FUNCTIONAL ORGANIZATION OF NERVOUS TISSUE
<a href=“http://www.innerbody.com/image/nervov.html”>THE NERVOUS SYSTEM</a>
FUNCTIONS OF NERVOUS SYSTEM:
1. Sensory input
3. Control of muscles and glands
5. Mental activity
A neuron is a nerve cell that is the basic building block of the nervous system. Neurons are similar to other cells in the human body in a number of ways, but there is one key difference between neurons and other cells. Neurons are specialized to transmit information throughout the body.
TYPES OF NEURONS
Astrocytes are star shaped glial cells that perform a variety of functions in the CNS. Astrocytes provide physical support to neurons and clean up debris within the brain. They also provide neurons with some of the chemicals needed for proper functioning and help control the chemical composition of fluid surrounding neurons. Finally, astrocytes play a role in providing nourishment to neurons.
The principle function of oligodendrocytes is to provide support to axons and to produce the Myelin sheath, which insulates axons. Myelin is 80% lipid and 20% protein and allows for the efficient conduction of action potentials down the axon. Oligodendrocytes unlike Schwann cells of the PNS, form segments of myelin sheaths of numerous neurons at once.
Microglia are the smallest of the glial cells. Some act as phagocytes cleaning up CNS debris. Most serve as representatives of the immune system in the brain. Microglia protect the brain from invading microorganisms and are thought to be similar in nature to microphages in the blood system.
Schwann cells are the supporting cells of the PNS. Like oligodendrocytes schwann cells wrap themselves around nerve axons, but the difference is that a single schwann cell makes up a single segment of an axon's myelin sheath.
PARASYMPATHETIC AND PARASYMPATHETIC
It is the junction between two cells, where two cells communicate each other.
<a href=“http://www.lrn.org/Content/Quizzes/Qnervous.html”>QUIZ QUIZ QUIZ</a>