Regulation of BP

Question 1

SNS and MAP

Answer 1

increases TPR, HR, SV

therefore increases MAP via vasoconstriction
also causes release of Epi from adrenal medulla which amplifies the effects of NE

Question 2

SNS and TPR

Answer 2

increases TPR through vasoconstriction (pressor effect) NE/Epi—>VC in smooth muscles

-exceptions include skeletal and cardiac m (Epi—>B2—>VD)

Question 3

Exercising vs. resting skeletal muscle and SNS

Answer 3

Resting skeletal muscle: neural control dominates—>VC

exercising: intrinsic regulation dominates—>VD
* *local metabolic effect overrides SNS output

Question 4

PSNS and MAP

Answer 4

indirect (think NO) promotion of VD—>decreased TPR (minimal effect due to lack of receptors)

decreases HR
Decreases contractility
*decreases MAP

Question 5

Medulla Oblongata

Answer 5

• *Major CV integrating center: vasomotor area
• regulates MAP
• mediates SNS and PSNS outputs

Question 6

Input to MO

Answer 6

Baroreceptors, chemoreceptors, cortex, skin, local Co2 and O2

Question 7

High pressure baroreceptors

Answer 7

Located at aortic arch and carotid sinus
inc MAP—>inc stretch—>inc receptor depol—>decrease SNS—>VD and bradycardia

rate(graded upon degree of stretch)
-respond to change in pressure:respond more to increased pulse pressure-not mean pressure

Question 8

Increased MAP on high pressure Baroreceptors

Answer 8

inhibition of vasomotor area—>dec SNS–>dec VC—>VD

Question 9

Impact of inc HR on baroreceptors

Answer 9

excitation of interneurons in cardioinhibitory area—>increases PSNS output—> dec HR

Question 10

Low pressure baroreceptors

Answer 10

located in cardiac chambers (RA) and large pulmonary vessels (IVC) (in low pressure regions)

inc filling pressure/stretch—>increase FR
—>monitor blood volume (atrial filling) —> inc HR and dec renal VC–>inc urine output—>decreased effective circulating volume

Question 11

Brainbridge reflex

Answer 11

increase VR/RAP–>inc HR (want to move extra blood volume through more quickly)

wins out over HPB response during times of high volume

counterbalance High pressure baros (which slow HR to compensate high pressure)

Question 12

SV and HPB

Answer 12

–>inc MAP—>activates HPB—>decrease SNS—>dec contractility and flattening (plateau) of starling releationship

Question 13

SV and LBP

Answer 13

activates LBP—>inc SNS output—>increase contractility and slope of Starling curve

Question 14

Peripheral chemoreceptors

Answer 14

located at the carotid bodies or aortic arch near HPB
**detect inc CO2 and dec pH (some dec O2

increase rate and depth of respiration, some influence of vascular tone, and HR

Question 15

Central chemoreceptors

Answer 15

in the MO
detect changes in central CO and decreased pH (indirect)

inc CO2—>stim vasomotor area—>VC—>increased TPR (in hopes of increasing MAP which maintains adequate driving force to supply the brain)

Question 16

Net effect of chemoreceptor activation

Answer 16

inc HR, inc TPR, inc MAP (thru inc SNS)

Question 17

Baroreceptor vs Chemoreceptor response

Answer 17

if there is a increase pCO2 and increase in MAP, both would be stimulated, but baro-mediated inhibition of VC wins out

Question 18

Epinephrine

Answer 18

from adrenal gland
VC (a1)
VD (B2)

Question 19

ANG II

Answer 19

converted from ANG I by ACE (lungs)

VC (from renin in Kidneys during blood loss and exercise )

Question 20

ADH/AVP

Answer 20

from posterior pituitary gland

—>VC, released during hemorrhagic shock

Question 21

Histamine

Answer 21

response to tissue trauma

Vasodilation and Venoconstriction

Question 22

ANP

Answer 22

from atrial myocytes (LPB receptors)—>VD

**causes increase Na excretion (H20 follows)

opposes ADH in RAS system in order to decrease MAP

Question 23

long term regulation of BP

Answer 23

done by non-vasoactive factors thru regulation of blood volume

**kidney is key

Question 24

RAAS

Answer 24

main function is to maintain Na reabsorption —>increase MAP

occur in response to dec blood volume

Question 25

Ortostasis

Answer 25

Gravity effects upon standing

from pooling in large veins—>dec VR–>dec CO—>Dec MAP

stimulates HPB—>inc SNS and inc muscle pump

Question 26

Vasovagal syncope

Answer 26

common response to emotional response

dramatic increase in PSNS (dec SNS)—>dec HR, CO, MAP (bradycardia, hypotension, apnea)—>causes dizziness/faintness or LOC, skin pallor, blurred vision, nausea

Question 27

FIght or Flight

Answer 27

Stress induced response from the CNS ONLY—>inc SNS—> inc skeletal m. flow (via B2 vasodilation) and generalized vaso and venoconstriction (via a1—>dec renal and splanchnic flow)

inc CO,
inc ADH—>inc blood volume
Inc MAP

Question 28

Exercise

Answer 28

inc CO and HR and SV
distribute blood flow based upon metabolic demand
Net decrease in TPR

Question 29

Early response to exercise

Answer 29

higher CNS activity

anticipation—>SNS
Inc CO (HR, contractility)
inc VC to non-essential areas (including skin)—>more blood to muscles

Question 30

Delayed response to execise

Answer 30

Mechanical (inc venous return)

Chemical (increased autoregulation in exercising muscles, overall VD—>dec TPR)

Question 31

Effects of exercise on muscles

Answer 31

Inc Pc
inc O2 delivery (dec Hb affinity for O2)
Inc O2 consumption

Question 32

Exercise pressor reflex

Answer 32

reflex originates in muscle—>neural drive

sustains SNS output

Question 33

Arterial baroreflex and exercise

Answer 33

re-set sensitivity by CNS (inc set-point)

—>maintains SNS output even with high MAP

Question 34

Epi and exercise

Answer 34

exercise increases adrenal medulla produciton of epi—>B1

Question 35

temperature regulation

Answer 35

inc metablism—>inc CBT–>cutaneous heat loss–> inhibits SNS VC to skin (from early response)—>inc cutaneous flow

SNS cholinergic fibers activate sweat glands

Question 36

MAP and Power relationship

Answer 36

has a small increase that CO does, due to dramatic decrease in TPR (due to VD to skeletal muscles)