Question

Riku is a 19-year-old college student. One morning, after a long night of studying, Riku woke up

and made himself a hot cup of coffee and toast. Much to his surprise, when he brought the cup

to his mouth to drink, the coffee spilt onto the table. Riku went to the bathroom mirror and

noticed the left side of his face seemed to droop. He quickly got dressed and ran to the medical

clinic on the college campus. As he ran, his left eye began to feel scratchy and dry, but he could

not blink in response. The physician at the clinic listened to Riku’s story and then did a careful

cranial nerve examination. She concluded that Riku had Bell palsy, an inflammatory condition of

the facial nerve most likely caused by a virus.

What are an afferent neuron and efferent neuron? What are efferent components of the facial nerve and their actions?

Under certain circumstances, axons in the peripheral nervous system can regenerate after sustaining damage. Why is axonal regeneration in the central nervous system much less likely?

At a healthy myoneural junction, acetylcholine is responsible for stimulating muscle activity. What mechanisms are in place to prevent the continuous

stimulation of a muscle fiber after the neurotransmitter is released from the presynaptic membrane?

Answer 1

Neurones: Neurones are electrically excitable cells that communicate with other systems through a connection called synapse..

Afferent neurones:  are those neurones that receive and transmit nerve impulses or information from the different organs to the central nervous system like brain amd spinal cord

Efferent neurones: are those neurones that transmit impulses from central nervous system to the peripheral organs to produce an action

Efferent components of facial nerve include:

A.General visceral efferent axons:which controls the action of sublingual, submandibular,lacrimal gland and mucosa of nasal cavity

B.Special visceral efferent:Which controls the muscles of facial expressions

The axones of the central nervous system will not regenerate generally like peripheral nervous system,so the damage of those axones will lead to permanant loss of functioning of affected area

Inhibitory neuro transmitter like GABA decreasee the action or firing of postsynaptic neurones to inhinbit the continuous stimulation of muscle fibre via various chemical reactions.