-the master integrating and coordinating system
-monitors and processes sensory info
-divided into central nervous system and peripheral nervous system

Nervous Tissue

-consists of brain and spinal cord

Central Nervous System

-includes all nervous elements located outside the central nervous system
*ex: nerves, sensory receptors, and some cluster of nerve cells

Peripheral Nervous System

-made up of neurons and neuroglia cells

Nervous Tissue

-serves the needs of the delicate neurons by bracing and protecting them
CNS: astrocytes, oligodendrocytes, microglial cells, and ependymal cells
PNS: Schwann cells and satellite cells

Neuroglia/ Glial Cells

-acts as phagocytes

Microglial Cells

-myelinate the cytoplasmic extensions of the neurons

Oligodendrocytes & Schwann Cells

-play a role in capillary-neuron exchanges and control the chemical environment around neurons

Astrocytes

-basic functional units of nervous tissue
-transmit messages from one part of the body to another in the form of nerve impulses

Neuron/Nerve Cells

-slender processes extend
-both the biosynthetic center of the neuron and part of its receptive region
-make up the gray matter of the CNS and form clusters there called nuclei and ganglia in PNS
-contains a large round nucleus surrounded by cytoplasm

Cell Body of Neuron

-cluster of neuron cell bodies in CNS

Nuclei

-cluster of neuron cell bodies in PNS

Ganglia

Neurofibrils and Chromatophilic Substance

Two structures found in the cytoplasm

-provide support for the cell and a means to transport substances throughout the neuron

Neurofibrils

-an elaborate type of rough endoplasmic reticulum involved in the metabolic activities of the cell

Chromatophilic Substance/Nissl Bodies

1.Dendrites
2.Axons

Two Types of Neuron Processes.

-receptive regions that bear receptors for neurotransmitters released by the axon terminals of other neurons

Dendrites

-form the impulse generating and conducting region of the neuron
-the white matter of the nervous system

Axons/Nerve Fibers

-bundles of axons in the CNS

Tracts

-bundles of axons in PNS

Nerves

Axon

Neurons may have several dendrites, but they only have a single _____________.

-branch off of the main axon forming more processes

Axon Collaterals

-conical area of origin of the axon from the nerve cell body

Axon Hillock

club-shaped endings by which axons make synaptic contacts with other nerve cells or effector cells
-stores the neurotransmitter chemical in tiny vesicles

Axon Terminals

- a narrow extracellular cleft between the presynaptic and postsynaptic membranes

Synaptic Cleft

-specialized synapses between neurons and skeletal muscles

Neuromuscular Junction

-long nerve fibers that are covered by fatty material (myelin)

Myelinated Fibers

Schwann Cells

Axons in the PNS are typically heavily myelinated by special supporting cells called ______________.

-wrap themselves tightly around the axon in jelly roll fashion, this wrapping is the myelin sheath

Schwann Cells

-gaps or indentations in the myelin sheath

Nodes of Ranvier

Oligodendrocytes

Within the CNS myelination is accomplished by neuroglia called ________________.

-one very short process which divides into peripheral and central processes, extends from cell body

Unipolar Neurons

-have two processes attached to the cell body
-rare

Bipolar Neurons

-many processes

Multipolar Neurons

- conduct impulses only toward the CNS

Sensory (Afferent) Nerves

-carry impulses only away from the CNS

Motor (Efferent) Nerves

-nerves carrying both sensory and motor fibers

Mixed Nerves

-delicate connective tissue enveloping individual nerve fibers

Endoneurium

-sheath of connective tissue enclosing a bundle of nerve fibers
-forming fascicles

Perineurium

sheath of connective tissue around all fascicles of nerve fibers

Epineurium