Physiology

Question 1

Myasthenia Gravis

Answer 1

1.D/o motor end plate
2.Ab against ACh receptor
3. Worsening of sympt by evening
4.Edrophonium challenge test - inhibit AchE

Question 2

Lambert Eaton Syndrome

Answer 2

D/D myasth
D/o presynaptic motor neuron
Ab agnst Voltage gated Ca2+ channel
Imprvmnt of sympt by rep effort
Asso with small cell lung cancer

Question 3

Depolarizing muscle relaxants

Answer 3

Similar to ach in chem & fn
Succinyl choline
Excitation of muscle +
Prolonged –> adaptation –> relaxation
Rapid seq intubation
Short acting
Pseudocholinesterase
Malgnt hyperthermia
Resp depression

Question 4

Non Depolarising muscle blocker

Answer 4

Muscle relaxant
Similar to ach - block Ach receptor
No excitation of muscle
Hypotension

Question 5

Duchenne muscular dystrophy

Answer 5

Complete deletion of dystrophin gene
Muscle biopsy neg for dystrophin
Late teenage survival
Gowers sign
Pseudohypertrophy of muscle
Death

Question 6

Beckers muscular dystrophy

Answer 6

Partial inactivagion of dystrophin gene
Muscle biopsy + for dystrophin

Question 7

Muscle fibre RMP

Answer 7

-90 mV

Question 8

Local Potential

Answer 8

Ligand gated sodium channels
Seen in Motor end plate

Question 9

Depolarization

Answer 9

Voltage gated sodium channel
Thru out cell

Question 10

Repolarization

Answer 10

K+ efflux - leaky K+ channel & Voltage gated K+ channel

Question 11

Sarcomere

Answer 11

Between 2 Z lines

Question 12

M line

Answer 12

Centre of 2 Z lines

Question 13

A Band

Answer 13

Region of thick filament
Partially contains thin filament also

Question 14

I Band

Answer 14

Region of thin filament alone

Question 15

H zone

Answer 15

Region devoid of thin filament in the thick filament zone

Question 16

C Zone

Answer 16

Interaction of both thick and thin filament

Question 17

Length of sarcomere at which max tension is generated

Answer 17

Optimal length

Question 18

In a skeletal muscle cell, optimal length is

Answer 18

Resting length

Question 19

Proteins of sarcomere

Answer 19

Thick – myosin
Thin – actin, tropomyosin, troponin
Troponin – I - binds actin
T - binds tropomyosin
C - binds calcium

Question 20

Structural proteins of sarcomere

Answer 20

Titin
Nebulin
Alpha actinin

Question 21

Calcium channels

Answer 21

Dihydropyridine receptor – voltage gated cal channels

Ryonidine receptor – mechanically gated cal channels

The gates of DHPR and RyR are connected and the jt is called as Electeomechanical coupling

Question 22

Contraction of sarcomere – ? A band ? I band ? H zone - fate

Answer 22

A band remains same
I band shortens
H zone disappears

Question 23

V snare proteins are

Answer 23

Synaptobrevin
Blocked by tetanus toxin
Spastic paralysis
Opisthotonus

Question 24

T SNARE proteins are

Answer 24

Syntaxin
SNAP-25
Blocked by Botulinum toxin
Flaccid paralysis

Question 25

Latch bridge mechanism

Answer 25

Calmodulin - calcium binding protein Sm can contract with very lil atp