They are there for many reasons and there are many things to discover about them. So for those folks eager to quench their thirst for canine knowledge, here are some interesting facts about dog nails just waiting to be discovered.

dog nail1) Dog Nails Come in Different Colors

Just like horse hooves, dog nails can come in different colors. Generally, the color of the nail varies based on the color of the surrounding skin and hair. White fur usually comes with white nails, while brown and black fur comes with black nails. In some cases, dog nails may be bi-color, featuring different colors on the same nail, as seen in the picture. Sometimes, dog owners may report changes in their dog’s nail color, such as a dog’s black nails becoming pale. When this happens, it can be simply a sign that the cells responsible for causing pigment (melanocytes) aren’t producing any pigment for some reason, explains veterinarian  Roger L. Welton. While these color changes may be normal, they can sometimes signify a health problem so should be brought to a vet’s attention.

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2) Dog Nails Have an Extended Quickdog quick

Ever wondered why dogs hate nail trims so much? Well for starters, they might not be used to having their feet handled, and secondly, they might be also scared of the noisy tools. In some cases though it could be these dogs got their quick accidentally cut on one occasion and they are aware of how painful that can be.

What is a dog’s quick? Just like humans, a dog’s nail is made of keratin – a protein made of dead cells, but unlike us, dogs have several nerves and blood vessels (which compose the quick) that extend into the nail. While us humans also have a “quick,” our quick stops at our finger tips while in dogs the quick extends into the nail causing bleeding and lots of pain when it’s accidentally cut.

Dogs are built for moving!
Dogs are built for moving!

3) Dog Nails Can Stay Short Naturally

How often you need to trim your dog’s nails may vary based on how much activity your dog gets. Just think about it: in the wild, canines don’t ever require a nail trim for the simple fact that they are often walking and digging and putting those nails to good use. Many working dogs who are on their feet for a good part of their day may also rarely need a nail trim. If your dog is running, walking and playing outside on rough surfaces for a good part of his day, there are chances that his nails will wear down naturally as the constant pressure makes the dog’s nail quick recede which leads to short nails. Be careful though not to overdo it with dogs who are not used to being exercised on hard asphalt; this may lead to blisters and abrasions, warns St. Bernard’s Animal Medical Center.

4) Dog Nails in Back Paws May Not Need Trimmeddog long nails

If your dog hates nail trims, count your blessings: in most cases if your dog is active and walks on abrasive surfaces, you may have to limit those dreaded nail trims to the front paws only. Indeed, a dog’s back claws are generally short, sometimes requiring little to no trimming. Why is that? It’s due to how the back legs are used compared to the front. A dog’s back legs are used for propulsion which means they are used more for traction and therefore the nails are ground much more than in the dog’s front legs which are mostly used for stability. So no, unless the nails in your dog’s back claws are long, as in the picture on the right,  or your dog is quite inactive, you likely won’t have to clip your dog’s back claws too. If you are unsure, ask your vet or groomer for advice.

5) Dog Nails May Loop

When a dog’s nails are allowed to grow very long, they can start curving and even form a 360-degree loop that may embed into the dog’s paw pad, explains veterinary behaviorist Dr. Nicholas Dodman in the book “Puppy’s First Steps.” Dealing with an ingrown toenail will require veterinary attention, especially when the tip of the nail is not visible because it’s embedded into the dog’s paw, which can be very painful. Even if the dog’s toenail is not embedded, it’s critical to be very careful in trimming the dog’s nail a little bit at a time considering the fact that, as nails grow, their quick will grow along them, sometimes even close to the tip. In the picture above, a curled nail forming a loop can be seen in the outlined square section.

dog nail
Whatever happens, think “pawsitive!”

6) Dog Nails Get Infections Too

Bacterial and fungal toenail infections can affect man’s best friend nails too. With bacterial infections, the most common cause is trauma, so it’s important to keep those nails clean and dry after sustaining an injury. Other causes of  nail infections in dogs can be triggered by systemic conditions such as immune-mediated diseases, diabetes and hypothyroidism.

When a dog’s nail is chronically infected, it could lead to permanent defective nail growth, explains veterinary dermatologist Dr. Patrick Hensel. Fortunately, unlike humans though, fungal infections of a dog’s nails are less common. When fungal infections of the nail are caused by malassezia, affected dogs will show a brown-red discoloration of the nail with a waxy brown-red seepage. This nail fungal infection is seen more in dogs suffering from allergies.

