Dog Anatomy & Dog Inner Organs
The main inner organs of the dog are similar to the ones on the human body and they fulfill the same functions. Dog anatomy is really simple as you can see here.
The lungs take up the most part of the thorax cavity. The muscles that control the breathing (the diaphragm and some muscles of the body) get dilated and contracted in a spectacular way when the dog is making any effort.
Here, the peristaltic movements (small intestine wall's muscle contractions) are in charge of pulling the food to the next part of the intestine. Once it is mixed up with the enzymes that come from the liver and the pancreas, its nutrients can be assimilated by the blood flow. The water contained in food is partially absorbed when going through the large intestine, where a huge quantity of bacteria are found. These bacteria contribute to decompose the disposal material. Finally, the remains are expelled by the body.
The dog's digestive system begin in its strong jaws and its powerful teeth. After chewing the food, this is guided to the back part of the mouth and from there to the throat and the esophagus. The walls of the canine esophagus are not like ours, they are thick but elastic, which allows the dog to ingest very big servings of meals. The stomach possesses some glands that produce acids and enzymes that contribute to the digestion and work as some kind of bag that keeps the food until it is ready to go through the pylorus on the way to the duodenum (first part of the small intestine).
The excreting system is in charge of eliminating the toxic substances and the metabolic residues from the body, besides regulating the quantity of water present in the body. The residues that are in the blood are filtered by the kidneys before going through the urethra, that flow into the urinary bladder, where the residues are stored, waiting for the appropriate moment to be evacuated. The urine is led to the exterior by the urethra through the male dog's penis or the female dog's vulva.
The reproductive system guarantees the perpetuation of the specie. In the male dog, the testicles are in charge of producing the sperm; in the female dog, the ovaries are in charge of producing the ovule, that after being mature enough, once all dog toys are in place, go through the Fallopian tube heading the uterus. The uterus of the female dog has a very characteristic shape since it is formed by two horns that meet at the womb. During pregnancy, the fetuses mature lined up on the uterine body, resembling the distribution of the peas in their pod.
The cardiovascular system guarantees the distribution of food and essential substances (specially oxygen) throughout the body through the blood and the lymphatic system. The speed in which the blood flows and its distribution vary according to the dog's activity level. Approximately 20% of the blood pumped from the heart goes to the brain permanently. In periods of intense activity, the amount of blood pumped is increased to rise the oxygen proportions. The blood flow of the different parts of the body is controlled by nerves and hormones.
THE NERVOUS SYSTEM
The nervous system controls many mechanisms in the body to adapt them to the animal necessities and the surrounding circumstances. The dog's central nervous system is formed by the brain and the spinal cord that is extended until the base of the tail. The nervous receptors of the skin, the muscles and the articulations collect the information related to the environment; for example, if it is hot or cold and also the information related to the own dog as its position, for example and constantly send it to the brain and the spinal cord for this information to be processed.
The dog's cerebral functions haven't been completely studied yet, even though it is known that it has learning centers that process all the information obtained by the senses, specially the senses of smell and sight. The dogs, as well as man, have emotional centers that provoke chemical reactions as an answer for the stimulus, which, at the same time, lead to certain types of conduct. What is not 100% known yet is if dog feels the way we do or in a different way.
The endocrine system contributes to the regulation of the corporal functions through certain glands and tissues able to produce hormones. The pituitary glands control the dog's whole hormonal system. The hormones are responsible for the presence of stress, sexual activity and sugar levels of the blood, three factors that have a clear influence on the dog's behavior.