Nervous system I

Histology:2nd stage
2016-2017
Department of Anatomy &Histology Dr. Raja Ali
--------------------------------------------------------------------------------------------
Nerve Tissue & the Nervous system I:

Chapter Outline:
Neurons (Cell Body (Perikaryon) , Dendrites , Axons ) .
Synaptic Communication.
Glial cells & Neural Activity :( Oligodendrocytes , Astrocytes , Ependymal cells ,Microglia ,Schwann cells(Neurolemmocytes), Satellite cells of Ganglia).
Myelin.
Central Nervous System (Brain &Spinal Cord , Meninges ).
Periperal NervousSystem : ( Nerves , Ganglia ) .

Learning Objective:

? Name and describe the divisions of nervous system.
? State the function of nerve cells.
? Name , locate &describe the structures of synapses.
? State the function of glial cells.
? Name , locate &describe the structures of the brain and spinal cord.
? Describe the peripheral nervous system.

Terminology:
• Input: sensory = sensory input.
– Receptors monitor changes.
– Changes called “stimuli” (sing., stimulus)
– Information sent by “afferent” nerves.
• Integration:
– Info processed.
– Decision made about what should be done.
• Output: motor = motor output.
– Effector organs (muscles or glands) activated.
– Effected by “efferent” nerves.
Remember the difference between the English words “affect” and “effect”.
• Neuron = nerve cell.
• Neuroglia = supporting cell.
• Nerve fiber = long axon.
• Nerve = collection of nerve fibers (axons) in PNS.
• Tract = collections of nerve fibers (axons) in CNS.
• Nucleus = cluster of cell bodies in CNS.
• Ganglia = cluster of cell bodies in PNS.
• Unilateral: on one side.
• Ipsilateral: on the same side.
• Contralateral: on the opposite side.
Remember also:
• CNS vs PNS.
• Input: sensory: afferent: to brain.
• Output: motor : efferent: from brain.
• Dense network of fibers from processes of both neurons and glial cells fills the interneuronal space of the CNS and is called the neuropil .