血管功能

1. 血管功能 夏强，PhD 浙江大学基础医学系

2. 学习目标 • 学生在学完本部分后，能够： • 列出三种类型的血管，并描述它们的结构与功能 • 说出循环系统的两个环路，追溯血液从心脏出发到任意器官、以及回到心脏的路径 • 定义脉搏 • 描述影响动、静脉及毛细血管血压和血流的因素 • 定义高血压，区分收缩压与舒张压 • 描述淋巴系统的结构与功能

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5. Functional parts of blood vessels

6. Hemodynamics Poiseuille Law: Q=pDPr4/8hL h: viscosity r: radius of the vessel L: length of the vessel • Blood flow Q= DP/R = (P1-P2)/R R= 8hL/pr4 Q= DP/R

7. Decreasing the radius of a vessel by one-half its original radius will have what effect upon blood flow to distal portion? A Blood flow will decrease to 50% of original flow. B Blood flow will decrease by 25% of original flow. C Blood flow will decrease to 10% of original flow. D Blood flow will decrease to 6% of original flow.

8. Arterial blood pressure

9. Systolic pressure (SP，收缩压): the maximum arterial pressure reached during peak ventricular ejection Diastolic pressure (DP，舒张压): the minimum arterial pressure just before ventricular ejection begins Pulse pressure (PP，脉压): the difference between SP and DP Mean arterial pressure (MAP，平均动脉压): the average pressure in the cardiac cycle (=DP+1/3PP)

10. To estimate systolic and diastolic pressures, pressure is released from an inflatable cuff on the upper arm while listening as blood flow returns to the lower arm. 查DynaMed

11. Classification of blood pressure for adults age 18 years and older The classification chart is based on adults, aged 18 and older, who are not taking high blood pressure medicines and who are not acutely ill. If systolic and diastolic measurements fall into different categories, the higher category should be used to classify the person's blood pressure status. 中国高血压防治指南?

12. 3 2 1 4 5

13. Arterial Pulse

14. In response to the pulsatile contraction of the heart: pulses of pressure move throughout the vasculature, decreasing in amplitude with distance

15. From: http://www.patient.co.uk/

16. 2 1 3 A-V shunt 4 5 Microcirculation

17. Arterioles（微动脉） • Two major roles: • To be responsible for determining the relative blood flow in individual organs at any given MAP • To be a major factor in determining MAP

18. Dynamic adjustments in the blood distribution to the organs is accomplished by relaxation and contraction of circular smooth muscle in the arterioles.

19. Local Control of Blood Flow • The mechanism independent of nerves or hormones by which organs and tissues alter their own arteriolar resistances, thereby self-regulating their blood flows • Active hyperemia（主动充血） • Flow autoregulation（血流自身调节） • Reactive hyperemia（反应性充血） • Local response to injury（对损伤的局部反应）

20. Local control of organ blood flow Active hyperemia and flow autoregulation differ in their cause but both result in the production of the same local signals that provoke vasodilation.

21. Extrinsic Control • Sympathetic nerves（交感神经） • Parasympathetic nerves（副交感神经） • Noncholinergic, nonradrenergic autonomic neurons (NO or other noncholinergic vasodilator substances)（NANC） • Hormones (epinephrine, angiotensin II, vasopressin, atrial natriuretic peptide)

22. Sympathetic stimulation of alpha-adrenergic receptors cause vasoconstriction to decrease blood flow to that location. Sympathetic stimulation of beta-adrenergic receptors lead to vasodilation to cause an increase in blood flow to that location.

