Transcript 01. INTRODUCTION OF N.S(Dr.Jamila)

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(1) Receives Snsory
Input:
Stimuli that arise outside
or inside the body from
different sensory
receptors.
(2) Integrates and
Correlates the sensory
input.
(3) Motor Output:
Effects a response to an
Effector (Muscle or
Gland).
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(1) Central Nervous System
(CNS)
(2) Peripheral Nervous
System (PNS)
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Brain.
Spinal Cord.
Occupies: Dorsal Body
Cavity.
Contains : Main Centers
for Correlation and
Integration of Sensory
Input.
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1.Cranial and Spinal
nerves.
2.Their Ramifications
within the body.
3.Associated Ganglia.
It forms the link
between the CNS and
peripheral structures.
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(1) Sensory
(Afferent):
Carry impulses
Toward the CNS.
(2) Motor (Efferent) :
Carry impulses From
the CNS.
(3) Mixed .
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A. Somatic :
1.Sensory (Afferent):
It delivers impulses from:
Skin.
Skeletal muscles.
joints.
2. Motor (Efferent )
It allows Conscious
(Voluntary) Control of
Skeletal Muscles.
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B. Autonomic
Visceral (Afferent):
It transmits impulses
from: Visceral Organs.
Visceral (Efferent):
Controls Involuntary
activity of Smooth, Cardiac
Muscles and Glands.
It is organized into:
 Gray and White matters.
 Gray Matter Composed of:
 Large number of Neurons
(excitable nerve cells)
Their processes
(Dendrites).
Neuroglia.
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Formed of:
Nerve Fibers
embedded in
Neuroglia.
Tracts :
Nerve processes
Sharing Common:
Connections.
Course.
Functions.
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It is the Structural and
Functional Unit of the
Nervous System.
Type of Neurons:
1. Sensory
Carry information from the
periphery to the CNS to
reach the conscious level.
Their cell bodies are always
Outside the CNS in a
Ganglion.
2. Motor (Efferent):
Upper and Lower Motor Neurons
Their cell bodies
are always
Located in the CNS.
3. Association (Interneurons):
They are:
 Relay neurons.
 Connect sensory and motor
neurons.
 Their cell bodies are always
Located in the CNS.
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Dendrites :
Receptive processes.
Can detect changes in the external
or internal environment.
Axons :
Carry information away from the
cell body.
Terminal Buttons are at the end of
the axons.
Transmission of information
between neurons is always by
Chemical not Electrical means.
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Meninges.
Cerebrospinal
Fluid.
Bones of the skull
& Vertebral
Column.
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Composed of:
Fore brain.
Mid brain.
Hind brain:
Cerebellum
Medulla .
Pons.
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Pons :
It appears as a Bridge
connecting the two
cerebellar hemispheres.
Medulla Oblongata:
Continuous Caudally
with the Spinal Cord.
Extends Rostrally to the
Pons.
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An important center for
Accurate, Coordinated and
Purposeful movements.
It operates at an
Unconscious Level.
It has an outer layer of Grey
Matter (Cerebellar Cortex)
It forms regular folds (Folia).
The White Matter forms the
Central Core.
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It is Rostral to the
Pons.
Its dorsal surface is
formed by Four
Rounded Eminences:
Superior and Inferior
Colliculi.
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It forms a small part of the
entire brain.
It consists of :
Medulla.
Pons.
Mid brain (It is the smallest
part of the brain stem).
It is attached to the
Cerebellum by three parts of
nerve fibers (Peduncles) :
Inferior to the medulla.
Middle ( largest peduncle)
to the pons.
Superior to the mid brain.
DIEN
CEPHALON
TWO
CEREBRAL
HEMISPHERES
EPI
THALAMUS
HYPO
SUB
THAALMUS THALAMUS
T
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Massive part of the
forebrain.
The two hemispheres
are separated by the
Great Longitudinal
Fissure.
The fissure is occupied
by the Falx Cerebri.
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The cerebral cortex
is highly convoluted.
These convolutions
are the Gyri.
The furrows
between them are
the Sulci
FRONTAL
OCCIPITAL TEMPORAL
PARIETAL
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Large masses of cell
bodies (Grey Matter)
which are buried within
the white matter.
They are concerned with:
Control of muscle tone &
posture.
They are important in:
1. Facilitation of
appropriate motor
behavior.
2. Inhibition of unwanted
movements.
CORPUS
STRIATUM
GLOBUS
PALLIDUS
PUTAMEN
CAUDATE
NUCLEUS
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Frontal Lobe
Precentral Gyrus:
It contains the primary
Motor Cortex.
Parietal Lobe
Postcentral Gyrus:
It contains primary
Somatosensory Cortex.
Occipital Lobe :
Visual cortex
Temporal Lobe :
Auditory cortex
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They are the Neurons
of the Motor area of
Cerebral cortex.
Their axons form:
Descending Tracts.
They control:
Activity of Lower
motor neurons.
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Their cell bodies are
in:
The Spinal Cord and
Brain Stem.
They Constitute:
The final pathway to
control the Skeletal
Muscles.
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Corona Radiata:
Radiating Fibers.
Composed of:
Afferent and Efferent fibers
between the Cerebral
Cortex and Subcortical
structures.
Internal Capsule:
A dense sheet of white
matter.
Deeply placed inside the
hemisphere.
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Corpus Callosum:
A sheet of Transversely
running fibers.
It links corresponding
areas of the two
cerebral cortices.
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The site of production of the
CSF.
Composed of:
Fourth ventriclrre
It is the Rostral Continuation
of the Central Canal of the
spinal cord.
It is on the dorsal surface of
the Medulla and Pons beneath
the Cerebellum.
Cerebral Aqueduct
 It runs through the Mid
Brain.
 Third ventricle
It is a slit like chamber.
Its lateral walls are formed
by the Diencephalon
especially the Thalamus.
 Lateral Ventricle
It is an extensive C –
shaped chamber
within the cerebral
hemisphere.
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