Cardiovascular Physiology

Question 1

This component of the vasculature system has the largest total cross-sectional and surface area

Answer 1

Capillaries
single layer of endothelial cells surrounded by basal lamina
site of exchange of nutrients, water and gas

Question 2

This portion of the vasculature system contains the greatest volume of blood

Answer 2

veins

Question 3

Largest decrease in pressure occurs in this portion of the vasculature

Answer 3

arterioles

Question 4

Where on a ECG do you find atrial repolarization?

Answer 4

It is buried in the QRS complex

Question 5

Absolute Refractory Period

Answer 5

Time in which no action potential can be generated

regardless of how much inward current is applied.

Question 6

Relative Refractory Period

Answer 6

period immediately after the ARP when repolarization is almost complete
AP can be elicited, but more than usual inward current is required.

Question 7

Effective Refractory Period

Answer 7

Conducted action potential cannot be elicited

Question 8

Parasympathetic effects on the heart use which NT and which receptor

Answer 8

Ach via Muscarinic

Vagal inervation

Question 9

Parasympathetic stimulation slows down the HR by effecting which phase of SA nodal firing?

Answer 9

Phase 4

Changes I_f

Question 10

Contractility is directly related to

Answer 10

Intracellular [Ca++]

Question 11

Sympathetic Stimulation Occurs via which receptor

Answer 11

Beta 1

Question 12

Sympathetic stimulation increases contractility via which two mechanisms

Answer 12

1. increases inward Ca++ during plateau phase
2. Increases activity of Ca++ pump of SR by phosphorylation of Phospholamban
   NB: both actions are mediated by Beta-1 activation of Gs that stimulates PKA

Question 13

Increased Pre-Load causes

The Pressure volume loop would appear ______

Answer 13

1. Increase in EDV as a result of increased venous return
2. Increase in stroke volume
   Displays increased width of pressure volume loop
   NB: Afterload is unchanged

Question 14

Increased Afterload causes

Answer 14

1. Increase in aortic pressure
2. Decrease in stroke volume since ventricle must eject against higher pressure
3. decreased width of pressure-volume loop
4. Increased ESV

Question 15

Cardiac Oxygen Consumption is increased by

Answer 15

1. Increased Afterload
2. Increased heart size
3. Increased contractility
4. increased heart rate

Question 16

Mechanism of Baroreceptor upon low ECV

Answer 16

Stretch receptors in carotid sinus note decrease pressure

• Decrease pressure = decrease stretch
• decrease stretch = decrease firing of glossopharyngeal nerve
• decrease IX decreases parasympathetic tone

Question 17

Four effects to increase MAP during low ECV by baroreceptors

Answer 17

1. Increase HR via decreased parasymp and increased symp of SA node
2. increase contractility and SV
3. Vasoconstriction of arterioles
4. Vasoconstriction of veins