Special Circulation Qang×A(夏强),PhD Department of Physiology School of medicine Te:88206417,88208252 Email:xiaqiang@zju.edu.cn
Special Circulation Qiang XIA (夏强), PhD Department of Physiology School of Medicine Tel: 88206417, 88208252 Email: xiaqiang@zju.edu.cn
System Overview The blood flow to organs depends on 1. The difference between aortic pressure and central venous pressure 2. The diastolic and systolic state of blood vessel in this organ The blood flow to individual organs must vary to meet the needs of the particular organ, as well as of the whole body
System Overview ➢ The blood flow to organs depends on ⒈ The difference between aortic pressure and central venous pressure ⒉ The diastolic and systolic state of blood vessel in this organ ➢ The blood flow to individual organs must vary to meet the needs of the particular organ, as well as of the whole body
System Overview Neural, myogenic, metabolic, and endothelial mechanisms control regional blood flow >Neural mechanism. Blood pressure Autonomic nervous system-+ Cardiac output (sympathetic division) Local blood flow >Myogenic mechanism: Autoregulation in the vessels of heart, brain, skeletal muscle, and kidneys >Metabolic mechanism: Local control in the vessels of heart PO2, pH, etc >Endothelial mechanism NO, EDHF, PGI2, ET, EDCF, etc Relaxing or contracting VSMCS
Neural, myogenic, metabolic, and endothelial mechanisms control regional blood flow ➢Neural mechanism: Autonomic nervous system (sympathetic division) ➢Myogenic mechanism: ➢Metabolic mechanism: PO2 , pH, etc. ➢Endothelial mechanism: NO, EDHF, PGI2 , ET, EDCF, etc. System Overview Autoregulation in the vessels of heart, brain, skeletal muscle, and kidneys Blood pressure Cardiac output Local blood flow Local control in the vessels of heart, brain, skeletal muscle during exercise Relaxing or contracting VSMCs
System Overview Sophisticated feedback, >Neural mechanism. Mechanical forces, etc Autonomic nervous system Local circulation (sympathetic division) Resting vasomotor tone >Myogenic mechanism: Vasomotor control >Metabolic mechanism. Electrical and chemical signalling PO2, pH, etc /SMCs→ ECS >Endothelial mechanism NO, EDHF, PGI2, ET, EDCF, etc Gap junction
➢Neural mechanism: Autonomic nervous system (sympathetic division) ➢Myogenic mechanism: ➢Metabolic mechanism: PO2 , pH, etc. ➢Endothelial mechanism: NO, EDHF, PGI2 , ET, EDCF, etc. System Overview Resting vasomotor tone ECs VSMCs Gap junction Electrical and chemical signalling Vasomotor control Sophisticated feedback, Mechanical forces, etc. Local circulation
Coronary circulation 冠脉循环 Copyright OThe MeGraw-Hill Cs Aorta Right coronary artery Left coronary artery Posterior inter-Marginal Anterior into ventricular circumflex ventricular er. artery artery artery artery Walls of Walls of Ventricular right atrium left atrium Ventricular walls and right and left walls ventricle ventricle Cardiac veins Coronary sinus Right atrium
Coronary circulation 冠脉循环
Coronary circulation Brachiocephalic Left common carotid artery perior vena cava subclavian artery Aortic arch Right Ligamentum ary arte Ascending Left pulmonary artery Pulmonary trunk Left pulmonary veins Left atrium Right pulmonary veins Auricle Right atrium Circumflex artery Right coronary artery(in right Left coronary atrioventricular groove) ry(in left atrioventricular groove Anterior cardiac vein Left ventricle Right ventricle Great cardiac vein Marginal artery Small cardiac vein interventricular artery Inferior (in ante vena cava interventricular sulcus) Heart: view from front
Coronary circulation Heart: view from front
Coronary circulation Aorta Superior Right pulmonary artery ulmonary artery Left pulmonary veins Right pulmonary veins Auricle of left atrium Right atrium Left atrium Inferior Great cardiac vein vena cava Right coronar Posterior vein artery(in right of left ventricle atrioventricular groove) Posteri Left ventricle interventricular artery (in posterior interventricular sulcus) Ap Middle cardiac vein Heart: view from diaphragm
Coronary circulation Heart: view from diaphragm
Coronary circulation Coronary circulation receives 5%of the resting cardiac output from the left heart, and mostly returns it to the right heart Heart muscle consumes as much O2 as does equal mass of sm during vigorous exercise Heart tissue extracts maximal amount of o2 at rest The only way to increase of energy is by increasing blood flow Autoregulation: relative stable flow between 70 and more than 150mmHg
Coronary circulation • Coronary circulation receives 5%of the resting cardiac output from the left heart, and mostly returns it to the right heart • Heart muscle consumes as much O2 as does equal mass of SM during vigorous exercise • Heart tissue extracts maximal amount of O2 at rest • The only way to increase of energy is by increasing blood flow • Autoregulation: relative stable flow between 70 and more than 150mmHg
Diagram of the epicardial, intramuscular and subendocardial coronary vasculature Epicardial coronary arteries Cardiac muscle Subendocardial arterial plexus The branches of left and right coronary artery often penetrate myocardium in direction perpendicular to cardiac surface Myocardial capillary distribution is extremely abundance Collateral coincidence between coronary is less
Diagram of the epicardial, intramuscular, and subendocardial coronary vasculature • The branches of left and right coronary artery often penetrate myocardium in direction perpendicular to cardiac surface • Myocardial capillary distribution is extremely abundance • Collateral coincidence between coronary is less
Systole Diastole 12 Extravascular compression Impairs器 coronary blood flow during systole sovo| uic contraction phase↓↓→ rapid ejection phase↑→ reduced ejection phase↓→ diastolic phase↑ 0 (isovolumic relaxation phasett) E≥=oo0 0 0.6 ime(sec)
Extravascular compression impairs coronary blood flow during systole Isovolumic contraction phase ↓↓→ rapid ejection phase ↑→reduced ejection phase ↓→ diastolic phase ↑ (isovolumic relaxation phase↑↑)