Free Neurophysiology MCQs with Answers

• A. Contraction of skeletal muscle
• B. Decrease of heart rate
• C. Secretion of saliva
• D. Contraction of pupils

Explanation: Acetylcholine acting on nicotinic receptors at the neuromuscular junction produces an end-plate potential that triggers skeletal-muscle…

• A. Inhibitory post synaptic potential
• B. Action potential
• C. Miniature end plate potential
• D. End plate potential

Explanation: Spontaneous release of a single small packet, or quantum, of acetylcholine at rest produces a miniature end-plate potential.

• A. Net current in an outward direction
• B. Cell interior becomes more negative
• C. None of the above
• D. Cell interior becomes less negative

Explanation: The upstroke results mainly from rapid Na+ entry, making the cell interior progressively less negative and then positive.

• A. Voltage inactivation of the Na+ channel
• B. Depletion of intracellular Na+
• C. Inactivation of Na+ k+ ATPase
• D. Insufficient neurotransmitter

Explanation: During the absolute refractory period, voltage-gated Na+ channels are inactivated and cannot reopen immediately, regardless of stimulus…

• A. Adaptation
• B. Accommodation
• C. Refractoriness
• D. Electrotonus

Explanation: Accommodation is the rise in threshold when a slowly increasing, subthreshold stimulus is applied.

• A. Extraocular muscles
• B. Pharyngeal muscles
• C. Muscles of middle ear
• D. Laryngeal muscles

Explanation: The smallest motor units are found where precise, fine control is required, especially in laryngeal muscles.

• A. Depolarizing the motor end plate of skeletal muscle
• B. Inhibiting the CNS
• C. Inhibiting cholinesterase
• D. Blocking the release of acetyl choline at the end plate

Explanation: Succinylcholine persistently activates nicotinic receptors at the motor end plate, causing depolarization followed by inability to…

• A. Dopamine
• B. Acetylcholine
• C. Nor epinephrine
• D. Epinephrine

Explanation: Somatic motor neurons release acetylcholine at the neuromuscular junction, where it activates nicotinic receptors on the muscle end plate.

• A. there is lack of acetyl choline
• B. There is isometric contraction
• C. Lack of acetyl choline receptors
• D. Muscles are rigid and tough

Explanation: Myasthenia gravis is an autoimmune disorder in which antibodies reduce functional acetylcholine receptors at the neuromuscular junction.

• A. EMG
• B. EEG
• C. Venn diagram
• D. ECG

Explanation: Electromyography, or EMG, records the electrical activity of skeletal muscle.

• A. Round electrode
• B. Surface electrode
• C. Hook electrode
• D. Needle electrode

Explanation: Surface electrodes detect muscle electrical activity through the skin and are painless because they do not enter the muscle.

• A. Less activity in the membrane
• B. There are no gaps between active sites
• C. There are gaps between tight junctions at the active sites
• D. Fibronectin provides a barrier for diffusion

Explanation: The blood-brain barrier is formed by continuous endothelial tight junctions, so gaps are not present between adjacent endothelial cells.

• A. Prefrontal cortex
• B. Neocortex
• C. Hippocampus
• D. Amygdala

Explanation: The hippocampus is important for consolidating newly acquired short-term memories into long-term memories.

• A. Sense muscle tension
• B. Involved in reciprocal innervation
• C. a- motor neuron stimulation
• D. Senses dynamic length of muscle

Explanation: Golgi tendon organs detect tension generated in a muscle and its tendon, especially during contraction.

• A. Somatostatin
• B. Glycine
• C. Substance P
• D. Calcitonin

Explanation: Glycine is a rapidly acting inhibitory neurotransmitter that opens chloride channels through ionotropic receptors.

• A. Plasma cell
• B. Mast cell
• C. Nerve terminal
• D. Vascular endothelium

Explanation: Substance P is a neuropeptide released mainly from peripheral sensory nerve terminals, especially nociceptors, where it contributes to…

• A. Structural changes in rhodopsin
• B. Activation of transducin
• C. Decreased intracellular cGMP
• D. Opening of Na+ channels

Explanation: Light activates rhodopsin and transducin, lowers cGMP, and closes cGMP-gated sodium channels, causing rod hyperpolarization.

• A. Impairment of both sensory and motor function
• B. Intact neural sheath is not present
• C. Wallerian degeneration
• D. Reversible loss, which will be regenerated i 6-8 wks

Explanation: In axonotmesis, the axon is interrupted but the surrounding neural connective-tissue sheath remains sufficiently intact to guide…

• A. Present in posterior part of temporal lobe
• B. Comprehends language not speaking
• C. Word formation
• D. Is the confluence of somatic , auditory and visceral areas

Explanation: Broca’s area in the dominant inferior frontal gyrus coordinates motor planning for speech, so it is associated with word formation and…

• A. They are metabolites of various neurogentic amines .Health
• B. They are acidic precursors of Brain amines
• C. They act as neuromodulators
• D. They cross Blood Brain Barriers

Explanation: DOPA and 5-hydroxytryptophan can cross the blood-brain barrier and are then converted to dopamine and serotonin, respectively, within the…