组胚论述（Embryology）.docVIP

组胚论述（Embryology） 1 、 the correlation function is relatively large, the similarities and differences of the arterial wall structure of the artery, middle artery, arteriole and arteriole. The thickness of the walls of the four arteries varies greatly, but the walls of the tubes can be divided into Intima, tunica intima and adventitia, and their main differences are in the structure of the tunica media. Large artery membrane containing a large amount of elastic film and elastic fibers, so it belongs to elastic artery; membrane in arteries and arterioles mainly containing smooth muscle fibers, which belongs to the muscular artery. Large artery and heart directly connected, when the systolic ejection time, because of its large artery elasticity and expansion, and saving energy; when the diastolic artery, with its elastic recoil force and contraction, promote blood flow to. Thus, the great artery changes the intermittent ejection of the heart into continuous blood flow in the blood vessel. The smooth muscle of the median membrane of the middle artery, which contracts and relaxes at the innervation of the nerve, regulates the flow of blood to all parts of the body and organs. The smooth muscle contraction of arterioles and arterioles, on the one hand, can significantly regulate the regional blood flow, and on the other hand determine the peripheral resistance and blood pressure of the bloodstream. The relaxation of arterioles and arterioles is regulated by nerve and a variety of humoral factors such as atrial natriuretic peptide (ANP). 2. The structure of the artery, middle artery, arteriole and arteriole is relatively large. The intima of the large artery is thicker and the inner elastic membrane is connected with the elastic membrane of the middle membrane, so the internal elastic membrane is not obvious. The membrane is mainly composed of 40~70 layers of elastic film, so it is also called elastic artery. There are collagen fiber, elastic fiber and circular smooth muscle