1. Cardiovascular System Blood Vessels

2. Anatomy of Blood Vessels Arteries carry blood from the heart to the tissues Arteries carry blood from the heart to the tissues

3. Anatomy of Blood Vessels Arterioles are small arteries that connect to capillaries Arterioles are small arteries that connect to capillaries

4. Anatomy of Blood Vessels Capillaries are the site of substance exchange between the blood and body tissues Capillaries are the site of substance exchange between the blood and body tissues

5. Anatomy of Blood Vessels Venules connect capillaries to larger veins Venules connect capillaries to larger veins

6. Anatomy of Blood Vessels Veins convey blood from the tissues back to the heart. Veins convey blood from the tissues back to the heart.

7. Arteries 1. Tunica interna (intima) – innermost 2. Tunica media – middle layer 3. Tunica externa – outer layer

9. Tunica Intima Composed of; Composed of; 1. simple squamous epithelium (endothelium) 2. Internal elastic membrane

11. Tunica Media Rich in smooth muscle and elastic fibers Rich in smooth muscle and elastic fibers

13. Tunica Media Maintains elasticity and contractility Maintains elasticity and contractility

14. Tunica Externa Rich in elastic and collagen fibers Rich in elastic and collagen fibers

16. Functional Properties of Arteries 1. Elasticity 2. Contractility

17. Elasticity Due to the elastic tissue in the tunica intima and media Due to the elastic tissue in the tunica intima and media

18. Elasticity Allows arteries to accept blood under great pressure from the contraction of the ventricles Allows arteries to accept blood under great pressure from the contraction of the ventricles

19. Contractility Due to the smooth muscle in the tunica media Due to the smooth muscle in the tunica media

20. Contractility Allows arteries to increase or decrease lumen size Allows arteries to increase or decrease lumen size

21. Contractility Sympathetic stimulation of alpha 1 receptors on cutaneous arteries causes vasoconstriction Sympathetic stimulation of alpha 1 receptors on cutaneous arteries causes vasoconstriction

22. Contractility Sympathetic stimulation of beta 2 receptors on arteries supplying skeletal muscle causes vasodilation Sympathetic stimulation of beta 2 receptors on arteries supplying skeletal muscle causes vasodilation

23. Elastic Arteries Elastic Arteries – Large arteries with more elastic fibers and less smooth muscle Elastic Arteries – Large arteries with more elastic fibers and less smooth muscle

24. Elastic Arteries Example: aorta, sublcavian, and pulmonary arteries Example: aorta, sublcavian, and pulmonary arteries

25. Elastic Arteries Also called conducting arteries because they conduct blood from the heart to medium sized arteries Also called conducting arteries because they conduct blood from the heart to medium sized arteries

26. Muscular or distributing arteries Medium sized and have a large amount of smooth muscle and distribute blood to various parts of the body Medium sized and have a large amount of smooth muscle and distribute blood to various parts of the body

27. Muscular or distributing arteries Examples: brachial, femoral, and popliteal arteries Examples: brachial, femoral, and popliteal arteries

28. Arterioles Very small arteries that deliver blood to capillaries Very small arteries that deliver blood to capillaries

29. Capillaries Connect arterioles and venules Connect arterioles and venules

30. Capillaries Microcirculation – flow of blood through the capillaries Microcirculation – flow of blood through the capillaries

31. Capillaries Capillaries are found near almost every cell in the body Capillaries are found near almost every cell in the body

32. Capillaries Function – Permit the exchange of nutrients and wastes between the blood and tissue cells Function – Permit the exchange of nutrients and wastes between the blood and tissue cells

33. Capillaries Composed of a single layer of cells (endothelium) and a basement membrane Composed of a single layer of cells (endothelium) and a basement membrane

34. Capillaries Two types; Two types; 1. Continuous 2. Fenestrated

35. Capillaries Continuous – composed of endothelial cells that form a continuous tube that contains gaps between cells called intercellular clefts Continuous – composed of endothelial cells that form a continuous tube that contains gaps between cells called intercellular clefts

36. Capillaries Fenestrated capillaries – plasma membrane contains small pores Fenestrated capillaries – plasma membrane contains small pores

37. Capillaries Materials can cross the blood capillary walls in four ways Materials can cross the blood capillary walls in four ways

38. Capillaries Four Ways; 1. Intercellular clefts 2. Trancytosis using pinocytic vesicles 3. Diffusion 4. Fenestrations

39. Intercellular clefts Open in response to histamine (released during inflamation) making capillaries more leaky Open in response to histamine (released during inflamation) making capillaries more leaky

40. Intercellular clefts This allows fluid and wbc, and antibodies to go from the bloodstream to the site of infection This allows fluid and wbc, and antibodies to go from the bloodstream to the site of infection

