CV Phy And Path 3

Question 1

What blood vessel quality affects flow and blood pressure?

Answer 1

Diameter

Question 2

What is the equation for blood flow? How can we calculate resistance?

Answer 2

Flow= P1-P2/ R

Resistance is proportional to 1/radius^4
Change in resistance affects pressure and flow downstream

Question 3

What is the relationship between blood velocity and total cross sectional area of blood vessel? Where do we have the largest drop in blood velocity?

Answer 3

Blood velocity is inversely proportional to the total cross sectional area of blood vessels.

Arterioles- largest drop in blood velocity
Capillaries- largest cross sectional area

Question 4

Where do we have the largest drop in BP?

Answer 4

Arterioles- control blood flow downstream

Question 5

Which ventricular wall is thicker?

Answer 5

Left ventricular wall

Question 6

Where do we have the greatest afterload (systemic or pulmonary)?

Answer 6

Greater afterload in systemic

Question 7

Is systemic blood flow constant? BP?

Answer 7

Yes constant though the whole circulatory system
BP is different in different places of circulatory system

Question 8

What is the formula for systemic blood flow?

Answer 8

=(P aorta - P vena cava)/ R= P arterial / R
=CO (HR x stoke volume)
= P arterial/ R= MAP/TPR= HR x SV
MAP= HR x SV x TPR= CO x TPR

Question 9

How do we calculate mean arterial pressure?

Answer 9

Regulated variable
MAP= 0.33 x pulse pressure + diastolic pressure

Question 10

What is total peripheral resistance (TPR)?

Answer 10

Arterioles contribute most to resistance

Question 11

What are 2 ways in which we can control blood pressure (and flow)?

Answer 11

Regulation of MAP: maintain 4-5L/min flow (at rest), increased flow as needed to meet metabolic demands

Local flow regulated by modulating resistance at the Arterioles: changes in vasomotor tone affect capillary function

Question 12

What two areas maintain a constant blood flow in the body to the heart?

Answer 12

Cerebral
Coronary

Question 13

How does smooth muscle activity affect blood flow?

Answer 13

Smooth muscle relaxation= decreased resistance
Smooth muscle contraction= increased resistance

Question 14

What kind of feedback system does the heart have?

Answer 14

Negative feedback
Positive feedback for blood clot formation

Question 15

What are the local factors that participate as metabolic vasoactive substances?

Answer 15

O2 (vasoconstrictor)
• CO2 (vasodilator)
• Adenosine (vasodilator)
• H+ (vasodilator)
• K+ (vasodilator)

Question 16

What substances participate in intrinsic local control of vessel diameter?

Answer 16

Histamine (vasodilator)
• Prostacyclin (vasodilator)
• Endothelial factors
• Endothelial Nitric Oxide Synthase (eNOS, vasodilator) Nitric Oxide (NO, vasodilator)
Endothelin (vasoconstrictor)

Question 17

What occurs when metabolism is increased?

Answer 17

Adenosine increases
Oxygen decreases
Vasodilation

Question 18

What occurs when metabolism is decreased?

Answer 18

Adenosine is less
More o2
Vasoconstriction

Question 19

What myogenic activity controls the vessel diameter (intrinsic)?

Answer 19

Vasoconstriction after the vessel stretches in response to a sudden increase in pressure Bayliss effect

Question 20

What auto regulation control the vessel diameter? (Intrinsic)

Answer 20

Active hyperemia:
• Increase in organ blood flow that is associated with
increased metabolic activity •
Examples:
• Increase in blood flow after muscle contraction
• Increase in coronary blood flow when HR is increased

Reactive hyperemia:
• Transient increase in organ blood flow following a brief period of ischemia (e.g., arterial occlusion)

Question 21

What is the presentation of hypertensive retinopathy?

Answer 21

Copper firing
Broadening of light reflex
Thickening of arterial wall