Physiology - Part 3

Question 1

which receptors in the blood vessels do sympathetic nerves act on?

Answer 1

alpha-1 receptors

Question 2

what effect do sympathetic nerves have on the blood vessels?

Answer 2

arteriolar constriction

Question 3

what effect do parasympathetic nerves have on the blood vessels?

Answer 3

usually nothing

Question 4

in which tissues does epinephrine act on beta-2 receptors?

Answer 4

skeletal and cardiac muscle

Question 5

what effect does epinephrine acing on beta-2 receptors have on the blood vessels?

Answer 5

arteriolar dilation

Question 6

which hormones can increase total peripheral resistance?

Answer 6

epinephrine
angiotensin II
vasopressin

Question 7

which hormones can decrease total peripheral resistance?

Answer 7

epinephrine
atrial natriuretic peptide
brain natriuretic peptide

Question 8

what effect does angiotensin II have on the blood vessels?

Answer 8

arteriolar constriction

Question 9

what effect does vasopressin have on the blood vessels?

Answer 9

arteriolar constriction

Question 10

what effect do atrial natriuretic peptide and brain natriuretic peptide have on the blood vessels?

Answer 10

arteriolar dilation

Question 11

what are the four different types of local (intrinsic) controls?

Answer 11

active (metabolic) hyperaemia
pressure (flow) autoregulation
reactive hyperaemia
injury response

Question 12

what is active (metabolic) hyperaemia?

Answer 12

an adaptation to match blood supply to the metabolic needs of that tissue

Question 13

how does active (metabolic) hyperaemia work?

Answer 13

increased metabolic activity causes increases concentration of metabolites
triggers release of EDRF
increased flow to wash out metabolites

Question 14

what is EDRF?

Answer 14

endothelium derived relaxing factor = nitric oxide

Question 15

what is pressure (flow) autoregulation?

Answer 15

an adaptation to ensure that a tissue maintains its blood supply despite changes in mean arterial pressure

Question 16

how does pressure (flow) autoregulation work?

Answer 16

decreased mean arterial pressure decreases flow
metabolites accumulate
triggers release of EDRF
arterioles dilate and flow is restored to normal

Question 17

what is reactive hyperaemia?

Answer 17

an extreme version of pressure autoregulation

Question 18

how does reactive hyperaemia work?

Answer 18

occlusion of blood supply causes a subsequent increase in blood flow

Question 19

what happens in the injury response?

Answer 19

arteriolar dilation
increased blood flow
increased permeability
aids delivery of blood born leukocytes etc to injured area

Question 20

what are the four ‘special’ areas of circulation?

Answer 20

coronary
cerebral
pulmonary
renal

Question 21

which local (intrinsic) control does the coronary circulation show?

Answer 21

active hyperaemia

Question 22

what protects the coronary circulation from sympathetic arteriolar constriction?

Answer 22

swamped by many beta-2 receptors

Question 23

which local (intrinsic) control does the cerebral circulation show?

Answer 23

pressure autoregulation

Question 24

what makes the pulmonary circulation different from most tissues?

Answer 24

decreased O2 causes arteriolar constriction

Question 25

which local (intrinsic) control does the renal circulation show?

Answer 25

pressure autoregulation

Question 26

which two broad levels of control does the body have over arteriolar radius?

Answer 26

extrinsic effects (neural, hormonal)
local (intrinsic) effects