Lab 4 Discussion Questions

Question 1

Characteristics of arteries vs. arterioles.

Answer 1

ARTERIES:
-lots of elastic fibers
-low and unchanging resistance to flow
ARTERIOLES:
-have more smooth muscle and less elastic fibers
-can change their diameter to change resistance to flow

Question 2

What are the smallest blood vessels?

Answer 2

Capillaries

Question 3

Which blood vessel has the highest total CSA?

Answer 3

Capillaries

Question 4

Where is the tricuspid valve located? Mitral valve?

Answer 4

• Tricuspid is b/t RA and RV

- Mitral is b/t LA and LV

Question 5

Where is the pulmonary valve located? Aortic valve?

Answer 5

• Pulmonary is b/t RV and pulmonary artery

- Aortic is b/t LV and aorta

Question 6

What were the effects of posture on BP when the subject went from supine to initial tilt?

Answer 6

Gravity induced venous pooling of blood in the leg’s distensible veins –> reduced VR to heart, SV, MAP, and BP

Question 7

How did the baroreceptors respond to the initial tilt? How did these changes affect the results recorded at 30 sec post tilt?

Answer 7

Decrease in stretch on the walls of the carotid sinus –> decreased the firing rate of baroreceptors –> decreased parasympathetic activity and increases sympathetic activity –> increased BP

Question 8

What part of the brain stem controls the CV system?

Answer 8

Medulla oblongata

Question 9

What causes the exercise pressor effect? What does it cause?

Answer 9

Result of sympathetic afferent nerve activity that causes peripheral vasoconstriction