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Physiology III - Freedman > Unit 2: Circulation Pt3 > Flashcards

Unit 2: Circulation Pt3 Flashcards

1
Q

What is the Vasomotor center? What are the four major regions?

A

collection of neurons in the medulla and pons

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2
Q

What are the four major regions of the Vasomotor Center?

A
  1. Pressor Center (“C1”)
  2. Depressor Center (“A1”)
  3. Sensory Area (“A2”)
  4. Cardioinhibitory area
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3
Q

What does the Pressor Center region of the Vasomotor Center do?

A

increases BP by stimulating SNS in mass

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4
Q

What does the Depressor Center of the Vasomotor Center do?

A

decrease BP by inhibiting SNS

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5
Q

What does the Sensory Area of the Vasomotor Center do?

A

mediates baroreceptor reflex by inhibiting SNS –> therefore inhibiting pressor center and lowering BP

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6
Q

What does the Cardioinhibitory Area of the Vasomotor Center do?

A

stimulates CN X (Vagus)

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7
Q

What does the Sensory Area of the Vasomotor Center primarily receive input from?

A

CN IX and X

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8
Q

A decrease in pressure with cause ___ in Barorectpor feedback, therefore causing ___ in SNS

A

decrease in feedback; therefore increase SNS

therefore an increase in P causes an increase in Baroreceptor feedback, and therefore a decrease in SNS

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9
Q

What does the short term control of BP involve?

A

NS effect on vascular smooth muscle –> SNS

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10
Q

What does the long term control of BP involve?

A

control is dominated by kidneys–> the Renal-Body fluid balance

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11
Q

What two things effect BP?

How is control of BP accomplished?

A 
blood volume (contents)
and
blood vessels (container)

affect vascular tone or blood volume

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12
Q

Where are baroreceptors abundent?

A
  • Carotid sinus (info to CN IX)

- Arch of Aorta (info to CN X)

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13
Q

Barorectpors are stimulated when stretched, what will this then inhibit in the Vasomotor center?

A

inhibits “Pressor Center” via CN IX and X and NTs

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14
Q

What are the Net Effects of Baroreceptors being stimulated?

A
  • vasodilation

- decreased cardiac output

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15
Q

T/F. Baroreceptors are more sensitive to static P than changing P.

A

False– they are more sensitive to changing pressure than static P

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16
Q

What is the Carotid sinus reflex?

A

When baroreceptors are stimulated and a quick change in pressure and could cause you to pass out

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17
Q

T/F. Baroreceptors lack long term control due to adaptation

A

True; they reset w/in 1-2 days

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18
Q

Where are Low Pressure baroreceptors located?

A
  • arterial walls and pulmonary arteries
  • augment arterial baroreceptors
  • minimize aterial pressure changes in response to blood volume changes
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19
Q

T/F. Blood volume changes mainly sensed on the low pressure side.

A

True

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20
Q

If there is stretch on the atrial wall and the heart rate decreases, what reflex is in dominant effect? What occurs?

A

Baroreceptor Reflex

  • decreases HR (inhibit SNS)
  • increasing urine production (decrease SNS in renal nerves and decreased secretion of ADH)
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21
Q

If there is stretch on the atrial wall and heart rate is increased, what is the dominant reflex?

A

Brainbridge reflex

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22
Q

Once there is stretch on the atrial wall, what will the release of Atrial Natriuretic Peptide (ANP) tell the body to do?

A
  • dirurectic (get ride of water)
  • natriuretic (get ride of Na+)
  • vasodilator
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23
Q

What will an increase in ECF have on arterial pressure? What occurs in response?

A

will cause arterial pressure to rise and in response the kidneys excrete excess ECF

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24
Q

What will shift for long term arterial pressure control?

A
  • shift the renal output curve for water and salt

- shift level of water and salt intake line

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25
Q

T/F. Increased total peripheral resistance will not create a long term elevation of BP if fluid intake and renal function do not change.

A

True

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26
Q

What type of arterioles supply the glomerular capillaries and what takes place here?

A

afferent arterioles supply the glomerular capillaries–where filtration takes place here

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27
Q

What type of arterioles drain the glomerular capillaries? What do these give rise to? What occurs here?

A

efferent arterioles drain the glomerular capillaries and give rise to peritubular capillaries–where reabsorption takes place

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28
Q

Where does filtration take place in the kidneys?

A

glomerular capillaries

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29
Q

Where does reabsorption take place in the kidneys?

