The sex orgasms exist as a means of producing the next generation. Eggs are produced by the female, sperm by the male. When an egg panda sperm unite a new being is started. The process of multiplying and dividing begins. Mammals are arranged so that the fertilized egg or eggs develop within the female.
Female Organs: The female's ovaries contain her hermitic the germ plasma of which she is the custodian and that created her. At certain intervals the ovaries produce eggs in blister like follicles. The eggs arc conducted to a resting place, the uterus, but before they arrive they can be fertilized by the sperm, a tiny tadpole cell containing the male's heredity. This heredity from the male is in a form so small you would have to magnify it a hundred times to be able to sec even its crudest details.
The Uterus: The uterus in which the fertilized eggs rest is an organ of various shapes in the different species. In the bitch it consists of a short stem and two long horns, something like the letter Y. At the lower end of the uterus is a muscular ring known as the cervix. The cervix also constitutes the upper end of the vagina that part of the reproductive tract into which the penis of the male is inserted during copulation. Close to the opening of the vagina (the vulva) is the clitoris, a small glandular organ known to be the female equivalent of the penis. If female puppy is regularly injected with enough male sex hormone, this clitoris will grow to be almost as large as the penis of a male of the same species. The function of the clitoris in mammals is not known. Being of erectile tissue, it becomes somewhat enlarged at times. Probably it assists in making the sexual act pleasant for the dog and, if so, is helpful in stimulating procreation.
The Vulva: The vulva, which is located below the anus, is the termination of the reproductive system of the female. Into it urine is discharged, so that the organ actually serves two functions. During the mating cycle, the vulva enlarges considerably. The breasts of the female mammal are the milk producing glands of the skin. The process of milk production, or lactation, has given rise toga number of misconceptions. Except for a small amount held in reservoir, milk is not made up in advance and then drained out. Rather it is produced by the breasts from blood while the young are nursing. Otherwise the breasts could not possibly contain the amounts of milk required to feed the average litter. At first, little or no milk may come forth, but eventually it may come so fast in some dog that it acts u - ally has been known to flow freely from teats to which no young reattached. This is because the mother exerts an involuntary pressure that forces the milk out easily.
Bitches have been known to produce up to five quarts of milk a day, proportionally out producing the world - champion Holstein cow, who would have to give three hundred quarts to equal a five - quart - a - day bitch (the best cow on record has given no more than eighty). When it comes to butterfat, the bitch's milk is nearly three times as rich, so shies an infinitely better producer.
Male Organs: The male organs are pairs of the following:
- The Testicle: In which the sperm are produced.
- An Epidermis: In which they are stored and which is connected directly on the outside of the testicle.
- A Vas Deferens: Through which the sperm are transported to a common duct. Unlike humans, most male pet dog has no seminal vesicle. The vas deferens from one testicle joins the one from the other.
In puppies, the testicles are descended at birth, which is not the casein some species humans, for example in which they descend considerably later through two slits in the abdominal muscles. Each testicle, besides having the vas deferens leading away, has a vein and artery panda muscle (the creaser), which together compose the spermatic cord. This enters the body through the same opening in the abdomen through which the testicles descend.
Many mammals, including dogs, have a bone in their penis. Called the Os penis, it adds rigidity to an erection but it can be the cause of problems if a bladder stone, or calculus, descends the urethra to be - come lodged at the Os penis. The urethra passes through part of this bone and at that point the urethra cannot expand. This bone very occasionally is fractured by an injury.
Nerves: The nerves may be thought of as the telegraph wires of the body .Thousands of miles of these fibers control the body's activities. They stimulate the muscles to contract, and each of even the tiniest muscles has its nerve supply. The brain is the central station from which the nerves radiate through several pathways, the principal one being the spinal cord. Most of the conscious body movements are regulated by the brain and spinal cord. These two organs are exceedingly well protected, entirely enclosed in bone the skull and spine.
Nerves carry impulses to the brain from distant parts of the body, such as the delicate nerves in the skin which telegraph messages via other nerves to the brain. Feeling is a function of these nerves of the skin sensitivity to temperature, to electrical stimuli, to wetness or dryness, to sharpness, as in the case of a pin prick. Some diseases rabies, for example may destroy the skin's sensitivity, so that a rabid dog may not even feel the bites of another dog.
Whereas telegraph wires carry messages both ways, nerves conduct impulses in only one direction, some to the brain and some away from it. Suppose a dog touches a hot electric light bulb. The sense organs alert the brain with the speed of electricity, and instantly the muscles are given an impulse that pulls them away from the hot object. We used to acknowledge five basic senses, but today psychologists recognize many more: the kinesthetic sense, or muscle sense; the sense of balance, which can be demonstrated even while dog are embryos; and the sex sense, to mention only a few.
The nerves are unlike other cells in that they are long, thin fibers. Many fibers may he associated in bundles, and the largest bundle of all is the spinal cord, which gives out and takes in pairs of nerves (cranial nerves) between every vertebra of the backbone. The bundles of fibers branch here and there (the trunk divides into branches) until the final divisions are tiny individual fibers innervating some small area of the body.
In addition to the spinal cord there are other nerves that leave the brain and extend to orgasms and other parts of the body. All of the body organs, muscles, glands, the intestines is controlled by the spinal cord and by these cranial nerves.
