BP Regulation I, II

Question 1

Baroreceptors are?

Answer 1

mechanoreceptors that respond to passive stretch w/ a generator potential

Question 2

Baroreceptor reflex is?

Answer 2

rapid, neg feedback pathway,

controls mean arterial pressure (Pa) around a setpoint for Pa

Question 3

Baroreceptor reflex follows what type of NS pathway?

Answer 3

afferent (toward CNS)

Question 4

Baroreceptor reflex sends signals from aortic baroreceptors to brain via what CN?

Answer 4

CN X (vagus)

Question 5

Baroreceptor reflex sends signals from carotid sinus baroreceptors to brain via what CN?

Answer 5

CN IX (glossopharyngeal)

Question 6

Baroreceptor reflex mechanism?

Answer 6

Setpoint Pa compared to actual Pa,
feedback signal proportional to difference,
brain responds until difference = 0

Question 7

Interruption in efferent branch of baroreceptor reflex results in what?

Answer 7

↓ Pa

which indicates ↑ resting symp tone and basal (resting) activity of C1, A1 vasomotor area of medulla

Question 8

Valsalva Maneuver?

Answer 8

“pop your ears”
causes ↓ Pa ->
kicks off baroreceptor reflex

Question 9

Glomus cells play what role in control of Pa?

Answer 9

respond to ↓ in Po2 and pH or ↑ Pco2 with APs

Question 10

Baroreceptor setpoint resets if what?

Answer 10

long term ∆s in Pa

Question 11

Glomus cells are?

Answer 11

chemsensitive cells in aortic arch and carotid bodies

Question 12

Primary action of aortic/carotid chemoreceptors and central chemoreceptors working together under normal circumstances is?

Answer 12

enhancement of respiratory ventilation

Question 13

How does enhanced respiratory ventilation cause increased heart rate?

Answer 13

↑ resp ventilation ->
↓ Pco2 ->
inhibit cardioinhibitory center ->
↑ HR

Question 14

Glomus cells APs travel where?

Result in?

Answer 14

up CN IX and X to NTS of medulla

vasoconstriction (↓ HR)

Question 15

Overall response to ↓ Po2
or ↓ pH
or ↑ Pco2
is what?

Answer 15

reflex tachycardia

Question 16

2 types of Low Pressure Atrial Receptors?

Answer 16

A Fibers

B Fibers

Question 17

A Fibers found where?

Answer 17

entry to R atrium

Question 18

A Fibers do what?

Answer 18

signal pressure ↑ associated w/ atrial contraction

Question 19

B Fibers found where?

Answer 19

superior and inferior vena cavae

Question 20

B Fibers do what?

Answer 20

signal pressure ↑ associated w/ vent contraction

Question 21

↑ pressure in vena cavae indicates what?

Produces what?

Answer 21

↑ venous return to R heart

reflex ↑ HR,
renal vasodilation,
↓ in AVP (antidiuretic hormone)

Question 22

What is Brainbridge Reflex?

Answer 22

reflexive ↑ in HR

Question 23

Purpose of renal vasodilation?

Answer 23

↑ renal bloodflow and urine output

causing ↓ circulating volume

Question 24

Purpose of reducing AVP release?

Answer 24

↓ AVP = ↓ H2O reabsorption from kidney

causing ↓ circulating volume

Question 25

Summary: when high pressure baroreceptors (arterial side) sense ↑P, reflex response does what?

Answer 25

↓ BP

Question 26

Summary: when low pressure receptors (venous side) sense ↑P, reflex response does what?

Answer 26

↓ blood volume

Question 27

Compliance eqn

Answer 27

C = V/P | typically, ↓ V means ↓ P and ↑ V means ↑ P

Question 28

Atrial Natriuretic Peptide (ANP) promotes what?

Answer 28

Na+ and H2O excretion in kidney -> | reduces effective circulating volume

Question 29

↑ venous return causes ↑ what?

Answer 29

atrial stretch

Question 30

↑ atrial stretch affects release of ANP how?

Answer 30

↑ release of ANP

Question 31

Summary: High Pressure Baroreceptors' primary output variable is? Control what end of circulation? Type of control?

Answer 31

Pa (mean arterial pressure) arterial end short term control

Question 32

Renin-Angiotensin System for interm/long term BP control fxns primarily by regulating what?

Answer 32

effective circulating volume

Question 33

Summary: | Chemoreceptor Integrated Response involves control of what?

Answer 33

ventilation and secondary effects on HR

Question 34

Summary: Low Pressure Receptors response is to do what? Controls what end of circulation? Output Variable is?

Answer 34

↑ HR (thru Bainbridge reflex) venous end ↑ in effective circulating volume

Question 35

Summary: Renin-Angiotensin activated by? Controls what end of circulation? Primary output variable is?

Answer 35

Sympathetic NS renal perfusion effective circulating volume

Question 36

Pa eqn

Answer 36

CO x TPR TPR = total peripheral resistance

Question 37

Which receptors are more sensitive to pressure changes, aortic or carotid sinus?

Answer 37

carotid sinus | Ѧ ∆ in carotid sinus P causes > compensatory effect on Pa than a ∆ in aortic pressure

Question 38

5 kinds of Vasoconstrictors?

Answer 38

1) Epi (α1) 2) Serotonin 3) Ang II 4) AVP 5) Endothelin

Question 39

5 kinds of Vasodilators?

Answer 39

1) Epi (β2) 2) Histamine 3) ANP 4) Bradykinins 5) PGE2, PGI2, NO

Question 40

Flow charts to review in lecture

Answer 40

slide 14 and 15