The Anatomy and Physiology of Cats and Dogs
A number of basic skills are essential for any pet owner to properly care for their pet, monitor vital signs and prevent disease, including regular observation and knowledge of normal and abnormal signs of health.
Dog and cat health can be monitored through knowledge of their anatomy, physiology, behaviour, body condition and vital signs.
Body Care & Health for Dogs
Anatomy refers to the form and structure of organisms. In comparison, physiology is the study of the functions of the body and its parts. Physiology looks at the body systems, organs, tissues and cells.
The anatomy of dogs varies a great deal from breed to breed. However, all dogs share basic physical characteristics. All dogs have a skeletal and muscular system that supports speed and endurance as well as muzzles that are designed to catch and hold prey.
A dog owner has a responsibility to know and understand their dog’s anatomy and physiology.
Healthy dogs generally show the following signs of well being:
- Healthy dogs have flexible and smooth skin, without scabs, growths, white flakes or red spots or areas.
- A dog’s hair and coat are glossy and pliable or soft. There are no signs of dandruff, bald spots or oiliness.
- The nose should be moist and cool and any discharge should be clear.
- The dog’s ears should be clean and light pink, with little sign of wax. There should be no evidence of redness, swelling or scratching around the ears and the dog should not shake his head frequently.
- The dog’s tongue and gums should be firm and a healthy shade of pink. Gums may also be dark or spotted, depending on the colour of the dog’s skin.
- A healthy dog has eyes that are bright and shiny, with no signs of inflammation, swelling or discharge. The whites of the dog’s eyes should not be yellowish and its eyelashes should not touch the eye.
- Urine should be yellow and show no signs of blood. Stools should be brown and firm. A dog that has difficulty passing stools or frequently urinates may be ill.
Skin & Hair
A dog’s skin and hair coat make up the outer covering of its body and is its largest sensory organ. The skin protects the muscles, skeletal system and internal organs and the hair coat covers and protects the skin and helps keep the body warm. The skin on the pads of the dog’s feet is much thicker than the skin on the body.
The skin can range in colour from pale pink to brown to black, depending on the breed. Spotted skin is normal.
A dog’s whiskers are also hairs and are found on the face as well as different places on the body. They are very sensitive to touch and help the dog sense movement.
Dogs should be checked regularly for fleas, lice, ticks and other parasites by brushing the hair backwards in different places. Dogs should also receive regular parasite control if recommended by their veterinarian.
Senses
A dog’s field of vision can vary, depending on the breed. A dog that has eyes that are more forward facing has a narrower field of vision than a dog whose eyes are set to the side. Dogs are not colour blind. Dogs are dichromats and can see in blue, yellow, and shades of grey. Dogs’ range of hearing is much broader than the range of human hearing, and they are very sensitive to sound. The ears also work with the brain to help with balance. When listening, the dog will move its head this way and that, turning its ears in the direction of the sound.
A dog’s sense of smell is also very sensitive and broader than the human sense of smell. Dogs use scents to mark territory and to recognize and communicate with other dogs.
The sense of taste is not very highly developed, but dogs can detect tastes that are sour, bitter, salty and sweet.
Skeleton & Muscles
The skeletal system and musculature of the dog gives it unique abilities. The dog’s skeletal system provides the framework for its muscular system and allows for important movements. The skeleton supports the spine and legs, protects internal organs, produces blood cells and stores important minerals. Tails are important for balance as well as communication.
Digestion
Dogs are omnivores, which means dogs eat both animals and plants. They have sharp canines that are meant for grabbing prey, but chew with their flatter back teeth. A dog is a non-ruminant. Non-ruminants (humans, cats and dogs) digest carbohydrates, protein and fat by enzymatic action. Ruminants (cattle, sheep and deer) use bacteria in the fore stomachs to digest fibre by fermentation and use enzymatic digestion in the small intestine.