Lecture 18

Question 1

What is the average resting CO in L/min?

Answer 1

5 L/min

Question 2

What is the average exercising CO L/min?

Answer 2

25 L/min

Question 3

What is the % change in CO flow to the heart from resting to exercising?

Answer 3

No change, it remains the same at ~4%

Question 4

T or F? CO flow to the brain increases during exercise.

Answer 4

False, blood flow to the brain decreases, skeletal muscle increases.

Question 5

T or F? Active tissue can require up to 20x increase in blood flow.

Answer 5

True

Question 6

CO can increase to approximately ____ times normal during exercise.

Answer 6

6

Question 7

CO alone cannot meet the demand of active tissues, what must happen to help increase blood flow to the tissues?

Answer 7

Changes in microcirculation, vasoconstriction.

Question 8

Smooth muscle in small arteries and arterioles can be stimulated to contract or relax via ____ signals, _____ stimuli, ______, and changes in _____ environment

Answer 8

nervous signals, hormonal stimuli, stretch, chemical environment

Question 9

T or F? Contraction of arteries and arterioles require an action potential to stimulate contraction.

Answer 9

False, no action potential needed

Question 10

What 3 main categories regulates blood flow?

Answer 10

SNS
Local chemical factors
Long-term angiogenesis

Question 11

T or F? The PNS innervates the majority of blood vessels.

Answer 11

False, PNS does not innervate the majority of blood vessels but does regulate dilation of some blood vessels in specific areas of the body, such as the genitals. SNS innervates blood vessels.

Question 12

The SNS causes generalized vasoconstriction and venoconstriction due to stimulation of ________ receptors.

Answer 12

α1-adrenergic

Question 13

The ____ and _____ circulations have poor SNS vasoconstrictor innervation so are spared the vasoconstrictor effect.

Answer 13

coronary ; cerebral

Question 14

Local ____, and release of _____ _______, is the primary controller of coronary and cerebral blood flow.

Answer 14

metabolism;vasodilator substances

Question 15

Stimulation of B2 receptors causes __________ in few vascular beds.

Answer 15

Vasodilation

Question 16

What local chemical factors are released from metabolically active or hypoxic tissues that cause relaxation of smooth muscle and vasodilation of small arteries and arterioles?

Answer 16

Adenosine, CO2 , H+, K+, lactate.

Question 17

Endothelial cells release _____ in response to sheer stress from blood flow, causing vasodilation.

Answer 17

nitric oxide

Question 18

What produces nitric oxide (NO)?

Answer 18

Endothelial NOS (Nitric Oxide Synthase)

Question 19

T or F? Local chemical factors such as autocrine/paracrine peptides endothelin, bradykinin, prostaglandins, and histamine causes arteriole dilation and capillary permeability.

Answer 19

False, all is true except endothelin. Endothelin causes vasoconstriction.

Question 20

How is long term blood flow regulated to various tissues?

Answer 20

Angiogenesis

Question 21

In response to chronic ischemia, tissues release angiogenic factors, (_______, etc) which stimulate angiogenesis.

Answer 21

VEGF

Question 22

T or F? Angiogenesis can decrease the number of blood vessels than can occur.

Answer 22

True. Increase or decrease in number of blood vessels can occur.

Question 23

What is the a abbreviation for oxygen consumption?

Answer 23

V(O2)

Question 24

A-V(O2) difference is the abbreviation for what?

Answer 24

Arteriovenous oxygen difference.

Question 25

What is A-V(O2) difference?

Answer 25

It is the difference in the Po2 between the arterial blood and the venous blood. (the Po2 of the blood entering a tissue -the Po2 of the blood leaving the tissue).

Question 26

T or F? If the A-VO2 difference increases, it represents an increase in oxygen uptake by that tissue.

Answer 26

True

Question 27

What factors contribute to the changes in HR, SV, CO, SBP, & DBP during exercise?

Answer 27

``` HR - Increase HR by SNS via B-1 SV - Increase contractility via B-1 CO - Increase HR /SV increases CO SBP - Increase CO increases SBP DBP - Decrease TPR decreases DBP ```

Question 28

During exercise, how does more blood get to the muscles if SNS causes vasoconstriction?

Answer 28

Local factors such as adenosine, CO2, H+, K+, Lactate and NO2 causes vasodilation of small arteries and arterioles.

Question 29

_______ _____ increases local factors to cause vasodilation in skeletal muscle and myocardium.

Answer 29

Metabolic rate

Question 30

During exercise, SV increases at first, then levels off and stays constant?

Answer 30

HR increases, filling time is shorter. (Normally it's contract, rest, rest; exercise it is contract, rest contract)

Question 31

As Aseel plays racket ball, her SBP is expected to increase due to increase in CO. Why would her DBP remain the same or decreases?

Answer 31

The primary determinant of DBP is TPR since local factors override the SNS and vasodilate the arteries, the TPR is constant or may decrease.

Question 32

What is rate-pressure product (pressure-rate product or double product)

Answer 32

It is an indirect index of myocardial O2 consumption, how hard the ventricle is working. (HRxSBP(or MAP))