BIO 240 Dr. Gilley Lecture 23Outline of Last Lecture I. Nervous System  The master controlling and communicating system of the body. Nervous cells communicate by electrical or chemical signals. A. 3 BROAD functions B. Nervous System Divisions1. Structural2. FunctionalC. Cell types of the Nervous System Outline of Current LectureC. Cell types of the Nervous System1. Neurons2. Multipolar Neuron Anatomy3. NeurogliaCurrent LectureC. Cell types of the Nervous System1. Neurons  The only true cells of the nervous system that can elicit and transmit an impulse. i. Unipolar  Only carry sensory information for touch, pressure, pain, and temperature. ii. Bipolar  Very rare in the body. Only carry sensory information for sight, hearing, taste, and smell. Can find them in the retina of the eye. iii. Multipolar  Motor neurons and interneurons. a. Are motor in the PNS and carry impulses away from the CNS. b. Interneurons (association neurons) Occur between motor and sensory neurons in the CNS, linking the sensory and motor nervous systems. 2. More about the Multipolar Neuroni. Cell body  Somaii. Dendrites  Shorter processes attached to the soma. Carry sensory information into the cell body. iii. Axonal hillock  Area where the cell body narrows to go down and meet the axon. iv. Axon  Long process leading away from the cell body. These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.v. Axonal terminals  The feet at the very end of the axonal branches. Also referred to synaptic knobs where they plug into theneuromuscular junction. vi. Schwann Cells  supporting cells in the PNS that cover part of theaxon in myelin to speed up conduction. 3. Neuroglia – “Glial Cells”  Support, protect, and provide nutrients for thenervous system. i. PNS:a. Schwann Cells  Myelinate and wrap around neural processes in the PNS. It takes many to Myelinate a single neuron. i. Myelin  A lipid sheath that protects, insulates, and increases the speed of transmission of a nerve impulse. It is white. ii. Multiple Sclerosis  A diseases where our bodies start attacking our schwann cells. b. Satellite Cells  Cells that wrap around cells bodies in the PNS. Function to protect the cell body and provide nutrients to the cell body. ii. CNS:a. Oligodendrocytes  The functional equivalent of schwann cells. Arms wrap around processes in the CNS. Arms can goin any direction, myelinating multiple neurons or a single neuron in multiple places. The body is not in contact with the axon. b. Astrocytes  Secretion and reabsorption of neurotransmitters, and maintenance of the blood brain barrier. Have a star shape and arms that reach out to the neurons in the CNS and the blood vessels. i. Blood vessels in the CNS are different from other blood vessels. They have a thicker endothelium with cells packed more tightly together and IPMPs keeping the cells packed tightly. The endothelium isthe true BBB.ii. 98% of drugs do not cross the BBB.iii. Alzheimer’s Disease  An age dependent, neurological disease. It is a CNS disorder. Astrocyte function breaking down an allowing other things to sneak through the BBB may be one of the leading causes. c. Microglia  Provide surveillance, phagocytize cell debris, viruses, bacteria, and are cytotoxic. Can release hydrogenperoxide and nitric oxide to kill any invading substance. Start as monocytes. d. Ependymal cells  Ciliated cells that help make and circulate cerebral spinal fluid. They line ventricles of the brain and the central canal of the spinal chord. i. Column shaped cells completely lining the inside of the spinal chord. Replenish and keep the CSF fresh, and the cilia constantly beat to keep CSF