Week 9 Lecture 1

Front 1

Blood vessels are well innervated by sympathetic nerves.

Back 1

True

Front 2

Vessels dont have parasymp. innervation.

Back 2

False. Some do have.

Front 3

What is the main agonist of the symp. NS on blood vessels?

Back 3

Noradrenaline

Front 4

What acts on blood vessels from the para. NS?

Back 4

ACh

Front 5

Where do you get limited innervation of blood vessels by the parasymp. NS ?

Back 5

Salivary glands
Genitalia
Bowel

Front 6

What happens at alpha adrenoceptors in blood vessels?

Back 6

Constriction(by both epi and norad)

Front 7

What happens at B2 adrenoceptors in blood vessels?

Back 7

Dilatation

Front 8

Change in arteriolar tone offers most resistance change.

Back 8

True.

Front 9

Arteriolar response to symp. activation depends on

Back 9

Adrenoceptor population
-Alpha constriction in skin,coronary,brain,viscera
-beta dilatation in skeletal muscle

Front 10

At which adrenoceptor is Norad a better agonist?

Back 10

Alpha adrenoceptors.---> vasoconstriction in BV.

Front 11

Adrenaline in low dose causes

Back 11

Dilatation(skeletal muscles)

Front 12

Adrenaline in high doses causes

Back 12

Vasoconstriction(increase BP)

Front 13

Isoprenaline acts only on Beta adrenoceptors.

Back 13

True-vasodilatation

Front 14

What are the 2 types of adrenoceptors found in BV?

Back 14

Alpha and beta

Front 15

What is Prazosin?

Back 15

Alpha adrenoceptor antagonist ---> vasodilatation

Front 16

Propanolol is

Back 16

Beta antagonist causing vasoconstriction.

Front 17

Right Coronary artery supplies the right atrium and right ventricle and likewise for left coronary artery.

Back 17

True,with some overlap.(right dominant in 50 % of population)

Front 18

What are the factors that influence coronary blood flow?

Back 18

-Physical
-Neural
-Metabolic

Front 19

When does most of blood flow through left coronary arteries?

Back 19

During diastole.(extravascular forces prevent blood flow)

Front 20

Right coronary blood flow is max. during systole.

Back 20

True

Front 21

What does symp. stimulation do to coronary blood flow?

Back 21

Increase coronary blood flow

Front 22

What is the direct effect of symp. NS on coronary blood flow?

Back 22

Vasoconstriction because more alpha receptors.

Front 23

WHat is the INDIRECT effect of symp. stimulation on coronary blood flow?

Back 23

Increase cardiac contractility (Beta 1) and extravascular compression + decrease diastole impairing flow----> this increases O2 consumption causing metabolic vasodilatation---> increase flow.

Front 24

What is the parasymp. effect on coronary blood flow?

Back 24

Negligible direct effect except for indirect effect of bradycardia which leads to decreased flow.

Front 25

What is the primary regulator of coronary arterial tone?

Back 25

Metabolic control

Front 26

CBF is in proportion to the O2 requirements of the myocardium.

Back 26

True

Front 27

What is active hyperemia?

Back 27

Increase in blood flow in response to increased metabolic demands

Front 28

O2 is efficiently removed by heart from blood.

Back 28

True(65-70 % at rest)

Front 29

What are the mediators of metabolic vasodilatation?

Back 29

Adenosine(breakdown of ATP)
CO2
H+
lactic acid

Front 30

There is a linear relationship between CBF and O2 metabolic demands.

Back 30

True(doesnt happen in other organs as they will initially extract more O2)

Front 31

What is the major influence of blood flow to the skin?

Back 31

Temperature regulation.

Front 32

What are the 2 types of resistance vessels in skin?

Back 32

-arterioles
-AV anastomoses(shunt blood from arterioles to venules bypassing capillaries)

Front 33

If AV anastomoses open up, large blood flow THROUGH skin but not large blood flow TO skin.

Back 33

True

Front 34

AV anastomosoes contain thin muscular walls.

Back 34

False.Thick muscular walls.

Front 35

AV anastomoses contain rich SYMP. innervation.

Back 35

True.

Front 36

Nerve interruption to skin causes

Back 36

Maximum dilatation

Front 37

What does nerve stimulation cause to skin?

Back 37

Total occlusion

Front 38

Where do you find AV anastomoses?

Back 38

feet,hands,lips,nose,ears.

Front 39

Closing blood flow to anastomoses will not stop flow to skin

Back 39

Because of capillaries.

Front 40

Cutaneous blood flow

Back 40

-normal:400 ml/min
-severe cold : 50
-severe heat : 2800

Front 41

What regulate body temp. ?

Back 41

Hyppthalamus

Front 42

What happens at normal temp. ?

Back 42

Sympathetic constriction

Front 43

At high temp.,

Back 43

Decreased symp. outflow with vasodilatation.

Front 44

Skeletal muscle blood flow has

Back 44

large capacity to respond to exercise
-3-4 ml/min per 100 g at REST
-50-80 ml/min per 100 g during EXERCISE.(CO incr. by 4)

Front 45

At rest,what determines skeletal muscle blood flow?

Back 45

Neural

Front 46

During exercise,what determines skeletal muscle bloow flow?

Back 46

Local.
-O2 deficiency
-release of local dilator factors(adenosine,K+,H+,CO2)
-circulating epi--->stimulates B2 adrenoceptors---> vasodilatation.

Front 47

Neural control in skeletal muscles in via

Back 47

Norad. released from symp. nerves causing constriction by activating Alpha adrenoceptors.
-reduced baroreceptor stimulation causes vasoconstriction.

Front 48

At rest, there is not much circulating adrenaline

Back 48

True