Cardiovascularsystem

1、apex 顶，上部 myocardium 心肌 epicardium 心外膜 endocardium 心内膜 sac 囊 pericardium 心包atrium 心房 atria (pl) ventricle 心室 septum 膈coat 层 tunic 膜 endothelium 内皮 aorta 主动脉 arteriole 微动脉，小动脉epithelial 上皮的心血管系统由心脏和血管组成。心脏位于双肺之 间，其顶部朝向左侧。 心脏的肌性壁结构主要有三层。 心壁的主体由心肌构成， 称为心肌 （组织）。心肌外衬 心外膜，内衬心内膜。心脏被称为心包的纤维囊性结 构包被。心脏上部受血小室是

2、心房， 下部泵血小室为心室。 室间隔将两心室分开，房间隔将两心房分开。血管主要有三种类型，即动脉、静脉和毛细胞血 管。动脉从心脏移出血液。因要承受心室泵血压力， 动脉血管壁最厚。类似于心脏的三层结构，动脉壁具 有三层，它们是 内部的内皮层，形成血液易于流动 的光滑表面； 较厚的第二层由非随意肌和弹性结缔 组织构成； 外层由支持结缔组织构成。 最大的动脉， 主动脉，直径约1英寸且管壁最厚。动脉的最小分枝 称为微动脉，其管壁相对较薄，含极少结缔组织但相 对较多肌细胞。动脉的小分枝（小动脉）携血液至最Cardiovascular systemThe cardiovascular system is

3、made up of the heart and blood vessels. The heart is situated between the lungs with its apex directed toward the left. The muscular walls of the heart consist of three major layers. The bulk of the walls is made up of a layer of cardiac muscle and is called the myocardium. The muscle is enclosed on

4、 the outside by the epicardium and on the inside by the endocardium. The heart is also 5 covered completely by a fibrous sac called the pericardium.The upper receiving chambers of the heart are the atria. The lower pumping chambers are the ventricles. The interventricular septum separates the two ve

5、ntricles; the interatrial septum divides the two atria.There are three major types of blood vessels, i.e., arteries, veins, and capillaries. 10 Arteries lead blood away from the heart. These blood vessels have the thickest walls because they receive the pumping drive from the ventricles of the heart

6、. There are three coats (tunics) which resemble the three tissue layers of the heart. These are: 1) the innermost membrane of endothelium, which forms a smooth surface over which the blood may easily move; 2) the second, more bulky layer, which is made of 15 involuntary muscle combined with elastic

7、connective tissue; and 3) and outer tunic, which is made of a supporting connective tissue. The largest artery, the aorta, is about 1 inch in diameter and has the thickest wall. The smallest subdivisions of arteries, the arterioles, have thinner walls in which there are very little connective tissue

8、s but relatively more muscle. These smaller branches of the arteries carry blood to the 20 tiniest of blood vessels, the capillaries.Capillaries have walls that are only one epithelial cell thick. The capillary walls are transparent and are made of smooth plate like cells that continue from the lini

9、ng of the arteries. The walls are so thin that they can allow passage of oxygen and nutrients out of the bloodstream and into the tissue fluid surrounding the cells. At the25lining 内层venule 微静脉valve 瓣膜mass 肿块oxygenate 氧合 pulmonary 肺的 pulmonary circuit 肺循环 replenish 补充 systemic circuit 体循环same time,

10、waste products such as carbon dioxide and water pass out of the cells and into the thin - walled capillaries. The capillary boundaries are the most important center of activity of the entire circulatory system.Veins are thinner-walled than arteries. They conduct waste-filled blood toward the heart f

11、rom the tissues. Veins have little elastic tissue and less connective tissue 30 than arteries, and blood pressure in veins is extremely low compared with pressure in arteries. The smallest veins, called venule, are formed by the union of capillaries. Their walls are only slightly thicker than those

12、of the capillaries. As the veins become larger, the walls become thicker. However, veins have much thinner walls than those of comparable arteries. Although there are three layer of material in the walls of the35larger veins, as in the artery walls, the middle tunic is relatively thin in vein walls.

13、 Therefore, veins are easily collapsed, and slight pressure by a tumor or some other mass may interfere with the return blood flow. Most veins are equipped with one-way valves that permit the blood to flow in only one direction. They are most numerous in the veins of the extremities. 40The heart pum

14、ps blood through two circuits. The right side of the heart pumps blood to the lungs to be oxygenated through the pulmonary circuit. Pulmonary vessels include the pulmonary artery and its branches, and the veins that drain the lung capillaries. The pulmonary arteries carry blood low in oxygen from th

15、e right ventricle, while the pulmonary veins carry blood high in oxygen from the lungs into45the left atrium. This circuit concerns itself with eliminating carbon dioxide from the blood and replenishing its supply of oxygen. The left side of the heart pumps blood to the remainder of the body through

16、 the systemic circuit. This circuit is concerned with supplying food and oxygen to all the tissues of the body and carrying away waste materials from the tissues for disposal.50小的血管，毛细血管。毛细血管壁只有单层上皮细胞厚，其透明并由延 续动脉内层的光滑片状细胞构成。管壁极薄，允许氧 及营养物质离开血流，进入（胞外）组织液。同时， 像二氧化碳及水等代谢产物离开细胞进入薄壁的毛细 血管。毛细血管网为整个循环细胞最重要的

