Neurons: Parts & Types

Neurons

• Fundamental units of the nervous system.

• Responsible for receiving, processing, and transmitting information through electrical and chemical signals.

Parts of a Neuron

• Dendrites: Receive signals from other neurons.

• Cell Body (Soma): Maintains the cell; contains the nucleus.

• Nucleus: Contains genetic material.

• Axon: Conducts electrical impulses along the neuron.

• Myelin Sheath: Fatty insulation around the axon; speeds up transmission.

• Axon Terminals: Transmit signals to the next neuron.

Glial Cells

• Surround and support neurons.

• Provide nourishment, insulation, and clean up waste.

Types of Neurons

• Sensory Neurons (Afferent):

  • Receive environmental stimuli.

  • Carry information to spinal cord/brain.

• Motor Neurons (Efferent):

  • Transmit commands to muscles and glands.

  • Carry information from CNS to the body.

• Interneurons (Association/Relay Neurons):

  • Act as a bridge between sensory and motor neurons.

  • Found in the brain and spinal cord (CNS).

Reflex Arc

• Neural pathway for quick/automatic responses (reflexes).

• Communication bypasses the brain for speed: Sensory → Interneuron → Motor neuron.