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