Cardio/Renal Lab 1

Question 1

Depolarization

Answer 1

• Na, Ca, K move into the cell

Question 2

Repolarization

Answer 2

K moves out of the cell

Question 3

Resting potential (Phase 0)

Answer 3

-90 mV

Question 4

Atrial and ventricular cardomyocyte depolarization

Answer 4

• Systole (contraction)

Question 5

Resting membrane potentional corresponds to?

Answer 5

Diastole (relaxation)

Question 6

Phase 0

Answer 6

• Na channels open
• influx of Na
• cell rapidly depolarizes and trigger muscle contraction

Question 7

Phase 1

Answer 7

• Na channel closes
• K channels open to removed K+ out of the cells
• Partially repolarized

Question 8

Phase 2

Answer 8

• calcium channels open and Ca+ flows into the cell
• cells remains depolarized for 0.3 seconds
• Plateau segment of action potential

Question 9

Phase 3

Answer 9

• cell repolarizes
• Potassium channel opens and K+ flows out
• cell returns to resting potential

Question 10

Absolute refractory period

Answer 10

• cariomyocytes are unable to generate, propogate or respons to the arriving action potential

Question 11

Relative refractory period

Answer 11

• the cell is only able to respons when there is a strong enough stimulus from action potential

Question 12

Electrocardiogram

Answer 12

• recording of the electrical activity of the heart
• currents generated can reach to the surface of the chest
• recorded by electrodes

Question 13

P wave

Answer 13

• first wave of the ECG
• represents the depolarization of the atrium
• before atrial contraction
• short period after (straight line) allows for ventricular filling

Question 14

QRS complex

Answer 14

• depolarization of the ventricles
• Q = depolarization from V septum (left to right)
• R = largest wave, depolarization of the V
• S = final stage of V depolarization

Question 15

T wave

Answer 15

• ventricular repolarization
• before the end of ventricular contraction

Question 16

ST segment

Answer 16

• zero potential between depolarization and repolarization

Question 17

PQ interval

Answer 17

• time between the beginning of the P wave and the beggining of the QRS complex

Question 18

QT interval

Answer 18

• ventricular contraction
• begins at Q wave until the end of T wave

Question 19

Atrial fibrillation

Answer 19

• no P waves
• irregular narrow QRD complex at random irregular intervals

Question 20

Atrial flutter

Answer 20

• sawtooth P wave form

Question 21

Bradycardia

Answer 21

• sinus node dysfunction caused by coronary artery disease
• hypothyroidism

Question 22

Tachycardia

Answer 22

• abnormal impulse formation / conduction

Question 23

Sinus
tachycardia

Answer 23

• caused by drug toxicity or disease

Question 24

Triggered activity

Answer 24

• when depolarization occurs before the cell is fully repolarized
• not related to SA node firing

Question 25

Re-entry arrhythmias

Answer 25

- abnormal conduction - retrograde conduction is blocked as the cells originating the stimuli are still in refractory period - antrograde conduction is blocked in one of the paths and impulse travels through the paths which are not blocked

Question 26

Class 1

Answer 26

- block inward Na (slow conduction velocity) - block outward K channels (prolong APD)

Question 27

Class 1B

Answer 27

- shorten APD (shorten rate of depolarization)

Question 28

Class 1C

Answer 28

- slows conduction - sympatholytic drugs

Question 29

Class 2

Answer 29

- B-blockers - slow heart rate, reduced the influx of calcium ions

Question 30

Class 3

Answer 30

- potassium channel blockers - slow down electrical impulses

Question 31

Class 4

Answer 31

- calcium channel blockers - decrease HR and contraction

Question 32

Inverted T-wave

Answer 32

- due to mild ischemia in the apex of the ventricle

Question 33

causes of cardiac arrhythmias

Answer 33

- damage to heart muscle leads to alterations to conduction and heart rhythm

Question 34

Sinoatrial Block

Answer 34

- sudden stop of P waves, atrium is at standstill - ventricles pick up rhythm

Question 35

Atrioventricular block

Answer 35

- Prolonged PR or PQ interval - P wave is present but conduction is slowed - ventricle beats drop but still generate impulses

Question 36

# [](http://) AV premature contraction

Answer 36

- P wave missing + QRS complex is placed over it's original place

Question 37

Ventricular Fibrillation

Answer 37

- Coarse contraction of ventricles disappear - irregular spasmodic waves

Question 38

Class 1A drugs -- Sodium Channel Blocker

Answer 38

- quinidine - procainamide - dispyramide

Question 39

Class 1B drugs

Answer 39

- lidocaine - mexiletine - tocainide

Question 40

Class 1C drugs

Answer 40

- flecainide - encainide - propafenone

Question 41

Class 2 -- BB

Answer 41

- propranolol - esmolol - metoprolol - atenolol - timolol

Question 42

Class 3 - K channel blocker

Answer 42

- Sotalol - ibutilide - bretylium - dofetilide - amiodarone

Question 43

Class 4 -- CCB

Answer 43

- diltiazem - verapamil