Cardiovascular

Question 1

What is the ability of a cell to respond to an external electrical stimulus, usually in the form of an action potential?

Answer 1

Excitability

Question 2

What is the ability for a cell or a group of cells to initiate an action potential?

Answer 2

Automaticity

Question 3

What is the ability of a cell or region of cells to receive and transmit an action potential?

Answer 3

Conductivity

Question 4

What is the inability of a cell to receive and transmit an action potential?

Answer 4

Refractoriness

Question 5

What is the ability of cells to alter the rate of electrical conduction?

Answer 5

Dromotropism

Question 6

Why is it that the SA node is the pacemaker part of the heart, and not the AV node?

Answer 6

SA node is faster

Question 7

Why is it that potassium channel blockers prolong the QRS complex?

Answer 7

Prevent the K channels from releasing K to balance out Ca that has rushed into the cell

Question 8

True or false: the electrical activity always precedes the mechanical activity

Answer 8

True

Question 9

What does the P wave represent?

Answer 9

Depolarization of the AV node

Question 10

What does the Q wave represent?

Question 11

What does the R wave represent?

Question 12

What does the S wave represent?

Question 13

What does the T wave represent?

Answer 13

Repolarization of the ventricles

Question 14

Where is the EKG line of repolarization of the atria?

Answer 14

Hidden in the QRS complex

Question 15

What allows for the spontaneous depolarization of phase 4 in the SA and AV nodes?

Answer 15

Funny channel If (Leaky Na channels)

Question 16

What causes the initial depolarization of the AV node? (phase 0)

Answer 16

Opening of Na channels (influx)

Question 17

What causes the prolonged phase 2 in the AV node?

Answer 17

influx of Ca and efflux of K

Question 18

Draw the phases of the AV node AP.

Answer 18

Draw

Question 19

What is responsible for the phase 3 repolarization of the AV node?

Answer 19

Ca channels close, K continues to leak out

Question 20

What are the two types of Ca channels? When do they open?

Answer 20

L type (long)
T type (transient)

Both open at beginning of phase 1

Question 21

What is the ion exchange that is occurring in phase 2?

Answer 21

Ca goes in, K goes out

Question 22

What happens with the ion exchange in phase 3 of the AP?

Answer 22

Ca stops

K continues to efflux to balance out charges

Question 23

What is the channel that is responsible for the upward depolarization in phase 4?

Answer 23

Funny Na Channel

Question 24

What are the three phases of the Na channels?

Answer 24

1. Activation gate closed
2. Gates opened
3. Inactivation gate closed (repeat)

Question 25

What happens in phase 3 of the cardiac myocytes?

Answer 25

Ca channels close | K continues to leak out

Question 26

What is responsible for the phase 4 current in the AV/SA node?

Answer 26

If (funny Na channel)

Question 27

True or false: the Na channels have two gates, which respond in the same way to depolarization

Answer 27

False--respond in opposite ways

Question 28

What is the resting state of the Na channels? What happens when depolarization occurs?

Answer 28

Activation gate closed, inactivation gate open Rapid opening of the activation gate

Question 29

What happens when the activation gate on Na channels open in response to depolarization?

Answer 29

Inactivation gate closes

Question 30

What happens to Na channels when repolarization occurs?

Answer 30

First, activation gate closes, then inactivation gate opens

Question 31

What happens when you block the opening of the activation gate? Relate this to the phases of depolarization.

Answer 31

Prolong Na intake, prolong phase 0

Question 32

What happens when you block the inactivation state of Na channels?

Answer 32

Shorten AP

Question 33

What happens when there is an enhanced late I(Na)? Relate this to Ca levels.

Answer 33

prolonged depolarization of Na, causes more Na to enter. NCX transporter also causes increased intracellular Ca, leading to cellular instability/mechanical dysfunction

Question 34

What are the 4 cardiovascular conditions that are caused by increased late I(Na) channel closing?

Answer 34

1. Ischemic heart disease (angina) 2. Heart failure 3. Arrhythmias 4. PAD/claudication

Question 35

What are the two neurological disorders that are caused by increased late I(Na) channel closing?

Answer 35

Szs | Neuropathic pain/muscle paralysis

Question 36

Draw out the SA/AV node depolarization curve vs the ventricular muscle fiber depolarization curve.

