Microcirculation and Hemodynamics DSA

Question 1

In which vessels is the site of highest resistance and largest drops in pressure

Answer 1

Arterioles

Question 2

Which vessels contain the largest % of blood at any time

Answer 2

Venules and Veins

contain unstressed blood

Question 3

Eq. for blood flow velocity

Answer 3

v=Q/A
v - velocity
Q - flow
A - cross-sectional area

Question 4

What is the major mechanism to change flow?

Answer 4

change resistance of a vessel (especially at arteriole level)

Question 5

What is laminar flow

Answer 5

streamlined

Question 6

In a vessel where is the fastest velocity found

Answer 6

velocity - greatest in the center, least toward the vessel walls

Question 7

what causes turbulent flow

Answer 7

a disruption of laminar flow

Question 8

what is reynold’s number used for

Answer 8

to determine if flow will be turbulent or laminar

less than 2000 predicts laminar flow

Question 9

in which vessels are compliance the greatest?

Answer 9

veins

Question 10

what does arteriosclerosis do to SBP, pulse pressure, MAP, and DBP

Answer 10

increase SBP, pulse pressure and MAP

not much change to DBP

Question 11

what does aortic stenosis do to SBP, pulse pressure and MAP

Answer 11

all decreased

Question 12

Special circulations: Autoregulation

Answer 12

maintenance of a constant blood flow in face of changing arterial pressure

Question 13

Special circulations: Active hyperemia

Answer 13

blood flow to an organ is proportional to its metabolic activity

Question 14

Special circulations: reactive hyperemia

Answer 14

increase in blood flow in reaction to a period of decreased blood flow

example: heart after an ischemic event such as an occlusion or thrombus, blood flow may be restored perfusing the previously unperfused region

Question 15

Neuronal and hormonal control of circulation: Histamine and bradykinin

Answer 15

released in response to trauma and causes dilation of arterioles and constriction of venules. Net effect is an increase in hydrostatic pressure and filtration = local edema

Question 16

Neuronal and hormonal control of circulation: Serotonin (5-HT)

Answer 16

released in response to damage and is involved in vascular spasm, and is generally a local vasoconstrictor

Question 17

Neuronal and hormonal control of circulation: Prostaglandins

Answer 17

confusing.
prostacyclin and prostaglandins in the E-series cause dilation.

thromboxane A2 and prostagladins in the F-series cause constriction

Question 18

Neuronal and hormonal control of circulation: Angiotensin II and Vasopressin

Answer 18

constrictors that increas TPR

Question 19

Neuronal and hormonal control of circulation: NO

Answer 19

vasodilator and acts to relax vascular smooth muscle