41. Pinocytosis Large fats cross via pinocytosis Large fats cross via pinocytosis

42. Diffusion Water, CO2, and O2 cross capillaries by diffusion Water, CO2, and O2 cross capillaries by diffusion

43. Fenestrations Allow small molecules such as water and electrolytes to get into the urine Allow small molecules such as water and electrolytes to get into the urine

44. Fenestrations Prevent large proteins and red cells from getting into the urine Prevent large proteins and red cells from getting into the urine

45. Sinusoids Discontinuous capillaries Discontinuous capillaries

46. Sinusoids Present in the liver Present in the liver

47. Sinusoids Allow large molecules such as protein and bilirubin to get from the bloodstream into hepatocytes Allow large molecules such as protein and bilirubin to get from the bloodstream into hepatocytes

48. Venules They are small vessels that are formed from the union of several capillaries They are small vessels that are formed from the union of several capillaries

49. Venules Merges to form veins Merges to form veins

50. Venules Drain blood from capillaries into veins Drain blood from capillaries into veins

51. Veins Contain 60% of our blood volume Contain 60% of our blood volume

52. Veins Consist of the same three tunics as arteries Consist of the same three tunics as arteries

54. Veins Have a thinner tunica intima and media Have a thinner tunica intima and media

56. Veins Thicker tunica externa Thicker tunica externa

58. Veins Thinner walled than arteries due to less elastic tissue and smooth muscle Thinner walled than arteries due to less elastic tissue and smooth muscle

59. Veins Low pressure systems Low pressure systems

60. Veins Contain valves to prevent backflow Contain valves to prevent backflow

61. Veins Squeezing of the veins by muscles and inspiration promote venous return Squeezing of the veins by muscles and inspiration promote venous return

62. Venous Return The volume of blood returning back to the heart from the systemic veins The volume of blood returning back to the heart from the systemic veins

63. Veins Vascular sinuses – veins with very thin walls with no smooth muscle to alter their diameter Vascular sinuses – veins with very thin walls with no smooth muscle to alter their diameter Example: Coronary sinus Example: Coronary sinus

64. Anastomoses Union of the branches of two or more arteries supplying the same region Union of the branches of two or more arteries supplying the same region

65. Anastomoses Provide alternate routes for blood to reach a tissue or organ Provide alternate routes for blood to reach a tissue or organ

66. Anastomoses Collateral circulation is the alternate flow of blood to a body part through an anastomosis Collateral circulation is the alternate flow of blood to a body part through an anastomosis

67. Anastomoses What is the importance of arteries that anastomose? What is the importance of arteries that anastomose?

68. Anastomoses Occlusion of an end artery interrupts the blood supply to a whole segment of an organ, producing necrosis of that segment Occlusion of an end artery interrupts the blood supply to a whole segment of an organ, producing necrosis of that segment

69. Blood Pressure Pressure exerted on the walls of a blood vessel Pressure exerted on the walls of a blood vessel

70. Blood Pressure In a clinical sense, it refers to pressure in arteries In a clinical sense, it refers to pressure in arteries

71. Blood Pressure BP=CO X TPR BP=CO X TPR

72. Blood Pressure Systolic and Diastolic fluctuations in the pressure are only seen in the arteries and arterioles Systolic and Diastolic fluctuations in the pressure are only seen in the arteries and arterioles

73. Systolic Pressure Peak pressure in the arteries with each cardiac cycle during ventricular contraction Peak pressure in the arteries with each cardiac cycle during ventricular contraction

74. Systolic Pressure Due to the stroke volume being ejected into the aorta Due to the stroke volume being ejected into the aorta

75. Diastolic Pressure Lowest pressure in the arteries with each cardiac cycle Lowest pressure in the arteries with each cardiac cycle

76. Diastolic Pressure Force of blood recorded during ventricular relaxation Force of blood recorded during ventricular relaxation

77. Blood Pressure Young adult male = 120/80 mm Hg (8-10 mm Hg less in a young adult female) Young adult male = 120/80 mm Hg (8-10 mm Hg less in a young adult female)

78. Resistance Depends on three variables; Depends on three variables; 1. Blood viscosity 2. Vessel length 3. Blood Vessel Radius

79. Blood Viscosity Increased viscosity increases resistance Increased viscosity increases resistance

80. Vessel length Increased length increases resistance Increased length increases resistance

81. Blood Vessel Radius Increased radius decreases resistance Increased radius decreases resistance

82. Systemic vascular resistance Total peripheral resistance (TPR) Total peripheral resistance (TPR)

83. Systemic vascular resistance All of the vascular resistance offered by systemic blood vessels All of the vascular resistance offered by systemic blood vessels

84. Mean Arterial Pressure MAP = Diastolic Pressure X 1/3(systolic pressure – diastolic pressure) MAP = Diastolic Pressure X 1/3(systolic pressure – diastolic pressure)

