Blood Vessels and BP (Part 1) Flashcards


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1

Functions of the circulatory system

  • Deliver O2 and nutrients to tissues
  • Remove CO2 and waste
  • Transport hormones and WBC
  • Temp. regulation

2

Which part of the circulatory circuit transports blood to tissues?

Aorta and arteries

3

Which part of the circulatory circuit is under high P (100 mm Hg)?

Aorta and arteries

4

Which part of the circulatory circuit has low resistance?

Aorta and arteries

5

Which part of the circulatory circuit controls blood flow to tissues via constricting and relaxing?

Arterioles

6

Which part of the circulatory circuit is the major site of vascular resistance?

Arterioles

7

Which part of the circulatory circuit is the primary site of action for many anti-hypertensive drugs?

Arterioles

8

Which part of the circulatory circuit is the primary site for nutrient and gase exchange b/w blood and tissues?

Capillaries

9

Which part of the circulatory circuits returns blood to the heart?

SVC, IVC, Veins, venules, and venous sinuses

10

Which part of the circulatory circuit is under low pressure?

SVC, IVC, Veins, venules, and venous sinuses

11

Which part of the circulatory circuit serves as a blood reservoir?

SVC, IVC, Veins, venules, and venous sinuses

12

Which part of the circulatory circuit is distensible (small P increase = large vol increase)?

SVC, IVC, Veins, venules, and venous sinuses

13

Which part of the circulatory circuit is responsible for O2 and CO2 exchange?

Pulmonary circulation

14

Which major blood vessels are responsible for distribution of blood to tissues?

Aorta and large artery

15

Which major blood vessels are responsible for resistance?

Arteriole and small artery

16

Which major blood vessels are responsible for exchange of gases and nutrients?

Capillaries and venules

17

Which major blood vessels are responsible for capacitance of blood volume in the body?

Veins and vena cava

18

List the structures located in the tunica intima

  • Endothelium
  • Subendothelial layer
  • Internal elastic membrane

19

What structure in the tunica intima lines the lumen of all vessels and is continuous with the endocardium?

Endothelium

20

T/F: The rough surface of the endothelium helps veins control flow by increasing resistance.

False

21

The subendothelial layer of the tunica intima can be found in vessels larger than ________ and has a connective tissue basement membrane

1 mm

22

Where are layers of smooth muscle cells found in blood vessels?

Tunica media

23

Function of smooth muscle cells in the tunica media

Contract and relax to alter vessel diameter

24

What structure of the tunica media allows for bending and flexing?

Sheets of elastin

25

Where are sympathetic nerve fibers located in blood vessels?

Tunica media

26

How can sympathetic nerve fibers regulate BP?

By causing vasoconstriction and vasodilation in the tunica media

27

What is the function of the tunica externa?

Collagen fibers protect and reinforce; anchors to surrounding structures

28

T/F: The tunica media contains nerve fibers (nervi vasorum) that are poorly myelinated

False

29

______________ of larger vessels nourishes external layer of the blood vessel

Vasa vasorum

30

What allows for the direct connection b/w endothelial and smooth muscle cells?

Myoendothelial jxn

31

Where are myoendothelial jxns present?

Small, resistance sized arteries and arterioles

32

T/F: Myoendothelial jxns allow for direct electrical coupling (EDHF response)

True

33

Define Endothelium Derived Hyperpolarization Factor (EDHF)

Change in endothelium AP can be passed onto smooth muscle via myoendothelial jxn

34

T/F: Ca2+, Na+ influx and Cl-, K+ efflux can lead to depolarization which leads to contraction

False

35

T/F: Capillaries and venules only have endothelial cells

True

36

Describe the properties of an elastic artery (conducting arteries)

  • Elastin in all 3 tunics
  • Low resistance
  • Inactive vasoconstriction
  • Act as P reservoirs

37

Describe the properties of muscular arteries (distributing arteries)

  • Deliver blood to body organs
  • Think tunica media w/ more smooth muscle
  • Active in vasoconstriction

38

Describe the properties of arterioles (resistance vessels)

  • Involved in autoregulation
  • Smallest arteries, lead to capillary beds
  • Control flow to capillaries by vasodilation and vasoconstriction

39

Describe the properties of precapillary sphincter

  • Smooth muscle "cuff"
  • Regulates capillary blood flow

40

Describe the properties of venules

  • Form when capillary beds unite
  • Very porous; allow fluids and WBC into tissues
  • Consist of endothelium and a few pericytes
  • Larger venules have 1 or 2 layers of smooth muscle cells

41

Describe the properties of veins

  • Form when venules converge; capacitance vessels (blood reservoirs)
  • Thinner walls, larger lumens compared to arteries
  • Thin tunica media; thick tunica externa
  • BP lower than arteries

42

Describe the properties of vena cava

  • Capacitance vessels
  • Return deoxygenated blood to heart
  • Thoracic vena cava P = central venous P

43

Microscopic vessels involved in nutrient and gas exchange; wall consists of the endothelial layer surrounded by basement membrane

Capillaries

44

Which capillary:

Most common, complete endothelial lining w/ tight jxns b/w endothelial cells.