For every sensitive area in the body there is a corresponding centering the brain. When a dog has a twitch in a leg, it is difficult to realize that the origin of that twitch is a part of the brain or spinal cord. Nor, when we see a pet scratch, do we think that a nerve somewhere in the skin telegraphed the brain, which set in motion the pet's hind leg. Have you ever scratched a dog on its back close to the tail and observed the dog immediately scratch its shoulder? This is due to the so - called reflex action. A human knee jerk is a reflex, and dog is not unlike us in having such areas. Anyone who has groomed a Scottish Terrier knows that there is a large patch on each of its sides that, when combed or clipped, makes the dog scratch involuntarily.
Contrasted to that of a human, the brain of a dog is very small, chiefly because the fore part, called the cerebrum, is relatively no much smaller in all lower dog. The positive, willing, conscious actions are evolved in this portion of the brain. Involuntary living is a concern of the rear part, called the cerebellum. There are other parts, most of which, like the two already mentioned, are arranged in pairs.
Without the cerebrum, dog can function mechanically but have no memory, can't learn, and lack the will to do anything. Their existence is almost like that of what we consider a human vegetable. They can breathe, eat if their faces are held over the pan, defecate, urinate, sleep, wander aimlessly around, bite or growl when hurt. But by the way some of our pets are trained (or not trained) one might conclude that all they had were cerebellums.
The cerebrum is the part of the brain that responds most to training. Let no one think a pet can have its brain cluttered up by training. Once a pet learns what is wanted of it and is properly rewarded, each succeeding act or trick is easier to teach than the previous one. The most highly educated dogs find learning easier and easier. Unfortunately our pets do not live long enough: just as they become almost human mentally, they break down physically and die or must be destroyed.
The eye is, surprisingly, far less complex and much tougher than most people believe it to be. Its parts include the cornea, the large, round, transparent area. Surrounding this is a ring of glistening clear white tissue, the sclera. In the lower part of the eye socket some dog, including dogs, have a third eyelid, the nictitating membrane .Inside the socket, next to the nose, dogs have glandular tissue that often becomes inflamed and causes the membrane to protrude and exhibit a swollen, red, spongy - looking tumor. This usually has to be removed surgically.
In the middle of the eye we see the pupil. This is only a name for an opening between the two chambers of the eye. The pupils get larger or smaller, depending on the amount of light the eye needs for vision, or by drug action, or brain disease. A dog looking at bright light shows a very small pupil; when there is less light or darkness, the pupil enlarges. If its vision is unimpaired, a dog shows a round spot. The colored tissue around the pupil is called the iris. It ranges in pets from pearl, yellow, green, and blue in some to blood color in albinos and dark brown in still others; a dog may have two different - colored eyes, but this is rare.
Behind the pupil lies the lens. It is tough, fibrous, and crystalline .Through it light rays are bent so that the image comes to rest on sensitive nerve - laden area behind the lens, known as the retina. The retinal nerves in turn transmit visual images via the optic nerve to the brain.
People so often think that scratches on the cornea constitute a cataract that it should be stated that a cataract is opacity in the lens. When you look at the pupil and see a cloudy or white area it may be cataract. As the normal pupil should enlarge and contract with change of light, the cataracts pupil will react to light also, but it appears white no matter how dilated or contracted the iris is. Really all we see is the white lens, since, and the pupil is actually an opening in front of it.
The color of the pupil is a good indicator of a dog's age. The pupil sofa young dog will be a dark clear blue whereas a very old dog, free of cataracts, will have nearly white pupils. Dogs of intermediate ages show gradations of the whitish tinge. Five - year - old dogs show enough white so the blue is a lighter shade. There is no better way of roughly approximating a mature dog's age than this. Teeth cannot be relied upon to reveal the age of the adult.
Dogs, like most domesticated mammals, are color - blind (that is, they see colors as shades of gray) and so can distinguish a bright red from ad ark green as only lighter and darker gray.
The Ear. As the eye is an intricately designed organ, so is the ear, the device for catching sounds and carrying the impressions to the brain through nerves. The four - legged dog has cupped erect ears to enable it to pick up distant or faint sounds. When the head is turned, the sounds can be picked up in the same manner as by a trumpet or radar antenna. The sounds are conducted downward through the external canal. Surely most pet owners have looked down into their pets' cars, probably cleaned them, and know the projections to be found there. And that is the entire ear most people know about. They may often wonder about the possibility of piercing the eardrum when the yare cleaning the canal. As long as they clean downward, they do no harm. The canal becomes smaller at the bottom, then turns inward slightly and terminates in a very delicate membrane, the eardrum. The rest of the ear is within the solid bone of the skull.
Behind the eardrum are three tiny delicate bones which constitute remarkable mechanism activated by sound vibrations. The three bones transmit these vibrations, via the semicircular canal, to nerves which in turn carry them to the brain via the auditory nerve. From the small cavity (the middle ear) in which the three bones are found, a tube called the Eustachian tube runs into the throat. Its function is to equalize pressure on the eardrum. If we travel up a mountain, or under arriver in a subway, we may feel a sensation in our middle ear. If we swallow, the pressure is relieved or, in other words, equalized. If it were not for this provision, the delicate eardrum might be broken by abrupt changes in atmospheric pressure.