Regulation of Arterial Blood Pressure

Question 1

Response to head up tilt normally and in autonomic neuropathy

Answer 1

HR increase

HR stays the same

Question 2

5 elements of baroreflex

Answer 2

Sensor to detect BP

Affarent from sensor to controller

Controller/integrater that compares current with desired

Efferent that carries to effectors

Effectors

Question 3

Sensors of baroreflex

Answer 3

Stretch receptors in the carotid sinus and arch of aorta

Inc BP—inc stretch—–inc activation of these receptors

Question 4

Loop with SNA

Answer 4

Inc AP…inc barorecptor….dec sympathetic….dec arteriolar smooth muscle contraction….dec resistance…dec BP

Question 5

Majority of baroreflex depends on

Answer 5

SNA - NE, Beta 1

Important exception is PS control of HR

Question 6

PS control

Answer 6

BP increases….inc PS nerve activity which dec HR via Ach/muscarinc

Question 7

Plasma volume effect

Answer 7

Due to atrial stretch receptors in the RA

Question 8

If you eleiminate baroreflex

Answer 8

Sinoaortic denervation

BP fluctuates widely but overall average is about the same

Question 9

Barorelfex summary

Answer 9

Minimizers moment to moment fluctuations in BP

Other mechs responsbile for LT BP regulation

Question 10

Overview of neural control

Answer 10

Vagus acts on heart from BS

Sympathetic nerves from IML…sensory from heart back to IML

Chainganglion also to vasomotor fibers

Fagus nerves to lungs

Question 11

BS anatomy of baroreflex

Answer 11

NTS - receives info from caerotid sinus and aortic arch

Nuc ambiguous - vagal efferent to the AV node

RVLM to symp chain to myocardium for sympathetic

Question 12

Full tract of baroreflex in terms of inc BP

Answer 12

Sensory to NTS —–to N amb—-activates vagal stimulation

Sensory to CVLM…inhibits RVLM…RVLM normally activates sympathetic

Question 13

Sequence in ogoing from supine to UR

Answer 13

Gravity bloods

Starves heart

Dec CO…dec BP…dec cerebral flow

Dec carotid sinus pressure activates baroreflex

Inc SNA, dec PNA,—–tachycardia, inc SV

Question 14

Renovascular
Neurogenic
Salt sensitive

Answer 14

Renal artery occlusion to RAAS

Inc SNA means inc CO and TPR

High salt load means inc BV

Question 15

Arterial pathologies
Obesity related
Endothelial dysfunction
Essential

Answer 15

Artrial compliance
????
Impaired release of NO
???

Question 16

Why does baroreflex dec in older age

Answer 16

Dec in compliacne of the arteires in which baroreceptors reside

Question 17

Mutliple causes of HTN

Answer 17

INteractive efrects of dietary sodium and behavioral stress

Humans learn to elevate arterial BP to minimize perception of pain

Question 18

Pmc

Answer 18

This is where the arteiral pressure and CVP meet

Mean circulatory filling pressure

Question 19

Vascular function equation

Answer 19

VR = (resistance)(Pmc-Pra)

Question 20

Vascular function curve with vasoconstrction

Answer 20

Increase the Pmc and moves the curve to the right

Question 21

Starlings curve and vascular ufnction curve plotted on same graph

Answer 21

Find the intersetion and this is steady state operating point

Question 22

Effects on vascular fxn/starling curve

Answer 22

Inc in SNA shifts the starling curve up

Inc in contractility shifts the vascular function curve to the right

This means heart can perform more work without an increase in preload

Question 23

Positive inotropism on PV loop

Answer 23

Dec in ESV and therefore dec in LV diastolic pressure

Inc in SV automatircally fosters increase in pressure graident for venous return