23. Renin-angiotensin system（肾素-血管紧张素系统）

24. ANGII can be produced directly by conversion of angiotensinogen by the tissue plasminogen activator (tPA), cathepsin G and tonin or by hydrolysis of angiotensin I by chymase and cathepsin G. CAGE = chymostatin-sensitive angiotensin II-generating enzyme

25. Vasopressin（血管升压素）

26. Endothelium-derived vasoactive substances • Vasodilator factors • PGI2 – prostacyclin（前列环素） • EDRF (endothelium-derived relaxing factor, nitric oxide) • EDHF (endothelium-dependent hyperpolarizing factor)

28. Vasoconstrictor factors – Endothelin-1（内皮素-1）

29. Major factors affecting arteriolar radius Diversity among signals that influence contraction/relaxation in vascular circular smooth muscle implies a diversity of receptors and transduction mechanisms.

30. From the biologically active substances produced from arachidonic acid which are listed below, select which is a vasodilator and platelet aggregation inhibitor produced by endothelial and smooth muscle cells A Thromboxane A2 B Lipoxin A C Lipoxin B D Leukotriene C4 E Leukotriene D4 F Leukotriene B4 G Leukotriene F4 H Leukotriene E4 I Thromboxane B2 J Prostacyclin (PGI2)

31. Capillaries

32. Relationship between total cross-sectional area and flow velocity Six balls in per minute mandates six balls out per minute. Therefore, the velocity of the balls in the smaller tubes is slower.

33. Capillary walls are a single endothelial cell in thickness. The capillary is the primary point exchange between the blood and the interstitial fluid (ISF). Intercellular clefts assist the exchange.

34. There are many, many capillaries, each with slow-moving blood in it, resulting in adequate time and surface area for exchange between the capillary blood and the ISF.

35. Movement of fluid and solutes out of the blood is called filtration. Filtration Absorption Movement of fluid and solutes into the blood is called absorption.

36. Net filtration pressure (or Effective filtration pressure)

37. Effects of arteriolar vasodilation or vasoconstriction on capillary blood pressure Dynamic changes in vasodilation/vasoconstriction in the arterioles regulate downstream pressures and flow rates.

38. In which of the following lists of blood vessels is the sequence of vessels arranged from highest to lowest total cross-sectional area in the body? A Arteries, arterioles, capillaries, veins B Arterioles, capillaries, arteries, veins C Capillaries, arterioles, veins, arteries D Veins, capillaries, arterioles, arteries E Arteries, veins, arterioles, capillaries

39. Venous pressure and venous return • Venous pressure • Peripheral venous pressure（外周静脉压）-- the pressure in the peripheral veins • Central venous pressure (CVP，中心静脉压) -- the pressure in the thoracic vena cava & the right atrium 4~12cmH2O

40. Determinants of venous pressure • Contraction of venous smooth muscle • Sympathetic neurons • Hormonal and paracrine vasodilators and vasoconstrictors • Skeletal muscle pump • Respiratory pump

41. Varicose vein（曲张静脉）

42. Skeletal muscle pump • Respiratory pump

43. Alterations in “venous return” alter end-diastolic volume (EDV); increased EDV directly increases stroke volume and cardiac output.

44. The Lymphatic System

45. Lymphatic pump

46. Elephantiasis Also known as lymphatic filariasis, this condition occurs when parasitic worms (any of several types of filaria worms) infest the lymphatic system.  The filaria are transmitted by mosquitoes to the blood and can build a population in the lymph nodes, blocking fluid drainage from arms, legs, genitals, or breasts.  It is called elephantiasis (literally, "elephant condition") because in extreme cases, the arms and legs look like the limbs of an elephant. Elephantiasis affects over a 100 million people around the world.  However, most cases are not as extreme as in this photo!

47. Lymph flow from the foot is: A Increased when an individual rises from the supine to the standing position. B Increased when the foot is massaged. C Increased when capillary permeability is decreased. D Decreased when the valves of the leg veins are incompetent. E Decreased in exercise.

48. A summary of dynamic changes in MAP and TPR.

49. Regulation of Cardiovascular Activities 夏强，PhD 浙江大学基础医学系

50. Control of Cardiovascular Activities • Nervous Regulation • Humoral Regulation • Autoregulation