Answer 36

Draw

Question 37

What is responsible for phase 0 depolarization of the SA node?

Answer 37

Ca influx

Question 38

What is responsible for phase 0 depolarization in ventricular muscle fibers?

Answer 38

Na influx

Question 39

What is the main ion change that is occurring in phase 3 of the nodal depolarization curve?

Answer 39

K efflux

Question 40

What is the main ion change that is occurring in phase 4 of the nodal depolarization curve?

Answer 40

Na influx

Question 41

What is the main ion change that is occurring in phase 1 of the ventricular muscle depolarization curve?

Answer 41

K efflux

Question 42

What is the main ion change that is occurring in phase 2 of the ventricular muscle depolarization curve?

Answer 42

Ca influx | K efflux

Question 43

What is the main ion change that is occurring in phase 3 of the ventricular muscle depolarization curve?

Answer 43

K efflux

Question 44

What is the effect of blocking Ca influx on the nodal cell?

Answer 44

Decrease in automaticity

Question 45

What is the effect of blocking Na on ventricular muscle fibers?

Answer 45

Decrease in phase 0 depolarization

Question 46

What is the effective refractory period?

Answer 46

the period in which the tissue will not respond to any additional stimulus

Question 47

What does the ERP/APD ratio determine?

Answer 47

the ability of abnormal impulses to depolarize the tissues

Question 48

What is the relative refractory period?

Answer 48

time after the effective refractory period in which it is difficult, but not impossible, to generate an action potential

Question 49

A lower ERP/APR ratio means what?

Answer 49

easier to depolarize

Question 50

What does the SANS affect on cardiac function?

Answer 50

``` SA node AV node ventricular myocardium Atria His-Purkinje system ```

Question 51

What does the PANS affect on the cardiac function?

Answer 51

vagal nerve SA/AV nodes atrial/ventricular myocardium

Question 52

What happens in sinus node tachycardia?

Answer 52

Increase in the depolarization of the sinus node and increased conduction velocity

Question 53

What does SA node tachycardia look like on an EKG?

Answer 53

Increased rate

Question 54

What is the pathophysiology of atrial tachycardia?

Answer 54

Ectopic foci in the atria cause depolarization,

Question 55

How does atrial tachycardia present on an EKG?

Answer 55

P waves without QRS complex

Question 56

What are early afterdepolarizations?

Answer 56

Depolarizations that occur before the total repolarization of the ventricular muscle.

Question 57

What are "triggered activities"?

Answer 57

Abnormal upstrokes that occur after a normal upstroke

Question 58

What metabolic disturbance can result in early after depolarizations?

Answer 58

Hypokalemia

Question 59

EADs are induced more readily in what part of the heart?

Answer 59

Purkinje cells

Question 60

What is torsades de pointes?

Answer 60

QRS complex occurs when a P wave is supposed to happen, triggering a ventricular fibrillation

Question 61

What does a U wave represent?

Answer 61

Depolarization of papillary muscle

Question 62

What are delayed after depolarizations?

Answer 62

Ca overload (secondary to some condition) causes a depolarization after the normal depolarization, which can generate aberrant beats if it reaches threshold

Question 63

What is the EKG of a first degree block?

Answer 63

Increased PR

Question 64

What is the EKG of a second degree AV block?

Answer 64

Not all P waves pass (followed by a QRS complex)

Question 65

What is the EKG of a third degree block?

Answer 65

no P/QRS relationship

Question 66

What is the cause of reentry?

Answer 66

Existence of conduction routes with different conduction velocities

Question 67

What is AV node reentrant tachycardia?

Answer 67

Two different conduction pathways in the AV node with different conduction speeds. A premature beat causes circus motion between the loops

Question 68

P waves that come after the QRS complex = ?

Answer 68

Accessory pathway mediated SVT

Question 69

Atrial flutter is caused by what?

Answer 69

Reentry circuit

Question 70

What does the EKG of a ventricular reentry look like?

Answer 70

Huge QRS complexes

Question 71

What is the difference between sinus tachy/bradycardia and atrial flutter/fibrillation?

Answer 71

Sinus atrial and ventricular rate = A-fib/flutter has different ventricular and atrial rates