Nervous System Part One

Describe the transmission of a nerve impulse.

Polarization (resting state). Propagation. Repolarization.

Explain the importance of the myelin sheath.

Protects and electrically insulates fibers from one another. Increases the speed of transmission of nerve impulses. Associated only with axons. Dendrites are unmyelinated. Fatty protein-lipoid.

Differentiate between a nerve and tract.

Nerve: Bundles of neuron processes in the PNS. Tract: Bundles of neuron processes in the CNS.

Define neurotransmitter and name several classes of neurotransmitters.

Neurotransmitters are chemicals that act to open or close ion channels. Acetylcholine; Norepinephrine; Dopamine; Serotonin; Endorphins; Histamine; Glycine

Differentiate between a nuclei and a ganglia.

Nuclei: Cluster of cell bodies in the CNS. Ganglia: Cluster of cell bodies in the PNS.

List the basic functions of the nervous system

-Master controlling and communication system of the body. -Responsible for all behavior -Regulates and maintains body homeostasis. -Rapid acting and complex: communicates by means of electrical signals which are rapid, specific, and cause immediate response.

Classify neurons structurally and functionally.

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List the types of supporting cells and cite their functions.

Are nonnervous cells closely associated with all neurons. There are 6 types. 4 in the CNS and 2 in the PNS. Collectively called neuroglia or glial cells. CNS: Astrocytes; play a role in making exchanges between capillaries and neurons. Microglia; protection against invading microorgnisms and damaged nerve cells. Ependymal; line central cavities of brain and spinal cord forming a permeable membrane for cerebral spinal fluid. Oligodendrocytes; role in producing insulating coverings called myelin sheaths. PNS: Satellite cells; role in controlling chemical environment of neurons. Schwann cells; surround and from myelin sheaths around larger nerve fibers.

Describe how neurons communicate and the role of the synapse.

Synapse; site of communication between neurons. One neuron triggers an impulse in another neuron. Typically the axon of one neuron will form a synapse with a dendrite with another neuron.

Explain the structural and functional divisions of the nervous system.

The central nervous system (CNS). The integrating and command center. Interprets incoming sensory information and dictates responses. The peripheral nervous system (PNS). Outside the CNS. Consists of nerves that extend from the brain and spinal cord Spinal nerves carry impulses to and from spinal cord. Cranial nerves carry impulses to and from the brain.