NMJ Flashcards
The resting membrane potential in a neurone is maintained predominantly
Leak of potassium ions out of the cell
What is Ach broken down into
Acetate and choline
What moves calcium back into the sarcoplasmic retinaculum
SERCA pumps
3 types of fibres
Slow oxidative - fatigue resistant fast oxidative (type A ii) fast glycolytic fibres ( type B)
what is Myasthenia gravis
an autoimmune disease that destroy the nAchR
Clinical signs of myasthenia gravis
does it get better as the day goes on ?
Ptosis, , Gower sign(struggle getting up) , diplopia(double vision) , slurred speech and facial paralysis
normal gets better as day goes on too
Treatment for Myasthenia Gravis
Pyridogostigmine - this inhibits AchE so there is enough Ach to bind to remaining receptors
What are the problems with Organophosphate poisoning - farmer
Inhibits AchE
Signs and symptoms of organophosphate poisoning
Increase saliva and tear production. Miosis, sweating, tremors and confusion and vomit
Treatment of OP poisoning
Atropine - blocks and bind to receptors so less Ach can bind
Function of Botulinum toxin
inhibits Ach to be released from the synaptic cleft
Signs and symptoms of botulinum toxin
Muscle paralysis, respiratory and heart failure , Dysphagia
medical uses for migraines
What do depolarising neuromuscular blockers do ?
Ach receptor agonists so bind to Each receptors and generate AP so prolonged and cannot depolarise
What do non-depolarising neuromuscular blockers do?
how is it treated
competitive antagonists so don’t let ion channels open so Ach cannot bind
treated via inhibition of AchE
What is a motor unit?
Group of muscle fibres and a single motor neurone that supplies it
What is the Epimysium?
and where does it come from
Outer layer of connective tissue that surrounds the muscle. Comes from the tendon.
What is the Function of the Epimysium? -2
it allows the muscle to contract more powerfully whilst still maintaining structural integrity.
It separates muscles from other tissues allowing them to act independently.
What are fascicles?
They are made up of bundles of muscle fibres(cells) - next subdivision within the muscle
What is the connective tissue layer around the Fascicles?
And what is its function?
Perimysium surrounds muscle fibres
plays role in transmitting lateral contractile movements.
What is the connective tissue around each muscle fibre? and its function( what does it contain)
Endomysium - this contains all the capillaries and nerves
By what process do myoblasts differentiate into Muscle fibres
Myogenesis
What are myofibrils?(actin and myosin)
These are fibrous proteins that make of muscle cells and they are made of thick and thin filaments
Triad system to T tubules consist of
Two terminal cisternae ( release CA2+ ) and central T tubule
When the wave of depolarisation travels along the sarcolemma what type of calcium channels are opened?
Voltage gated L type channels or DHPR for drugs