Continuous

45

T/F: Fenestrated capillaries are found in the small intestine, kidneys, and BBB

False

46

Which capillary:

Has pores as well as tight jxns in endothelial lining

Fenestrated

47

Which capillary:

Least common, extensive intercellular gaps and incomplete basement membranes in addition to intercellular clefts and fenestrations.

Sinusoid

48

Where are sinusoid capillaries found?

Liver, bone marrow, lymph nodes, pituitary and adrenal glands

49

Blood flow through capillaries is known as ______________

Microcirculation

50

_____________ is the most important force for substance transfer. Concentration differences enhance this.

Diffusion

51

T/F: Lipid insoluble substances diffuse through capillary membranes, while lipid soluble substances cross through intercellular clefts.

False

52

Drainage of large particles that cannot pass through capillary pores drain via ______________

Lyphatic system

53

T/F: The lymph nodes contain B and T lymphoctes, other WBCs, and filters out foreign particles

True

54

Area where there can be a direct connection b/w arteries and veins

Arteriovenous anastomosis

55

Maximal aortic P after LV contraction and blood ejection into aorta (120 mm Hg)

Systolic P

56

Lowest P in aorta, occurs just before LV ejects blood into aorta (80 mm Hg)

Diastolic P

57

Average arterial P during single cardia cycle

MAP (2/3 diastolic + 1/3 systolic = 93 mm Hg)

58

Difference b/w systolic and diastolic P

Pulse P

59

Capillary P average:

17 mm Hg

60

Rate of BF into the heart from the vein; important controller of CO

Venous Return

61

VR =

(VP - RAP) / Venous vasc resistance

62

Distensibility is a property of ________

Veins

63

Compliance is a property of ________

Arteries

64

Resistance is a property of ___________

Arterioles

65

Ability of a vessel to distend and increase vol w/ increasing P

Compliance

66

Opposition or impediment to BF

Resistance

67

T/F: PP increases as aortic elasticity deceases w/ age/pathological alterations

True

68

PP ranges b/w ______ mm Hg under normal physiological conditions

40-50

69

T/F: Dampening = compliance x distensibility

False

70

Progressive diminishment of pressure pulsations in the periphery.

Damping

71

What is dampening caused by?

  • Resistance of small vessels
  • Compliance of large vessels

72

Defined as the velocity of flow in the center of the vessel is far greater than at the outer edges

Laminar flow

73

Defined as disordered flow caused by fast flow rate, obstruction in the vessel, sharp turn in the vessel, or passing over a rough surface.

Turbulent flow

74

T/F: Turbulent flow decreases resistance

False

75

T/F: Blood flow is equivalent to CO for the entire vascular system

True

76

BP =

CO x TPR

77

CO = HR x SV =

BP/TPR

78

T/F: Resistance can be measured

False

79

R =

ΔP/F

80

List the factors affecting resistance and blood flow

  • Vessel diameter (related to conductance)
  • Hematocrit and blood viscosity
  • Pressure

81

Defined as a measure of blood flow through a vessel for a given pressure

Conductance

82

T/F: Conductance is sensitive to diameter changes

True

83

T/F: Flow through a vessel changes to the 3rd power of the diameter

False

84

How does flow change when the radius increases?

Flow increases

85

How does flow change when the viscosity of the blood increases?

Flow decreases

86

How does flow change when the length of a vessel increases?

Flow decreases

87

An adaptive mechanism used by tissues in our body to maintain constant perfusion despite fluctuations in arterial P

Blood flow autoregulation

88

At what pressure does autoregulation occur?

b/w 70 - 175 mm Hg

89

List acute theories of autoregulation

  • Metabolic theory
    • Vasodilator theory
    • Oxygen lack theory
  • Myogenic theory

90

List long-term theories of autoregulation

Angiogenesis

91

Defined as the greater the rate of metabolism or the lower the availability of oxygen/nutrients, the greater to formation of vasodilators by tissues

Vasodilator theory

92

Defined as vascular smooth muscle vasodilating metarterioles and precapillary sphincters due to absence of oxygen or other nutrients

Oxygen lack theory

93

Defined as an increase in intraluminal P stimulates vasoconstriction of the small arteries and arterioles

Myogenic response / Bayliss effect

94

T/F: The myogenic response is caused by smooth muscle cells in the tunica media, and is not related to metabolism.

True

95

T/F: The myogenic response controls venule diameter and vascular resistance

False

96

T/F: The myogenic response maintains constant blood flow to the tissues and pathological alterations of myogenic tone is seen in HTN, stroke, and diabetes

True

97

Shear stress/ACh/Bradykinin will stimulate the following to act on the endothelium and cause vasodilation

  • NO
  • PGI2
  • EDHF

98

Endothelial injury/Ang-II will produce the following to cause vasoconstriction

  • ET-1
  • PGH2 / TXA2
  • Superoxide