Overview

Question 1

What is the main site of TPR?

Answer 1

arterioles

Question 2

What contains most blood under resting conditions?

Answer 2

veins

Question 3

What is another way MAP can be calculated (other than 2xdiastolic+systolic/3)?

Answer 3

MAP = DBP + 1/3 difference between SBP and DBP

Question 4

What does vasoconstriction do to TPR and MAP?

Answer 4

increase

Question 5

What is resistance to blood flow directly proportional to?

Answer 5

blood viscosity and length of blood vessel

Question 6

How is resistance to blood flow related to radius of blood vessel?

Answer 6

inversely to the power of 4

Question 7

Are vascular smooth muscles controlled by extrinsic or intrinsic factors?

Answer 7

Both

Question 8

What is it called when the vascular smooth muscles are partially constricted at rest?

Answer 8

vasomotor tone

Question 9

What is vasomotor tone caused by?

Answer 9

by tonic discharge of sympathetic nerves resulting in continuous release of noradernaline

Question 10

What will increased sympathetic discharge do?

Answer 10

it will increase the vasomotor tone resulting in vasoconstriction

Question 11

“There is no significant parasympathetic innervation of arterial smooth muscles” - what are the exceptions to this?

Answer 11

exceptions are penis and clitoris

Question 12

What hormone is involved in exstrinsic control of vascular smooth muscle?

Answer 12

adrenaline

Question 13

Adrenaline acting on what receptors causes vasoconstriction?

Answer 13

alpha

Question 14

Adrenaline acting on what receptors causes vasodilation?

Answer 14

beta

Question 15

Where are alpha receptors predominant?

Answer 15

skin, gut, kidney arterioles

Question 16

Where are beta receptors predominant?

Answer 16

cardiac and skeletal muscle arterioles

Question 17

What helps with strategic redistribution of blood e.g. during exercise?

Answer 17

Extrinsic stimulation of vascular smooth muscle by adrenaline

Question 18

What other hormones affect vascular smooth muscle?

Answer 18

Angiotensin II: causes vasoconstriction
Antidiuretic hormone (vasopressin): causes vasoconstriction

Question 19

Which type, intrinsic or extrinsic, can override the control of the other?

Answer 19

instrinsic

Question 20

Which metabolic changes cause vasodilation?

Answer 20

Decreased local PO2

Increased local PCO2

Increased local [H+] (decreased pH)

Increased extra-cellular [K+]

Increased osmolality of ECF

Adenosine release (from ATP)

Question 21

Which local chemical (humural agents) cause vasodilation?

Answer 21

Histamine
Prostaglandins
Bradykinin
Nitric Oxide (NO)

Question 22

Which chemical agent is continuously released by endothelial cells of arteries and arterioles from the amino acid L-arginine?

Answer 22

Nitric Oxide

Question 23

Does NO have a short or long half life?

Answer 23

short (a few seconds)

Question 24

What causes activation of nitric oxide synthase?

Answer 24

increased FLOW and release of calcium in vascular endothelial cells

Question 25

where does nitric oxide diffuse and what does it do there?

Answer 25

from the vascular endothelium into the adjacent smooth muscle cells where it activates the formation of cGMP that serves as a second messenger for signalling smooth muscle relaxation

Question 26

Which humoral agents cause vasoconstriction?

Answer 26

Serotonin Thromboxane A2 Leukotrienes Endothelin

Question 27

What stimulates production of endothelin?

Answer 27

angiotensin II and vasopressin

Question 28

Does the cold cause vasoconstriction or vasodilation?

Answer 28

Vasoconstriction

Question 29

What is the myogenic response to stress and what tissues is it important in?

Answer 29

If MAP rises resistance vessels automatically constrict to limit flow If MAP falls resistance vessels automatically dilate to increase flow Important in tissues like brain and kidneys

Question 30

What does "shear stress" response mean?

Answer 30

Dilatation of arterioles causes sheer stress in the arteries upstream to make them dilate. This increases blood flow to metabolically active tissues

Question 31

What does increased venomotor tone do to venous return?

Answer 31

increases

Question 32

What does contraction of muscles aid?

Answer 32

venous return

Question 33

Does sympathetic stimulation cause slop of pacemaker cells to increase or decrease?

Answer 33

increase

Question 34

What does sympathetic nerve contraction do to Frank Starling Curve?

Answer 34

shifted to LEFT