NCLEX Study Guide: Nervous System Overview & Mnemonics

The nervous system is the body’s communication network, transmitting signals between the brain, spinal cord, and the rest of the body to control movement, sensation, and bodily functions, facilitating both voluntary and involuntary actions. The nervous system can be divided into two main parts: the Central Nervous System (CNS) and the Peripheral Nervous System (PNS).

Central Nervous System (CNS)

The Central Nervous System (CNS) comprises the brain and spinal cord, serving as the main processing center for sensory information, motor commands, and higher cognitive functions in the body.

The Spinal Cord

• The spinal cord is a long, cylindrical bundle of nervous tissue that extends from the base of the brain down through the vertebral column.
• It is made up of nerve cells that carry messages between the brain and the rest of the body.
• It serves as a pathway for transmitting sensory information from the body to the brain and motor commands from the brain to the body, while also facilitating reflex actions.

The Brain

The brain is the central organ of the nervous system, responsible for processing sensory input, regulating bodily functions, coordinating movements, and enabling higher cognitive functions. The functions of the central nervous system are distributed across various regions of the brain.

Cerebral Cortex:

• Frontal Lobe: Controls voluntary movements, decision-making, planning, expressive speech, and personality. It contains Broca’s Area, which manages expressive speech.
• Parietal Lobe: Controls touch, temperature, and pain. It handles sensation and visual perception. It also contributes to spatial perception and attention.
• Temporal Lobe: Manages auditory processing, memory formation, and language comprehension. It houses Wernicke’s Area, responsible for language comprehension.
• Occipital Lobe: Central to visual processing and interpreting visual stimuli. It handles discerning shapes, colors, and motion.

Limbic System & Basal Ganglia:

• Amygdala: Processes emotions, particularly fear and aggression.
• Hippocampus: Crucial for memory formation and retrieval.
• Hypothalamus: Regulates essential bodily functions like hunger, thirst, sleep, body temperature, and hormone release.
• Basal Ganglia: Responsible for motor control, procedural learning, habit formation, and emotional processing.

Brainstem & Cerebellum:

• Medulla Oblongata: Controls involuntary functions like breathing, heart rate, and blood pressure.
• Pons: Regulates sleep, respiration, swallowing, bladder control, and facial movements.
• Midbrain: Involved in visual and auditory reflexes, arousal, and motor control.
• Cerebellum: Coordinates voluntary movements, maintains balance, posture, and facilitates motor learning.

Peripheral Nervous System (PNS)

The Peripheral Nervous System (PNS) consists of nerves outside the brain and spinal cord. It is a network of nerves and ganglia that transmits sensory information from the body to the CNS and carries motor commands from the CNS to muscles and glands, enabling voluntary and involuntary actions.

1. Somatic Nervous System (SNS)

The Somatic Nervous System controls all 5 senses and movement. It is the division of the PNS responsible for voluntary movements and sensory perception.

Memory Trick: Think S for senses.

• Sensory Neurons: Also known as afferent neurons, they detect stimuli such as touch, temperature, pressure, and pain. They receive info from the body to the brain and contain dorsal root ganglion.
• Motor Neurons: Also referred to as efferent neurons, they control voluntary movements by carrying signals from the CNS to skeletal muscles. They send info from the brain to the body and contain ventral root ganglion.
• Reflex Arcs: Neural pathways for involuntary reflex actions that bypass conscious control to generate rapid, automatic responses to stimuli.

Somatic Memory Tricks:

Mnemonic	Meaning
S A M E	Sensory Afferent Motor Efferent
D A V E	Dorsal Afferent Ventral Efferent
AFFERENT	Arrives (Signals arrive at CNS)
EFFERENT	Exits (Signals exit CNS to body)

2. Autonomic Nervous System (ANS)

The Autonomic Nervous System regulates involuntary bodily functions, including heart rate, digestion, respiratory rate, and glandular secretion.

Memory Trick: Think things that Automatically occur.

Feature	Sympathetic Nervous System	Parasympathetic Nervous System
Core Function	Mobilizes body’s resources during stress or danger (“fight or flight”).	Promotes relaxation, rest, and restoration (“rest and digest”).
Memory Trick	Remember S for Stress.	Remember R in para for relax.
Heart Rate & BP	Increases heart rate and blood pressure.	Slows heart rate and decreases blood pressure.
Airways	Dilates airways/bronchi.	Constricts airways/bronchi.
Pupils	Dilates pupil.	Constricts pupils.
Digestion	Inhibits flow of saliva, peristalsis & secretion.	Stimulates flow of saliva, peristalsis & secretion.
Bladder	Inhibits bladder contraction / relaxes bladder.	Contracts bladder.

Interactive Practice NCLEX Questions

Question 1: To what does the neural synapse refer?

• a. Length of time it takes for afferent neurons to carry impulses to the central nervous system (CNS)
• b. Length of time it takes for efferent neurons to carry impulses to the motor neurons
• c. Space between the axons and the dendrites of a neuron
• d. Space between the axons of one neuron and the dendrites of the next

Click to View Answer & Rationale.

ANS: D
Smooth, coordinated transmission must travel from one neuron to another across the neural
synapse.

Question 2: An older adult patient is experiencing extreme stress related to an admission to the hospital. Which physical change should the nurse expect the patient to demonstrate?

• a. Decreased heart rate
• b. Decreased blood pressure (BP)
• c. Irregular respiration
• d. Dilation of the pupils

Click to View Answer & Rationale.

ANS: D
Stress stimulates the fight-or-flight reaction with the release of epinephrine and
norepinephrine, which causes increased heart rate and BP, reduced peristalsis, and pupil
dilation.

Recommended Resources:

• Davis Advantage for Understanding Medical-Surgical Nursing 7th Edition Test Bank
• Lewis’s Medical-Surgical Nursing 12th Edition Test Bank