Neurotransmitters and Muscle Physiology Quiz

What is the neurotransmitter released at the neuromuscular junction?

• Dopamine

• Acetylcholine

• Norepinephrine

• GABA

Which ion is essential for release of neurotransmitter at NMJ?

• Sodium

• Potassium

• Calcium

• Chloride

Which enzyme breaks down acetylcholine in the synaptic cleft?

• Choline acetyltransferase

• Acetylcholinesterase

• Monoamine oxidase

• Tyrosine hydroxylase

Myasthenia gravis is caused by antibodies against?

• Voltage-gated calcium channels

• Muscle actin

• Acetylcholine receptors

• Dopamine receptors

Which drug is used to diagnose myasthenia gravis?

• Physostigmine

• Edrophonium

• Atropine

• Neostigmine

Which type of muscle shows plateau phase in action potential?

• Skeletal muscle

• Cardiac muscle

• Smooth muscle

• All of the above

Motor unit is defined as?

• Motor neuron + sensory neuron

• Sensory neuron + muscle fibers

• Single motor neuron + all muscle fibers it innervates

• All muscle fibers in one muscle

Rigor mortis occurs due to depletion of which substance?

• Calcium

• ATP

• Sodium

• Potassium

Which protein masks the myosin binding site on actin in resting muscle?

• Tropomyosin

• Actin

• Troponin

• Myosin

Which type of muscle contraction occurs without change in length?

• Isometric

• Isotonic

• Isokinetic

• Concentric