17、活动中心。静脉壁薄于动脉壁。它们引导来源于组织含代谢 废物的血液至心脏。静脉比动脉含更少弹性玫结缔组 织。与动脉相比，静脉血压极低。最小的静脉（微静 脉）由毛细血管汇集而成。微静脉壁略厚于毛细血管 壁。随着静脉变大，管壁变厚。但静脉壁薄于同等级 动脉。像动脉壁一样，大静脉也具有三层结构，但静 脉壁的中层相对较薄。因此，静脉易于塌陷，肿瘤或 其它肿块的轻微压力可干扰血液回流。许多静脉具有 单向瓣膜，使血液单向流动。四肢静脉瓣膜更多。心脏经双循环泵血，右心将血液泵入肺，经肺循Blood returning from tissues other than the lungs enters the h

18、eart by way of the venae cavae; the superior vena cava and the inferior vena cava. The venae cavae empty into the right atrium. When the atria contracts, blood in the right atrium isvena cava 腔静脉 semilunar 半月形的 tricuspid valve 三尖瓣mitral valve 二尖瓣 bicuspid valve 二尖瓣 ascending aorta 升主动脉 aortic arch 主

19、动脉弓 thoracic 胸的 thoracic aorta 胸主动脉 vertebral 脊骨的，脊椎的 vertebral column 脊柱 pleura 胸膜 abdominal 腹部的 abdominal aorta 腹主动脉 cavity 腔forced through the tricuspid valve into the right ventricle. When the ventricles contract, blood in the right ventricle is forced through the pulmonary semilunar valve55into

20、 the pulmonary artery; at the same time, the tricuspid valve closes to prevent the backward flow of blood into the atrium. Blood that enters the pulmonary artery is carried to the lungs. There it undergoes oxygenation, a process in which carbon dioxide (a waste product of cellular metabolism) is exc

21、hanged for oxygen from the environment. 60Oxygenated blood returns to the heart by way of pulmonary veins, which empty into the left atrium. Atrial contractions force blood from the left atrium through the mitral valve, also called bicuspid valve, into the left ventricle. When the ventricles contrac

22、t, blood in the left ventricle is force through the aortic semilunar valve into the aorta, the body lsargest artery, for distribution to the tissues. The aorta is one 65 continuous tube divided into the following regions: 1). the ascending aorta, which is near the heart and inside the pericardial sa

23、c; 2). the aortic arch, which curves from the right to the left, and also extends backward; 3). the thoracic aorta, which lies just in front of the vertebral column behind the heart and in the space behind the pleura; and 4). the abdominal aorta, which is the longest section of the aorta, spanning t

24、he 70 abdominal cavity.There are two phases of the heartbeat: diastole (relaxation) and systole (contraction). This diastole-systole cardiac cycle (relaxation-filling, then contractionpumping) lasts about 0.9 second and occurs between 70 and 80 times per minute. This is to say, the ventricles pump b

25、lood into the arteries regularly about 70 to 80 75 times a minute. The force of ventricular contraction starts a wave of increased pressure which begins at the heart and travels along the arteries. This wave is called the pulse. It can be felt in the arteries that are relatively close to the surface

26、, particularly if the vessel can be pressed down against a bone. At the wrist the radial artery passes over the bone on the thumb side of the forearm, and the pulse is most80环氧合，肺血管包括肺动脉及其分枝，和毛细血管流 入的静脉。肺动脉运送来自于右心低氧的血液，而肺 静脉将来自于肺的富氧血液运至左心房。肺循环负责 从血中排除二氧化碳并补充氧气。左心将血液经体循 环泵入机体其它部位，负责为全身组织提供营养及氧 气，并运走要

27、处理的代谢废物。来自于除肺外其它全身组织的血液经腔静脉回流 至心脏。腔静脉将血液运至右心房。当心房收缩时， 右房内血液将三尖瓣进入右室。当心室收缩时，右室 血液经肺半月瓣进入肺动脉，同时三尖瓣关闭防止血 液回流至心房。进入肺动脉的血液被运至肺，进行氧 合过程，即与周围环境进行氧及二氧化碳的交换。氧合血经肺静脉回流至心脏，进入左心房。心房收缩驱动左房血液经二尖瓣进入左室。 当心室收缩时，commonly obtained here. Other vessels sometimes used for obtaining the pulsediastole 舒张期 systole 收缩期radial

28、 桡侧的，桡骨的 carotid artery 颈动脉 dorsalis pedis 足背include the carotid artery in the neck and the dorsalis pedis artery of the top of the foot.Blood pressure is the force exerted by blood on the walls of the arteries.Thispressure varies over the course of the cardiac cycle, increasing when blood is ejecte

29、d 85 from the heart (during systole), and decreasing as the heart relaxes (during diastole). Since the pressure inside the blood vessels varies with the condition of the heart and the arteries as well as with other factors, the measurement of blood pressure together with careful interpretation may p

30、rove a valuable guide in the care and evaluation of a person hsealth. The pressure decreases as the blood flows from arteries into 90 capillaries and finally into veins. Ordinarily, measurements are made of arterial pressure only. The instrument used is called a sphygmomanometer. The two measurements made are of: 1) the systolic pressure, which occurs during heart muscle contraction and averages around 120, expressed in millimeters of merc