NMS Set 3 Quiz - NMJ's, NMJ pharmacology and muscles.

Question 1 of 36

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What two receptor types are found in abundance on the post synaptic membrane found at the NMJ?

Select one or more of the following:

  • Voltage gated sodium

  • nAchR

  • Voltage gated calcium

  • NMDA

Question 2 of 36

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What is the correct process of synaptic transmission?

Select one of the following:

  • Action potential received at pre-synaptic terminal -> Ca2+ entry due to VG Ca2+ open -> binds to synaptotagmin -> conformational change -> Ach vesicles fuse with pre-synaptic membrane.

  • Ca2+ entry -> Action potential produced -> Ach vesicles fuse with the pre-synaptic membrane.

Question 3 of 36

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When Ach binds to the post-synaptic membrane, the resting membrane potential of the muscle cell goes from -90mV to...

Select one of the following:

  • -20mV

  • +10mV

  • 0mV

  • -55mV

Question 4 of 36

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Binding of Ach causes production of an end plate potential. How does this end plate potential permit the subsequent initiation of an action potential?

Select one of the following:

  • The EPP causes voltage gated sodium channels to open which leads to an action potential being produced in the muscle cell.

  • The EPP causes voltage gated chloride channels to close which leads to an action potential being produced in the muscle cell.

Question 5 of 36

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Acetylcholine is recycled from the synaptic cleft as what two components?

Select one or more of the following:

  • Acetate

  • Choline

  • Chlorine

  • Acetyl

Question 6 of 36

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What enzyme reincorporates the two components of Ach back into Ach?

Select one of the following:

  • Cholineacetyltransferase

  • Acetylcholinetransferase

  • Acetylcholinesterase

Question 7 of 36

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After the initiation of an end plate potential and subsequent action potential, how does this action potential resulting in calcium efflux from the sarcoplasmic reticulum?

Select one of the following:

  • The action potential travels down T-tubules. A receptor called the DHP receptor (a voltage sensor) detects this voltage change and undergoes a conformational shape change. This conformational change leads to unplugging of ryanodine from the sarcoplasmic reticulum which allows mass efflux of calcium from the sarcoplasmic reticulum.

  • The action potential travels down T-tubules. A receptor called the DNP receptor (a voltage sensor) detects this voltage change and undergoes a conformational shape change. This conformational change leads to unplugging of ryanodine from the sarcoplasmic reticulum which allows mass efflux of calcium from the sarcoplasmic reticulum.

Question 8 of 36

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What is the function of the light chain of botulinum toxin?

Select one of the following:

  • The light chain binds to the pre-synaptic membrane at the point where neurotransmission is occuring. This causes the botulinum toxin to be up-taken into the pre-synaptic terminal.

  • The light chain is a protease which cleaves proteins that are fundamental for exocytosis of neurotransmitter to occur. This therefore means that exocytosis of neurotransmitter does not occur and the muscle remains paralysed.

Question 9 of 36

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What is the function of the heavy chain of botulinum toxin?

Select one of the following:

  • The heavy chain binds to the pre-synaptic membrane at the point where neurotransmission is occuring. This causes the botulinum toxin to be up-taken into the pre-synaptic terminal.

  • The heavy chain is a protease which cleaves proteins that are fundamental for exocytosis of neurotransmitter to occur. This therefore means that exocytosis of neurotransmitter does not occur and the muscle remains paralysed.

Question 10 of 36

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Very active muscle fibres are amongst the first to be affected by botulinum toxin.

Select one of the following:

  • True
  • False

Question 11 of 36

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Name a depolarising blocker of the NMJ

Select one of the following:

  • Tubocurarine

  • Pancuronium

  • Suxamethonium

  • Hexamethonium

Question 12 of 36

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Give two examples of non-depolarising neuromuscular junction blockers

Select one or more of the following:

  • Tubocurarine

  • Pancuronium

  • Suxamethonium

  • Hexamethonium

Question 13 of 36

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Anti-cholinesterases can cause suxamethonium-like properties in the synaptic cleft.

Select one of the following:

  • True
  • False

Question 14 of 36

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What are anti-cholinesterases used for treatment of myasthenia gravis?

Select one of the following:

  • Auto-antibodies that bind to nAchR's at NMJ's which are indicated in Myasthenia Gravis compete for the agonist binding site (Ach being the agonist). By using an anti-cholinesterase, you increase the amount of Ach present in the synaptic cleft which can out-compete the auto-antibodies for the nAchR binding site and thus reverse the inhibitory effects.

