A&P Chapter 8 The Nervous System

Oligodendrocytes

Cells that form myelin sheath of CNS neurons

Cell body

Contains nucleus

Peripheral Nervous System (PNS)

Cranial and spinal nerves and skeletal muscles

What does the myelin sheath do

Insulates and protects the neuron, enhances impulse conduction, gives peripheral nerves a white appearance(white matter)

Neurons

Nerve cells

Coordinates and regulates all bodily functions, receives and interprets info from external environment

Nervous system

Neurolemma

Outer layer of myelin sheath, nuclei, and cytoplasm of Schwann cells; some nerve regeneration occurs here

Regeneration of nerves can only happen here

PNS

Dendrites

Projections that transmit impulses toward the cell body

Function of PNS

Relays info to CNS

forms myelin sheath in the PNS

Schwann cells

Neuroglia (glial cells)

Specialized cells only found in the brain and spinal cord

Central Nervous System (CNS)

brain and spinal cord

parts of neurons

cell body, dendrites, axon

Autonomic Nervous System (ANS)

nerves that carry involuntary impulses to smooth muscle, cardiac muscle, and various glands

Why does severing of the spinal cord result in permanent damage?

neurons cannot regenerate in the CNS

Functions of Nervous System

1. To detect changes and feel sensations 2. Initiates appropriate responses to changes 3. To organize the info for immediate use or to share it for future use