7) Dog Nails  Can Be Affected by Cancer

Nails are a place that one really wouldn’t suspect cancer to take place, but they can actually be affected by different types of cancers. Squamous cell carcinoma and mast cell tumors can affect a dog’s nails. Also, nail changes in dogs can be observed when dogs develop melanoma of the toe. According to the Veterinary Cancer Place, when this cancer takes place, one of the first signs owners may notice is swelling of the toe, and in some cases, the nail may fall off. While malignant melanoma is more likely to affect a dog’s mouth, its second preferred site are the dog’s toes which can lead to fragile, easily damaged nails.

8) Dog Nails May Need a Gripdog hardwood

Dog nails weren’t meant for our modern settings; those nails were purposely designed by Mother Nature so to allow dogs to walk on natural terrains. If we take a closer look at our dog’s nails we will notice how they’re shaped like cleats purposely crafted to dig into earthen terrains, explains Dr. Julie Buzby. When we welcomed our dogs into our modern homes, we therefore introduced them to a totally unnatural environment where they may have a bit of a hard time getting a grip on, such as when walking on tiles, linoleum and hardwood floors.

Things may be particularly problematic for dogs with long nails which have a tough time gaining traction on hard, slippery floors. Because long nails cause dogs to rock their foot back, their toe pads fail to make normal contact with the floor, explains veterinarian Dr. MelJ. Additionally, senior dogs, rehabilitating dogs, and special needs dogs may be less capable to compensate on hard-surface flooring, which is why Dr. Buzby created special toe grips with these dogs in mind.

Disclaimer: this article is not meant to be used as a substitute for professional veterinary advice. If your dog’s nails appear abnormal or are bleeding, seeping pus or showing other worrisome signs, please see your vet.

References:

  • DVM360, Nail Diseases, by Patrick Hensel, retrieved from the web on July 8th, 2016
  • Puppy’s First Steps: The Whole-dog Approach to Raising a Happy, Healthy …By Nicholas H. Dodman, Lawrence Lindner, Houghton Mifflin Harcourt (April 18, 2007)
  • Saint Bernard’s Animal Medical Center, The Quick and the Dead: Nail Trims, retrieved from the web on July 8th, 2016
  • Toe Grips, Frequently asked questions about Dr. Buzby’s ToeGrips: the traction aid to help stop dog slipping, retrieved from the web on July 8th, 2016

Photo Credits:

  • Flickr, Creative Commons, Wendy Berry, 029/366: My Dog’s Pretty Nails, (CC BY 2.0)
  • Wikipedia, Damian Galan Kaiser,  GNU Free Documentation License, Version 1.2
  • Flickr, Creative Commons, PROTony Alter Oops, Jimmy Dean pulled the blanket over his head but exposed his backside. CC BY 2.0
  • Flickr, Creative Commons, Brenda Kirk, Booties are Funny, CC BY 2.0

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I am Your Dog’s Eardrum

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Just like us, dogs have an eardrum that plays a big role in a dog’s sense of hearing. A dog’s eardrum is not readily visible since it’s set deep into the dog’s ear canal, but when this structure incurs into problems, we can sometimes recognize that something is amiss. Sometimes, the things we do with our dogs may play a role in problems with a dog’s eardrum, so it’s very important to keep this structure in mind. So today, let’s discover more about a dog’s ear drum and let’s listen to this important membrane’s story.

ear drum non perforated
Intact eardrum

Introducing Your Dog’s Eardrum

Hello, it’s your dog’s eardrum talking! If you prefer, you can call me “tympanic membrane.” This makes me sound more important, no?

As mentioned, you might not be very familiar with me as I live in the shadow, tucked deeply within your dog’s ear canal. I am simply a thin membrane that’s  stretched tight, just like a drum.

I basically separate your dogs’s external ear canal from his middle and inner ear. I play some important functions, and yes, sometimes I even get damaged, which is why you may sometimes see your veterinarian checking on me with his otoscope.

 

I am Protective

dog sense of hearing

Since I am placed in a strategic spot between the external ear canal and the middle and inner ear, I play a protective role, keeping bacteria and fungi from entering the middle ear and potentially causing a middle ear infection. Middle ear infections (otitis media) are a far cry from the average outer ear infections (otitis externa.) According to veterinarian Ernest Ward,  a middle ear infection is a serious condition that requires aggressive treatment. Sometimes middle ear infections may even progress into inner ear infections (otitis interna) which may cause deafness and loss of balance. So, yes, you must thank me if your dog is often spared from these maladies–when all goes well.

