VASCULAR SYSTEM Flashcards

1
Q

Components of the vasculature:

A

Arteries
Arterioles
Capillaries
Venules
Veins

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2
Q

______
• Thick walled, extensive elastic tissue & smooth muscle

A

Arteries

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3
Q

______
• High pressure

A

Arteries

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4
Q

Arteries
• The blood volume contained in them are called the ______

A

stressed volume

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5
Q

______
• Smallest branches of the arteries

A

Arterioles

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6
Q

______
• Site of highest resistance in the cardiovascular system

A

Arterioles

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7
Q

______
• Have smooth muscle walls which have extensive autonomic innervation

A

Arterioles

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8
Q

Arterioles
• ______ - in the skin and splanchnic arterioles

A

a1 adrenergic

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9
Q

Arterioles
• ______ - in the skeletal muscle arterioles

A

B2 adrenergic

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10
Q

______
• Have the largest cross sectional surface area

A

Capillaries

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11
Q

______
• Consist of a single layer of cells - thin walled

A

Capillaries

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12
Q

______
• Are the site of exchange of nutrients, water & gases

A

Capillaries

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13
Q

______
• Are formed from merged capillaries

A

Venules

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14
Q

______
• Progressively form larger and larger veins

A

Veins

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15
Q

______
• thin walled and are under low pressure

A

Veins

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16
Q

______
• Contains the highest proportion of blood in the cardiovascular system

A

Veins

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17
Q

Veins
• Blood volume in the veins is called the ______

A

unstressed volume

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18
Q

Veins
• Are innervated by ______

A

autonomic fibres

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19
Q

______ - greatest cross-sectional area

A

Capillaries

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20
Q

______ - Pressure varies bet. systole and diastole

A

Arteries

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21
Q

Velocity of blood flow
• Can be expressed by:
V = ______

A

Q/A

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22
Q

Velocity of blood flow

v = ______ (______)
Q = ______ (______)
A = ______ (______)

A

velocity, cm/sec
blood flow, ml/min
cross sectional area, cm^2

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23
Q

Velocity of blood flow

Therefore, velocity is higher in the ______ (smaller cross sectional area)
is lower in all the ______ - Why?

To maximize the ______

A

aorta, capillaries, exchange of substances

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24
Q

Blood flow
• Can be expressed by:
Q = ______

A

🔺P / R

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25
Q

Blood flow

Q = ______ (______)
🔺P = ______ (______)
R = ______

A

blood flow, ml/min
pressure gradient, mmHg
resistance

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26
Q

______ flow is in a straight line and ______ flow is not.

A

Laminar, turbulent

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27
Q

______ predicts whether blood flow is turbulent or laminar.

A

Reynold’s number

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28
Q

When Reynold’s number is increased, there will be ______ and ______ (bruits)

A

turbulence, audible vibrations

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29
Q

Reynold’s number is increased by:
______ (low haematocrit, anaemia)
______ (narrowing of a vessel)

A

reduced viscosity
increased velocity

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30
Q

______ (______)
• Describes the distensibility of blood vessels

A

Capacitance, compliance

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31
Q

______ (______)
• Is inversely related to elastance

A

Capacitance, compliance

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32
Q

Capacitance (compliance)

Capacitance is given by:
C = ______

A

V / P

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33
Q

Capacitance

C = ______ (______)
V = ______ (______)
P = ______ (______)

A

capacitance, ml/mmHg
volume, ml
pressure, mmHg

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34
Q

______ (______)
• Describes how volume changes in response to changes in pressure

A

Capacitance, compliance

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35
Q

Capacitance is much greater for ______ than for ______

A

veins, arteries

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36
Q

Changes in venous capacitance changes the ______

A

venous blood volume

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37
Q

decrease in venous capacitance decreases the ______ (______) and increases the ______ (______)

A

unstressed volume, venous volume, stressed volume, arterial volume

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38
Q

Capacitance of arteries ______ with age.
Arteries become stiffer and less distensible)

A

decreases

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39
Q

______
• pulsatile
• Varies during the cardiac cycle
• Systolic pressure
• Diastolic pressure

A

Arterial pressure

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40
Q

Pulse Pressure

______
• most important determinant of pulse pressure

A

Stroke volume

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41
Q

Pulse Pressure
• decrease in ______ due to aging can cause an increase of pulse pressure

