Nervous Tissue

Two main cell types

Neurons

Support cells (neuroglial cells)

Neuroglia (Glia or Supporting Cells)

Function: Support and protect the neurons

Astrocytes

Neuroglia

Function: Destroy bacteria through phagocytosis

Microglia

Neuroglia

Oligodendrocytes

Function: Produce lipid covering called myelin sheath

Neuroglia

Function: Produce lipid covering called myelin sheath

Schwann Cells & Satellite Cells

Neuroglia: Structure

Neurons (Nerve Cells)

The human body contains billions of neurons.

Neurons are the basic structural units of the nervous system.

Neurons: Function

Conduct electrical impulses along the plasma membrane.

Neurons: Special Characteristics

•Longevity

•Do not divide

•High metabolic rate

Structure of a Typical Large Neuron

Synaptic Terminals (Synaptic Bulbs)

Myelin Sheaths and Nodes of Ranvier

Two Neurons Communicating at a Synapse

Neurotransmitters: Acetylcholine

• Controls muscle contractions

Neurotransmitters: Norepinephrine

• Increases heart rate

Neurotransmitters: Dopamine

• Associated with “pleasure” system of the brain

Neurotransmitters: GABA

• Major inhibitory neurotransmitter

Neurotransmitters: Serotonin

• Involved in inducing sleep, temperature regulation, and control of mood

Neuron Function (Action Potentials)