A

peritubular capillaries

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30
Q

List in order the path through the kidneys starting with afferent arterioles.

A

Afferent arterioles—> glomerular capillaries (filtration takes place) –> efferent arterioles –> peritubular capillaries (reabsorption takes place)

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31
Q

What are specialized peritubular capillaries assoicted with juxtamedullary nephrons?

A

vasa recti

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32
Q

How does renal control of blood pressure work, as in when ECF levels rise?

A

the arterial pressure rises–> kidney excretes more fluid –> this brings pressure back to normal

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33
Q

What is the quickest mechanism for volume pressure control?

A

Baroreceptors

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34
Q

What is the better mechanism for volume pressure control, as in it has the most “gain”?

A

Renal Fluid Volume

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35
Q

How do we express the degree of effectiveness with which a control system (i.e. NS) maintains constancy of a controlled variable (i.e. BP)?

A

can be expressed as the “gain of a feedback system”

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36
Q

What is Gain equal to?

A

Gain = compensation / remaining error

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37
Q

The higher the gain the (more/less) effective the control system.*

A

more!!

Ex: Gain = 9; then 90/10

if Gain = 100/0; that equals infinity

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38
Q

For an acute renal output curve was is the effect?

A

effect of arterial pressure alone

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39
Q

For a chronic renal output curve, what is the effect?

A

effect of arterial pressure plus:

  • SNS stimulation
  • Renin-angiotensin system
  • Aldosterone
  • ADH
  • ANP** inhibit–makes diff than others
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40
Q

If we want to incrase arterial pressure, we will stimulate all of the following except:**

  • SNS
  • Renin-angiotensin system
  • Aldosterone
  • ADH
  • ANP
A

ANP will be inhibited in order to aid in promoting an increase in pressure

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41
Q

What three hormones will decrease renal blood flow (RBF)?

A
  • NE
  • Epinephrine
  • angiotensin II
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42
Q

What hormones will increase renal blood flow (RBF)?

A

prostaglandins (E and I)`

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43
Q

What monitors NaCl in the Macula densa of the distal tubule in the kidney?

A

Tubuloglomerular feedback

44
Q

If the Tubuloglomerular feedback detects a decrease in NaCl in Macula densa, what occurs?

A

stimulates renin release from JG (juxtaglomerular) cells
- increase in renin –> increases angiotensin II levels —> increase efferent arteriole resistance

also causes dilation of afferent arteriole

collectively increases filtration (GFR)

45
Q

Where is the primary source of renin?

A

smooth muscle cells in afferent arteriole (synthesis, storage, and release takes place here)

46
Q

What will stimulate renin to be released?

A
  • decrease perfusion pressure
  • stimulate SNS
  • decrease NaCl delivery to macula densa (distal tubule)–> Tubuloglomerular feedback
  • Hormonal stimulation (Thyroid hormone, GH)
47
Q

What is an ezyme that catalyses the formation of Angiotension I from angiotensinogen? Where does this occur?

A

Renin; in the liver

48
Q

Where does the conversion of angiotension I –> angioensin II occur?

A

primarily in lung via angiotensin converting enzyme ass. with pulmonary endothelium

49
Q

What are the functions of Angiotensin II?

A

Stimulate:

  • adrenal cortex to release aldosterone
  • release of ADH/vasopressin
  • kidney
  • thirst/drinking behavior at level of hypothalamus
50
Q

What is the net effect of the function of Angiotensin II?

A

decrease Na+ and H2O secretion and therefore increase BP

51
Q

Experimentally what occurs if:

  1. tie off one renal artery
  2. tie of one renal artery and remove kidney
  3. tie off and remove both kidneys
A
  1. develop systemic hypertension (increase in renin and angiotensin II); but NO development of uremia
  2. NO development of hypertension or uremia
  3. develop BOTH hypertension and uremia
52
Q

What will slow breathing (6/min) do to the arterial baroreflex?

A

increase the arterial baroreflex sensitivity

53
Q

What are some beneficial effects of slow breathing in Congestive Heart Failure patients?

A
  • increase resting oxygen saturation
  • improve ventilation/prefusion mismatching
  • improves exercise tolerance by decreasing sensation of dyspnea
  • decrease chemoreflex activation
  • decrease sympathetic activity
  • decrease SBP and DBP
54
Q

What effect does nitric oxide have on endothelium?
How is NO inactivated?
How can we prevent this?

