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OLD "MBS 603" > Vodcasts > Flashcards

Vodcasts Flashcards

1
Q

What are intercalated disks?

A

connects branched cardiac muscle fibers

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2
Q

What is the benefit of intercalated disks in cardiac muscles?

A

improves conduction of electrical pulses

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3
Q

What is the biggest difference between cardiac and skeletal muscles?

A

cardiac are branched

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4
Q

Are cardiac muscles smaller or larger than skeletal muscles?

A

smaller

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5
Q

Are cardiac muscles mono or multinucleated?

A

mononucleated

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6
Q

Do cardiac muscles or skeletal muscles have NO motor units?

A

cardiac

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7
Q

What are demosomes?

A

connections between muscle cells that aid in contraction

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8
Q

what are gap junctions?

A

allows for ion flow in muscles (spread of action potential)

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9
Q

Cardiac muscles contain sacroplasmic reticulum just like skeletal muscles, but hold more/less Ca2+

A

less Ca2+

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10
Q

Why is it important cardiac muscles have less Ca2+ in the sarcoplasmic reticulum?

A

strength of contraction depends on influx of Ca2+

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11
Q

What is a consequence of cardiac muscles having to bring in Ca2+ from outside of cell for contracts (since it has less Ca in SR than skeletal muscles)?

A

longer depolarization phase

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12
Q

Do cardiac muscles have a longer or shorter refractory period than skeletal muscles? And why?

A

longer
prevents tetany

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13
Q

What is tetany?

A

sustained contraction of muscle

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14
Q

What makes the refractory period longer in cardiac muscles?

A

tension in muscle peaks during refractory period NOT during action potential to prevent tetany

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15
Q

Longer refractory period in cardiac muscles aids in contraction _________

A

delays

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16
Q

Where does the heart muscles get most of its energy?

A

fatty acid oxidation from mitochondria

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17
Q

What is the second place the heart muscles get thier energy from?

A

glucose

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18
Q

Is there a change in [ATP] in cardiac muscles?

A

NO
hydrolysis = synthesis

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19
Q

What are the 3 other system that are used to regulate blood pressure?

A
  1. RAS (Renin-Angiotensin system)
  2. chemoreceptors
  3. low pressure baroreceptors
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20
Q

What is RAS (Renin-Angiotensin system)?

A

regulates BP by regulating blood volume via the kidneys

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21
Q

What are the steps to RAS (Renin-Angiotensin system) regulating a drop in BP?

A
  1. drop in BP
  2. drop in blood level in kidneys
  3. renin (protease) is proiduced and cleaves AN (angiotensinogen) into AT I
  4. AT I circulates to lungs where its converted into AT II
  5. AT II causes release of aldosterone (steroid hormone)
  6. aldosterone increases Na2+ reabsorption whch increases H2O in ECF
  7. increased fluid volume
  8. increased BP
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22
Q

What is the protease in the RAS (Renin-Angiotensin system)?

A

renin

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23
Q

What is released in the RAS (Renin-Angiotensin system) that causes increased Na2+ reabsorption to increase blood volume?

A

aldosterone

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24
Q

How does angiotensinogen II aid in resitance?

A

vasoconstrictor = increased resistance

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25
Q

How does aldosterone work in the RAS?

A

enters kidney cells where receptor is located and enters nucleus to increase transcription of Na and K channels so Na and H2O can increase fluid volume

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26
Q

What in the RAS increases Na+ and H2O absorption?

A

aldosterone

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27
Q

What is the actual main role of chemoreceptors?

A

stimulate breathing

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28
Q

Where are chemoreceptors located?

A

carotid and aortic bodies

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29
Q

What specialized nerves do chemoreceptors have?

A

type I glomus cells

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30
Q

What do type I glomus cells do?

A

sensory receptors for O2, CO2 and pH

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31
Q

If arterial PO2 is low…
vasocontrstriction or vasodilation of gut, kidneys and muscles and why?

