Lecture 8 Unit 1 Flashcards

1
Q

What are the levels of control of blood pressure and blood flow?

A
  • neural control
  • hormonal control
  • local control
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2
Q

what makes up neural control?

A

cardiovascular reflexes

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3
Q

what makes up hormonal control?

A
  • catecholaminies, ADH, angiotensin II, and aldosterone
  • ANP
  • histamine
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4
Q

where is the main center for neural control?

A

cardiac centers of the medulla oblongata

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5
Q

what happens in the CV center?

A

it includes a collection of gray matter regions (nuclei) : 2 cardiac centers and the vasomotor center

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6
Q

what does the CV center help regulate

A

HR, SV and the blood vessel diameter

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7
Q

what higher brain centers does the CV center receive input from?

A

the cerebral cortex, the limbic system, and the hypothalamus

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8
Q

what peripheral afferent nerve fibers does the CV center receive input from?

A

baroreceptors, chemoreceptors, and proprioceptors

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9
Q

what are the 3 major functional regions in the CV center?

A
  1. cardioacceleratory center
  2. cardioinhibitory center
  3. vasomotor center
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10
Q

what is the cardioacceleratory center?

A

a collection of sympathetic neurons that increase heart rate and contractility

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11
Q

what is in the cardioinhibitory center?

A

collection of parasympathetic neurons that decrease heart rate

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12
Q

what is in the vasomotor center?

A

a collection of vasomotor neurons that regulate blood vessel diameter via sympathetic nerves that synapse on arteriolar smooth muscle and cause vasoconstriction

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13
Q

cardiovascular reflexes are produced by afferent signaling of what?

A
  1. baroreceptors
  2. chemoreceptors
  3. proprioceptors
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14
Q

what are the most important receptors in cardiovascular regulation?

A

baroreceptors and chemoreceptors

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15
Q

where are high pressure baroreceptors located?

A

in the carotid sinus and aortic arch

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16
Q

how do baroreceptors enter the CV center/

A

via cranial nerves IX and X

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17
Q

where are low pressure baroreceptors located and how do they enter the CV center?

A

located in the walls of the right atrium and vena cavae and enter via cranial nerve X

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18
Q

what is a baroreceptor?

A

initiated reflex in response to decreasing blood pressure

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19
Q

where are chemoreceptors located?

A

in the carotid sinus and in the walls of the ascending aorta

20
Q

how do chemoreceptors in the carotid sinus signal the medulla

A

via cranial nerve IX

21
Q

how do chemoreceptors in the aortic bodies signal the medulla?

A

va cranial nerve X

22
Q

what do chemoreceptors respond to?

A

increased hydrogen ion content, increased CO2 and most strongly to hypoxia

23
Q

what do Chemoreceptors do?

A

activate the sympathetic division leading to increased HR, SV and vasoconstriction

24
Q

what are catecholamines?

A

(NE and epinephrine) circulate and bind directly to cardiac muscle fibers and to blood vessel smooth muscle cells

25
Q

what is the effect of catecholamines?

A

increase in HR and Sv and contraction of veins and arterioles

26
Q

what does antidiuretic hormone cause?

A

an increase in vasoconstriction in cases of extremely low BP

27
Q

what does angiotensin II cause?

A

intense vasoconstriction when renal perfusion is inadequate

28
Q

what does aldosterone cause?

A

water retention and increases blood volume

29
Q

what is ADH produced by?

A

the hypothalamus

30
Q

what is ADH released from?

A

the posterior pituitary when blood loss is severest and blood pressure is reduced

31
Q

what does ADH cause?

A

widespread vasoconstriction

32
Q

what is one of the most powerful vasoconstrictor substances known?

A

angiotensin II

33
Q

what does angiotensin II do?

A

acts on all arterioles simultaneously when it is released into the blood

34
Q

what is the result of angiotensin II?

A

an increase in vascular resistance when blood pressure is too low

35
Q

what hormone is released in response to low blood pressure?

A

renin by the kidney

36
Q

what happens in the RAA system?

A

angiotensin converts renin into angiotensin I, and the lungs covert angiotensin I into angiotensin II by angiotensin converting enzyme (ACE)

37
Q

where is ACE located?

A

in the endothelial cells of the lung

38
Q

what happens when AT II levels are increased?

A

aldosterone is secreted by the adrenal cortex

39
Q

what happens when aldosterone is secreted?

A

salt and water reabsorption is also increased in an effort to raise blood pressure by raising blood volume

40
Q

when is atrial natriuretic peptide (ANP) released and by what?

A

released by cells of the atria when blood pressure is high

41
Q

what is the result of atrial natriuretic peptide (ANP)?

A

vasodilation and promotes the loss of water and salt by the kidneys which reduces blood volume and vasoconstriction which lowers BP

42
Q

what is histamine released by?

A

mast cells

43
Q

what does histamine cause?

A

vasodilation by relaxing blood vessel smooth muscle.

44
Q

what is histamine important in?

A

increasing the rate of blood flow to inflamed or damaged tissue

45
Q

what is neural regulation?

A

refers to changes in flow due to vasoconstriction

46
Q

what is humoral flow control/

A

refers to changes in vessel diameter due to circulating hormones but major regulatory factor is tissue metabolic activity

47
Q

what is metabolic or local regulation?

A

blood vessel dilation due to substances that are released by tissue cells