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Chapter 11
Fundamentals of the Nervous System and Nervous Tissue
19
Anatomy
03/11/2009

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Term
List the basic functions of the nervous system
Definition
The nervous system is the master controlling and communicating system of the body
Term
Explain the structural and functional divisions of the nervous system
Definition

divided into 2 different division

(1) central nervous system (CNS)-constists of the brain and spinal cord, which occuppy the dorsal cavity; It interprets sensory input and dictates motor responses based on past experience, reflexes, and current conditions

(2)peripheral nervous system (PNS)-the part of the nervous system outside the CNS, consists mainly of the nerves (bundles of axons) that extend from the brain and spinal cord;Spinal nerves carry impulses to and from the spinal cord; cranial nerves carry impulses to and from the brain. These peripheral nerves serve as the communication lines that link all parts of the body to the CNS.

Term
List the types of neuroglia and cite their functions.
Definition

6 types of neuroglia

Neuroglia in the CNS include

astrocytes-A type of CNS supporting cell; assists in exchanges between blood capillaries and neurons;most abundant and most versatile glial cells

microglia-small ovoid cells with relatively long “thorny” processes;  type of CNS supporting cell; can transform into phagocytes in areas of neural damage or inflammation

ependymal cells-range in shape from squamous to columnar, and many are ciliated;  type of CNS supporting cell; lines the central cavities of the brain and spinal cord.

oligodendrocytes-A type of CNS supporting cell that composes myelin sheaths

Two kinds of PNS neuroglia

Satellite cells surround neuron cell bodies located in the peripheral neurons system (Figure 11.3e), but their function is still largely unknown.

Schwann cells (also called neurolemmocytes) surround and form myelin sheaths around the larger nerve fibers in the peripheral nervous system

Term
Define neuron, describe its important structural components, and relate each to a functional role
Definition

The billions of neurons, also called nerve cells, are the structural units of the nervous system;Cell of the nervous system specialized to generate and transmit electrical signals (action potentials and graded potentials).

Characteristics:

1.   They have extreme longevity. Given good nutrition, neurons can function optimally for a lifetime (over 100 years).
2.   They are amitotic. As neurons assume their roles as communicating links of the nervous system, they lose their ability to divide. We pay a high price for this neuron feature because they cannot be replaced if destroyed. There are exceptions to this rule. For example, olfactory epithelium and some hippocampal regions contain stem cells that can produce new neurons throughout life. (The hippocampus is a brain region involved in memory.)
3.   They have an exceptionally high metabolic rate and require continuous and abundant supplies of oxygen and glucose. Neurons cannot survive for more than a few minutes without oxygen.

Term
Differentiate between a nerve and a tract, and between a nucleus and a ganglion
Definition
Term
Explain the importance of the myelin sheath and describe how it is formed in the central and peripheral nervous systems
Definition
Term
Classify neurons structurally and functionally
Definition
Term
Define resting membrane potential and describe its electrochemical basis.
Definition
Term
Compare and contrast graded and action potentials
Definition
Term
Explain how action potentials are generated and propagated along neurons.
Definition
Term
Define absolute and relative refractory periods
Definition
Term
Define saltatory conduction and contrast it to conduction along unmyelinated fibers
Definition
Term
Define synapse. Distinguish between electrical and chemical synapses structurally and in their mechanisms of information transmission
Definition
Term
Distinguish between excitatory and inhibitory postsynaptic potentials
Definition
Term
Describe how synaptic events are integrated and modified
Definition
Term
Define neurotransmitter and name several classes of neurotransmitters
Definition
Term
Describe common patterns of neuronal organization and processing
Definition
Term
Distinguish between serial and parallel processing
Definition
Term
Describe the role of astrocytes and nerve cell adhesion molecules in neuronal differentiation
Definition