A

relaxes smooth muscle

inactivated by superoxide radical

increase antioxidants to reduce free radicals and all NO effects to last longer–> lowering BP

55
Q

What are some antioxidants?

A
  • Glutathione
  • Melatonin
  • Superoxide dismutase
  • Beta-carotene
  • Lutein
  • Lycopene
  • Selenium
  • Vit A C E
56
Q

What effect does serotonin have on CNS? What about NO?

What may this promote?

A

serotonin–>to inhibit reflex SNS activation
NO–> inhibit sympathetic nerve activity

–this may promote bradycardia and hypotension

57
Q

How does blood flow get to the placenta? How does it return to the fetus?

A

gets to placenta–> via umbilical arteries, branch of anterior iliac arteries

returns to fetus–> via umbilical vein

58
Q

What are the three fetal shunts and what are they b/w?

A
  1. Ductus arteriosis (pulmonic trunk–> aorta)
  2. Foramen ovale (b/w R and L atrium)
  3. Ductus venosus (umbilical vein/portal vein —> IVC)
59
Q

How many fetal shunts are there to bypass the lungs? What are they?

A

Ductus arteriosis AND Foramen ovale

60
Q

What fetal shunt allows umbilical and portal blood to bypass the liver?

A

ductus venosus

61
Q

Describe pattern of blood flow with the Ductus arteriosis in the fetus? Start with Superior vena cava.

A

SVC –> RA –> RV –> Pulmonic trunk –> DUCTUS ARTERIOSIS –> aorta

62
Q

Describe the pattern of blood flow with the Foramen ovale in the fetus, starting with inf. vena cava.

A

IVC –> RA –> FORAMEN OVALE –> LA –> LV –> aorta

63
Q

Most blood in the fetus coming from the superior vena cava will go through what fetal shunt?

A

ductus arteriosis

64
Q

Most blood in the fetus coming from the inferior vena cava will go through what fetal shunt?

A

foramen ovale

65
Q

In fetal blood, where is the highest amount of oxygen saturation?*

A

umbilical vein– 80%

66
Q

What are these fetal shunts b/w:

  1. Dustuc arteriosis
  2. Foramen ovale
  3. Ductus venosus
A
  1. pulmonary trunk and aorta
  2. RA and LA
  3. Portal vein to IVC and Umbilical vein to IVC
67
Q

At birth, what are the circulatory readjustments?

A
  • increase blood through lungs and liver
  • loss of blood flow through placenta
  • closure of FO, DA, and DV
68
Q

At birth, what doubles the systemic vascular resistance in the baby?*

A

loss of blood flow through the placenta

- increased LA pressure, LV pressure, and aortic BP

69
Q

T/F. In the fetus the R and L ventricles pump in series into the aorta.

A

False—-they pump in parallel

in us they pump in series

70
Q

What is the low pressure in the aorta due to in the fetus?

A

due to low Total Peripheral Resistance (TPR) b/c of placenta-umbilical arteries

71
Q

In the fetus:
The ______ shunts most blood returning to the heart from the inferior vena cava to the left atrium.

The _____ shunts most blood returning to the heart from the superior vena cava to the aorta.

A
  1. foramen ovale

2. ductus arteriosus

72
Q

What has the greatest stress on the cardiovascular system?*

A

exercise

73
Q

How much is cardiac output increased during exercise? How is blood flow shifted?

A

5-6 fold; primarily from organs to active skeletal muscles

74
Q

What three things occur from cerebral cortical activation of the SNS during exercise?

A
  1. vasoconstriction of arterioles to decrease flow to non active tissues (viscera)
  2. vasoconstriction of veins to increase MCFP with increases VR
  3. stimulation of heart to increase HR and SV and therefore increase CO
75
Q

During exercise, what will decrease due to vasodilation in active muscle?

A

TPR (total peripheral resistance)

76
Q

During exercise there is an increase O2 uptake by active tissues, what effect does this have on VO2?

A

decrease VO2 and therefore increases A-VO2 difference

77
Q

T/F. AO2 stays relatively the same during exercise.

A

True

b/c pushing blood to lungs, but also ventilating more to get the adequate O2

78
Q

During exercise, SNS stimulation could be due to, what?

A
  • cerebral cortex stimulation
  • reflex signals from active joint proprioceptors and muscle spindles
  • local chemoreceptor signals from active muscle
79
Q

During exercise, how does the SNS effect the heart?

