Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

555- Physiology & Pathophysilogy > Exam 9 - Short Term Control Of BP > Flashcards

Exam 9 - Short Term Control Of BP Flashcards

1
Q

Local flow to tissues

A
  • Depends on constant pressure drop across tissues

- MAP - CVP = constant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Arterial compliance

A

2 mls/mmHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Venous compliance

A

100 mls/mmHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Hormonal mechanisms for controlling BP

A
  • Aldosterone

- Renin-angiotensin-vasoconstriction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Nervous mechanisms for BP control

A
  • Baroreceptors (moment to moment / normal changes)
  • Chemoreceptors
  • CNS ischemic response
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Physiologic mechanisms for BP control

A
  • Capillary fluid shift (normal to abnormal changes)

- Stress relaxation of vasculature (normal to abnormal changes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Renal mechanism for BP control

A
  • Renal-blood volume pressure control

- long term control….everything else short term

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Filtration/absorption rate

A
  • If MAP increase….filtration increase

- If MAP decrease….absorption increase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

4 quickest activated mechanisms

A
  • Within seconds
  • Baroreceptors
  • Chemoreceptors
  • CNS ischemic response
  • Stress relaxation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

2 average reaction time mechanisms

A
  • Within minutes
  • Renin-angiotensin-vasoconstriction
  • Capillary fluid shift
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

2 slowest reacting mechanisms

A
  • Within hours
  • Aldosterone
  • Renal-blood volume pressure control
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

5 average strength mechanisms

A
  • Max feedback of 4% increase relative
  • Bring BP back CLOSE to normal
  • Chemoreceptors
  • Stress relaxation
  • Renin-angiotensin-vasoconstriction
  • Capillary fluid shift
  • Aldosterone
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

2 strong mechanisms

A
  • Max feedback of 7 & 11
  • Bring BP back CLOSE to normal
  • Baroreceptors
  • CNS ischemic response
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

1 infinite strength response

A
  • Renal-blood volume pressure control

- Can bring BP back to NORMAL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Which mechanisms play role on bypass

A
  • All except Aldosterone and Renal-blood volume pressure
  • CPB not on long enough to activate those two
  • Average case only 90 minutes
  • These two take 4 hours to activate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Which change in BP to these mechanisms respond to

A
  • Mostly drops in BP

- Except Baroreceptors…they do both

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Innervation of the heart

A
  • Sympathetic and Parasympathetic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Innervation of arterioles

A
  • Sympathetic
19
Q

Parasympathetic control

A
  • Regulates HR
  • Small/No affect on contractility
    - only atrial filling
  • Minimal regulation of circulation
20
Q

Sympathetic control

A
  • Regulate contractility

- Regulates circulation

21
Q

Vasomotor center pathways

A
  • Efferent pathways
  • Parasympathetic impulses via vagus nerve
  • Sympathetic impulses via spinal cord and peripheral sympathetic nerves to arteries, arterioles, and veins
22
Q

Sympathetic nerve fibers

A
  • Exit spinal cord via thoracic spinal nerves and first 2 lumbar
  • Enter sympathetic chains either side of spinal cord
  • To circulation 2 ways:
    • specific nerves directly to heart and internal viscera
    • peripheral portions of spinal nerves to peripheral vasculature
23
Q

Which vessels innervated by sympathetic

A
  • Arteries / Arterioles - change resistance and flow to tissue
  • Veins / Venuoles - change volume held…changing return
  • SOME metarterioles and pre-cap sphincters of mesenteric
    - most are not
  • Most are vasoconstrictors: kidney/ intestines/ spleen/ skin
    - weak vasoconstriction in skeletal muscle / brain
  • When impulses sent to vessels…also sent to adrenal medulla
    - releases Epi and NE
24
Q

Vasomotor center location

A
  • Bilateral
  • all efferent neurons come out of here
  • In medulla and lower third of pons
  • regulates amount of vascular constriction AND cardiac activity
    - like HR and contractility
25
Q

3 parts of vasomotor center

A
  • Vasoconstrictor
  • Vasodilator
  • Sensory
26
Q

Vasoconstrictor area

A
  • Bilateral
  • Anterolateral part of upper medulla
  • sends out efferent neurons to all areas of spinal cord
  • excite vasoconstrictor neurons of sympathetic
  • increase cardiac activity (sympathetic)
27
Q

Vasodilator area

A
  • Bilateral
  • Anterolateral part of lower medulla
  • Sends efferent neurons to vasoconstrictor area
  • fibers inhibit vasoconstrictor area
  • decrease cardiac activity (parasympathetic)
28
Q

Sensory area

A
  • Bilateral
  • In medulla and lower pons (tractus solitarius)
  • Receives signal via vagus and glossopharyngeal nerves
  • Sends output to vasoconstrictor and vasodilator areas
    - based on input from circulatory system
29
Q

