1. 21 Blood Vessels and Circulation C h a p t e r
PowerPoint® Lecture Slides prepared by Jason LaPres
Lone Star College - North Harris
Copyright © 2009 Pearson Education, Inc.,
publishing as Pearson Benjamin Cummings

2. Structure of vessel walls
Walls of arteries and veins contain three distinct layers
Tunic intima
Tunica media
Tunica externa

3. Figure 19.1 A Comparison of a Typical Artery and a Typical Vein

4. Differences between arteries and veins
Compared to veins, arteries
Have thicker walls
Have more smooth muscle and elastic fibers
Are more resilient

5. Arteries Undergo changes in diameter
Vasoconstriction – decreases the size of the lumen
Vasodilation – increases the size of the lumen
Classified as either elastic (conducting) or muscular (distribution)
Small arteries (internal diameter of 30 um or less) are called arterioles

6. Capillaries An endothelial tube inside a basal lamina These vessels
Form networks
Surround muscle fibers
Radiate through connective tissue
Weave throughout active tissues
Capillaries have two basic structures
Continuous
Fenestrated
Flattened fenestrated capillaries = sinusoids

7. Figure 19.2 Histological Structure of Blood Vessels

8. Figure 19.4 Capillary Structure

9. Capillary Beds An interconnected network of vessels consisting of
Collateral arteries feeding an arteriole
Metarterioles
Arteriovenous anastomoses
Capillaries
Venules

10. Figure 19.5 The Organization of a Capillary Bed
Figure 19.5a, b

11. Veins
Collect blood from all tissues and organs and return it to the heart
Are classified according to size
Venules
Medium-sized veins
Large veins

12. Venous Valves Venules and medium-sized veins contain valves
Prevent backflow of blood

13. Figure 19.6 The Function of Valves in the Venous System

14. Distribution of blood Total blood volume is unevenly distributed
Venoconstriction maintains blood volume
Veins are capacitance vessels
Capacitance = relationship between blood volume and pressure
PLAY
Animation: Anatomy review: Blood vessel structure and function

15. Figure 19.7 The Distribution of Blood in the Cardiovascular System

16. Circulatory Pressure
Circulatory pressure is divided into three components
Blood pressure (BP)
Capillary hydrostatic pressure (CHP)
Venous pressure

17. Figure 19.8 An Overview of Cardiovascular Physiology

18. Resistance (R)
Resistance of the cardiovascular system opposes the movement of blood
For blood to flow, the pressure gradient must overcome total peripheral resistance
Peripheral resistance (PR) is the resistance of the arterial system

19. Overview of Cardiovascular Pressures
Factors involved in cardiovascular pressures include
Vessel diameter
Cross-sectional area of vessels
Blood pressure
Blood viscosity

20. Figure Relationships among Vessel Diameter, Cross-sectional Area, Blood Pressure, and Blood Viscosity
Figure 19.9

21. Arterial blood pressure
Maintains blood flow through capillary beds
Rises during ventricular systole and falls during ventricular diastole
Pulse is a rhythmic pressure oscillation that accompanies each heartbeat
Pulse pressure = difference between systolic and diastolic pressures
Mean arterial pressure (MAP)

22. Figure 19.10 Pressures within the Cardiovascular System

23. Capillary Exchange
Flow of water and solutes from capillaries to interstitial space
Plasma and interstitial fluid are in constant communication
Assists in the transport of lipids and tissue proteins
Accelerates the distribution of nutrients
Carries toxins and other chemical stimuli to lymphoid tissues

24. Processes that move fluids across capillary walls
Diffusion
Filtration
Hydrostatic pressure (CHP)
Reabsorption

25. Figure 19.11 Capillary Filtration

26. Forces acting across capillary walls
Capillary hydrostatic pressure (CHP)
Blood colloid osmotic pressure (BCOP)
Interstitial fluid colloid osmotic pressure (ICOP)
Interstitial fluid hydrostatic pressure (IHP)

27. Filtration and reabsorption
Processes involved in filtration and reabsorption include
Net hydrostatic pressure
CHP - IHP
Net colloid osmotic pressure
BCOP - ICOP

28. Figure 19.12 Forces Acting across Capillary Walls

29. Venous pressure and venous return
Assisted by two processes
Muscular compression
The respiratory pump
PLAY
Animation: Factors that affect blood pressure

30. Cardiovascular Regulation
Autoregulation
Neural mechanisms
Endocrine mechanisms

31. Autoregulation of blood flow within tissues
Local vasodilators accelerate blood flow in response to:
Decreased tissue O2 levels or increased CO2 levels
Generation of lactic acid
Release of nitric acid
Rising K+ or H+ concentrations in interstitial fluid
Local inflammation
Elevated temperature

32. Figure Homeostatic Adjustments that Compensate for a Reduction in Blood Pressure and Blood Flow
Figure 19.13

33. Neural Mechanisms Adjust CO and PR to maintain vital organ blood flow
Medullary centers of regulatory activity include
Cardiac centers
Vasomotor centers control
Vasoconstriction via adrenergic release of NE
Vasodilation via direct or indirect release of NO

34. Reflex control of cardiovascular function
Baroreceptors reflexes monitor stretch
Atrial baroreceptors monitor blood pressure
Chemoreceptor reflexes monitor CO2, O2, or pH levels
PLAY
Animation: Autoregulation and capillary dynamics

