Outline - 3, BIO 2310, Nervous Tissue

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I. INTRODUCTION

A. Overall function

1. Sensory {senses changes}

2. Integrates {interprets info.}

3. Motor {responds to info.}

B. Organization

1. Central Nervous System

a. Brain

b. Spinal cord

2. Peripheral Nervous System

a. Definition

b. Afferent System (sensory)

1. Somatic

Surface of body

2. Visceral

Internal

c. Efferent System (motor)

1. Somatic

To skeletal muscles

2. Visceral = Autonomic Nervous System

To smooth muscle, cardiac muscle, glands

a. Parasympathetic

Rest & relax

b. Sympathetic

Fight or flight

II. NERVOUS TISSUE

A. Neuron

= Nerve cell

1. Cell body

a. Nuclei

Groups of cell bodies in CNS

b. Ganglia

Groups of cell bodies in PNS

2. Cytoplasmic Processes

a. Dendrite

Receptive end

b. Axon (nerve fibers)

Conducting end

B. Nerve

Bundle of axons in PNS

C. Structural Classification

1. Bipolar

Two cytoplasmic extensions, one dendrite and one axon. e.g. nervous layer of retina

2. Multipolar

Many extensions, one axon and numerous dendrites. e.g. motor neurons

3. Unipolar

"T" shaped extensions that branch into dendrite and axon. e.g. sensory neurons

D. Neuroglia

"Nerve glue", supporting and protecting tissue

1. Schwann Cells

PNS

a. Myelin

1. White matter

2. Function

Insulate and greatly speed up rate of nerve impulse transmission

b. Nodes of Ranvier

Gaps in myelin sheath

2. Regeneration of axons [1-5 mm/day]

Possible due to Schwann cells providing structural scaffold. Slow process.

3. Oligodendrocytes

Myelin production in CNS

4. Astrocytes

Maintenance of blood brain barrier