Neuromuscular

Question 1

What pathway makes a muscle contract?

Answer 1

Motor neurone –> neuromuscular junctionv–> muscle

Question 2

What innervates skeletal muscle fibres?

Answer 2

Motor neurons whose cell bodies arise in the ventral horn of the spinal cord

Question 3

What are the synapses that are formed between motor neurons and muscles called?

Answer 3

Motor end plate

Question 4

How many neurons does a muscle cell respond to?

Answer 4

Just 1

Question 5

What occurs at the motor end plate?

Answer 5

Depolarisation

Question 6

What is Lambert Eaton Myasthenic Syndrome?

Answer 6

Antibodies to presynaptic calcium channels leads to less vesicle release .
Strong assoc. with underlying small cell carcinoma

Question 7

What is Botulism?

Answer 7

Clostridium botulinum
Cleave presynaptic proteins involved in vesicle formation and block vesicle docking with the presynaptic membrane. Rapid onset weakness without sensory loss.

Question 8

What is Myasthenia Gravis?

Answer 8

Autoimmune
Antibodies to ACH receptors
Muscle weakness

Question 9

What do 75% of patients with Myasthenia Gravis also have?

Answer 9

A thymus problem such as hyperplasia or thymoma

Question 10

What is the treatment for Myasthenia Gravis?

Answer 10

Acetylcholinesterase inhibitor - Pyridostigmine

Thymectomy

Question 11

What are treatments for acute Myasthenia Gravis?

Answer 11

Immunomodulating
Steroids / azathiprine
Plasma exchange or immunoglobulin in emergency

Question 12

What surrounds skeletal muscle?

Answer 12

Thin layer of Endomysium

Question 13

What are the fasicles encapsulated by?

Answer 13

Perimmysium

Question 14

What helps form an individual muscle?

Answer 14

Large number of fascicles ensheathed in epimysium

Question 15

Describe skeletal muscle?

Answer 15

Fibres are the stonest contractile unit

Long, cylindrical containing nucleii, mitochondria and sacromeres

Question 16

Describe smooth muscle

Answer 16

Cells not striated
Single central nucleus
Gap junctions between cells
No sacromeres
More actin than myosin

Question 17

How many muscle fibre types are there?

Answer 17

3

Question 18

Describe muscle fibre type 1?

Answer 18

Slow oxidative, dense capillary network, myoglobin, resist fatigued

Question 19

Describe type IIa muscle fibre?

Answer 19

Fast oxidative, aerobic metabolism

Question 20

Describe type IIb muscle fibre?

Answer 20

Fast glycolytic, easily fatigued

Question 21

What are fasciculations?

Answer 21

Visible, fast, fine spontaneous twitch
Occur when muscle becomes hyperexcitable
Issue with the MOTOR NEURON

Question 22

What is Myotonia?

Answer 22

Failure of muscle to relax after use

Problem wit Chloride channel

Question 23

What are symptoms/signs of muscle disease?

Answer 23

Myalgia
Muscle weakness
Wasting
Hyporeflexia