11 - Blood Flow

Question 0

name 3 vasodilators

Answer 0

CO2
Adenosine
Histamine
Potassium ions
Hydrogen ions

Question 1

explain the vasodilator theory behind acute blood flow control?

Answer 1

Inc. Metabolism –> Dec. O2 –> formation vasodilators

Question 2

Explain the Oxygen/nutrient lack theory of acute blood flow control?

Answer 2

Dec. in O2/nutrients –> smooth muscles relax –> vasodilation

Question 3

what is vasoMOTION?

Answer 3

The cyclical opening and closing of precapillary sphincters.

Question 4

obviously, if tissues determine acute blood flow, therefore when they get low on O2. (if they demand the O2 over local vessels) the precapillary sphincters relax b/c?

Answer 4

They don’t have oxygen to contract, and therefore allow for inc blood flow acutely.

Question 5

Hyperemia means?

Answer 5

more than normal blood flow to an area?

Question 6

What are the 2 types of Hyperemia? and define.

Answer 6

Reactive - flow is blocked to an area, and then upon unblock flow inc. 4-7 times.
Active - when use an area, blood flow to that area with inc.

Question 7

Auto regulation will occur when blood flow to an area increase upon the increase of blood pressure. Explain what autoregulation would do in this circumstance and the 2 theories behind why it occurs?

Answer 7

Blood flow will be returned to NORMAL, AND BP CAN STAY THE SAME.
2 theories - Metabolic and myogenic .

Question 8

Explain the metabolic theory of autoregulation when blood flow is HIGH?

Answer 8

washing out of O2/Nutrients means there will also be the washout of vasodilators

Question 9

Explain the Myogenic Theory of Autoregulation of blood flow?

Answer 9

Stretching of vessels –> reactive vascular constriction

Question 10

in broad terms Differentiate between autoregulation of blood flood and local control of blood flow? Why doing this (b/c both of these have 2 different Mechanisms/theories that are completely different yet have similar results.

Answer 10

auto regulation is controlling blood flow due to changes in blood pressure and local blood flow control is due to need flow or lack there of.

Question 11

When 3 organs have special blood flow regulation mechanisms that are used constantly by the body?

Answer 11

Kidneys, Brain and skin

Question 12

this signal molecule released from healthy cells, causes vasodilation when it activates the cGTP -> cGMP pathway.

Answer 12

NO

nitrous oxide

Question 13

in damaged endothelial cells (caused by hyptertension, athersclerosis etc) there is a release of what peptide hormone that causes vasoconstriction? and this peptide also prevents vasodilation by blocking what?

Answer 13

Endothelin
Nitrous Oxide (NO) pathway blocked

Question 14

for Humoral Circulation Control name the common activators of Vasoconstriction?

Answer 14

• Norepinephrine
• Epinephrine
• Angiotensin II
• Vasopressin

Question 15

name the 2 Vasodilators that are common in Humoral circulation control?

Answer 15

• Bradykinins

* Histamine

Question 16

T/F The SNS innervates all blood vessels?

Answer 16

False, everything BUT capillaries

Question 17

The SNS primarily does Vaso constriction, dilation or both?

Answer 17

vasoconstriction

Question 18

The Vasomotor center in the brain is located in which region? and where are the constriction and dilation portions represented?

Answer 18

Medulla Oblongota
VC - Upper anterolateral
VD - Lower anterolateral

Question 19

TQ - between vasoconstriction and vasodilation centers of the brain, which of these act to inhibit the other?

Answer 19

Vasodilation works through the inhibition of vasoconstriction center of the brain.

Question 20

Which 2 cranial nerves carry vasomotor sensory information?

Answer 20

9 and 10

Question 21

Are Baroreceptors are stimulated by High/or/Low B.P.?

Answer 21

Low

Question 22

T/F, Baroreceptors are located in carotid but not aortic sinuses?

Answer 22

False, they are located in both sinues

Question 23

are baroreceptors in the carotid or aortic sinus more sensitive and which pressures are they stimulated at?

Answer 23

Carotid baroreceptors are more sensitive, being stimulated by BP< 60 mmHg
Aortic sinus baroreceptors are stimulated by pressures < 30 mmHg

Question 24

T/F Baroreceptors can cause either increases or decreases in arterial BP?

Answer 24

true, even though