BMS 420 - Quiz #1lectures 1-8

Question 1

Cardiovascular system transfers heat from deep in body to the outside environment. True or false?

Answer 1

True.

Question 2

What is the normal pathway of innervation in the heart?

Answer 2

SA node -> AV node -> Bundle of his -> Bundle branches -> Purkinje fibers.

Question 3

Sympathetic innervation increases the release of what neurotransmitters?

Answer 3

Epinephrine (Positive inotropic) and Norepinephrine (Positive chronotropic)

Question 4

During exercise what response is activated? Causing what innervation?

Answer 4

Fight or flight - increasing sympathetic innervation.

Question 5

A patient complains of being lightheaded when they are standing up straight, and his blood pressure shows a significant decrease in arterial pressure upon standing. What is the most likely causation of this?

Answer 5

A decrease in cardiac output. There is less blood ejected during systole, causing a lower aortic pressure, and in turn, a lower MAP.

Question 6

What is responsible for establishing the resting membrane potential in cardiac myocytes?

Answer 6

Potassium conductance.

Question 7

While sleeping, what type of innervation is going to slow down the heart rate?

Answer 7

Parasympathetic - Slows.
Sympathetic - Speeds up.

Question 8

Norepinephrine is released from what innervation, and has what effect?

Answer 8

1. Sympathetic.
2. Positive chronotropic (Increases heart rate)

Question 9

Epinephrine is released from what innervation, and has what effect?

Answer 9

1. Sympathetic.
2. Positive inotropic. (Increases strength of contraction)

Question 10

What causes the conduction delay at the AV node?

Answer 10

1. Small size of the AV nodal cells.
2. The slow rate of rise in action potential during phase 0.

Question 11

What ensures that electrical signal is not propagated between atrial myocytes and ventricular myocytes. Making sure that the signal only passes through the atria to ventricles via the AV node?

Answer 11

The cardiac skeleton.

Question 12

Relative refractory period:

Answer 12

The period of an action potential that is not responsive to normal stimuli, but will respond to supra-threshold stimuli.

Question 13

Absolute refractory period:

Answer 13

The period of an action potential that is not responsive to any level of stimuli, no matter what.

Question 14

Cardiac introphy is increased by?

Answer 14

Increased activity of calcium channels. Calcium will bind to troponin C, and allow for more cross bridge formation, and over all greater contractility.

Question 15

What will occur due to extremely decreased intropy?

Answer 15

Heart failure.

Question 16

Increased intropy causes what?

Answer 16

Increased ejection fraction.

Question 17

The area of vasculature with the most surface area and the lowest blood pressure:

Answer 17

Capillaries.

Question 18

The vasculature with the highest resistence:

Answer 18

Arterioles

Question 19

What would happen with inhibition of the Na+/K+ ATPase pump?

Answer 19

This pump takes Na+ out of the cell, and if it was inhibited we would see an increase in intracellular Na+, which will depolarize the cell and bring it closer to the threshold.

Question 20

______ increases stroke volume, increases ventricular contractility, increases atrial contractility, and increases lusitropy (relaxation).

Answer 20

SNS - Sympathetic Nervous System

Question 21

What is an effect of phosphorylation of calcium channels?

Answer 21

Increased cardiac inotropy.

Question 22

Dephosphorylation of phospholamban will primarily cause:

Answer 22

A negative lusitropic effect.

Question 23

A positive lusitropic effect will be caused by:

Answer 23

Phosphorylation of phospholamban.

Question 24

Binding of extracellular calcium to the ________ _________ will cause sarcoplasmic reticulum to release stored calcium.

Answer 24

Ryanodine receptors.

Question 25

Define trigger calcium:

Answer 25

The calcium that binds to ryanodine receptors, to cause calcium-induced-calcium release from the sarcoplasmic reticulum.

Question 26

What mechanism is primarily utilized to increase tension when a sarcomere length is increased:

Answer 26

Increased calcium affinity of troponin-C augmenting myofilaments interactions.

Question 27

Pacemaker current is due to movement of ions through what channels?

Answer 27

HCN channels.

Question 28

Rapid change in membrane potential is due to what ion?

Answer 28

Calcium.

Question 29

Term for slow heart rate:

Answer 29

Brachycardia.

Question 30

What will an anticholinergic drug do?

Answer 30

It will block the actions of acetylcholine, which is released from the parasympathetic nervous system. This will increase the heart rate.