A

vasoconstriction to redirect oxygen in blood to brain/heart/lungs

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32
Q

What is ischemia?

A

cut off blood flow to brain

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33
Q

If brain becomes ischemic, chemoreceptors will cause increased/decreased resistance and why?

A

increased
redirects blood to brain

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34
Q

What do low pressure baroreceptors respond to?

A

stretch in right atria (low pressure side)
change in blood volume

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35
Q

What does low pressure baroreceptors release when right atrium stretches? What about right ventricle?

A

ANP
BNP

36
Q

If atrium stretches more than normal Na2+ and H2O is excreted or uptaken to bring BP back to normal?

A

excreted

37
Q

If atrium stretches more than normal blood volume increases/decreased to bring BP back to normal?

A

decreased

38
Q

When BP is low and its sensed by a regular baroreceptor, what is the affect on…
resistance –
HR –
stroke volume –
vasodilation/constriction

A

resistance – increases
HR – increases
stroke volume – increases
vasoconstriction

**sympathetic response

39
Q

When there is an increase in pressure at the atrial receptors, what is the affect on HR to get BP back to normal and why?

A

increase HR to increase CO so there is an increase in renal excretion of salt and H2O do decrease volume

40
Q

When BP is high and its sensed by a regular baroreceptor, what is the affect on…
resistance –
HR –
stroke volume –
vasodilation/constriction

A

resistance – decrease
HR – decrease
stroke volume – decrease
vasodilation

** parasympathetic response

41
Q

When pressure is high at the low pressure baroreceptors, is blood volume going to try and be reduced or increased?

A

reduced

42
Q

How does the low pressure baroreceptor decrease blood volume in regards to HR to decrease BP?

A

increase HR—> increase CO so there is an increase in renal excretion of salt and H2O in urine

43
Q

How does the low pressure baroreceptor affect pre-load to increase blood volume to increase BP?

A

increase pre-load
*sympathetic response

44
Q

What happens when you have orthostatic hypertension?

A

after standing up, upper body BP drops and body raises BP to compensate

45
Q

What physiological affects happen when you have orthostatic hypertension and you stand up?

A

(drop in BP so body is trying to raise BP)
vasoconstriction (to increase resistance)
increase stroke volume and HR (to increase CO)

46
Q

Why does the body think there is a sudden drop in BP when you stand up when you have orthostatic hypertension?

A

arterial pressure increases when laying down (since blood is not going to lower body) which tricks kidneys into thinking blood volume is higher than it actually is so when you stand up its seen as a sudden drop in pressure

47
Q

What is autoregulation?

A

ability of some tissues/capillaries to regulate their own blood flow

48
Q

What are 6 tissues that can autoregualte?

A

renal
cerebral
cornoary
skeletal
muscles
pulmonary

49
Q

What is active hyperemia?

A

response to physical activity that causes blood to flow to an organ/tissue to meet the increased need for oxygen and nutrients

50
Q

What is an example of active hyperemia?

A

working out; muscles are supplies with more O2 and blood

51
Q

During active hyperemia, what happens to…
arterioles dilate/constrict
resistance increases/decreases
blood flow increases/decreases

A

arterioles dilate
resistance decreases
blood flow increases

52
Q

What is reactive hyperemia?

A

temporary increase in blood flow to an organ after a brief period of ischemia, or when blood flow is temporarily restricted

53
Q

What is an example of reactive hyperemia?

A

wrapping rubber band around a finger

54
Q

In auto regulation, if more blood flow is needed locally the local arterioles will constrict/dilate and the resistance will increase/decrease?

A

local arterioles dilate
decreased resistance

55
Q

What are 4 local vasodilators?

A

increased CO2
decreased O2
increased H+
increased K+

56
Q

What is the most important local vasodilator?

A

CO2

57
Q

When O2 in the coronary circulation decreases, coronary dilates/constricts and CO2 rises/drops?

