Nervous System

Why This Matters for Nursing: The nervous system controls everything from vital signs to consciousness. Understanding it helps you assess neurological status, recognize stroke symptoms, and understand how many medications work.

What You Need to Know

The nervous system is the body's control and communication center. It detects changes, processes information, and coordinates responses.

Two Main Divisions:

🧠 Memory Trick

CNS = "Central Station" — Brain and spinal cord, the main hub

PNS = "Peripheral Pathways" — All the nerves branching out

Neuron parts: "Neurons Deliver Action To" = Dendrite → Axon → Terminal

Neuron Structure

The neuron is the functional unit of the nervous system.

Signal Pathway:

Dendrites → Cell body → Axon → Axon terminals → (Synapse) → Next neuron

Peripheral Nervous System

Somatic Nervous System

• Voluntary control
• Controls skeletal muscles
• "I decide to move my arm"

Autonomic Nervous System

• Involuntary control
• Controls internal organs, glands
• "I don't think about my heartbeat"

Autonomic Divisions:

Memory: - Sympathetic = Stress response - Parasympathetic = Peace and rest

Central Nervous System

Brain Regions

Cerebral Lobes

Neurotransmitters

✏️ Worked Examples

Example 1: Neuron Parts

Question: Which part of a neuron receives incoming signals?

Step 1 — Picture the neuron like a tree. The cell body is the trunk. The dendrites are the branches reaching out in multiple directions — their whole job is to catch incoming signals from other neurons. The axon is the long root growing down from the trunk — it sends signals outward to the next neuron.

Step 2 — Apply the directionality rule. Signals flow in ONE direction through a neuron: into dendrites → through cell body → down the axon → to the next neuron via the axon terminals. Dendrites are always at the receiving end.

Answer: Dendrites — They receive incoming signals and carry them toward the cell body.

Memory: Dendrites = Download (receive incoming). Axon = Away (send outgoing).