The circulatory system of birds has a striking difference from the circulatory system of reptiles: it has a complete separation of arterial and venous blood flow. A feature of birds is their large heart. Moreover, in small birds, the size of the heart is larger, and the heartbeat is noticeably more intense than in large ones.
Feathered blood pressure exceeds double the rates of reptiles and mammals. This applies to the quantitative content of blood, hemoglobin, the total number of red blood cells, and the sugar content, as well as the oxygen capacity of the blood. The circulatory system of birds has all these features due to the high level of metabolic processes. A large heart and a fast pulse cause accelerated blood circulation in the system, which, combined with a large oxygen capacity and an increased amount of sugar, allows you to intensively and immediately saturate tissues and all organs with nutrients and oxygen. This leads to the removal of products from poultry organs resulting from metabolic processes.
The heart of the bird is four-chamber, consists of 2 atria and 2 ventricles. Through large veins, venous blood collects in the right atrium and flows into the right ventricle. The pulmonary artery leaves the right ventricle and then splits into the left and right branches. Through them, venous blood tends to the lungs, where it is oxidized. Further, the oxidized arterial blood moves through the veins into the left atrium. The circulatory system of birds has 2 circles of blood circulation (small and large). The large consists of the left ventricle, the right aortic arch - the main artery, from which, when leaving the heart, two arteries are also separated: the right and left nameless. She herself returns over the right bronchus along the spine, like a dorsal aorta. Unnamed arteries, each in turn, are divided into the carotid, going to the head, and the large subclavian. The subclavian artery is divided into the brachial, directed into the wing muscles, and the powerful thoracic artery, which goes into the muscles of the sternum.
The internal and mesenteric depart from large trunks of the dorsal aorta; they supply blood to the abdominal muscles, pelvic organs, hind limbs, intestines, and stomach.
The circulatory system of birds collects venous blood from the head of the bird into the jugular veins, which, together with the vessels, merge into the right and left vena cava, which flow into the right atrium. From the cloaca, small veins collect blood, then merge together, forming three large ones.
The circulatory system of insects is an open circle. The blood is not completely enclosed in a muscle capsule attached to the back, the rest of the blood washes and fills the cavities and spaces between the organs.
The endocrine glands secrete hormones that are found in the hemolymph (blood) of insects. They are responsible for physiological processes. Thanks to blood, the insect's body creates internal pressure, which allows you to spread your wings, helps the process of molting, unfolding proboscis, supports the soft bodies of some species.
The circulatory system of insects consists of a heart, united by several successively contracting chambers. There can be up to 8. As a result of contractions, blood moves in the body. Its circulation in the adnexal organs occurs with the help of pulsating membranes - ampoules located in the extremities of the insect.
The circulatory system of arthropods is also an open circle. The internal organs of arthropods are located in cavities - sinuses, filled with hemolymph washing the internal organs, then it returns to the heart and blood vessels. The circulatory system of arthropods has a heart - a central organ (not present in annelids), which is simple in structure. Hemolymph does not take part in the transfer of gases, this function is performed by the trachea.