Integration of CDV mechanisms

Question 1

resistance to blood flow is ..

Answer 1

directly proportional to blood viscosity and length of lood vessel

Question 2

what is resistance to blood flow inversely proportional to

Answer 2

the radius of the blood vessel to the power of 4

Question 3

vasomotor tone

Answer 3

caused by tonic discharge of sympathetic nerves resulting in continuous release of noradrenaline

Question 4

what fcators cause relaxation of arteriolar smooth muscles resulting in vasodilation

Answer 4

Decreased local PO2
Increased local PCO2
Increased local [H+] (decreased pH)
Increased extra-cellular [K+]
Adenosine release (from ATP)

Question 5

humoral agents which cause vasodilation

Answer 5

histamine
bradykinin
nitric oxide

Question 6

what is continously produced by the vascular endothelium

Answer 6

nitric oxide

Question 7

nitric oxide

Answer 7

potent vasodilator

Question 8

what does nitric oxide activate

Answer 8

cGMP which serves as a second messenger for smooth muscle relaxation

Question 9

humoral agents causing vasoconstriction

Answer 9

serotonin
thromboxane a2
leukotrienes
endothelin

Question 10

what happens when MAP falls

Answer 10

vessels dilate to increase blood flloq

Question 11

what happens when map increases

Answer 11

vessels constrict to limit flow

Question 12

what happens to the pressure during inspiration

Answer 12

intrathoracic pressure decraeses and intra abdominal increase