The cardiovascular system of animals, lymphatic system of animal
Circulatory system consists of three independent parts, closely related topographically and functionally: the circulatory system with a central body - the heart, the lymphatic system, organs hemodialysis and lymphopoiesis.
Circulatory system consists of the heart and the system of blood vessels, which are divided into arteries (blood vessels that carry blood from the heart), veins (blood vessels that carry blood to the heart) and microvasculature.
|Heart, cardiovascular system of animals|
Cardiac muscle is characterized by four features:
1-avtomatyya - the ability to contract rhythmically influenced by impulses arising in the very heart muscle, and possible special thanks to the neuromuscular system, which consists of sinoatrial, atrioventricular node and bundle branch block;
2-excitability - impulse excitation of the stimulus;
3-conductivity - spreading the excitement of sinoatrial node around the heart;
4-contractility - the ability to meet the reduction only to single pulse excitation.
|cardiovascular system of animals|
Systolic volume flow, the amount of blood ejected by the ventricle of the heart per systole (calculated as a private in the distribution of minute volume on the number of cuts in 1 min). This rate in horses is 850 ml in cattle - 580 ml, small livestock - 55 ml in dogs - 14-25 ml.
Regulation of the heart is provided by neural and hormonal mechanisms. Neural mechanisms of regulation related to the activity of the autonomic nervous system and the presence of some vessels reflex zones (accumulation of chemo-and pressosensornyh receptors).Hormonal mechanisms regulating hormones made by the adrenal medulla and the thyroid gland, and potassium ions (urezhayut and weaken the heart reduction), calcium (stimulates cardiac contraction) and other chemicals.
|Blood vessels, cardiovascular system of animals|
|venous, cardiovascular system of animals|
Venous system creates two vena cava. Cranial vena cava (v. cava cranialis) collects blood from the head (on the jugular veins), neck and thoracic limbs (branches of the subclavian vein), as well as the chest wall (right azygos vein in dogs and horses).
The left azygos vein in pigs and cattle runs directly into the heart. Caudal vena cava (v. cava caudalis) collects blood from the pelvic cavity (internal iliac veins), pelvic limb (external iliac vein) and paired abdominal organs (kidneys, adrenals, gonads). From odd abdominal organs (the gastrointestinal tract) veins empty into the portal vein, and it is in the liver, which produce excellent vascular network of the liver and liver already cleared of toxic products in the blood of hepatic veins enters the caudal vena cava. The colon is located in the pelvic cavity, so most of the blood from it enters the caudal vena cava, bypassing the liver barrier. This feature is used in the administration of soluble substances through the rectum.
|Arterial, cardiovascular system of animals|
Regulation of blood flow is reduced to change the diameter of blood vessels that are in constant tone, and the number of circulating blood. This process involves the autonomic nervous system andcardiovascular reflex zones (nervous regulation), and adrenal hormones, pituitary, kidneys and central nervous system neurotransmitters (substances involved in the transmission of nerve impulses).At rest, about half the mass of blood is in the blood depots: 20% in liver, 16% in spleen and 10% in the subcutaneous tissue.
|lymphatic system, cardiovascular system of animals|
1-immune (associated with the activity of lymphocytes), drainage (removal of excess fluid from the tissues);
2-barrier-filtration (delay in lymph node tissues of toxins, bacteria, viruses and foreign particles);
3-transport (transport protein, some vitamins, fat).
The structure of the lymphatic system consists of lymph capillaries, vessels, nodes, collectors, trunks and ducts. Lymph - a colorless transparent liquid, similar in chemical composition to blood plasma. It contains proteins (less than in the blood), nitrogenous substances, glucose, salt, enzymes, hormones, vitamins and antibodies. In lymph no red blood cells and platelets, but it is able to coagulate due to the presence of fibrinogen and several other clotting factors. For lymphatic capillaries typical blind beginning in tissues. Association, they form the lymphatic heart. Lymphatic vessels are equipped with valves (like the valves in the veins), so that they have expansion and contraction. Lymph nodes are bean-shaped form and may be superficial and deep. Group lymph nodes that collect lymph from the total body surface, forming limfotsentr. The most important is limfotsentrami parotid (collects lymph from the brain skull), mandibular (collects lymph from the front of the skull), retropharyngeal (regionarny is for the whole head), superficial and deep neck (collect lymph from the neck), mediastinum (regionarny for thoracic ), axillary (collects lymph from the thoracic limbs), groin (collects lymph from the abdominal wall and pelvic limbs), mesenteric, and abdominal (regional to the abdominal cavity). The major lymphatic collectors have thoracic lymph duct (collects lymph from 3/4 of the body except the right half of the head, neck, right thoracic limb and the right half of the chest wall) right lymphatic duct (collects lymph from the right half of the head, neck, right thoracic limb and the right half of the chest wall). Both ducts open into kranyalnuyu vena cava. Thus the whole lymph collected in kranyalnuyu vena cava. In the process of moving lymph vessels involved but sticks feature thoracic cavity, the pressure difference in the lymph capillaries and ducts, muscles of the body, particularly the diaphragm, rhythmic contraction of lymph vessels and pulsation thoracic duct. Innervated lymph elements sympathetic nerve fibers, and the speed of movement of lymph varies reflex.
|lymphatic system, cardiovascular system of animals|