Vasomotor center cardiac control

A
  • Lateral portions: excitatory impulses to heart
    - Sympathetic
  • Medial portion: impulses to vagus nerve which sends parasympathetic impulses to heart -> inhibitory
    - Parasympathetic
30
Q

Sympathetic vasoconstrictor tone

A
  • more impulses -> constrict
  • less impulses -> dilate
  • vasoconstrictor center sends 1.5-2.0 impulses/sec
    - normal vasomotor tone
  • If efferent paths blocked….MAP will drop by at least half
31
Q

Vasomotor center control by CNS

A
  • Pons / mesencephalon / diencephalon
    - lateral/superior portions: excite
    - medial/inferior portions: inhibit
  • hypothalamus
    - posterolateral: excite
    - anterior: mild excite or inhibit…..depends which part
  • cerebral cortex
    - motor cortex: excites
    - other areas: excite or inhibit depending
32
Q

Effect of CNS control

A
  • Can produce rapid increase in BP
    - double within 5-10 seconds
  • stimulate vasoconstrictor area
  • stimulate increase in cardiac activity
  • inhibit parasympathetic Vargas signals to heart
33
Q

If MAP drops…what is CNS response

A
  • constriction of most arterioles
    - increase SVR -> increase MAP
  • strong constriction of veins and larger arteries
    - move volume -> more preload -> more SV -> increase MAP
  • increase cardiac performance
    - increase HR (major effect) -> more CO -> increase MAP
    - increase contractility -> up SV -> up MAP (curve up and left)
34
Q

Barroreceptors

A
  • Stretch receptors in large arteries of thorax and neck
    - aortic and carotid bodies are big areas
  • Carotid: Hering nerve to glossopharyngeal nerve to sensory area
  • Aortic: vagus nerve to sensory area of vasomotor center
  • help maintain more constant MAP
    - If removed….MAP is all over the place
  • CAN normalize to if pressure changes and remains at new level
    - takes 1-2 days / no matter which way pressure changes
    - may mediate changes of tone to kidneys
35
Q

Carotid barroreceptors

A
  • In play more often
  • responds to lowest of 50 - 60 mmHg
    • then stretch happens
36
Q

Aortic barroreceptors

A
  • In play when MAP is a bit higher
  • 80 - 90 mmHg
  • receptors produce greater response when pressure is changing
    - not standing still….same with carotid receptors
37
Q

Chemoreceptors

A
  • sensitive to lack of O2 and excess CO2/H ions
  • In carotid bodies (2)
  • In aortic bodies (3)
  • excite nerve fibers through Herring’s nerve and vagus nerve
  • If flow to receptor drops -> impulse increase -> excites vasomotor
    - kick in when pressure drops below 80 mmHg
38
Q

CNS ischemic response

A
  • Very powerful
  • direct response of vasomotor center to ischemia
    - increased levels of CO2
  • can increase BP to 250 mmHg
  • will cut off flow to less important tissues
  • kicks in when BP below 60 mmHg
  • greatest level of stimulation at 15-20 mmHg
39
Q

Atrial / Pulmonary stretch receptors

A
  • low pressure receptors
  • minimize changes in atrial pressure due to sudden changes in blood volume (baroreceptors respond to stretch….these to flow)
  • bigger help in maintaining BP due to increase in volume
40
Q

Atrial reflex and Kidney - A

A
  • increase atrial stretch
  • reflex dilation of afferent arterioles in kidney
  • increase glomerular cap pressure
  • increase glomerular filtration
  • increase urine output
  • decrease CBV
  • decrease venous return
  • decrease CO
  • brings pressure down / happens slowly
41
Q

Atrial reflex and Kidneys - B

A
  • Increase atrial stretch
  • hypothalamus makes less ADH
  • decrease reabsorption of H2O in renal tubes
  • increased urine output
  • decrease CBV
  • decrease venous return
  • decrease CO
  • brings pressure down / happens slow…but little quicker than A
42
Q

Bainbridge reflex

A
  • increase atrial stretch -> increase in HR
    • via vagus nerve
    • 40-60% boost
43
Q

Respiratory waves

A
  • Change in arterial pressure 4-6 mmHg during each breath
  • Inspiration: pressure negative…vessels expand…decrease CO
  • Expiration: positive pressure…vessels constrict…increase CO
  • These can trigger vascular and atrial stretch receptors
44
Q

Vasomotor waves

A
  • slow oscillation of MAP of 10-40 mmHg
  • dynamic equilibrium
  • cycle is 7-10 seconds
  • oscillation due to baroreceptors / chemoreceptors

555- Physiology & Pathophysilogy (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions