Vascular Control

Question 1

Preferential Channel

Answer 1

Larger capillary not separated by sphincter, so blood flows from metarteriole through here at rest

Question 2

Pericytes Central vs. Peripheral

Answer 2

Essential part of BBB w/ contractile action vs. stem cells

Question 3

Importance of Endothelial -> SM Gap Junction

Answer 3

Transfers hyperpolarizing factor from endo -> SM

Question 4

Activation of Smooth Muscle

Answer 4

Ca-calmodulin activates MLCK, leading to P-Myosin and contraction

Question 5

2 Mechs to get Ca for Contraction

Answer 5

Electromechanical coupling -> CICR and RyR

Chemomechanical Coupling -> NE activating alpha1 -> IP3R

Question 6

3 Pathways for Beta2 Inhibition of Contraction

Answer 6

cAMP activates K+ channels leading to hyperpol
PKA releases just enough Ca from SR to activate Na-Ca exchanger and extrude Ca
Blocks IP3R

Question 7

CGRP

Answer 7

Something that activates Beta2s and causes vascular relaxation

Question 8

Epi Concentration and Vasodilation/Constriction Results

Answer 8

Low = dilator high = constrictor

Question 9

2 Locations of Parasympathetic bv Effect

Answer 9

Heart (SA Node/Atria)

External Genitalia

Question 10

Dual Innervation of Skeletal Muscle Arterioles

Answer 10

From symp, NE but also ACh acting on MRs on endothelial cells

Question 11

IV Infusion of Epi (CO, PVR, and ABP [sys, mean, dias], and Rs for 1st 2)

Answer 11

CO increase via Beta1s
PVR decrease via Beta2s
So systolic increase, dystolic decrease in BP, and mean relatively constant

Question 12

IV Infusion of NE (CO, PVR, and ABP and explanation)

Answer 12

No effect (require higher conc, like NE released from synapse)
Increase via alpha1s
All 3 increase (sys, mean, dias)

Question 13

Angiotensin II (production and 4 targets for effects)

Answer 13

Produced by ACE in lungs from AT1 from low BP. Acts on hypothal to increase thirst, adrenal cortex to release aldosterone, renal prox tubules to decrease Na excretion, and peripheral arterioles to increase SVR, all increasing bv and arterial pressure

Question 14

2 HTN Treatments Related to ATII

Answer 14

ACE inhibitors or ATII R inhibitors, bc most HTN not at renal origin

Question 15

2 Hypotheses for Local Regulation

Answer 15

Vasodilator Hypothesis: Metabolites from tissue use causes vasodilation, and are then washed away proportional to blood flow
Oxygen Demand Hypothesis: Smooth muscle requires O2, so high O2 means sphincters contracted and low means open. Simplistic

Question 16

Active vs. Reactive Hyperemia

Answer 16

Increased blood flow caused by activity of tissue vs. transient increase due to temporary deprivation (metabolites accumulate)

Question 17

2 Sources of ATP Release

Answer 17

Endothelial cells in response to shear stress

Erythrocytes from shear stress or low O2 content

Question 18

Oxygen Delivery Pathway of ATP

Answer 18

Ecytes release ATP when sense low O2. Activates ATP-induced ATP release Rs on ecytes and endothelial cells via IC Ca from IP3 activation. So signal propagates but also activates eNOS in endothelials to produce NO and relax smooth muscle. So more blood/O2 comes in acting as own neg feedback

Question 19

Pannexins

Answer 19

Modified gap junction prots that now in verts just act as ATP release channels. Who gives a damn about all that evolutionary bullshit these professors seem to jizz to

Question 20

Autoregulatory Range

Answer 20

Tissue-specific range of arterial pressure in which a change will cause only a transient change in blood flow and then resettlement to a similar steady-state.

Question 21

2 Theories of Autoregulation of Blood Flow

Answer 21

Metabolic Theory - Flow washes out vasodilator substances

Myogenic Theory - stretch sensitivity of smooth muscle

Question 22

3 Locations of Mainly Metabolic Control and 3 of Mainly Nerval Control

Answer 22

Heart, skeletal muscle, brain

Kidneys, skin, splanchnic organs

Question 23

Coronary Blood Flow Metabolic and Neural Control

Answer 23

Adenosine from myocardial cells vs. beta2s stimulated by symp resulting in relaxation

Question 24

Difference in L and R Coronary Blood Flow

Answer 24

Highest pressure from LV causes L coronary flow to decrease and even retrograde. R Coronary decreases but maintains continuous perfusion

Question 25

3 Aspects of Skeletal Blood Flow Control

Answer 25

Metabolic control relaxes arterioles
Collateral vasoconstriction in nonreactive part of muscle to shift blood w/in muscle
Cholinergic Symp Fibers onto endothelials stimulate eNOS for relaxation

Question 26

Kidney Decrease in Blood Flow

Answer 26

Cont’d Maximal effort decreases blood flow, so can get kidney failure in marathons and shit

Question 27

Bayliss Effect

Answer 27

Pronounced autoregulation in isolated (denervated) kidney. Mainly myogenic