An Overview of the Design and Function of the Cat

The systems that make up the feline are all rather remarkable. The most important physical systems of the cat include: nervous, endocrine, respiratory, lymphatic, digestive, reproductive, urinary, circulatory, and musculoskeletal.

The nervous system is made up of the cerebrum, cerebellum, midbrain, spinal cord, twelve pair of cranial nerves, and paired sets of peripheral nerves that extend from the spinal cord to all parts of the body. There are many functions governed by the nervous system, including learning, reasoning, memory, and judgment. Involuntary action, which is controlled by the cerebrum, is also considered a part of the nervous system. Blood pressure, respiratory rate, and heart rate are monitored by the midbrain and so also contained within the nervous system.

The endrocine system comprises the glands that secrete hormones into the bloodstream. The most important gland, sometimes referred to as the master gland, is the pituitary, located at the very base of the brain. The pituitary gland, in addition to producing growth-stimulating hormone, controls the activities of the other glands, including the thyroid, adrenal gland, and the testicles or ovaries of the cat. In turn, these glands control the activities of the body.

The respiratory system includes the nose, throat, larynx (voice box), trachea (windpipe), bronchial tubes, and lungs. This system is vitally important to the cat as a cat at rest completes 25 to 30 breaths a minute. This is approximately twice as many as a human completes. In the cat, inhaling takes about half as long as exhaling.

The lymphatic system is one of the main defenses of the cat's body. It is a network of vessels that transport lymph, which is made up up excess tissue fluids, protein, and other substances. This system functions without the benefit of a pump and carries out its mission through the venous side of the circulatory system. Lymph nodes, another important component of the lymphatic system, filter out foreign particles found throughout the body.  Lymph nodes contain lymphocytes, a types of white blood cell, which produce antibodies that neutralize bacterial poisons.

The digestive system comprises the mouth, teeth, esophagus, stomach, small and large intestines, liver, pancreas, and rectum. Of all the carnivores, cats have the fewest number of teeth, barely 30. These teeth were not made for chewing, but rather for killing prey ad tearing their flesh. Therefore, cats tear off chunks of food and swallow them whole.

The kidneys, ureters, bladder, and urethra make up with urinary or excretory system in both sexes. Closely related to the urinary system is the reproductive system. The testicles and sperm ducts comprise the male reproductive system with the fallopian tubes, uterus, womb, and vagina are part of the female reproductive system.

The other systems mentioned here, such as the circulatory and musculoskeletal, are complex systems deserving of elaboration. The musculoskeletal systems is the bedrock of conformation and body type at its most elementary. The circulatory system is the medium through which many of the body's other systems function. However, the details of these two systems are deserving of their own articles and will be covered in detail in coming weeks.

All About Cat Breeds and Personalties

There are dozen of recognized cat breeds around the world. With so many to choose from, a prospective cat owner can find a kitten that suits any taste, living arrangement, or budget. However, it is simply not true that each and every breed has a personality that is unique and distinct from every other breed of cat. Considering the sheer number of cat breeds, there are simply not enough personality types to go around.

It would be more accurate to say that feline personalities are related to body type. If you look closely at the individual breeds and their personalities, you'll notice some similarities. For example, Siamese cats tend to be active, vocal, curious, and intelligent. But they share these traits with other breeds such as the Oriental Shorthair, Balinese, Abyssinian, and Cornish Rex. In other words, all the slim, elegant, and tubular breeds share these qualities and have similar personalities.

On the other hand, the Persian is laid back and easygoing. But so are the other stocky breeds such as the Burmese, British Shorthair, and Exotic Shorthair. And then there are the breeds that fall firmly in the middle. The pedigreed American Shorthair comes immediately to mind. This cat is a perfect middle-of-the-road personality, as are other breeds that share the same  body type.

But there are also traits that all cats share. No matter what the breed, the process of domesticating the cat retards the development of certain adult behaviors. This means that domesticated cats never really grow up, and we don't really want them to. Their kittenish behavior is a part of their charm. The adult behaviors of self-sufficiency, aggression, and marking are not at all desirable in the animals we share our homes with.

Personality is also determined by socialization. Kittens which are handled daily from three weeks old are more attached to people than those which are handled later or not at all. They are also more likely to tolerate being turned on their backs and approach humans faster and with more curiosity than nonhandled kittens. You can almost always tell which kittens have been handled daily simply from their reactions to people in general.