85. Mean Arterial Pressure MAP = CO X TPR MAP = CO X TPR

86. Mean Arterial Pressure Factors that increase BP Factors that increase BP increase SV increase SV increase HR increase HR constrict the blood vessels (increases resistance) constrict the blood vessels (increases resistance)

87. Mean Arterial Pressure Factors that decrease BP Factors that decrease BP Decrease CO Decrease CO Dilate the arteries Dilate the arteries

88. Cardiovascular Center A group of neurons in the medulla that regulate heart rate, contractility, and blood vessel diameter A group of neurons in the medulla that regulate heart rate, contractility, and blood vessel diameter

89. Cardiovascular Center CV receives input from higher brain regions and sensory receptors (baroreceptors and chemoreceptors) CV receives input from higher brain regions and sensory receptors (baroreceptors and chemoreceptors)

90. Cardiovascular Center Sympathetic impulses along cardioaccelerator nerves increase heart rate and contractility Sympathetic impulses along cardioaccelerator nerves increase heart rate and contractility

91. Cardiovascular Center Parasympathetic impulse along vagus nerves decrease heart rate Parasympathetic impulse along vagus nerves decrease heart rate

92. Cardiovascular Center The sympathetic division also continually sends impulses to smooth muscle in blood vessel walls via vasomoter nerves resulting in a moderate state of tonic vasoconstriction The sympathetic division also continually sends impulses to smooth muscle in blood vessel walls via vasomoter nerves resulting in a moderate state of tonic vasoconstriction

93. Neural Regulation of Blood Pressure Baroreceptors Baroreceptors Chemoreceptors Chemoreceptors

94. Baroreceptors Pressure-sensitive sensory neurons that monitor stretching of the walls of blood vessels Pressure-sensitive sensory neurons that monitor stretching of the walls of blood vessels

95. Baroreceptors If blood pressure falls, the baroreceptor reflexes; If blood pressure falls, the baroreceptor reflexes; accelerate heart rate accelerate heart rate increase force of contraction increase force of contraction promote vasoconstriction promote vasoconstriction

96. Baroreceptors If pressure increases above normal, the reflexes cause; If pressure increases above normal, the reflexes cause; decrease in sympathetic tone decrease in sympathetic tone increase in parasympathetic tone increase in parasympathetic tone

97. Hormonal Regulation Renin leads to the formation of angiotensin II Renin leads to the formation of angiotensin II

98. Hormonal Regulation Angiotensin II causes; Angiotensin II causes; 1. Vasoconstriction 2. Secretion of aldosterone, which leads to sodium and water retention

99. Hormonal Regulation Epinephrine and norepinephrine increase CO and cause vasoconstriction Epinephrine and norepinephrine increase CO and cause vasoconstriction

100. Hormonal Regulation ADH causes water retention and a little vasoconstriction ADH causes water retention and a little vasoconstriction

101. Hormonal Regulation Nitric oxide from the endothelial cells causes vasodilation Nitric oxide from the endothelial cells causes vasodilation

102. Hormonal Regulation Cortisol keep our arteries sensitive to vasoconstricting hormones Cortisol keep our arteries sensitive to vasoconstricting hormones

103. Shock Is an inadequate CO that results in failure of the CV system to deliver adequate amounts of O2 and nutrients to meet the metabolic needs of body cells Is an inadequate CO that results in failure of the CV system to deliver adequate amounts of O2 and nutrients to meet the metabolic needs of body cells

104. Shock Could result in; dysfunction of cellular membranes dysfunction of cellular membranes abnormal cellular metabolism abnormal cellular metabolism cellular death cellular death

105. Types of Shock 5 main types 5 main types

106. Hypovolemic Shock Due to decreased blood volume Due to decreased blood volume

107. Cardiogenic Shock Due to poor heart function Due to poor heart function

108. Vascular Shock Due to inappropriate vasodilation Due to inappropriate vasodilation

109. Obstructive Shock Due to obstruction of blood flow Due to obstruction of blood flow

110. Neurogenic shock Due to decreased sympathetic outflow Due to decreased sympathetic outflow

111. Homeostatic Response Activation of renin-angiotensin- aldosterone system Activation of renin-angiotensin- aldosterone system

112. Homeostatic Response Secretion of ADH Secretion of ADH

113. Homeostatic Response Activation of the sympathetic division of the ANS Activation of the sympathetic division of the ANS

115. Circulatory Routes Systemic Systemic Pulmonary Pulmonary Hepatic Portal Hepatic Portal Fetal Fetal

116. Hepatic Portal Circulation Collects blood from the veins of the pancreas, spleen, stomach, intestines and gallbladder and directs it into the hepatic portal vein of the liver before it returns to the heart Collects blood from the veins of the pancreas, spleen, stomach, intestines and gallbladder and directs it into the hepatic portal vein of the liver before it returns to the heart

118. Hepatic Portal Circulation Enables nutrient utilization and blood detoxification by the liver Enables nutrient utilization and blood detoxification by the liver