Circulation: Local Control of Blood Flow

Question 1

what are the 2 types of blood flow control?

Answer 1

local
long term

Question 2

what are 3 aspects of local control?

Answer 2

• tissue needs
• neural
• hormonal

Question 3

what factor has the greatest impact on local control?

Answer 3

tissue needs

Question 4

what are 2 aspects of long term control?

Answer 4

• kidney
• angiogenesis

Question 5

what is angiogenesis?

Answer 5

change in number or size of blood vessels
(occurs with tumors -> highly vascularized)

Question 6

what 3 things can stimulate the growth of new blood vessels?

Answer 6

• vascular endothelial growth factor (VEGF)
• fibroblast growth factor
• angiogenin
  each of these cause increased vasculature of tumors

Question 7

what is the vasodilator local control theory?

Answer 7

increased tissue metabolism causes release of vasodilators:
- increases vessel size
- decreases resistance and
- increases blood flow

Question 8

what is the oxygen/nutrient lack local control theory?

Answer 8

increased tissue metabolism or decreased O2 causes:
- precapillary sphincter to relax
- more blood flow to capillary
- increases vessel size
- decreases resistance
- increases blood flow

Question 9

both theories of local control of blood flow lead to…

Answer 9

increased vessel size + decreased resistance = increased blood flow

Question 10

blood flow is proportional to ____

Answer 10

blood pressure

Question 11

name the metabolic vasodilators

Answer 11

• adenosine
• AMP, ADP
• CO2 (lack of O2)
• H+ (lower pH)
• K+
• lactic acid

Question 12

name the other vasodilators

Answer 12

• NO
• bradykinin
• substance P
• histamine
• leukotrienes
• lack of O2 (CO2)

Question 13

name the vasoconstrictors

Answer 13

• serotonin
• NE
• epinephrine
• angiotensin II
• vasopressin (ADH)
• endothelin
  (contain “in”)

Question 14

what is active hyperemia?

Answer 14

increase in blood flow & BP brings more nutrients & O2 into tissue

Question 15

what is reactive hyperemia?

Answer 15

increase in blood flow & BP brings increase in O2 to tissues, which causes rebound vasoconstriction back to normal size

Question 16

active hyperemia and reactive hyperemia account for the theory of ____

Answer 16

autoregulation

Question 17

what is the autoregulation theory?

Answer 17

if a vessel has either increased blood flow OR increased BP (=increased size), the blood vessel will react by decreasing in size (vasoconstriction), and vice versa

Question 18

what percent of blood volume is in the systemic circulation?

Answer 18

84%

Question 19

what percent of blood volume is in the systemic veins?

Answer 19

64% (*veins have the most volume)

Question 20

what percent of blood volume is in the cardio-pulmonary system?

Answer 20

16%

Question 21

which vessels have the largest compliance?

Answer 21

veins

Question 22

what 3 factors determine venous return?

Answer 22

• skeletal muscle pump
• respiratory pump
• sympathetic NS

Question 23

backflow in veins is prevented by ____

Answer 23

valves

Question 24

problems with valves leads to ____

Answer 24

varicose veins

Question 25

central venous pressure is equal to…

Answer 25

right atrial pressure
(0-4mmHg)

Question 26

mean arterial pressure is equal to…

Answer 26

2/3 diastolic + 1/3 systolic

Question 27

pulse pressure is equal to…

Answer 27

systolic - diastolic

Question 28

what factors increase pulse pressure?

Answer 28

increased systolic pressure:
- increased SV
- increased HR
- decreased aortic compliance

Question 29

what changes would occur to vascular conductance, capillary filtration, and blood flow in response to decreased vessel diameter?

Answer 29

all would decrease

Question 30

under normal physiological conditions, blood flow to the skeletal muscles is determined mainly by ____

Answer 30

metabolic needs

Question 31

if nitric oxide is infused into the brachial artery, what changes would occur to capillary hydrostatic pressure, interstitial hydrostatic pressure, and lymph flow?

Answer 31

all would increase

Question 32

during exercise, increased plasma adenosine concentration leads to…

Answer 32

arteriolar vasodilation

Question 33

what change in arterial compliance would increase pulse pressure?

Answer 33

decrease

Question 34

what would happen to venous hydrostatic pressure in the legs with movement of leg muscles?

Answer 34

decrease