The heart has four valves: the tricuspid valve, the pulmonary semilunar vale, the bicuspid valve, aortic semilunar valve.相关知识点: 试题来源: 解析 答: 心脏分为四个腔:左、右心房, 左、右心室, 心房在心室的上面,比心室小。 右心房和右心室之间有三尖瓣;左心房和左心室之间有二尖瓣;在右心室和肺...
The fine structure of the mitral valve in the chicken heart is described. The chicken has no distinct muscular component within the mitral valve; on the other hand, the tricuspid valve is a muscular fold. The mitral valve is a thin, membranous, fibrous structure and is composed of three ...
Smaller arteries that branch off the aorta distribute blood to various parts of the body. Four valves within the heart help prevent blood from flowing backward in the heart. The valves open easily in the direction of blood flow, but when blood pushes against the valves in the opposite ...
Blood flows from the atria into the ventricles through the atrioventricular orifices (right and left)–openings in the atrioventricular septa. These openings are periodically shut and open by the heart valves, depending on the phase of the heart cycle. Although there are a lot of structures in...
Heart Structure Your heart is small, but it's a hard worker. It is about the size of your fist and beats roughly 2.5 billion times in a lifetime. It's also made up of several smaller parts that work together to pump blood. The main parts of the heart are the chambers and valves,...
not specifically named but are closest to the capillary beds in the tissues arterioles vein (2)carry blood toward the heart valves (4)cusps in the endothelium of tunica intima that prevent backflow lumen (5) larger in veins than in arteries tunica intima A tunica media B tunica externa C tu...
Lymphatic valves assure the forward propulsion of fluid along the lymphatic vessels. A description of valve function in skeletal muscle must be based on a knowledge of the valve morphology. To this end, histological sections of valves from lymphatic microvessels of the rat spinotrapezius muscle were...
Heart, organ that serves as a pump to circulate the blood. It may be as simple as a straight tube, as in spiders and annelid worms, or as complex as the four-chambered double pump that is the center of the circulatory system in humans, other mammals, and
1.(Botany) plant life as a whole, esp the plant life of a particular region 2.(Botany) the process of vegetating 3.(Pathology) the process of vegetating 4.(Pathology)patholany abnormal growth, excrescence, etc 5.a vegetative existence ...
the wall of a vein is much thinner them that of an artery because the middle layer of muscle and elastic fibers is thinner. Within some veins, valves allow blood to flow only toward the heart when they are open and prevent the backward flow of blood when they are closed....