Excitable Tissue

Question 1

Amount of neurotransmitter released from presynaptic bud is directly related to

Answer 1

Rise in cystolic Ca

Question 2

P wave:

Answer 2

Atrial depolarization

Question 3

E_Ca²+

Answer 3

+125 mV

Question 4

PR interval:

Answer 4

Conduction delay in AV node

Question 5

Lead 1+ and Lead aVF- =

Answer 5

Left axis deviation

Question 6

Upstroke of AP in nodal cells mediated by

Answer 6

Ca current rather than Na

Question 7

QRS complex:

Answer 7

Ventricular depolarization

Phase 0

Question 8

Hypercalcemia on the heart

Answer 8

Increases QT interval

Question 9

E_Na+

Answer 9

+70 mV

Question 10

T wave:

Answer 10

Ventricular repolarization

Phase 3

Question 11

Mobitz type 1

Answer 11

Second-degree heart block

Progressive prlongation of PR until a ventricular beat is missing and then cycle begins again

Unsteady rhythm

Question 12

E_Cl-

Answer 12

-76 mV

Question 13

Hyperkalemia on the heart

Answer 13

Increases rate of repolarization

Sharp-spiked T waves and shortened QT intervals

Question 14

Lead 1+ and Lead aVF+ =

Answer 14

Normal axis

Question 15

Wolff-Parkinson-White syndrome

Answer 15

Bundle of kent between atria and ventricles becomes activated

Short PR

Steady rhythm and normal rate

Widened QRS

Question 16

First-Degree heart block

Answer 16

Long PR

Slowed conduction through the AV node

Rate and Rhythm are typically normal

Question 17

Phase 0 AP of cardiac creats what of EKG

Answer 17

QRS

Question 18

Mobitz type 2

Answer 18

Second-degree heart block

PR is consistent

Steady or unsteady rhythm depending on block ratio

Question 19

E_K+

Answer 19

-95 mV

Question 20

Hypokalemia on the heart

Answer 20

Decreases rate of repolarization

Resulting in U waves and prolonged QT

Question 21

ST segment:

Answer 21

Ventricles are depolarized during this segment

Phase 2

Question 22

Phase 2 AP of acridac creates what of EKG

Answer 22

ST segment

Question 23

Hypocalcemia on the heart

Answer 23

Decreases QT interval

Question 24

Phase 3 of AP of cardiac creates what of EKG

Answer 24

T wave

Question 25

Relative refractory period is

Answer 25

period during which a greater than threshold stimulus is required to induce a second action potential

Question 26

What channels are important to determining RMP of a cell

Answer 26

Ungated (leak) channels

Question 27

What blocks fast Na channels

Answer 27

Extracellular Ca

Question 28

Absolute refractory period is

Answer 28

Period during which no matter how strong the stimulus, it cannot induce a second action potential

Question 29

Lead 1- and Lead aVF+ =

Answer 29

Right axis deviation