A

capacitance

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42
Q

Pulse Pressure
• Generally ______ mmHg

A

~ 40

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43
Q

______
• average arterial pressure with respect to time

A

Mean Arterial Pressure

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44
Q

Mean Arterial Pressure
• ______ + ______ pulse pressure

A

DBP, 1/3

45
Q

______
• very low
• has a high capacitance
• able to hold a large volume without an increase in pressure

A

Venous pressure

46
Q

Regulation of arterial blood pressure
Most important mechanisms are:
• the fast ______ mediated ______
• the slower ______ mediated ______

A

neurally, baroreceptor mechanism
hormonally, renal mechanisms

47
Q

Regulation of arterial blood pressure
Other mechanisms:

A

Atrial stretch receptors
Local vasoconstrictors and dilators

48
Q

pressure receptors (______) that monitor arterial pressure are present in the:
• ______
• ______

A

baroreceptors, carotid sinus, aortic arch

49
Q

low-pressure receptors (______)
• walls of ______ at vena caval entrance
• wall of ______ (pulmonary circulation)

A

cardiopulmonary receptors, right atria, left atria

50
Q

• Increase baroreceptor discharge
- ______ the tonic discharge of sympathetic nerves

A

inhibits

51
Q

• Increase baroreceptor discharge
- ______ the vagal innervation of the heart

A

excites

52
Q

Baroreceptor reflex

These neural changes produce:

A

• Vasodilation
• Venodilation
• Hypotension
• Bradycardia
• Decrease in cardiac output

53
Q

Cardiopulmonary receptors

two types of stretch receptors in the atria:
• those discharging in ______
• those discharging in ______ during atrial filling

A

atrial systole, late diastole

54
Q

Cardiopulmonary receptors

Effects of increase discharge:

A

• vasodilatation & a fall in BP
• increase in heart rate

55
Q

Renin
- hormone/enzyme
- synthesized as ______

A

prorenin

56
Q

Renin
- ______ form

A

active

57
Q

Renin
- secreted from the ______ of the ______ as renin or prorenin

A

JG cells, kidney

58
Q

Renin
- produced exclusively by the ______

A

kidney

59
Q

Renin
- only know function is to ______ and ______

A

cleave angiotensinogen, form angiotensin-l

60
Q

Juxtaglomerular apparatus
- Comprise of ______, ______ and ______

A

JG cells, Lacis cells, Macula densa

61
Q

Renin is produced by ______ - located in the media of ______

A

JG cells, afferent arterioles

62
Q

Renin is also found in ______ that are located in the junction between the afferent & efferent arterioles

A

lacis cells

63
Q

______ - modified efferent arteriolar cells in close proximity to JG cells

A

Macula densa

64
Q

Factors that affect renin secretion.

Stimulatory:

A

Increased sympathetic activity via renal nerves
Increased circulating catecholamines
Prostaglandins

65
Q

Factors that affect renin secretion.

Inhibitory:

A

Increased Na+ and Cl- absorption across macula densa
Increased afferent arteriolar pressure
Angiotensin lI
Vasopressin

66
Q

______
- Alpha-2 globulin; released by the liver

A

Angiotensinogen

67
Q

______
- increase by: glucocorticoids, thyroid hormones, estrogens, several cytokines and angiotensin II.

A

Angiotensinogen

68
Q

______ is formed by endothelial cells and happens in many parts of the body
• conversion of ______ (lungs)
• inactivates ______

A

Angiotensin Converting Enzyme (ACE), Angiotensin I, bradykinin

69
Q

______
• very short half life of 1-2 min
• active substance

A

Angiotensin-ll

70
Q

Actions of Angiotensin Il

______
- acts on AT1, receptors
- constricts arterioles and elevate SBP & DBP

A

Potent vasoconstrictor

71
Q

Actions of Angiotensin Il

Directly acts on adrenal cortex to ______

A

increase aldosterone secretion

72
Q

Actions of Angiotensin Il

Facilitates the ______ from sympathetic postganglionic neurons

A

release of NE

73
Q

Actions of Angiotensin II

Contraction of ______ with a decrease in GFR

A

mesangial cells

74
Q

Actions of Angiotensin II

Has a direct effect on the renal tubules to increase
______.

