Cardiodynamics

Question 1

What is tissue perfusion?

Answer 1

Flowing of blood into tissues; delivers O2 and nutrients to cells, removes cellular waste; allows gas exchange (lungs), absorption of nutrients in digestion, formation of urine (kidneys)

Question 2

What controls blood flow into the capillary bed?

Answer 2

Precapillary sphincter muscles

Question 3

Are all capillary beds in the body perfused?

Answer 3

Capillary beds are only perfused when that area of the body needs blood flow

Question 4

What is the average cardiac output at rest? moderate exercise?

Answer 4

5L/min
17.5L/min

Question 5

Describe the difference between the distribution of blood flow to different areas of the body during rest vs. moderate exercise

Answer 5

At rest, visceral organs like the digestive organs and kidneys are receiving more blood flow. During moderate exercise, skeletal muscles receive a much higher percentage of blood flow while visceral organs decrease. The brain uses roughly the same volume of blood, but the percentage is less due to increased overall volume flowing.

Question 6

Why is cutaneous blood flow greater during moderate exercise?

Answer 6

Blood carried to the skin helps cool the body

Question 7

What is cardiac output measuring?

Answer 7

The volume of blood being pumped by each ventricle per minute. Each ventricle pumps an equivalent amount.

Question 8

What is the cardiac output equation?

Answer 8

CO=HR*SV (stroke volume)

Question 9

What is stroke volume?

Answer 9

The volume of blood pumped out of a ventricle each time it contracts

Question 10

What is the stroke volume equation?

Answer 10

SV=end diastolic vol (mL)-end systolic vol (mL)

Question 11

What can affect heart rate?

Answer 11

Hormones & autonomic innervation

Question 12

What is venous return?

Answer 12

The amount of blood returning to the heart from systemic veins

Question 13

What is the Frank-Starling mechanism?

Answer 13

More in -> more out. The primary intrinsic controller of SV. Describes impact of greater end diastolic volume

Question 14

Describe what the Frank-Starling mechanism does

Answer 14

The more blood is returned to the heart, the more the cardiac muscle stretches. The more the muscle stretches, to a certain threshold, the stronger the contraction that can be produced and the more blood that can be pumped out

Question 15

What is the Bainbridge Reflex?

Answer 15

In response to increased end diastolic volume (stretch), the heart rate increases

Question 16

What is the difference between the Frank-Starling mechanism and the Bainbridge reflex?

Answer 16

Both are in response to increased cardiac muscle stretch, but FSM explains cardiac output while BR explains heart rate

Question 17

What are the two ways to increase SV?

Answer 17

Greater EDV or lower ESV

Question 18

Where in the brain do cardiac innervations synapse?

Answer 18

Medulla oblongata

Question 19

What receptors communicate with the cardiac center of the brain?

Answer 19

Baroreceptors (pressure/stretch in aorta, carotid)
Chemoreceptors (pH, O2 sat, etc at aorta and carotid)
Proprioceptors in skeletal muscle