circulatory system (non-closed and closed) is the mechanism by which the implementation of possible co-ordinated movement of blood (hemolymph) of the body, which ensures its full life.Needless its movement in the system arises from the pulsing heart muscle contractions or thickening of the walls of the aorta and the arteries or organs of movement and trunk muscles.It is through the blood circulation going and heat transport of substances for the metabolic processes that influence on the metabolic rate.Closed or open circulatory system: how do they differ and for whom the characteristic?Answers to these questions will be discussed in the article.
circulatory system unclosed found in almost all invertebrates, as well as in lower chordates (from Amphioxus).Blood flow in these organisms is caused by heartbeat or "hearts" and, to some degree, reduction in body musculature.A characteristic feature - a large amount of blood at a low speed of its movement.
closed circulatory system can consist of a single circulation (fish and cyclostomes) and two - small and large (reptiles, amphibians, birds, mammals).Flowing through the small and large circle of blood periodically changes its composition, and is venous, arterial something.And cold-blooded animals, even mixed venous and arterial in the aorta or the heart, and the blood flow velocity is low.The exchange of substances between the blood and tissues of the body is carried out by thin walls of the capillaries.Filtering decomposition products occurs mainly in the kidney or in other organs of excretion.
not closed circulatory system is very imperfect, but among the owners of a closed circulatory system the most ideal in birds and mammals.The representatives of these classes, it consists of two four-chambered heart and circulation.Normally, the arterial blood is never mixed with the venous blood.Characteristically enough high pressure.Another advantage - a considerable rate of blood flow through the vessels (compared to the time of one revolution of the blood of insects is approximately 22 minutes, the dog - this is 16 seconds, and a rabbit - 7.5 seconds).It is because of these features the highest possible warm-blooded animal species, which allows you to have a constant temperature of the body, regardless of the environmental conditions.Peculiar to birds and mammals, and high metabolic efficiency.
blood circulation in the human body is provided by contraction of the heart, which works like a pump.Among other factors contributing to the movement of the blood - breathing movements, reduce skeletal muscles, the difference in pressure vessels.One of the characteristics of cardiac activity - heart rate.Pulse - is a periodic expansion of the arteries, which coincides with the contractions of the heart muscle.Its frequency is dependent on many factors, including the body weight, temperature and state of the body, the physical and emotional stress, and so on.Normally, the heart rate of an adult is 60-80 strokes per minute.Different velocities of blood flow in vessels ranging from less than 1 mm / sec in the capillaries of 50 cm / s in large arteries.The entire circulation of blood throughout the body is approximately 20-25 seconds.Blood moves downward pressure is greatest in the aorta and large arteries and the smallest, even negative in the hollow veins.Reverse the movement of blood and prevent the valves are closed atrioventricular openings, the mouth of the pulmonary artery and the aorta, and valves located on the walls of the large veins.With sufficient contractile function of the heart blood flow is not disturbed.
As you can see, not a closed circulatory system and closed have very special features that are sure to know every erudite, and not just humans.