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dog ear anatomyI Detect Sounds

I play a big role in your dog’s sense of hearing. When puppies are born, I am actually sealed closed so I am unable to carry sound as of yet. The ability to detect sounds starts when the puppy is about three weeks old, so from that day on I am on my way to my auditory mission. You see, I tend to vibrate when sound waves hit me. My vibrations move the small bones, known as the malleus, incus, and stapes, found in your dog’s middle ear, which then send the vibrations to your dog’s inner ear. From here, the auditory message finally reaches the dog’s brain. The reactions to these auditory messages may range from “Woohooo, my owner is grabbing my leash! to “Eeeek, fireworks! I  am so scared, I better seek shelter under the bed and stay safe!”

perforated eardrum
Ruptured eardrum

When Things Go Wrong

Remember how I said that I was a thin membrane? Well, this is my weak point. Even though I am tucked deep inside your dog’s ear canal, I am vulnerable and prone to rupturing. How can this happen? Well in several ways. Very loud noises can sometimes cause me to rupture if close enough, so this is another good reason to keep your dog away from fireworks, gun shots or air horns. I can also rupture when there are severe changes in atmospheric pressure, or more commonly, when your dog has a middle ear infection. Sometimes toxins and ear infection may be culprits. I can also perforate when instruments are inserted in the dog’s ear too deeply or if a foxtail manages to work itself through me. Fortunately, your dog will likely let you know if I am ruptured. Here are a few symptoms of a ruptured eardrum in dogs:

  • Pain. Your dog may whimper or yelp when his ear is touched or he may shake his head or paw or scratch at it. He may tilt his head or rub his ear. When the pain is intense, some dogs may become reluctant to open their jaws and this may mean that they may become reluctant to eat, especially crunchy foods like kibble.
  • Ear Discharge. If your dog develops an middle ear infection, fluid may accumulate and since it has no where to escape, it can put pressure on me causing me to rupture or tear. When this happens, a pus-like discharge, sometimes tinged with blood, may seep out into the dog’s external canal, becoming visible. Usually, when I burst, the dogs feels a bit relief from the pain as there’s no more pressure.
  • Loss of Hearing. Since I transmit sounds to the dog’s inner ear, when I rupture I can affect your dog’s ability to hear. However, you might hardly notice this, because dogs are good in compensating hearing loss by using their other ear.
  • Neurological Problems. When I rupture because of a middle ear infection, affected dogs may develop neurological symptoms. You see, the middle ear hosts several facial and sympathetic nerves, so when bad things happen there, paralysis of the facial nerves may occur causing the dog’s face and mouth on the same side to appear droopy, the appearance of the dog’s third eyelid  and the inability to blink. When the inner ear is affected too, affected dogs may start showing balance-related symptoms such as staggering, walking in circles,  nystagmus, involuntary eye movements, and lack of coordination.

When I am ruptured, it’s very important that dog owners do not try to self-treat at home as using ear medications can cause future damage to me. There are very few products that are safe (and not ototoxic) to use in a ruptured eardrum. This is why, vets thoroughly check me out before prescribing ear drops. If you suspect I have ruptured, see your vet as he can only assess whether I am still intact or not, courtesy of the handy otoscope and other helpful tests. The good news is that, if I am truly ruptured, I have the ability to repair myself. Indeed, according to veterinarian Ernest Ward, I may heal within 3 to 5 weeks and if there is a middle ear infection, medications may be needed for 4 to 6 weeks.

As seen, I am quite an important membrane that plays a big role in keeping your dog’s ears healthy and your dog responsive to surrounding sounds. So make sure to keep me in good shape. Don’t expose your dog to loud noises, don’t stick things in your dog’s ears and avoid using ear drops without seeing your vet first. Your dog and me will thank you!

Yours truly,

Your Dog’s Eardrum. Dog Pawprint

 

References:

  • VCA Animal Hospitals, Tympanic Membrane Rupture and Middle Ear Infection in Dogs, retrieved from the web on July 4th, 2016
  • Merck Veterinary Manual, Otitis median and interna, retrieved from the web on July 4th, 2016
  • Pet Education, Ear Anatomy and Hearing, retrieved from the web on July 4th, 2016

Photo Credits:

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