circulatory and respiratory systems are linked structurally and functionally.Together, they provide a vital activity, allow to supply the tissues and organs of oxygen with nutrients.And from the first animals partially conquered the land, there is a unity of these systems.It provides a higher level of structural organization and optimization of physiology to the living conditions on the ground.
respiratory and cardiovascular system of mammals, amphibians, reptiles, birds and consists of the lungs, heart and blood vessels.In this scheme of pulmonary circulation entirely represented by light, ie pulmonary capillaries that supply blood to the arteries and veins is given.It is noteworthy that the structural barriers between circulation are absent, because of what the respiratory tract and the cardiovascular system is considered a single functional unit.
series circuit pulmonary circulation
small circle called the closed circuit of the vessels that carry blood from the heart to the lungs and is sent back out.At the same time, despite the differences in the physiology of blood circulation, pulmonary circulation circuit mammals different from that of amphibians, reptiles and even birds.With the latest in a mammal more in common than the others.In particular, a 4-chambered heart.
Since the boundaries between the vessels of the body does not exist, then the conditional beginning of the pulmonary circulation is considered the right ventricle of the mammal.From it the blood of the pulmonary trunk, deprived of oxygen, is directed to the pulmonary capillaries.Gas diffusion processes occurring in alveolar epithelial cells release a completed alveolar lumen and carbon dioxide capture oxygen.Last binds to hemoglobin and is directed to the left side of the heart by the pulmonary veins.Shows a diagram of the pulmonary circulation, it ends in the left atrium and the left ventricle begins systemic circulation.
Small circulation birds
on the physiology of the respiratory and cardiovascular system most similar to birds mammals, as well as have a 4-chamber heart.Amphibians and reptiles heart of a 3-chamber.As a result of the pulmonary circulation circuit such as birds, as in mammals.Here, from the right ventricle flows venous blood flow to the lung capillaries.Oxygenation enriches the blood with oxygen that red blood cells from the arterial blood is transported to the left atrium, and from there - in the ventricle and the systemic circulation.
pulmonary circulation birds and mammals
probably should figure out which blood flows in the veins of the pulmonary circulation in birds, mammals, reptiles and amphibians.Thus, in a mammal by pulmonary arteries to the capillaries, venous blood flow, and oxygen-depleted gas comprising carbon dioxide in a large amount.After oxygenation of arterial blood through the veins to the heart is directed.It is noteworthy that in the systemic circulation arterial blood from the heart always flows only through the arteries, and venous return to the heart through the veins.
pulmonary circulation reptiles and amphibians
scheme pulmonary circulation frog does not differ from that of mammals.However, they are different in physiology: because of the three-chamber heart blood mixed venous and arterial.Because the arteries of the body including lung, flowing the mixed biological fluid.A venous veins of the body back to the heart, and then mixed in a three-chamber heart.Therefore, the partial pressure of oxygen in the arteries of small and large circulation is virtually identical.Because amphibians are cold-blooded.
Reptiles are also three-chamber heart, but the upper and lower sections there is the germ of the total ventricular septum.Crocodiles and all the partition between the right and left ventricle practically formed.It has only a certain number of holes.As a result, crocodiles hardier and large compared to other reptiles.At the same time it is not known how the dinosaurs had a heart, also belong to the class of reptiles.Probably they also had almost a complete partition in the ventricles.While the evidence is unlikely to be obtained.
Parsing scheme pulmonary circulation Human
The man gas exchange occurs in the lungs.Here, the blood gives carbon dioxide and oxygenated.This is the main value of the pulmonary blood circulation.Any academic scheme of the pulmonary circulation, created on the basis of studies of respiratory physiology, begins with the right ventricle.Directly from the pulmonary valve pulmonary trunk moves.Due to its division into two parts, leaves the branch pulmonary artery to the right and left lung.
itself repeatedly pulmonary artery is divided and divided up the capillaries, thick cloth body piercing.Gas exchange occurs directly at them through the air-blood barrier is composed of alveolar epithelial cells.After oxygenation of the blood it collects in venules and veins.Two leaves from each lung and the left atrium empties has four pulmonary veins.They carry the arterial blood.In this scheme of pulmonary circulation ends and starts the systemic circulation.
biological significance of the pulmonary circulation
small circle appears in the phylogeny of organisms that begin to colonize the land.In animals living in water and treated with dissolved oxygen is absent.Evolution has created breathing and other body: first simple traheistye light and then - complicated alveolar.And it was with the advent of developing lung and pulmonary circulation.
Since then, the evolution of organisms living on land, aimed at optimizing the capture and transport of oxygen to tissues, to consumers.The lack of mixing blood in the ventricular cavity as an important evolutionary mechanism.Thanks to him, provided warm blooded mammals and birds.Also, more importantly, 4-chambered heart is to ensure the development of the brain, because it consumes a quarter of the total oxygenated blood.
