The anatomy of the nervous system
Divisions of Nervous System
Central nervous system
(CNS).
Peripheral nervous system
(PNS).
Central nervous system (CNS) consist
of :
• Brain
• Spinal cord
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 7.2
Peripheral nervous system
(PNS)consist of :
Cranial nerve ,spinal nerves autonomic
nervous system
Cells of the nervous system :
Neurons are the structural and
functional units of the nervous system
 Neuroglial cell which support and
nourishing the neurons.
Brain
is



divided into three parts :
Forebrain
Midbrain
Hindbrain
The forebrain include:
Cerebrum and diencephalon.
The hindbrain consist of :
pons ,medulla oblongata, and
cerebellum.
Lobes of the Cerebrum
Figure 7.15a
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Cerebrum
Is the largest part of the brain
Frontal
Parietal
Occipital
Temporal
Function of the cerebrum :
Responsible for motor
,intellectual ,personality
sensation , hearing ,memory and
vision
Brain stem
Parts of the brain stem :
Midbrain
Pons
Medulla oblogata
Functions of brain stem
it contains respiratory, the
cardiovascular centers
it contains the nuclei of cranial
nerves III – XII.
Diencephalon
 Sits on top of the brain stem
 Enclosed by the cerebral hemispheres
 Made of five parts
 Thalamus
 Hypothalamus
 Epithalamus
 Subthalamus
 Metathalamus
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Lobes of the Cerebrum
Figure 7.15a
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
Cerebellum
Lies posterior to the pons and the
medulla oblongata.
It consists of two cerebellar
hemispheres
Cerebellar
Peduncles
Functions of the cerebellum
 Co-ordination
of movement
 control of posture
 Equilibrium
Ventricular System
 Ventricles of the brain are cavities inside the
brain contain CSF.
 Lateral ventricles in each cerebral hemisphere
 Third ventricle between diencephalons
 Fourth ventricle in hind brain
Dr. Mohd. A/Salam
Spinal cord
 Is situated within the vertebral
canal of the vertebral column
Begins superiorly from the
foramen magnum in the skull,
where it is continuous with the
medulla oblongata of the brain
End in the adult at the level of
L1
Spinal Cord Anatomy
 Internal gray matter – ( cell
bodies)
 Dorsal (posterior) horns
sensory
 Anterior (ventral) horns
motor
 Lateral horn include
autonomic (thoracic
,lumbar ,sacral )
 External white matter(
fibers )
Slide
Protection of the central nervous
system :
 Skull ,vertebral column
 Meninges
 Cerebrospinal fluid
Peripheral Nervous
System
Spinal Nerves
 Spinal nerves arise from the spinal cord and
attach to it by anterior root which is motor
and posterior root which is sensory connect
together form trunk of the spinal nerve mix
then give two rami anterior and posterior also
mix
 31 pairs spinal nerve
8 Cervical
12 Thoracic
5 Lumbar
5 Sacral
1 Coccygeal
The Cranail Nerve
 I Olfactory : Smell
 II Optic: Vision
 III Oculomotor
 IV Trochlear
supplies the
 VI Abducent
 V Trigeminal:
 VII Facial:
 VIII Vestibulocochlear :
 IX Glossopharyngeal:

X Vagus : give parasympathetic for
the Heart, larynx, trachea, bronchi,
and alimentary tract , liver, kidneys,
and pancreas
XI Accessory :
XII Hypoglossal:
autonomic nervous system
Consist of two part :
A. Sympathetic
In the spinal cord from T1 –L2 segments(
thoracolumbar).
Preganglionic fiber short ,and the postganglionic
fiber long .
CENTRAL NERVOUS SYSTEM SYMPATHETIC
Sympathetic
Brain
Dilates pupil
Stimulates salivation
Relaxes bronchi
 “ Fight or flight”
response
 Increases heart rate and
blood pressure,and
respiratory rate .
 Vasoconstriction to the
blood vessels except ?
 Bronchodilatation
,decrease intestinal
motility,urination
.sweating
Spinal
cord
Salivary
glands
Lungs
Accelerates heartbeat
Inhibits activity
Heart
Stomach
Pancreas
Stimulates glucose
Secretion of adrenaline,
nonadrenaline
Relaxes bladder
Sympathetic
Stimulates ejaculation
ganglia
in male
Liver
Adrenal
gland
Kidney
B. Parasympathetic
Include nuclei of the cranial nerve in the
brainstem(3,5,7,9,10) and sacral spinal
nerve .
The preganglionic fibers long and the
postganglionic fibers short .
CENTRAL NERVOUS SYSTEMPARASYMPATHETIC
Brain
Parasympathetic
Contracts pupil
Stimulates salivation
Spinal
cord
 “ occur at Rest
 Lowers rate ,
breathing rate,Bp
 Stimulate intestinal
motility ,increase
the secretion of
gland
 Bronchoconstrictio
n ,vasodiltation .
Constricts bronchi
Slows heartbeat
Stimulates activity
Stimulates gallbladder
Gallbladder
Contracts bladder
Stimulates erection
of sex organs