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Human physiology PT > chapter 18- Exam 3 > Flashcards

chapter 18- Exam 3 Flashcards

1
Q

how do the nerves regulate the circulation

A
  • Redistribution of blood flow
  • Increasing pumping activity of the heart
  • Rapid control of arterial pressure
  • Regulates via the autonomic nervous system
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2
Q

what is apart of the autonomic nervous system

A

Sympathetic nervous system

Parasympathetic nervous system

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3
Q

what does the Sympathetic nervous system control in circulation

A

is important in control of circulation

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4
Q

what does the Parasympathetic nervous system control in circulation

A

is important in regulating heart function

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5
Q

what is the Parasympathetic nervous system main control in circulation

A

mainly controls heart rate via the vagus nerve

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6
Q

what does the Sympathetic nervous system innervate

A

Innervate Most vessels

  • small arteries,
  • arterioles,
  • large veins
  • heart
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7
Q

what doesNT the Sympathetic nervous system innervate

A

Do Not Innervate

  • capillaries
  • Precapillary sphincters
  • some metarterioles
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8
Q

what does the Sympathetic nervous system do for the circulation

A

Increase vascular resistance

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9
Q

where are the sympathetic vasoconstrictor systems located

A

Vasoconstrictor fibers are distributed throughout all segments of the circulation

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10
Q

where is the sympathetic vasoconstrictor systems in the MOST

A

Distribution is greater in kidneys, gut, spleen, and skin

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11
Q

where is the sympathetic vasoconstrictor systems in the LEAST

A

Less potent in coronary circulation and the brain

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12
Q

what equals arterial pressure

A

Q x total peripheral resistance

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13
Q

what can increase arterial pressure

A

=constricting arterioles
=constricting veins
=directly increasing Q

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14
Q

what does constricting arterioles do for increasing arterial pressure

A

which increases total peripheral resistance

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15
Q

what does constricting veins do for increasing arterial pressure

A

(mostly veins, but some other large vessels) increasing venous return and cardiac output

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16
Q

what does directly increasing Q do for increasing arterial pressure

A

by increasing heart rate and contractility

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17
Q

what does the vasomotor center do

A

VMC transmits impulses downward through the cord to almost all blood vessels

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18
Q

where is the VMC located

A

is located bilaterally in the reticular substance of the medulla and the lower third of the pons

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19
Q

what is the VMC composed of

A
  • vasoconstrictor area
  • vasodilator area, and
  • sensory area
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20
Q

what does the vasoconstrictor area of the VMC do

A

Transmits signals continuously to sympathetic nerve fibers → sympathetic vasoconstrictor tone

***This maintains partial state of contraction in blood vessels called vasomotor tone

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21
Q

Look at slide

A

9 there is a flow chart

22
Q

how does the nervous system increase the arterial pressure

A

via the VMC

23
Q

how does the VMC increase arterial pressure in seconds

A
  • constricting arterioles
  • constricting veins
  • directly increases Q
24
Q

when can rapid increase in arterial pressure occur

A

during exercise or with a fright

25
Q

look at slide

A

10 there is a flow chart at the bottom

26
Q

when is the arterial baroreceptor reflex important

A

in short term regulation of arterial pressure

27
Q

how is the baroreceptor reflex initiated

A

Reflex is initiated by stretch receptors called baroreceptors or pressoreceptors located in the walls of the large systemic arteries

28
Q

what does the rise in pressure in the arterial do

A

A rise in pressure stretches baroreceptors and causes them to transmit signals to the VMC and feedback signals are sent via the automonic nervous system to the circulation to reduce AP back to normal

29
Q

where are the Baroreceptors located

A

Baroreceptors are located in the walls of the carotid bifurcation called the carotid sinus and in the walls of the aortic arch

30
Q

how are signals form the carotid sinus transmitted

A

Signals from the carotid sinus are transmitted by the Hering’s nerve to the glossopharyngeal nerves and then to the nucleus tractus solitarius (NTS) of the medulla

31
Q

how are the signals from the arch of the aorta transmitted

A

Signals from the arch of the aorta are transmitted through the vagus into the NTS

32
Q

when do the carotid sinus receptors respond

A

baroreceptors respond to pressures between 60 and 180 mmHg

33
Q

what do the Baroreceptors respond to

A

respond to changes in arterial pressure

34
Q

when are the Baroreceptors the most sensitive

A

is most sensitive at a pressure of 100mmHg

35
Q

what happens when a pressure increases and the number of impulses from the carotid sinus increase

A

1) Inhibition of the vasoconstrictor

2) Activation of the vagal center

36
Q

what are the fx of the Baroreceptors

A

**Maintains relatively constant pressure despite changes in body posture

**Opposes either increases or decreases in arterial pressure thereby reducing daily variations in arterial pressure

**They are unimportant in long term control of arterial pressure because the baroreceptors adapt

37
Q

Look at slides

A

14, 15

38
Q

what are chemoreceptors

A

Chemoreceptors are chemosensitive cells sensitive to oxygen lack, CO2 excess, or H ion excess

39
Q

where are chemoreceptors located

A

are located in carotid bodies near the carotid bifurcation and on the arch of the aorta

40
Q

what does the activation of chemosensitive receptors result in

A

in excitation of the vasomotor center

41
Q

when are chemoreceptors stimulated

A

they will not stimulated until pressure falls below 80mmHg

– look at slide 16 at pic and chart

42
Q

when is the CNS ischemic response activated

A

in response to cerebral ischemia

43
Q

what happens when there is reduced cerebral blood flow

A

causes CO2 buildup which stimulates vasomotor center thereby increasing arterial pressure

44
Q

what is the most powerful activators of the sympathetic vasoconstrictor system

A

CNS Ischemic response

–look at slide 17 at the pic and the flow chart at the bottom

45
Q

when will the CNS ischemic response be activated

A

CNS Ischemic response is not activated until pressure falls below 60mmHg; Greatest activation occurs at pressures of 15-20mmHg

46
Q

what is a special type of CNS ischemic response

A

cushing reaction

47
Q

what effect does a prolonged CNS ischemia response have

A

Prolonged CNS ischemia has a depressant effect on the vasomotor center

48
Q

what do the low pressure receptor in the atria and the pulmonary arteries do

A

minimize arterial pressure changes in response to changes in blood volume

49
Q

what activates the low pressure receptors

A

Increases in blood volume activates low pressure receptors which in turn lower arterial pressure

50
Q

what does the activation of the low pressure receptors enhances

A

Na and water

51
Q

how does the activation fo the low pressure receptors enhances NA and water

A
  • Decreasing rate of antidiuretic hormone
  • Increasing glomerular filtration rate
  • Decreasing Na reabsorption

Human physiology PT (12 decks)

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