英文医学课件：6 circulatory system 循环系统

1、Circulatory system,Learning Objectives,To be familiar with the type of capillary. To be familiar with the type of artery and vein. To distinguish with all the types of blood vessels.,Concepts of organs and systems, Organ: composed of four kinds of the tissues in a particular way,Types,Hollow organs:

2、 studied from inside to outside,Substantial organs:, System: composed of many organs which have relationship with each other in structure and function.,parenchyma,interstitium,General outline,Blood vascular system (cardiovascular system),Lymphatic vascular system,-Closed tubular system According to

3、the circulating fluid in the tubes, blood or lymph:,Cardiovascular System,The histological study of the cardiovascular system includes two major components Heart mainly functions as a pump to move blood (and all the things blood carries) through the body. Blood vessels are the tubes that distribute

4、the blood to the cells and then back to the heart.,The blood vessels include three major divisions: Arteries deliver blood from heart to capillaries Capillaries the smallest blood vessels and closest to body cells, the interchanges between blood and tissues occur there Veins carry blood from body to

5、 the heart,Histological Structure of Blood Vessels,Structural feature of Arteries and Veins: Tunica intimae 1. Endothelium 2. Subendothelial layer 3. Internal elastic membrane Tunica media Mainly smooth muscle Tunica adventitia external elastic membrane Mainly connective tissue,medium-sized A,Artery

6、,transport blood from heart to capillaries according to their size, structure and function,Large artery Medium-sized artery D1mm Small artery D0.31mm Arteriole D0.3mm,are classified,The wall of Arteries consist of three layers or “coats” often referred to as tunics. Tunica intimae is the inner coat

7、Tunica media is the middle layer Tunica adventitia or tunica externa is the outer layer of the wall of the blood vessel Layers of arteries wall differ in different size blood vessels. The structure and function of arteries change as their diameter decreases.,Structure features of artery,Tunica intim

8、ae,is the inner coat and it consists of 1)inner endothelial layer 2)subendothelial layer: a layer of loose connective tissue 3)internal elastic membrane (often very distinct) This layer is relatively constant within different size arteries.,Tunica media,This layer makes up the greatest part of the w

9、all of the artery. It is comprised primarily of smooth muscle. In small arteries or arterioles it may be only 1-3 cells thick but in larger arteries may comprise hundreds of layers of muscle cells. In large arteries, there in increased amounts of elastin fibers.,Tunica adventitia,This is the outer l

10、ayer of the wall of the artery. It consists primarily of connective tissue and serves to attach the blood vessel into the surrounding connective tissue. Often contains adipose tissue and often contains blood vessels (vasa vasorum) that supply the walls of the blood vessels.,Medium-sized artery (Musc

11、ular artery):,muscular artery: diameter larger than 1mm,Tunica intima,Endothelium Subendothelial layer: LCT Internal elastic lamina: clear,Tunica media: contain 1040 layers of circular smooth muscle,Tunica adventitia,External elastic lamina LCT: contain vasa vasorum,Tunica Adventitia Tunica Media Tu

12、nica intima,Medium-sized artery,Classic muscular artery- elastic stain,Large (elastic) artery:,contains aorta, the pulmonary trunk and their main branches With a large lumen relative to wall thickness subendothelial layer is thicker with a few smooth muscles tunica media is thick, contains a 40-70 c

13、oncentrically-arranged elastic lamina internal and external elastic lamina are not distinguished tunica adventitia are thinner, abundant vasa vasorum,PT stain,Elastic artery,Muscular artery,Small artery:,muscular artery and peripheral resistance vessel internal elastic lamina is clear, while externa

14、l elastic lamina is not distinguished the tunica media contains 39 layers of smooth muscles,Arterioles:,Less than 0.3mm in diameter. Have similar and simpler structure as that of muscular artery. Several layers of smooth muscle in tunica media. Responsible for the presence of blood pressure.,Vein,la

15、rge lumen, thin wall, irregular internal and external elastic lamina are not clear tunica media is thin, with a few elastic fibers and smooth muscles tunica adventitia is thick (best-developed) some veins have valves,Large veins D10mm,Medium-sized vein D=29mm,Vein valves: Bag-like protrusion of tuni

16、ca intima, which prevents the blood flow from running to opposite direction. Exists only in the vein that has low position or far away from heart.,Vein with valve,A Comparison of a Typical Artery and a Typical Vein,elastic tissue is colored dark purple, cytoplasm (in smooth muscle and nerve) is ligh

17、ter purple, and collagen is pale pink.,Artery, vein, nerve, elastin stain,Artery, vein, nerve, elastin stain,elastic tissue is colored dark brown, collagen is pale pink and cytoplasm (in smooth muscle and nerve) is purple.,Artery, vein, nerve, trichrome stain,collagen is colored blue and smooth musc

18、le is red. Red blood cells in the venous lumen are brighter red.,Capillaries,Capillaries are the site where materials carried in the blood are unloaded and other materials are loaded into the blood. In many organs the capillaries form a network. Consist of a single layer of simple squamous epitheliu

19、m. the average diameter about 8um.,Capillaries,1) L/M: A single layer of endothelial cells Pericyte A basement membrane,Pericyte: long cytoplasmic processes have a contractile function, participating in the repair process,Capillary - pericyte,The types of Capillaries,Continuous C.,Fenestrated C.,Sin

20、usoid,E/M,The types of Capillaries,Continuous capillary Fenestrated capillary Sinusoid,Heart,a hollow muscular organ that contracts rhythmically pump blood through the circulatory system,The wall of heart,endocardium,myocardium,epicardium,The wall of heart,E,SE,subendocardial layer,endocardium,myoca

21、rdium,epicardium,Purkinje fibers,endocardium,Endothelium Subendothelial layer: fined CT Subendocardial layer: LCT, blood vessels, nerves and the impulse-conducting system of the heart,闰盘,线粒体,myocardium,thickest layer, consists of cardiac muscle, is richly supplied with capillaries three layers are divided roughly, cardiac muscle arrange spirally.,Cardiac muscle:HE100,构成心包脏层,心包受损 影响心脏功能,epicardium,LCT: contain adipose cells, blood vessels and nerves Methothelium,Conducting Systemcomponents: sinoatrial node (SA node): the primary