35. Figure 19.14 Baroreceptor Reflexes of the Carotid and Aortic Sinuses

36. Figure 19.15 The Chemoreceptor Reflexes

37. Hormones and cardiovascular regulation
Antidiuretic hormone – released in response to decreased blood volume
Angiotensin II – released in response to a fall in blood pressure
Erythropoietin – released if BP falls or O2 levels are abnormally low
Natriuretic peptides – released in response to excessive right atrial stretch

38. Figure 19.16 The Regulation of Blood Pressure and Blood Volume
Figure 19.16a

39. Figure 19.16 The Regulation of Blood Pressure and Blood Volume
Figure 19.16b

40. Exercise and the Cardiovascular System
Light exercise results in
Extensive vasodilation
Increased venous return
A rise in cardiac output
Heavy exercise results in
Increased blood flow to skeletal muscles
Restriction of blood flow to nonessential organs

41. Cardiovascular response to hemorrhaging: Short term
Carotid and aortic reflexes increase CO and peripheral vasoconstriction
Sympathetic nervous system elevates blood pressure
E and NE increase cardiac output and ADH enhances vasoconstriction

42. Cardiovascular response to hemorrhaging: Long term
Decline in capillary blood pressure recalls fluids from interstitial spaces
Aldosterone and ADH promote fluid retention
Increased thirst promotes water absorption across the digestive tract
Erythropoietin ultimately increases blood volume and improves O2 delivery

43. Figure 19.17 Cardiovascular Responses to Hemorrhaging and Blood Loss

44. Special circulation The brain
Four arteries which anastomose insuring constant blood flow
The heart
Coronary arteries arising from the ascending aorta
The lungs
Pulmonary circuit, regulated by local responses to O2 levels
Opposite other tissues (declines in O2 cause vasodilation)

45. The distribution of blood: General functional patterns
Peripheral distribution of arteries and veins is generally symmetrical
Except near the heart
Single vessels may have several names as they cross anatomical boundaries
Arteries and corresponding veins usually travel together

46. Figure 19.18 An Overview of the Patterns of Circulation

47. Pulmonary circuit consists of pulmonary vessels
Arteries which deliver blood to the lungs
Capillaries in the lungs where gas exchange occurs
Veins which deliver blood to the left atrium

48. Figure 19.19 The Pulmonary Circuit

49. Systemic arteries Ascending aorta
Right and left coronary arteries originate from base of aortic sinus
Aortic arch and branches
Brachiocephalic
Left common carotid
Left subclavian arteries
Descending aorta and its branches
Thoracic and abdominal aortas

50. Figure 19.20 An overview of the Major Systemic Arteries

51. Figure 19.21 Arteries of the Chest and Upper Limb

52. Figure 19.21 Arteries of the Chest and Upper Limb
Figure 19.21b

53. Figure 19.22 Arteries of the Head and Neck

54. Figure 19.23 Arteries of the Brain

55. Figure 19.24 Major Arteries of the Trunk
Figure 19.24a

56. Figure 19.24 Major Arteries of the Trunk
Figure 19.24b

57. Figure 19.25 Arteries Supplying the Abdominopelvic Organs

58. Figure 19.26 Arteries of the Lower Limb
Figure 19.26a, b

59. Figure 19.26 Arteries of the Lower Limb
Figure 19.26c

60. Systemic Veins Superior vena cava Drains blood from the head and neck
Inferior vena cava
Drains blood from the remainder of the body

61. Figure 19.27 An Overview of the Major Systemic Veins

62. Figure 19.28 Major Veins of the Head, Neck and Brain
Figure 19.28a

63. Figure 19.28 Major Veins of the Head, Neck and Brain
Figure 19.28b

64. Figure 19.29 The Venous Drainage of the Abdomen and Chest

65. Figure 19.31 Venous Drainage from the Lower Limb
Figure 19.31a, b

66. Figure 19.31 Venous Drainage from the Lower Limb
Figure 19.31c

67. Hepatic Portal System
Contains substance absorbed by the stomach and intestines
Delivers these compounds to the liver for
Storage
Metabolic conversion
Excretion

68. Figure 19.32 The Hepatic Portal System

69. Placental Supply
Fetal blood flow to the placenta is supplied via paired umbilical arteries
A single umbilical vein drains from the placenta to the ductus venosus
Collects blood from umbilical vein and liver
Empties into the inferior vena cava

70. Fetal Circulation of the Heart and Great Vessels
No need for pulmonary function in the fetus
Two shunts bypass the pulmonary circuit
Foramen ovale
Ductus arteriosus

71. Cardiovascular Changes at Birth
Lungs and pulmonary vessels expand
Ductus arteriosus constricts and becomes ligamentum arteriosum
A valvular flap closes the foramen ovale

72. Figure 19.33 Fetal Circulation
Figure 19.33a, b

73. You should now be familiar with:
The types of blood vessels
Fluid and dissolved material transport into and out of the cardiovascular system
The factors that influence blood pressure and blood pressure regulation
The mechanisms involved in the movement of fluids between capillaries and interstitial spaces

74. You should now be familiar with:
How blood flow and pressure in tissues is regulated
The principle blood vessels of each circuit and the areas they serve
Fetal circulation patterns and the changes that occur in these patterns at birth