The Neuron

​The Neuron: Building Blocks of the Nervous System

Learning Objectives

• Describe neuron structure and functions

• Differentiate between types of neurons

• Explain nerve impulse propagation

• Understand synaptic activity

Structure of a Neuron

• Cell Body: Contains nucleus and organelles

• Dendrites: Branch-like structures receiving information

• Axon: Sends messages away from cell body

• Myelin Sheath: Fatty insulation around axons

• Nodes of Ranvier: Gaps in myelin generating electrical signal

Match

Match the following parts with their function.

• neuroglia

• Schwann cells

• sympathetic

• myelin sheath

• dendrites

support cells of neurons

produce myelin sheath in PNS

flight or flight system

insulates axons

portion of neuron that receives impulse

• support cells of neurons

• produce myelin sheath in PNS

• flight or flight system

• insulates axons

• portion of neuron that receives impulse

Open Ended

Explain how the myelin sheath contributes to efficient signal transmission. (Use your own words.)

Multiple Choice

This type of neuron processes information from Sensory Neurons and passes the information onto Motor Neurons.

• Sensory Neurons

• Motor Neurons

• Interneurons

Multiple Choice

This type of neuron transmits signals from the brain to your muscles.

• Sensory Neuron

• Interneuron

• Motor Neuron

Audio Response

What might happen if interneurons failed to function properly?

Open Audio Recorder

Unique Features of Neurons

• Communicate through electrochemical processes

• Use neurotransmitters for communication

• Never directly touch each other

• Some axons wrapped in myelin sheath

• Signals jump between nodes of Ranvier

Video Response

How does the structure of neurons support their function in communication?

Open Video Recorder

Key Ions in the
Nervous System

• Potassium (K+)

• Sodium (Na+)

• Calcium (Ca++)

• Chloride (Cl-)

Audio Response

Predict what might happen if the sodium-potassium pump malfunctioned.

Open Audio Recorder

Resting Potential

• Inside membrane: Negative charge

• Outside membrane: Positive charge

• Maintained by sodium-potassium pump

• Creates electrical difference across membrane

Action Potential

• Temporary reversal of membrane polarity

• Triggered by stimulation

• Spreads along axon membrane

• Similar to "the wave" at sporting events

Audio Response

1. How does the distribution of ions produce a resting potential?

2. Describe the sequence of events that happen during an action potential.

Open Audio Recorder

Synaptic Communication

• Synapses: Communication points between neurons

• Synaptic cleft: Gap between neurons

• Synaptic vesicles: Store neurotransmitters

• Neurotransmitters: Chemical messengers

Open Ended

What role do neurotransmitters play in neural communication?

Impact of Neurotransmitter Levels

• Levels can be too high or too low

• Multiple roles for each neurotransmitter

• Complex relationship with behavior

• Critical for proper neural function

Open Ended

Predict how abnormal neurotransmitter levels might affect behavior.