So the fact of the matter is that breed is only a small part of the personality of a cat. If you're looking for a certain personality in your kitten, you will have to consider more than the breed of the cat. Consider the parents, as personality often passes from generation to generation. And certainly pay attention to the way a kitten has been raised. This will help you determine whether that particular kitten has the right personality for you and your family.

The Eye of a Cat: Blindness in Cats

Cats, just like people, can go blind. Blindness is defined as the loss of vision in both eyes and may arise from illness, disease, or even an accident. In cats, it is often difficult to detect the onset of blindness because they have such extraordinary and sense of smell. They often compensate so well that the cat owner does not notice at all.

However, when vision is completely lost in both eyes, there are usually signs the cat owner can watch for. If a change in environment confuses your cat, the feline may be dealing with blindness. For example, if you move your living room couch, your cat may walk into it unexpectedly. Often this leads owners to conclude that their cat has suddenly gone blind, but the reality is that the cat has probably been having vision problems for some time, but had memorized his surroundings to compensate. When the surroundings change, memory no longer serves its purpose and little things happen, such as walking into a couch, table, or open cupboard door.

The Causes of Blindness in Cats

There are several things that might cause blindness in cats. Corneal disease is one of the most common, but it's not the only cause of blindness. Cataracts, which can be diagnosed by the white opacity of the lens of the eye, can occur in older cats, though younger cats seldom suffer from this ailment. Other illness and diseases that can result in blindness include:

• Severe anterior and/or posterior uveitis
• Retinal inflammation or infection
• Retinal detachment
• Glaucoma
• Diseases of the optic nerve, visual pathways, or the occipital cortex

If you cat has had any damage to the eyes, there is an increased chance of blindness. Scratches due to cat fights might seem like they're no big deal, but have them checked by a veterinarian anyway, just in case. The longer you wait, the greater the chance of blindness.

Symptoms of Blindness in Cats

You'll have to watch your cat carefully to detect vision loss, as cats are quite good at hiding this particular disability. However, if you notice any of the following symptoms, take your cat to the veterinarian immediately.

• Clumsiness, even if it's only occasional
• Inability to locate food, water, or the litter box if any of these things are moved even a few feet
• Excessive sleeping or chronic inattentive behavior
• Suddenly fearful and easily startled
• No longer plays or exhibits normal hunting behavior
• Bumps into objects that are plainly visible but not always present

If you even suspect that your cat may be going blind, you should take your cat to the veterinarian immediately. Blindness, especially sudden-onset (acute) blindness, is not something you can treat at home, regardless of the cause.

The Eye of a Cat: Are Cats Colorblind?

I've often been asked if cats can see color. In truth, this is a difficult question to answer with certainty. Asking a cat is only likely to get you a blank stare. And in all honesty, it doesn't really matter. Cats are hunters, so brightness is more important to their vision than color. They have to be able to see movement and texture. While hunting, color is of little use.

However, an answer to the question of colorblindness and cats can be divined by studying the construction of a cat's eye. The retina is the nerve center at the back of the eye. This retina is composed of cells called cones and rods. Cones are responsible for converting light into color. Rods are responsible for black and white. In the eye of a cat, rods greatly outnumber cones, which is why cats are generally considered to be colorblind.

It's important to note, however, that a cat still has cones. So it is possible, even likely, that a cat can see color. But the number of cones is limited, so your cat probably can't see shades of red. Blues, certainly, and probably greens and yellows.

But your cat doesn't need to see very many colors. Your cat has another advantage. He can see even in the dimmest of lights. Take a look at the eyes of your cat and you'll see why. He can open his eyes wider than you can and his pupil expands to full almost the entire eye, letting as much light in as possible. So hunting in the dark is no trouble for your cat.

In scientific terms, your cat's retinas allow him to see in about one-sixth of the light you need to see clearly. Objects at night appear six times brighter to him than you do to you. And the added rods allow him to detect minute movement, which is only beneficial when hunting.

So, your cat can't see all the colors you can. But he can see some colors and his vision is sharper than yours. It's a trade-off. Less color means more visual acuity. And a cat needs all the visual acuity he can get.