A

Na+ reabsorption

75
Q

Actions of Angiotensin II

Acts on the brain to reduce the sensitivity of ______

A

Baroreceptor reflex

76
Q

Actions of Angiotensin II

Increase ______

A

thirst

77
Q

Actions of Angiotensin II

Increase ______ and ______ secretion

A

ADH, ACTH

78
Q

Hormones of the heart & other natriuretic factors

______
• Secreted from the muscle cells in the atria and, to a much lesser extent in the ventricles

A

ANP

79
Q

Hormones of the heart & other natriuretic factors

______
• Contain secretory granules
• increase in number when ECF expands due to increased Na+ in the body

A

ANP

80
Q

Hormones of the heart & other natriuretic factors

• ______ - Brain and heart

A

BNP

81
Q

Hormones of the heart & other natriuretic factors

• ______ - brain, pituitary, kidneys, and vascular endothelial cells (acts in a paracrine fashion)
- promotes natriuresis

A

CNP

82
Q

Hormones of the heart & other natriuretic factors ANP

Actions:
- Increase GFR by dilating ______ & relaxing ______

A

afferent arteriole, mesangial cells

83
Q

Hormones of the heart & other natriuretic factors ANP

Actions:
- Acts on the renal tubule to inhibit ______

A

Na+ reabsorption

84
Q

Hormones of the heart & other natriuretic factors ANP

Actions:
- Increases in ______, leading to extravasation of fluid and a decline in blood pressure.

A

capillary permeability

85
Q

Hormones of the heart & other natriuretic factors ANP

Actions:
- Relax vascular smooth muscle in ______ and ______.
(______) has a greater dilator effect on veins

A

arterioles, venules, CNP

86
Q

Hormones of the heart & other natriuretic factors ANP

Actions:
- Inhibit ______ secretion

A

renin

87
Q

Hormones of the heart & other natriuretic factors ANP

Actions:
- Counteract the pressor effects of ______

A

catecholamines

88
Q

Peripheral chemoreceptor reflex
• Peripheral chemoreceptors found in the ______ & ______ Bodies

A

Aortic, Carotid

89
Q

Peripheral chemoreceptor reflex

Peripheral chemoreceptors
• Have a very high ______

A

blood flow

90
Q

Peripheral chemoreceptor reflex

Peripheral chemoreceptors
• Activated by: low ______, ______ and ______

A

PaO2, PCO2, pH

91
Q

Peripheral chemoreceptor reflex

Peripheral chemoreceptors
• Stimulated by ______

A

hypoxic hypoxia

92
Q

Peripheral chemoreceptor reflex

Peripheral chemoreceptors
• Main effects are on ______, but also leads to ______

A

respiration, vasoconstriction

93
Q

Peripheral chemoreceptor reflex

Peripheral chemoreceptors
Direct effects of chemoreceptor activation:
• ______
• Increased ______ from adrenal medulla (increases HR and BP)

A

Hypoxia, catecholamines

94
Q

Central chemoreceptors

When intracranial pressure increases, the pressure on the Vasomotor Center along with ______ and ______ increases its discharge.
• rise of systemic ______
• reflex reduction in ______ (through baroreceptor reflex)

A

local hypoxia, hypercapnia, blood pressure, heart rate

95
Q

Central chemoreceptors

Therefore, increased ICP manifests as ______ and ______

A

hypertension, bradycardia

96
Q

______
• The capacity of tissues to regulate their own blood flow

A

Autoregulation

97
Q

Autoregulation
• Most vascular beds have an ______ to compensate for moderate changes in perfusion pressure so that blood flow remains relatively ______.

A

intrinsic capacity, constant

98
Q

Autoregulation
• mainly ______ as well as mesentery, skeletal muscle, brain, liver, myocardium.

A

kidney

99
Q

Autoregulation

Two theories for this:
• ______
- Constant blood flow at varying arterial pressure
• ______
- Vasodilator metabolites are produced as perfusion pressure is reduced

A

Myogenic autoregulation
Metabolic theory of autoregulation

100
Q

______
- Causes arteriolar dilatation & venous constriction

A

Histamine

101
Q

______
- Resulting in local edema

A

Histamine

102
Q

______
- Released in response to tissue trauma

A

Histamine

103
Q

______
- Exactly like histamine

A

Bradykinin

104
Q

______
- Causes arteriolar constriction

A

Serotonin

105
Q

______
- Released in response to vessel damage to prevent blood loss

A

Serotonin

106
Q

Prostaglandins
- ______ is a vasodilator in several vascular beds

A

Prostacyclin

107
Q

Prostaglandins
- ______ are vasodilators

A

E-series prostaglandins

108
Q

Prostaglandins
- ______ are vasoconstrictors

A

F-series prostaglandins

109
Q

Prostaglandins
- ______ is a vasoconstrictor

A

Thromboxane A2