What are the 2 principal cell populations that make up nervous tissue?
2. Neuroglia [glial cells]
The neuroglia in the central nervous system includes what 4 types of cells?
The neuroglia in the peripheral nervous system include these 2 important types of cells?
1. Schwann cells
2. satellite cells
What is the major functional difference between neuroglia and neurons?
Neurons are highly specialized to conduct and transmit nerve impulses from one part of the body to another; the basic functional units of nervous tissue
Neuroglia brace and protect neurons, but are not capable of generating and transmitting nerve impulses.
collections of neuron cell bodies outside the CNS; make up the gray matter of the nervous system
Neuron fibers running through the CNS form tracts of ___?___; in PNS they form ___?___.
1. white matter
2. peripheral nerves
What is the structure of dendrites
Thick, highly branched tapered extension of cell cytoplasm of the cell body
What is the function of dendrites
To conduct impulses toward the cell body an produce graded potentials
What is the function of Nissel bodies
ordely arrangement for protein synthesis, for growth of neurons and regeneration of nerve fibers
What is the function of an synapse
mediates info transfer from one neuron to the next or from one neuron to an effector cell
what are three functons of the myelin sheath
1. protects and electrically insulates fibers
2. increases the speed of transmission of nerve impulses
3. wraps/surrounds larger PNS axons
What is the neurilemma
The plasma membrane surrounding a schwann cell of myelinated nerve fier and separating layers of myelin
What is the function of the neurilemma
To surrond a schwann cell of a myelinated fier and does all the metabolic process for the schwann cell
What are the functions of Nodes of Ranvier
1. To increase the speed of conduction
2. Provides areas/gaps where collaterals can emerge
what anatomical characteristic determine whether a particular neuron is classified unipolar, bipolar or multipolar?
Number of processes extending from their cell body
What is the function of an unipolar neuron?
the most distal portion of perperal portion act as receptve endings; the rest act as axon along with central process and a sensory neuron
What is an example of a bipolar neuron
neurons in the retina of the eye, special sense organs-eyes, nose, ears
what is the function of sensory or afferent neuron
to carry impulses from sensory receptors in the internal organs(viscera), the skin, skeletal muscles, joints or special sensory organs; unipolar
what is the function of motor or efferent neuron
to carry impulses from the CNS to the viscera and/or body muscles and glands; multipolar
What is the function of association or interneurons
situated between and contriute to pathways that connect sensory and motor nerons; multipolar
How does a neuron differ from a nerve/tract
Neurons are structural units of nerves. A nerve is a bundle of nerve fibers found in the PNS and myelinated by schwann cells. A track is found in the CNS and it myelinated by oligodendrocytes
What is an mixed nerve
A nerve that contains both sensory and motor fibers and transmits impulses to and from the CNS
What is perineurium
the connective tissue that surronds bundles of nerve fibers and binds up a fasicle (bundle) of fibers
What are fascicles
bundle of nerve or muscle fibers bound together by connective tissue called the perineurium (neurons)
What is epineurium
Tough fibrous connective tissue sheath that surrounds the fascicles and blood vessels to form a nerve; outermost layer