Cardiovascular System Review!

Question 1

The Ventricles contract after the atria, because of the……

Answer 1

slow conduction of the AV node

Question 2

What causes the rapid depolarization of Autorythmic cardiac (nodal) cell AP?

Answer 2

Voltage gated Ca++ chapels opeing

Question 3

What causes the threshold graded depolarization in Autorhytmic cardiac (nodal) cell AP?

Answer 3

Na+ ions leaking in through funny channel PLUS Ca++ ions moving in through T-channels

Question 4

What causes repolarization in the autorythmic cardiac (nodal) cel AP?

Answer 4

Reopening of K+ channels plus closing of Ca++ channels

Question 5

What causes the prolonged plateau phase in myocardial ventricular cell AP?

Answer 5

Slow, prolonged opening of voltage gated Ca++ channels PLUS the closure of K+ channels.

Question 6

What causes the rapid depolarization in myocardial ventricular cell AP?

Answer 6

Rapid opening of Na+ channels

Question 7

What causes the repolarization of myocardial ventricular cell AP?

Answer 7

Opening of K+ channels

Question 8

How do you calculate stroke volume?

Answer 8

SV=EDV-ESV

Question 9

MAP = ?

Answer 9

MAP = CO x TPR

Question 10

CO = ?

Answer 10

CO = Stroke volume x Heart rate

Question 11

Sympathetic acting on _____ receptors in Atria increase the _______ which _______ heart rate.

Answer 11

• Beta1 receptors
• Increases the funny channel
• Increases Heart rate

Question 12

Parasympathetics acting on ______ receptors in the atria ________ the funny channel, which ________ the heart rate.

Answer 12

• Muscarinic receptors
• Decrease the funny channel
• increases heart rate because it decreases parasympathetics

Question 13

How do you control Stroke volume?

Answer 13

• Preload (EDV)
• Frank starling mechanism
• Afterload
• Contractility

Question 14

What 3 factors affect the stroke volume?

Answer 14

1. Preload (EDV) = the volume of blood in the ventricles just before contraction.
2. Magnitude of sympathetic input to the ventricles (Increases contractility, but not the same as Frank starling mechanism)
3. Afterload = the pressure against which the ventricle pumps.

Question 15

Increased adenosine in metabolically controlled organ will cause ______.

Answer 15

Vasodilation

Question 16

If arterial pressure decreases?

Answer 16

Baroreceptor discharge decreases and so fewer impulses travel up the afferent nerves to the medullary cardiovascular center and this induces:
1. Increased heart rate due to increased symp. and decreased parasymp. to heart.
2. Increased ventricular contraction due to increased Symp. to the ventricular myocardium.
3. Increased Arteriole and Venous constriction due to increased symp. to vasculature.
= Increased CO (increased HR and SV) and increased TPR = Normalization of BP.