Vascular Foundations 2

Question 1

How is blood flow maintained during ventricular diastole

Answer 1

elastic recoil of the arteries sends blood forward into the rest of the circulatory system

Question 2

Minimum Mean Arteriole Pressure

Answer 2

60 mmhg
- required to perfuse the systemic organs (nutrient dilivery etc)

Question 3

Pulse Pressure Equation

Answer 3

Systolic Pressure - Diastolic Pressure

Question 4

Mean Arterial Pressure (MAP) Equation

Answer 4

DIastolic pressure + (1/3)*(pulse pressure)

Question 5

MAP is determined by

Answer 5

1. Blood Volume
2. Cardiac Output
3. Resistance
4. Distribution of blood between venous and arterial vessels

Question 6

Blood Volume Determinents

Answer 6

1. Fluid intake
2. Fluid loss (which depends on kidney regulation and passiveness)

Question 7

Cardiac Output Determinents

Answer 7

1. Heart Rate
2. Stroke Volume

Question 8

Resistance Determinents

Answer 8

1. arteriole diameter

Question 9

Distribution of blood determinents

Answer 9

1. diameter of the veins

Question 10

Arteriole Resistance determination

Answer 10

arteriolar radius, which can be changed by
1. local factors
2. SNS

Question 11

Local Factors of Radius Change

Answer 11

1. Myogenic Autoregulation
2. Paracrines released in response to changes in tissue needs

Question 12

Myogenic Autoregulation

Answer 12

reflexive constriction of the blood vessel in response to an increased pressure
- decreases blood flow/pressure
- increases contraction and resistance

Question 13

Paracrines released in response to changes in tissue needs types

Answer 13

1. Active Hyperemia
2. Reaction Hyperemia

Question 14

Active Hyperemia

Answer 14

matching flow to metabolic demand
EX) increased demand will lead to increased blood flow by vasodilation

Question 15

Reactive Hyperemia

Answer 15

compensation following a period of reduced blood flow
EX) decreased blood flow due to blocked leads to vasodilation to increase blood flow and move the blockage

Question 16

SNS affect on Arteriole Resistance

Answer 16

SNS exerts tonic control with two neurotransmitters
1. Norepinephrine
2. Epinepherine

Question 17

Norepinepherine Pathway on arteriole resistance

Answer 17

1. binds to alpha-1 adrenergic receptors on most smooth muscle cells
2. coupled to Gq proteins that activate PLC
3. results in increased IP3
4. increased Ca release from SR
5. Smooth muscle contraction

Question 18

Norepinepherine Overall Effect

Answer 18

increases contraction and diverts the blood flow away from skin/visceral organs

Question 19

Epinepherine Pathway on arteriole resistance

Answer 19

1. binds to beta-2 adrenergic receptors on smooth muscle cells of the skeletal muscles/heart/liver
2. coupled to Gs protein AC
3. increases cAMP and PKA
4. Smooth muscle relaxation

Question 20

Epinepherine Overall Effect

Answer 20

increases relaxation and diverts the blood flow towards the heart/lungs/liver

Question 21

baroreceptors function

Answer 21

pressure sensors with stretch activated channels

-maintains arterial pressure homeostasis

Question 22

baroreceptors location

Answer 22

1. carotid sinus
2. aortic arch