A

coronary dilates
CO2 rises

58
Q

In the coronary circulation, when vasodilation is not enough, ________ is released to cause local hyperemia?

A

adenosine

59
Q

Do vasoactivitors have an affect on cerebral circulation? Why or why not?

A

no effect
cannot cross BBB

60
Q

What 3 ways is heart rate controlled during exercise via neural control?

A
  1. proprioreceptors
  2. chemoreceptors
  3. baroreceptors
61
Q

Cardiovascular adjustments during exercise are regulated by a combination of _______ and _______ factors

A

neural
local

62
Q

How do proprioreceptors regulate HR during exercise?

A

pick up movement in muscles/joints and will signal to increase HR and stroke volume

63
Q

How do chemoreceptors regulate HR during exercise?

A

pick up on chances in pH (lactate) and will signal to increase HR and stroke volume

64
Q

During exercise, systemic vaso______ occurs except in the heart/lungs/muscles which is caused by local vaso________ overriding ___________ nervous system response

A

vasodilation
local vasodilators
sympathetic NS response

65
Q

Is the cerebral circulation ever affected by exercise?

A

no

66
Q

During exercise, skin has a biphasic response, why?

A

blood flow is initially restricted to the skin but as body temperature rises blood flow increases in skin so you can sweat

67
Q

During exercise, the total peripheral resistance increases/decreases?

A

decreases
(less resistance in muscles so overall resistance decreases)

68
Q

What is a local factor that happens during exercise?

A

active hyperemia (muscles)

69
Q

During exercise, neural control is basically turning on the _________ nervous system

A

sympathetic

70
Q

During exercise, local control is basically vasodilation/constriction of blood flow to muscles?

A

vasodilation

71
Q

what 2 arteries does the blood flow to the brain come from?

A

basilar
carotid

72
Q

The basilar and carotid artery merge in brain to for the…

A

circle of Willis

73
Q

What are 3 methods of cerebral auto-regulation of circualtion?

A
  1. myogenic autoreg
  2. metabolic autoreg
  3. neurogenic autoreg
74
Q

What is myogenic auto regulation of cerebral circulation?

A

arteries dilate/constrict based on changes in BP and inter-cranial pressure

75
Q

What is metabolic auto regulation of cerebral circulation?

A

response to changes in CO2, pH or O2 levels

76
Q

What is neurogenic auto regulation of cerebral circulation?

A

sympathetic NS will constrict large vessels to prevents high pressure reaching small vessels to prevent stroke

77
Q

If CO2 levels in the blood decrease…
vasodilation/constriction
increased/decreased cerebral blood flow
good/bad cerebral circulation

A

vasoconstriction
decreased cerebral blood flow
bad cerebral circulation
** this is what happens when you hyperventilate

78
Q

When pH is low..
vasodilation/constriction
increased/decreased cerebral blood flow

A

vasodilation
increased cerebral blood flow
** during exercise pH drops

79
Q

What can easily pass the blood brain barrier?

A

gases and lipid soluble molecules (steroids)

80
Q

What cannot pass blood brain barrier at all?

A

proteins, Ab, large molecules

81
Q

What can sometimes pass the blood brain barrier?

A

ions and glucose

82
Q

Is renin and aldosterone secreted when pressure are high or low?

A

low

83
Q

Where in renin secreted from?

A

juxtaglomerular cells of the kidney

84
Q

Renin is responsible for the increase/decrease of Na+ retention which leads to increase/decrease of blood volume thus increasing/decreasing blood pressure.

A

increasing Na+ retention
increase blood volume
increase BP

85
Q

Is renin and aldosterone secreted when blood volume are high or low?

A

low

86
Q

What enzyme cleaves angiotensin I into angiotensin II?

A

ACE

87
Q

Where is ACE located?

A

lungs

OLD "MBS 603" (22 decks)

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