PRESENTED BY: ORJI JONATHAN ORJI ( DE GENIUS) GUIDED BY: PhD. TAMRIKO VALISHVILI DOCTOR OF MEDICINE LECTURER ATSU.
Jul 11, 2015
PRESENTED BY:ORJI JONATHAN ORJI ( DE GENIUS)
GUIDED BY:PhD. TAMRIKO VALISHVILIDOCTOR OF MEDICINELECTURER ATSU.
Nervous system:Central nervous system (CNS): brain and spinal cord
Peripheral nervous system (PNS): cranialnerves and spinal nerves
Two types of cells: neurons( cells of the nervous system that can receive and sends signals)
and supporting (glial) cells
Parts of a neuronCell body- contains the nucleus and other
organelles
Dendrites- transmit electrical impulses TO thecell body
Axon- transmits impulse AWAY from the cell body
axons can be several feet long
“Axon hillock” is located near the cell bodynerve impulses originate there
Myelin is wrapped around the axon of many neurons
In periphery, myelin is produced by Schwann
cells
In CNS, it is produced by oligodendrocytes
SUPPORTING CELLS
Schwann cells, oligodendrocytes- producemyelin
Satellite cells- support neurons in PNSMicroglia-phagocytes in CNSAstrocytes- induces blood-brain barrier.Ependymal cells- special epithelium that linebrain ventricles and central canal of spinal cord
also part of structure that makes CSF
CLASSIFICATION OFNEURON
FUNCTIONAL CLASSIFICATION
Interneuron- located entirely within CNS, (only in CNS) and connect neurons together
integrates functions in CNS
Sensory neuron: ( signals from sensory receptor to CNS)
Motor neuron: ( signals from CNS to effectors organ)
STRUCTURAL CLASSIFICATIONNeurons display great diversity in size and
shape . Structural classification : according to the number of processes extending from the cell body. A- Mutipolar neurons : - have several dendrites and one axon. - Neurons of brain and spinal cord.
B- Bipolar neurons :- have one dendrite and one axon.- found in the retina of the eyes , in the inner ear and in the olfactory area of the brain
c- Unipolar neurons : - have dendrites and one axon - these neurons are more appropriately called: pseudounipolar neurons because they begin in the embryo as bipolar neurons.unipolar neurons are located in dorsal root ganglia of spinal cor & sensory ganglion of cranial nerves.