Regulating Blood Flow

Question 1

What is blood flow affected by

Answer 1

MAP Blood pressure (CO x TPR)

Question 2

Where does the largest drop in pressure occur

Answer 2

Arterioles

Question 3

What is arterioles role in terms of blood flow

Answer 3

Match blood flow (determined by pressure) with metabolic need of cells

Question 4

What is the partial contraction of smooth muscle in vessels called

Answer 4

Tissue vessel tone

Question 5

What is it called when tissue vessel tone reduces diameter

Answer 5

Vasoconstriction

Question 6

When would vasoconstriction of the vessel tone occur

Answer 6

If some cells have higher metabolic need eg in exercise

Question 7

What is vasodilation

Answer 7

When tissue vessel tones increase in radius and decrease TPR therefore BP decrease (BF increases)

Question 8

What are the other way of saying arterioles

Answer 8

Sphincter

Question 9

What are the 3 mechanisms which control the vessel tone and therefore affect BF

Answer 9

Local control

Hormone control

Neural control

Question 10

What is auto regulation (local control) of vessel tone

Answer 10

Works on the fact if you increase pressure this will increase blood flow (P/ r)

Question 11

What happens when there is increased pressure which increases BF
(In auto regulation)

Answer 11

Pressure will stretch muscles and this promotes Ca2 influx

This causes muscle contraction which therefore regulates blood flow by increasing resistance = lowered blood flow (P/R)

Question 12

Metabolic control is also local, which metabolites cause vasodilation (increasing BF by decreasing resistance)

Answer 12

Co2, H+, K+ , temp, adenosine

Question 13

Which metabolite causes vasoconstriction to increase resistance and decrease BF

Answer 13

Oxygen

Cells don’t need supply of blood flow as much

Question 14

What are the 4 hormonal vasodilators which increase BF by reducing resistance

Answer 14

Histamine
NO
Kinins
Adrenaline

Question 15

Which receptor does adrenaline need to bind to to be a vasodilator

Answer 15

B2

Question 16

What does NO bind to which then produces cGMP for vasodilation

Answer 16

Guanylyl cyclase

Question 17

What are the 3 vasoconstrictor hormones

Answer 17

Adrenaline (bound to A1)

ADH

Angiotensin II

Question 18

What are the 3 neural controls of vessel tone / BF

Answer 18

Sympathetic vasoconstrictor fibres

Sympathetic vasodilation fibres

Parasympathetic vasodilation fibres

Question 19

How do sympathetic vasoconstrictors work

Answer 19

They release adr/nadr

When bound to A1 this causes vasoconstriction

(Unlike in heart when they bind to B1)

Question 20

What happens when there’s a lower frequency of sympathetic vasoconstrictor signals

Answer 20

Vasodilation due to less nadr binding at A1

Question 21

What do sympathetic vasodilators release and the effect of it

Answer 21

Ach

This causes increased Ca2+ (via ip3)

This causes NO synthesis and therefore vasodilation

Question 22

Do parasympathetic vasodilators work the same as sympathetic vasodilators

Answer 22

Yes

Question 23

CO affects pressure which if increased will also increase BF, what happens to CO when exercising

Answer 23

Increased CO from heart which causes vasodilation of the vessels to skeletal muscle to increase BF for supplying o2

Question 24

Why doesn’t BP increase during exercise despite CO increasing

Answer 24

Because TPR will decrease as vasodilation in vessels occurs to allow BF