Physiology of Vessels Flashcards

1
Q

The regulation of blood pressure must change in response to ______.

A

cellular activity

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2
Q

a collection of mechanisms that influence the active and changing circulation of blood

A

hemodynamics

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3
Q

Circulation control mechanisms must accomplish two functions:

A
  • maintain circulation

- vary the volume and distribution of the blood circulated

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4
Q

_____ is the only means by which cells can receive materials necessary for survival and have wastes removed.

A

circulation

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5
Q

Primary Principle of Circulation: Blood flows because a ________ exists between different parts of its volume; this is based on Newton’s first and second laws of motion.

A

pressure gradient

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6
Q

the symbol used to represent a pressure gradient. ___ represents the higher pressure and ___ represents the lower pressure.

A

P1-P2

  • P1
  • P2
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7
Q

A _____ gradient is needed to maintain blood flow through a local tissue

A

perfusion pressure (PP) gradient

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8
Q

A blood pressure gradient drives blood flow from the ______ to the _____.

A

right ventricle to the left atrium

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9
Q

fluid always travels from high pressure to low pressure. This is called

A

pressure gradient

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10
Q

The primary determinant of arterial blood pressure is the ____ of blood in the arteries

A

volume

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11
Q

A ____ relationship exists between arterial blood pressure and arterial blood volume

A

direct

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12
Q

volume of blood pumped out of the heart per unit of time.

A

cardiac output (CO)

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13
Q

the amount the cardiac output can increase above the resting cardiac output

A

cardiac reserve

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14
Q

Within limits, the longer or more stretched the heart fibers are at the beginning of contraction, the stronger the contraction.

The amount of blood in the heart at the end of diastole determines the amount of stretch or preload placed on the heart fibers

A

Starling’s Law of the heart

Frank-Starling mechanism

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15
Q

factors that affect strength of myocardial contraction and therefore stroke volume

A

inotropic factors

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16
Q

one mechanical factor that helps determine stroke volume:

A

myocardial fibers at the beginning of ventricular contraction.

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17
Q

Contractility can also be influenced by chemical factors:

A
  • neural: norepinephrine
  • endocrine: epinephrine
  • triggered by stress, exercise
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18
Q

ratio of stroke volume to end-diastolic volume

A

ejection fraction

usually expressed as a percentage

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19
Q

In a healthy adult, the ejection fraction is at least __%

A

55%

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20
Q

the pumping work the heart must do to push blood into the arteries

A

afterload

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21
Q

the harder it is to push blood out of the ventricles, the lower the _____.

A

stroke volume.

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22
Q

Abnormally high afterload from flow resistance in the arteries can cause _____.

A

heart failure

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23
Q

_______ and _______ are located in the aorta and carotid sinus.

They affect the autonomic cardiac control center in the Medulla, and therefore parasympathetic and sympathetic outflow, to aid in control of blood pressure.

A

Cardiac pressoreflexes:

aortic baroreceptors and carotid baroreceptors

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24
Q

factors that change the rate of the heartbeat

A

chronotropic factors

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25
Q

_________ reflex:

  • located at the beginning of the internal carotid artery
  • sensory fibers from carotid sinus baroreceptors run through the carotid sinus nerve and the glossopharyngeal nerve to the cardiac control center
  • parasympathetic impulses leave the cardiac control center and travel through the vagus nerve to reach the SA node
A

carotid sinus reflex

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26
Q

_____ reflex:

  • sensory fibers extend from baroreceptors in the wall of the aortic arch through the aortic nerve and through the vagus nerve to terminate in the cardiac control center
  • stimulation causes the cardiac control center to increase vagal inhibition, thus slowing the heart
A

aortic reflex

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27
Q

______ produce changes in the heart rate through the influence of impulses from the cerebrum by way of the hypothalamus

A

emotions

28
Q

other reflexes that influence heart rate (4):

A
  • emotions
  • exercise
  • increased blood temperature or stimulation of skin heat receptors
  • decreased blood temperature or stimulation of skin cold receptors
29
Q

resistance to blood flow imposed by the force of friction between blood and the walls of its vessels

A

peripheral resistance

30
Q

factors that influence peripheral resistance:

A
  • blood viscosity

- diameter of arterioles

31
Q

blood viscosity is determined mainly by the proportion of ______, but also partly by the number of ______.

A

red blood cells (hematocrit),

protein molecules

32
Q

arterial blood pressure tends to vary directly with ____.

