A 35-year-old male is admitted to a hospital following a minor car accident. He was driving home and fell asleep at the wheel. This is the third accident he has had in the past year. He also falls asleep regularly anywhere. When he becomes excited or enraged, he suddenly becomes weak and falls. At night, he often has bizarre, terrifying dreams. During these dreams, he feels as if he were paralyzed. Describe how a nerve impulse is transmitted from one neuron to the next. Compare the structure and functions of the central nervous system (CNS) and peripheral nervous system (PNS). Based on the probable diagnosis of narcolepsy, what parts of the person’s brain could have been affected ? What sleep state do these symptoms resemble?

The Nerve Impulse: An electrical impulse travels from the axon termini to the cell body of the neuron. The impulse begins when stimulating chemicals (such as neurotransmitters) bind to receptor sites on the neuron’s dendrites, creating a change in potential across the membrane. This changes propagates through the synaptic junctions and down the axon until it reaches target muscle or neuron cells.

Peripheral Nervous System and Central Nervous System. The central nervous (CNS), which is made up of the spinal cord, brain, and other nerves in the spine, controls information processing and coordinates voluntary movement. The peripheral nervous (PNS), which is all the nerves that are outside of our CNS, collects sensory information about our surroundings, controls involuntary functions like breathing and digestion, as well relays motor commands back from our brains to our muscles.

Probable Diagnosis Narcolepsy: Narcolepsy is caused by dysfunction of various regions in both sides of the brain including the hypothalamus, amygdala & locus coeruleus which are involved in regulating circadian rhythm & sleep/wake cycles . Other areas affected include thalamus & prefrontal cortex which play key roles in controlling arousal states & REM sleep respectively .

This patient’s symptoms closely resembles those of REM sleep, when individuals have vivid dreams and paralysis-like feelings while asleep. narcolepsy also has an increased REM-latency. This means patients are able to enter REM earlier than usual, causing them fall asleep quickly in the daytime even if they feel energized.