A

targets heart to increase HR and SV = CO

80
Q

During exercise, what will the increase in CO (HR and SV) by SNS induce?*

A

induces LOCAL metabolic vasodilation at the heart

–> increase flow directly to muscle by LOCAL override *

81
Q

During exercise what is the SNS effects on:

  1. pre-capillaries
  2. veins
  3. vascular smooth muscle in walls of arteries
A
  1. stimulates pre-capillary resistance vessels and decreases blood flow (organs and inactive muscle)
  2. vein constriction–mobilizes blood out of veins, increasing VR
  3. stimulates it to help maintain slightly increased BP
82
Q

What tissues escape the effects of SNS vasoconstriction?

A
  1. Heart
  2. Brain
  3. lungs
83
Q

What are the changes in arterial pressure during exercise? (SBP, DBP, PP)

A
  • increase SBP due to increase CO and decrease TPR
  • increase DBP only slightly
  • increase Pulse Pressure (PP = SBP - DBP)
84
Q

What is the pulse pressure for 120/80?

A 
PP = SBP -DBP
PP = 120-80
PP = 40
85
Q

What are three ways we increase venous return during exercise?

A
  1. SNS constriction of veins
  2. “Venous Pump”
  3. Increase frequency and depth of respiration
86
Q

How does the “Venous Pump” work?

A

intermittent skeletal muscle activity coupled with one way valves in veins
- primarily in lower extremities

87
Q

How does the increase in frequency and depth of respiration help increase VR during exercise?

A

increased cyclic negative thoracic pressure (helps pull blood up from thorax and increase VR)

88
Q

How is increased flow to active muscles mediated?

A

NOT by SNS; but by LOCAL release of tissue metabolites in response to increase in metabolism “Local vasodilators” (adenosine, CO2, K+, histamine, lactic acid)

89
Q

What is the average resting CO?

What about when exercising?

A

5.9 L/min

24 L/min

90
Q

During rest, what gets most blood flow?* Then least most to least.

A
  1. Organs
    - Brain
    - tie b/w active and inactive muscles
    - skin
    - coronary vessels
91
Q

During exercise what gets most blood flow?*

A

active muscle (~87%) due to local override

92
Q

During exercise how is blood flow affected at:

  1. coronary vessels
  2. Brain
  3. Organs
  4. Inactive muscle
  5. Active muscle
  6. skin
A
  1. coronary vessels–> increase 4 fold
  2. Brain–> CONSTANT
  3. Organs –> decreases
  4. Inactive muscle–> decreases
  5. Active muscle–> increases
  6. skin –> initially decreases, then increases as body temp increases
93
Q

The effects of exercise on cardiovascular endpoints increases in all, except what?*

A

decrease in Total Peripheral Resistance

94
Q

What causes the arteriovenous oxygen difference to increase when we exercise?*

A

due to decrease in VO2 (venous oxygen)

95
Q

T/F. we can improve our Stroke Volume by constant exercise.

A

True

96
Q

What is the maximum volume of oxygen that one can take up from the lungs and deliver to the tissues per minute?

A

VO2 maximum

97
Q

What can VO2 maximum range from?

A

cardiac patient–> 1.5 L/min

Sedentary man–> 3.0 L/min

Endurance athlete–> 6.0 L/min

98
Q

What is proportional to increases in SV as exercising training occurs?

A

function of CO and AV O2 difference

99
Q

What occurs if energy (E) demands of exercise cannot be met by oxidative phosphorylation?

A

Oxygen Debt occurs

100
Q

If Oxygen Debt occurs, what occurs after completion of exercise?

A

respiration remains elevated to repay the oxygen debt of about 11.5 L

101
Q

What is extra Oxygen used for?

A
  • restore metabolite levels (i.e. creatine phosphate and ATP)
  • metabolize lactate generated by glycolysis
102
Q

What is the equation of Oxygen Debt?

A

= E consumed during exercise - the E supplied by oxidative metabolism

103
Q

When is the phosphocreatine-creatine system used during exercise?

A

8-10 secs (if sprint)

Uses ATP and creatine phosphate

104
Q

When is the glycogen-lactic acid system used during exercise?

A

1.3-1.6 minutes

Uses glycolysis

105
Q

When is the aerobic system used during exercise?

A

unlimited with oxygen and nutrients

  • Uses oxidation of glucose, FA, aa –> Energy
  • occurs in mitochondria with sufficient O2

Physiology III - Freedman (18 decks)

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