Nerve-muscle Transmission

Question 1

NT of NMT and NMT is?

Answer 1

Ach

Question 2

Active zones on motor end plate of post synaptic muscle cell is?

Answer 2

Junctional folds

Question 3

What fits into junctional folds

Answer 3

Presynaptic nerve terminal

Question 4

In NMT, there is convergence of inputs

T/F

Answer 4

F. Just one presynaptic nerve terminal to one motor end plate

Question 5

What is a motor end plate of post synaptic muscle cell

Answer 5

thickened portion of the post synaptic muscle cell membrane at the NMJ

Question 6

Size of synaptic cleft in NMJ

Answer 6

30nm

Question 7

Contents of synaptic cleft in NMJ

Answer 7

ISF which is rich in Ca,Na,glucose, and Achesterase

Question 8

What covers post synaptic muscle cells

Answer 8

Sarcolemma

Question 9

Post synaptic muscle cell receptors are called

Answer 9

Muscle cell nicotinic AChRs

Question 10

Effects of influx of Ca into vesicle in NMT

Answer 10

It activate actin-myosin interaction

Question 11

Effect of Na influx in post synaptic muscle cell

Answer 11

Generation of a protomotive force called end plate potential

Question 12

What causes AP in NMT

Answer 12

EPP creates a current sink that depolarizes the membrane till AP is fired

Question 13

NMT can be bi-directional

T/F

Answer 13

F. It’s always unidirectional

Question 14

Delay period of NMT is how long?

Answer 14

0.5msec

Question 15

NMT is easily fatigued

T/F

Answer 15

T. Due to repeated stimulation and depletion of Ach and ATP

Question 16

How can we block NMT?

Answer 16

Curare. Competitive Ach antagonist

Question 17

Effect of calcium and magnesium on NMT

Answer 17

Ca supports

Mg inhibits

Question 18

Which is more

Ach molecules or Ach receptors

Answer 18

Ach molecules

By like 10 times

Question 19

EPP is always subthreshold to AP

T/F

Answer 19

F. It’s always Suprathreshold

Question 20

EPP is faster to generate than mEPP

T/F

Answer 20

F. They have the same time course(1msec)

Question 21

What hydrolyses ACH

Answer 21

Ach esterase

Question 22

choline is actively taken up while acetyl is passively taken up into axoplasm of presynaptic nerve terminal
T/F

Answer 22

T

Question 23

What are the substrates for Ach formation

Answer 23

Choline and acetyl coA

Question 24

What’s the enzyme for Ach formation

Answer 24

Choline acetyl transferase

Question 25

What moves Ach into vesicles

Answer 25

vesicular acetylcholine transporter

Question 26

List the 4 phases of excitability of muscle cells and the threshold needed to re-stimulate them

Answer 26

ARP- nothing RRP- Suprathreshold Supra normal-subthreshold Subnormal- Suprathreshold

Question 27

Condition of skeletal muscle in myasthenia gravis

Answer 27

Weak and easily fatigued

Question 28

Describe myasthenia chemically

Answer 28

due to the body producing antibodies that bind to the AchR; this AchR-antibody complex is now destroyed by phagocytes

Question 29

What is a paraneoplastic disorder

Answer 29

Disorders in which the effects of cancer occur at a site remote from the primary tumor

Question 30

MG is common more in which sex

Answer 30

Females

Question 31

Myotonia dystrophy is hereditary and recessive | T/F

Answer 31

F.it’s heriditary and dominant | Skips some generations tho

Question 32

Cause of myotonia dystrophy

Answer 32

Abnormal Na or Cl channels caused by mutated 7,17,19 muscle protein

Question 33

Characteristics of myotonia dystrophy

Answer 33

Contraction with no relaxation Muscle wasting and weakness Cattarh, atrophied gonads made worse by cold fatigue and emotion

Question 34

Difference between duchenne’s dystrophy, limb girdle dystrophy and Becker’s dystrophy

Answer 34

DD:absent dystrophin BD:altered or reduced dystrophin LGD: altered or reduced dystrophin

Question 35

Treatment of altered dystrophin issues into utrophin

Answer 35

Take a drug that coverts utrophin into dystrophin

Question 36

McArdle’s Syndrome. | Discuss

Answer 36

exercise intolerance. You work out and it leads to build up of harmful metabolites and breakdown of muscle

Question 37

What covers a sacromere

Answer 37

sarcolemma

Question 38

What covers sacrolemma

Answer 38

basal lamina

Question 39

sarcoplasmic reticulum ends in?

Answer 39

terminal cisternae

Question 40

T system of tubules invaginates from—- and contacts the ——- between the —— band and —-band —— in every sacromere

Answer 40

``` Sacromere Myofibrils A band I band Twice ```

Question 41

What makes up a triad in a sacromere

Answer 41

One T tubule and 2 adjacent terminal cisterns

Question 42

``` Difference between A band I band H band M line Z line ```

Answer 42

Z lines are in the I bands(light)(actin - M lines are in A bands(dark)(myosin) - H band is a lighter shade in A bands

Question 43

To contact skeletal muscle, Ca is released from which part of the sacromere

Answer 43

Sarcoplasmic reticulum

Question 44

Ca from sarcoplasmic reticulum binds to ——— to ———-

Answer 44

Troponin C | To uncover the myosin binding site on actin

Question 45

How many heads does myosin have

Answer 45

2

Question 46

From one Z line to another Z line makes a -

Answer 46

Sacromere

Question 47

What binds troponin I and T together

Answer 47

Troponin C

Question 48

Sliding of actin and myosin is what bond

Answer 48

Hydrogen bonding

Question 49

What covers the heavy head of myosin

Answer 49

Troponin T

Question 50

Heavy head of myosin is also called ?

Answer 50

Active site of myosin

Question 51

What covers active site of actin

Answer 51

Troponin I and tropomyosin

Question 52

Difference between isometric and isotonic contraction

Answer 52

Metric: constant length ;postural muscles Tonic: varying length; axial muscles

Question 53

``` Difference between type 1 and 2 of skeletal muscle fibers in terms of Names Glycolytic ability Oxidative ability Prolonged exercise Extremities Myoglobin content Capillary density Ca pumping capacity Myosin ATP rate Energy source ```

Answer 53

``` Xterics Type 1 Type 2 Names Slow Fast Names Red White Names Oxidative Glycolytic Myoglobin content High Low Capillary density High Low Ca pumping capacity Moderate High Myosin ATP rate Slow Fast Energy Phosphorylcreatine & ATP Glycolysis Prolonged exercise Yes! No ```

Question 54

T tubules use - receptors | Sarcoplasmic reticulum uses— receptors

Answer 54

Dihydropiridine Ryanodine

Question 55

``` Differentiate between skeletal, cardiac , and smooth muscles under the following. Fatigue Sacromere Summation Tetanus ```

Answer 55

S(possible);C(not);Sm(not) S(present);C(present);Sm(not) S(possible);C(not);Sm(possible) S(possible);C(not);Sm(possible)

Question 56

MG is common in which gender more?

Answer 56

Female