Nervous+System+Anatomy

__** COORDINATION IN THE HUMAN BODY **__ [IN PROGRESS] NERVOUS COORDINATION........................................................................................... CHEMICAL COORDINATION Fixed pathways (landlines)..................................................................................................................................................... +++++++ No mapped pathways (wireless)  Neurotransmitters......................................................................................................................................................................................... === Hormones **__ THE NERVOUS SYSTEM __**
 * __ ANATOMY __**

Internal system of ectodermal origin, thus closely linked with outer environment by means of special senses - all of which are in contact with the external environment.

DIVISIONS: .CENTRAL NERVOUS SYSTEM ; ...................PERIPHERAL NERVOUS SYSTEM ..........................................PNS Divided into Somatic Nervous system (SNS), Autonomic Nervous system (ANS) and some identify Enteric NS

__** CELLS OF THE NERVOUS SYSTEM **__
 * GLIAL CELLS **: Helper cells =**__ Neuroglial cells __**

Astrocytes, Microglial cells, Ependymal cells, Oligodendrocytes in CNS

Schwann cells, Satellite cells in PNS





Types of neurons based on STRUCTURE : Unipolar, Bipolar, Multipolar , Pyramidal
 * NEURONS ** : Impulse conducting cells



__ Types of Neurons based on FUNCTION __


 * SENSORY NEURON ** or Afferent Neuron[[image:SensoryNeuron.jpg width="412" height="120" align="right"]]

Cell body off mid axis

- on the side

Outside of CNS

MOTOR NEURON or Efferent Neuron

Cell body in line with axon and located in CNS

INTERNEURON / CONNECTOR NEURON / ASSOCIATION NEURONS

Virtually just a cell body with

extensions Found in CNS




 * __ THE STRUCTURE OF A NEURON : __**using a motor neuron as a model.



Neurons do not make direct contact The GAP between successive neurons = synaptic cleft SYNAPSE = terminal of one neuron, synaptic cleft, dendrite of next neuron

NEURONS ARE GROUPED INTO NERVES

that connect CNS to the organs these nerves innervate

Nerves that carry only sensory neurons are termed SENSORY NERVES Nerves that carry only motor neurons are termed MOTOR NERVES Nerves that carry both sensory and motor neurons are termed MIXED NERVES




 * Note the insulatory and protective measure to prevent 'short-circuiting' . **

**__ THE CENTRAL NERVOUS SYSTEM __** **__ BRAIN ..........................and..............................SPINAL CHORD __** __ THE BRAIN __ __ Location and protection __ **__ Structure of the brain __** ** two hemispheres - left and right half, each of which is subdivided ** Note the position of the grey matter __VENTRICLES OF THE BRAIN__ __PRODUCTION AND FLOW OF CEREBROSPINAL FLUID__ __** Gross functions of the brain **__ __ THE SPINAL CHORD __ __ Location and Protection __ __ Structure of the Spinal Chord __ Note the position of the grey matter **__ PERIPHERAL NERVOUS SYSTEM __** SOMATIC NS _______________________________________________ AUTONOMIC NS _____________________________________________________ ENTERIC NS
 * In Cranium of skull --- revise bones that form cranium, special features, fossae, ridges etc.
 * Triple membrane = meninges : DAP - Duramater, Arachnoid layer ; Piamater
 * Cerebrospinal fluid = waterbed around brain
 * Blood-brain barrier = special capillaries, virtually impermeable , tight junctions , hemidesmosomes
 * Cells of the immune system are not able to reach the nervous tissue
 * Blood-brain barrier = special capillaries, virtually impermeable , tight junctions , hemidesmosomes
 * Cells of the immune system are not able to reach the nervous tissue
 * Cells of the immune system are not able to reach the nervous tissue

__ THE SOMATIC NERVOUS SYSTEM __ CRANIAL NERVES _______________________________ SPINAL NERVES 12 pairs ___________________________________________31 pairs

__ Cranial Nerves __ : OOO TT AFA(V) GVA(S)H __ The OPTIC CHIASMA __

__ SPINAL NERVES __ 31 pairs

Cervical 8

Thoracic 12

Lumbar 5

Sacral 5

Coccygial 1

__Origin of spinal nerves__



__**SPECIAL NERVE PLEXES**__

__The Brachial Plexus__ origins C 4 - T 1

__The Lumbar Plexus__ (p 514 ) L 1 - L 4 iliohypogastric

ilioinguinal genitofemoral lateral femoral cutaneous femoral

anterior femoral cutaneous

saphenous

obturator (L 2, L4)

__The Sacral Plexus__

__ THE AUTONOMIC NERVOUS SYSTEM __