A

peripheral resistance

33
Q

_____ is caused by viscosity and small diameter of arterioles and capillaries

A

friction

34
Q

_____ have a muscular coat that allows them to constrict or dilate and change the amount of resistance to blood flow

A

arterioles

35
Q

controls changes in the diameter of arterioles; it plays a role in maintenance of the general blood pressure and in distribution of blood to areas of special need

A

vasomotor control mechanism

36
Q

controls changes in the diameter of arterioles; it plays a role in maintenance of the general blood pressure and in distribution of blood to areas of special need

A

vasomotor control mechanism

see slide 24 for more info

37
Q

local mechanism produce vasodilation in localized areas

A

hyperemia

38
Q

amount of blood returned to the heart by veins

A

venous return

39
Q

____ occurs when a change in blood pressure causes a change in vessel diameter (because of elasticity) that accommodates the new pressure and thereby keeps blood flowing

A

the stress-relaxation effect

40
Q

the pull of gravity on venous blood while sitting or standing tends to cause a decrease in venous return

A

orthostatic effect

41
Q

facilitate venous return by increasing the pressure gradient between the peripheral veins and the venae cavae

A

venous pumps

42
Q

facilitate venous return by increasing the pressure gradient between the peripheral veins and the venae cavae

A

venous pumps:

  • respirations
  • skeletal muscle contractions
43
Q

inspiration increases the pressure gradient between peripheral and central veins by decreasing central venous pressure and also by increasing peripheral venous pressure

A

respirations

44
Q

promote venous return by squeezing veins through a contracting muscle and milking the blood toward the heart

A

skeletal muscle contractions

45
Q

changes in ________ change the amount of blood returned to the heart

A

total blood volume

46
Q

The _____ the total volume of blood, the greater the volume of blood returned to the heart

A

greater

47
Q

the mechanisms that change total blood volume most quick;y, making them most useful in maintaining constancy of blood flow, are:

A

those that cause water to move quickly:

  • into plasma
  • out of the plasma
48
Q

the ______ system recovers the fluid not recovered by the capillary and returns it to the venous blood before it is returned to the heart

A

lymphatic

49
Q

reduces amount of water lost by the body by increasing the amount of water the kidneys reabsorb from urine before the urine is excreted from the body

this mechanism is triggered by input from baroreceptors and osmoreceptors

A

the anti-diuretic hormone (ADH) mechanism

50
Q

renin is released when blood pressure in the kidneys is low

  • leads to increased secretion of aldosterone which simulates retention of sodium
  • angiotensin II is an intermediate compund that causes vasoconsriction

this complements volume-increasing effects of renin and promotes an increase in overall blood flow

A

Renin-Angiotensin-Aldosterone System (RAAS)

51
Q

adjusts venous return from an abnormally high level by promoting the loss of water from plasma, thereby causing a decrease in blood volume

increase urine sodium loss

A

Atral-Natriuretic-Hormone (ANH) mechanism

52
Q

Arterial blood pressure is measured with the aid of a _______ and ______.

A

sphygmomanometer and stethoscope

53
Q

force of the blood pushing against artery walls as ventricles contract

A

systolic blood pressure

54
Q

force of the blood pushing against artery walls when ventricles are relaxed and during isovolumetric ventricular contraction

A

diastolic blood pressure

55
Q

difference between the systolic and diastolic blood pressures

A

pulse pressure

56
Q

average blood pressure in the arteries for the perfusion of tissues

A

mean arterial pressure (MAP)

57
Q

a mercury-filled pressure sensor used in clinical and research settings to measure the arterial blood pressure quickly and accurately

A

sphygmomanometer

58
Q

volume of blood circulating through the body per minute

A

minute volume of blood

59
Q

_____ Law:

minute volume = pressure gradient / resistance

the minute volume of blood is determined by the magnitude of the blood pressure gradient and peripheral resistance

A

Poiseulle’s Law

60
Q

______ mechanism:

reveals important information about the cardiovascular system, blood vessels, and circulation

expansion stores energy released during recoil, conserving energy generated by the heart and maintaining relatively constant blood flow

A

pulse mechanism

61
Q

each pulse starts with ventricular contraction and proceeds as a wave of expansion throughout the arteries

it gradually dissipates as it travels, disappearing in the capillaries

A

pulse wave

62
Q

the ____ can be felt where ever an artery lies near the surface and over a bone or other firm background

A

pulse

63
Q

detectable pulse exists only in large veins, most prominently near the heart; this pulse is not clinically important

A

venous pulse

64
Q

Where pulse can be felt (7)

A
  • radial artery: at the wrist
  • temporal artery: in front of the ear or on the outer side of the eye
  • common carotid: anterior edge of the SCM muscle
  • facial artery: lower margin of the lower jawbone
  • brachial artery: bend of the elbow, along inner margin of the biceps muscle
  • femoral artery: middle of groin
  • popliteal artery: behind the knee
65
Q

occurs when force exerted by the arterial blood vessel exceeds 140/90 mmHg

A

hypertension HTN

66
Q

lower than normal blood pressure. Acute or chronic.

A

hypotension