Neurons & Neuroglia

Lesson 3

Basic Cell Biology Eukaryotic cells Cell membrane Nucleus

chromosomes Cytoplasmic organelles

Mitochondria Endoplasmic reticulum ribosomes microtubules & microfilaments ~

Neurons Basic functional unit of N.S.

Specialized cell All cells have same basic properties

Regulation of behavior Information processing

Transmits Integrates Stores ~

Dendrites & Soma Receives & Integrates information electrical signal within ~

Axon carries information away from soma Electrical signal within Axon terminal releases chemical message ~

Stimuli

By function (connections)

Interneuron

Sensory Motor

UnipolarBipolarMultipolar

By morphology (# of neurites)

Neurons vs. Nerves

Neurons - cells microscopic

Nerves - bundles of axons seen with

naked eye ~

Neuroglia Neural support cells

local influence at synapse no role long distance signaling

Functions exchange molecules with neurons physical support maintains microenvironment Blood-brain barrier immune system ~

Astrocytes

Provide physical support Regulating chemical content of

extracellular fluid localizes neurotransmitters K+ concentration

Blood-brain Barrier (BBB) ~

BBB: Function

Maintains stable brain environment large fluctuations in periphery

Barrier to poisons Retains neurotransmitters & other

chemicals Regulates nutrient supplies

glucose levels active transport ~

TypicalCapillary

Blood-Brain Barrier

Fenestra

Intercellular cleft

BrainCapillary

tight junction No

fenestra

astrocytes

Neuroglia: Myelin

Wrap around axon Saltatory Conduction

faster transmission CNS: oligodendrocytes PNS: Schwann cells ~

Microglia

Immune-like function macrophage foreign cells cellular debris ~