Excitable Tissue

Question 1

NMDA receptor

Answer 1

Both voltage and ligated gated

Question 2

K equilibrium potential

Answer 2

-95

Question 3

Cl equilibrium potential

Answer 3

-76

Question 4

Na equilibrium potential

Answer 4

+70

Question 5

Ca2 equilibrium potential

Answer 5

+125

Question 6

Resting membrane potential of K in nerves

Answer 6

-70

Question 7

Resting membrane potential of K in muscle

Answer 7

-90

Question 8

Mecanism of action of tetrodotoxin, saxitoxin and local anesthetics (“caine drugs”)

Answer 8

Block fast Na+ channels

Question 9

Mecanism of action of ciguatoxin and batrachotoxin

Answer 9

Block inactivation of fast Na+ channels

Question 10

Absolute refractory period

Answer 10

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

Question 11

Relative refractory period

Answer 11

Period in which a greater than threshold stimulus is required to induce a second action potential

Question 12

Neurotrasmitor used in alpha-motor synapses

Answer 12

Acetylcholine

Question 13

Endogenous ligand of nicotinic receptors

Answer 13

Acetylcholine

Question 14

Endogenous ligand of non-NMDA receptor

Answer 14

Glutamate

Aspartate

Question 15

Endogenous ligands of NMDA receptor

Answer 15

Excitatory amino acids

Question 16

Pathophysiology of myasthenia gravis

Answer 16

Autoimmune condition in which antibodies are created that block the Nm receptor

Question 17

Pathophysiology of Lambert-Eaton

Answer 17

autoimmune condition in which antibodies block the presynaptic voltage-gated Ca2+ channels

Question 18

Class I antiarrhythmic agents

Answer 18

Block fast Na+ channels

Question 19

Class III antiarrhythmic agents

Answer 19

Block K+ channels, delaying repolarization resulting in a long QT interval

Question 20

Class II antiarrhythmic agents

Answer 20

Beta-blockers

Question 21

Class IV antiarrhythmic agents

Answer 21

Block the Ca2+ channels

Question 22

Funny current

Answer 22

Inward Na+ current

Question 23

Mean electrical axis

Answer 23

-30 to +110

Question 24

Causes of left axis deviation

Answer 24

left heart enlargement
Conduction defects in the left ventricle, except in posterior left bundle branch
acute MI on the right side tends to shift axis left unless right ventricle dilates

Question 25

Causes of right axis deviation

Answer 25

Right heart enlargement
Conduction defects of right ventricle or the posterior left bundle branch
Acute MI on the left side tends to shifht axis right unless left ventricle dilates

Question 26

Phase 0 of cardiac action potential

Answer 26

Upstroke of action potential
Mediated by opening fast Na+ voltage gated channels
QRS complex

Question 27

Phase 2 of the cardiac action potential

Answer 27

ST segment of the ECG
Inward Ca+ influx offsets the outward K+ current
Voltage gated Ca2+ (L-type)

Question 28

Cardiac action potential phase that creates the T wave

Answer 28

Phase 3

Question 29

Beta-1 receptor type

Answer 29

Gs-cAMP

Question 30

Calcium channel type found in the SA and Av nodes

Answer 30

T-type

Question 31

Bundle of kent

Answer 31

Electrical pathway that runs between atria and ventricles

Question 32

ECG changes in transmural infarct

Answer 32

Elevated ST segment

Question 33

ECG changes with hyperkalemia

Answer 33

Sharp spiked T waves and shortened QT intervals

Question 34

ECG changes with hypokalemia

Answer 34

U waves and prolonged QT interval

Question 35

ECG changes with hypercalcemia

Answer 35

Decreased QT interval

Question 36

ECG changes with hypocalcemia

Answer 36

Increased QT interval