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1、Contents1. Introduction 2. Location, relationship its color changes from scarlet to dark red. Blood vessels in the systemic circuit also (1) pick up nutrients from the digestive tract and deliver them to cells throughout the body, and (2) receive nitrogenous wastes from body cells and transport them
2、 to the kidneys for elimination in the urine. The pulmonary (lesser) circulation is blood circulation through which blood flows from the right ventricle into pulmonary trunk and its branches to the lungs, and returns to the left atrium via the pulmonary veins. When blood flows through capillaries in
3、 the lungs, it discharges carbon dioxide and picks up oxygen from the lung alveoli. So the blood changes back from venous blood to arterial blood, its color changesfrom dark red to scarlet as well.The arteries and veins of the pulmonary circuit have thinner walls than do systemic vessels of comparab
4、le diameter, reflecting the fact that the maximum arterial pressure here is only one-sixth that in the systemic circuit. In spite of the blood circulation can be divided into the systemic circulation and pulmonary circulation, the systemic circulation and pulmonary circulation are interdependent. Th
5、e heart connects systemic circulation and pulmonary circulation, and the heart not only provides dynamic to systemic circulation, but also to pulmonary circulation.Functions of Vascular SystemTransport Maintain of internal environment Immune and Defensive EndocrineVascular Anastomosis and Significan
6、ceBetween artery and artery Between vein and vein Between artery and vein: For instance, existing on tips of fingers, apex of nose and auricleColleteral Anatomosis female: 250gThe size of the heart varies fromperson to person2. Locationin the thoracic cavity occupies middle medastinum Enclosed by pe
7、ricardium 2/3 in left, 1/3 in rightThe angle between the cardiac axis and midsagittal plane is proximately 45 degree.Since the heart has rotated slightly to the left during embryonic development, therefore, the atria are posterior and superior to theventricles, and the right atrium and ventricle are
8、 anterior to the left atrium and ventricle and to the right. So: The right atrium forms the right border of the heart. The right ventricle forms most potions of sternocostal surface and small portions of diaphragmatic surface. The left atrium forms the base of the heart and lies in the back of the h
9、eart. The left ventricle forms the left border, apex and most portions of the diaphragmatic surface of the heart.心的位置与体型有关，故正常心按位置分三型：（1）垂位心 纵径与垂直轴的夹角 45，见于矮胖型（3）斜位心 纵径与膈的夹角=45，见于适中型心的位置异常位于胸前壁皮下 位于腹腔 反位3. RelationshipsAnterior-sternum, 26 cartilages Posterior-58 thoracic vertebraeInferior-Diaphragm
10、 Superior-great blood vessels Lateralpleural cavity, lungsPlease note:The heart varies in location during different phases of respiration and inpneumothorax.心和心包的前方大部分被左、右肺前缘及胸膜腔遮掩，仅在下部有一三角形 区域不被肺及胸膜腔遮掩，心及心包在此三角区与胸骨体下部及左侧第4、5肋 软骨相邻，此区成为心包裸区，为心内注射的入路。故心内注射时可选择胸骨 左缘第四肋间隙进针，而不会伤及肺和胸膜。心和心包前面的上部可有部分胸 腺残余
11、。Posteriorly, there are the thoracic aorta, esophagus, bronchi, thoracic duct, azygos vein, vagus nerves, posterior mediastinal lymph nodes between the heart and vertebral column. Since the left atrium forms most portions of the base (posterior surface of the heart), an enlarged left atrium may comp
12、ress the esophagus.Laterally, the heat is closely related to the pleural cavities and the lungs, the phrenic nerve and pericardiacophrenic vessels descend between the pericardium and mediastinal pleura.Superiorly, great blood vessels leave and enter the heart. The pumonary trunk arises from the righ
13、t ventricle. Its inferior part is enclosed by the pericardium. The ascending aorta arises from the left ventricle and is also enclosed by the pericardium. The space between the bifurcation of pulmonary trunk and aortic arch is the aortic window. The superior vena cava enters the right atrium, its in
14、ferior part is within the pericardial cavity. Inferiorly, the fibrous pericardium is fused with the diaphragm. The diaphragm separates the heart from the left lobe of live and stomach. The angle formed by the pericardium and diaphragm is known as the cardiodiaphragmatic angle. Lateral to this angle,
15、 between the pericardium and mediastinal pleura are some fats, which form fatty pad.4. Shape The heart is anteroposterior a little flattened pyramidal in shape. Therefore, it is generally described as having an apex, a base, two surfaces, three borders and four groves.Apexformed by left ventricle po
16、int to the left, forward, downward9 cmBasePosterior part of the heart Formed by left, right atria and one part of the left ventricle face to the right, dorsalward, upwardBase High posterior wall (straight posterior wall)从心底面观察： 上腔静脉于主动脉右侧垂直下行，约平第三胸肋关节高度注入右心房，其下半部位于心包腔内。 下腔静脉穿过膈后立即注入右房下部，在胸腔内下腔静脉很短，约0.5cm。全部位于心包腔内。 左、右各两条肺静脉穿过心包后分别注入左心房后壁两侧。其中，在心包腔内左下肺静脉最易观察，右下肺静脉最短。约25的个体左上、下肺静脉在心包内合成一条总左肺静脉
