Flashcards in Neuromuscular Deck (23):
What pathway makes a muscle contract?
Motor neurone --> neuromuscular junctionv--> muscle
What innervates skeletal muscle fibres?
Motor neurons whose cell bodies arise in the ventral horn of the spinal cord
What are the synapses that are formed between motor neurons and muscles called?
Motor end plate
How many neurons does a muscle cell respond to?
What occurs at the motor end plate?
What is Lambert Eaton Myasthenic Syndrome?
Antibodies to presynaptic calcium channels leads to less vesicle release .
Strong assoc. with underlying small cell carcinoma
What is Botulism?
Cleave presynaptic proteins involved in vesicle formation and block vesicle docking with the presynaptic membrane. Rapid onset weakness without sensory loss.
What is Myasthenia Gravis?
Antibodies to ACH receptors
What do 75% of patients with Myasthenia Gravis also have?
A thymus problem such as hyperplasia or thymoma
What is the treatment for Myasthenia Gravis?
Acetylcholinesterase inhibitor - Pyridostigmine
What are treatments for acute Myasthenia Gravis?
Steroids / azathiprine
Plasma exchange or immunoglobulin in emergency
What surrounds skeletal muscle?
Thin layer of Endomysium
What are the fasicles encapsulated by?
What helps form an individual muscle?
Large number of fascicles ensheathed in epimysium
Describe skeletal muscle?
Fibres are the stonest contractile unit
Long, cylindrical containing nucleii, mitochondria and sacromeres
Describe smooth muscle
Cells not striated
Single central nucleus
Gap junctions between cells
More actin than myosin
How many muscle fibre types are there?
Describe muscle fibre type 1?
Slow oxidative, dense capillary network, myoglobin, resist fatigued
Describe type IIa muscle fibre?
Fast oxidative, aerobic metabolism
Describe type IIb muscle fibre?
Fast glycolytic, easily fatigued
What are fasciculations?
Visible, fast, fine spontaneous twitch
Occur when muscle becomes hyperexcitable
Issue with the MOTOR NEURON
What is Myotonia?
Failure of muscle to relax after use
Problem wit Chloride channel