  • Auto-antibodies that bind to nAchR's at NMJ's which are indicated in Myasthenia Gravis compete for the agonist binding site (Ach being the agonist). By using an anti-cholinesterase, you increase the amount of Ach present in the synaptic cleft which can out-compete the auto-antibodies for the nAchR binding site and thus reverse the excitatory effects.

Question 15 of 36

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Although suxamethonium is a depolarising NMJ blocker, it is broken down more slower than Ach and therefore sustains depolarisation of the muscle cells, leading to fasciculations.

Select one of the following:

  • True
  • False

Question 16 of 36

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Suxamethonium leads to paralysis because the sustained depolarisation that it causes eventually leads to inactivation of VG Na+ channels.

Select one of the following:

  • True
  • False

Question 17 of 36

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Myosin heads have GTPase activity that can hydrolyse GTP to recock the myosin head.

Select one of the following:

  • True
  • False

Question 18 of 36

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What are the three main energy systems of muscle contraction?

Select one or more of the following:

  • Phosphocreatine

  • Lactic acid

  • Oxidative phosphorylation

  • Substrate level phosphorylation

  • Glycogenolysis

Question 19 of 36

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Slow twitch fibres mostly take part in anaerobic respiration.

Select one of the following:

  • True
  • False

Question 20 of 36

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Phosphocreatine is broken down to get inorganic phosphate that can be used in ATP that partakes in muscle contraction.

Select one of the following:

  • True
  • False

Question 21 of 36

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Pumping of Ca2+back into the sarcoplasmic reticulum to aid in relaxation of the muscle fibre requires ATP.

Select one of the following:

  • True
  • False

Question 22 of 36

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A motor unit is...

Select one of the following:

  • A motor neurone that innervates severe muscle cell sarcomeres to produce co-ordinated responses

  • A group of motor neurones that innervate a single muscle cell each to produce co-ordinated responses

Question 23 of 36

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If there is a large force required for a muscle to carry out a task, would slow twitch or fast twitch fibres be used?

Select one of the following:

  • Fast twitch

  • Slow twitch

Question 24 of 36

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Recruitment of motor units describes what?

Select one of the following:

  • Increasing the number of motor units firing

  • Increase the frequency of motor units firing

Question 25 of 36

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Rate coding of motor units describes what?

Select one of the following:

  • Increasing the number of motor units firing

  • Increasing the frequency of motor units firing

Question 26 of 36

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Name some examples of neurogenic motor unit disease

Select one or more of the following:

  • Guillain-Barre syndrome

  • ALS

  • Duchenne muscular dystrophy

  • Dermatomyositis

Question 27 of 36

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Name some examples of myopathic motor unit diseases

Select one or more of the following:

  • Guillain-Barre syndrome

  • ALS

  • Dermatomyositis

  • Duchenne muscular dystrophy

Question 28 of 36

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Most treatment for ALS (motor neurone disease) is symptomatic.

Select one of the following:

  • True
  • False

Question 29 of 36

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ALS affects what part of the motor system?

Select one or more of the following:

  • Upper motor neurones

  • Lower motor neurones

  • Sensory neurones

Question 30 of 36

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What symptoms can ALS present?

Select one or more of the following:

  • Weakness

  • Wasting

  • Fasciculation

  • Cognitive decline

Question 31 of 36

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Guillain-Barre syndrome affects what aspects of the motor system?

Select one or more of the following:

  • Upper motor neurones

  • Lower motor neurones

  • Sensory neurones

  • Peripheral motor neurones

Question 32 of 36

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Guillain-Barre is due to cross-reacting antibodies that attack peripheral nerves.

Select one of the following:

  • True
  • False

Question 33 of 36

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How could you treat Guillain-Barre?

Select one or more of the following:

  • Plasma exchange to get rid of cross-reacting antibodies

  • Intravenous immunoglobulin to try to get rid of cross-reacting antibodies

  • Intraneurone injection to stimulate nerve regrowth

Question 34 of 36

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What is responsible for DMD?

Select one of the following:

  • The dystrophin protein which anchors intracellular actin to the muscle membrane.

  • A mutation in the dystrophin protein which leads to failed anchorage of intracellular actin to the muscle membrane.

Question 35 of 36

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DMD leads to muscle wasting and weakness.

Select one of the following:

  • True
  • False

Question 36 of 36

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Serum creatine kinase levels are an indicator of muscle damage in DMD.

Select one of the following:

  • True
  • False
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NMS Set 3 Quiz - NMJ's, NMJ pharmacology and muscles.

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Quiz by , created over 1 year ago

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