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


Neuroglialcells.jpgSchwannCells.jpg






SatelliteCells.jpgSchwannMyelin.jpg





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

NeurontypeBasic.jpg



Types of Neurons based on FUNCTION

SENSORY NEURON or Afferent NeuronSensoryNeuron.jpg

Cell body off mid axis

- on the side

Outside of CNS




MOTOR NEURON or Efferent Neuron
MotorNeuronStr.jpg

Cell body in line with axon and located in CNS















INTERNEURON / CONNECTOR NEURON / ASSOCIATION NEURONS
ConnectorNeuron.jpg

Virtually just a cell body with

extensions
Found in CNS


Interneuron.jpg




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

MotoNeuronStruc.gifNeuronDetailStructure 001.jpg
NerveStructure 001.jpg



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


NervestrTortora 001.jpg



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


THE CENTRAL NERVOUS SYSTEM
BRAIN ..........................and..............................SPINAL CHORD
THE BRAIN

Location and protection
  • 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


Structure of the brain
two hemispheres - left and right half, each of which is subdivided
brainlobes 001.jpg


Note the position of the grey matter

brainIntStr 001.jpg


VENTRICLES OF THE BRAIN
brainVentricles 001.jpg


PRODUCTION AND FLOW OF CEREBROSPINAL FLUID
brainVentrCSF 001.jpg


Gross functions of the brain
brainsensoryareas 001.jpg


THE SPINAL CHORD
Location and Protection
SpinalcordWhole 001.jpg

Structure of the Spinal Chord
SpinalCordCut 001.jpg


Note the position of the grey matter

SpinalCordXS 001.jpg

PERIPHERAL NERVOUS SYSTEM
SOMATIC NS _ AUTONOMIC NS _ ENTERIC NS


THE SOMATIC NERVOUS SYSTEM

CRANIAL NERVES
_ SPINAL NERVES
12 pairs _31 pairs


Cranial Nerves : OOO TT AFA(V) GVA(S)H
CranialNerves.gifCranialNerveNo'sOnly.jpg





The OPTIC CHIASMA
OpticChiasma.jpg


SPINAL NERVES
SpinalNerves31.jpg
31 pairs

Cervical 8

Thoracic 12

Lumbar 5

Sacral 5

Coccygial 1
















Origin of spinal nerves

SpinalCordXS 001.jpg




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__