Central and peripheral nervous system mbbs anatomy.....

1. CENTRAL AND PERIPHERAL
NERVOUS SYSTEM

2. Anatomical division of nervous system
• Central nervous system (CNS)
• Consist of brain located in cranial cavity and spinal card
located in vertebral canal.
• CNS is responsible for integrating, processing , and
coordinating sensory data, and giving appropriate
motor command.
• It is also the seat of higher functions such as
intelligence, memory, learning and emotions.

3. • Peripherar nervous system (PNS) includes all
the neural tissues outside the CNS , such as 12
pairs of cranial nerves, 31 pairs of spinal
nerves and plexus, ganglia associated with
cranial, spinal nerves and autonomic ganglia.
• The PNS provides sensory information to the
CNS and carries its motor commands to the
peripheral tissues and systems.

4. C5-T1
L1-L4

5. Functional division
• Afferent brings sensory information to the CNS
• Efferent carries motor commands to the muscles
and glands.
 somatic nervous system (SNS) it provides the
voluntary control over the skeletal muscle
contraction
 autonomic nervous system (ANS) innervates
involuntary structures such as heart, smooth
muscle and glands and thus provides an
involuntary regulation of smooth muscle,
cardiac muscle, and glandular activity

6. Central nervous system
Brain and spinal card
• Both of them consist of gray matter and white matter
• In brain the gray matter consist of nerve cell bodies and dendrites
and present at the periphery,while white matter is made up
predominantly of myelinated nerve fibres present in the centre.
• In spinal cord the white matter is outside and gray matter in side.
• Both grey and white matter contain neuroglia(supporting cells) and
blood vessels

7. Brain
• The adult brain constitutes about one-fiftieth (1/50) of body
weight(2%of body wt) and weighs about 1400g in male(to
accommodate more body mass and muscle group) and 1200g in
female.
• Neurons=100 billion, uses 20% of body energy, 20% ardiac out
put,25% of total body glucose, low gluse leeds to coma
• It consist of following parts
1. Cerebrum
2. Diencephalon
3. Medbrain
4. Pons
5. Medulla oblongata
6. Cerebellum
Brain stem

8. A. Prosencephalon –forebrain (1,2)
-telecephalon:- cerebral hemispheres + lateral ventricles
Foramen of monro
- diencephalon:- -thalamus + 3rd ventricle
-hypothalamus
- optic cup
-pituitary
-pineal body
B. Mesencephalon: midbrain (3,4) aqueduct of sylvius
C. Rhombencephalon: hind brain
- metencephalon – pons(5), cerebellum
-Myelencephalon- medulla oblongata (6-12) + 4th ventricle
F. Luschka
F. magendie
-central canal
-subarachnoid space

10. Functions of the brain
• It receives information from, and controls the activities of
trunk and limbs mainly through its connections with the
spinal cord.
• It receives the information from, and controls the activities
of head and neck structures though cranial nerves
• It assimilates experiences, a requisite to higher mental
processes such as memory, learning and intelligence
• It is also responsible for one’s personality, thoughts and
aspirations.

11. Cerebrum
• Consists of two hemispheres left and right,
occupy the anterior and middle cranial fossae,
and supratentorial region of posterior cranial
fossa.
• The two hemispheres are separated by
longitudinal cerebral fissure, the fibres of
corpus callosum interconnect the
corresponding cortical areas of the two cerebral
hemispheres, and lies in the floor of cerebral
fissure.
• The surface of cerebral hemisphere is
convoluted, have elevations(gyri) and shallow
depressions (sulci)

15. Cerebrum (cont)
• The central sulcus runs downwards and forwards from superomedial
border to the lateral sulcus.
• The superolateral surface of each cerebral hemisphere is divided into
four lobes, which are named after the overlying skull bones.
• Frontal lobe: is anterior to the central sulcus, is important for voluntary motor functions,
motivation, aggression, emotions, effect, drive and awareness of self.
• Parietl lobe is posterior to the sulcus , is the major center for reception and evaluation of all
sensory information except for smell hearing, and visions
• Occipital lobe is behind the parieto-occipital sulcus, is responsible for occupation and
integration of visual input
• Temporal lobe is below the lateral sulcus , receives and evaluates input for smell and
hearing and plays an important role in memory

16. Cerebrum (cont)
• Limbic system / lobe is a
complex ring-shape
mass of grey matter
situated at the junction
of telencephalon and
diencephalon.
• It consisting of cingulate
gyrus, isthmus
parahippocampal gyrus,
uncus, dentate gyrus
• It is associated with basic
survival instincts, viz.
acquisition of food and
water and reproduction
(sexual behaviour)

17. Cerebrum (cont)
• Basal Ganglia is subcortical
masses of gray matter which are
situated in the white core of each
cerebral hemisphere
• It include the lentiform nucleus,
caudate nucleus, claustrum, and
amygdaloid body (these also
called extraphramidal nuclei.
• It regulate the muscle tone and
helps in smoothening the
voluntary motor activities of the
body.
• It control automatic associated
movements, like swinging of
arms during walking
• Control reflex muscular activity
• Its lesion cause parkinsonism

21. Diencephalon
Part of the brain between
cerebrum and brain stem
Thalamus is the Largest part of
the diencephalon, thalamus in
each hemisphere are separated
from one another by 3rd
ventricle
• Functions: it forms a great
gate-way for all sensory
impulses except smell, crude
sensations like pain and
touch.
• It project sensation to the
cerebral cortex

24. Hypothalamus:
• it is the inferior portion of
diencephalon, which forms
the floor and inferolateral
wall of the third ventricle.
Grossly it is about 4.0 gm
• It componints are optic
chiasma, infundibulum,
tubercinereum and
mammillary bodies
• it contains several small
nuclei and nerve tracts.
• It regulate visceral activity
through autonomic nervous
system and hormonal
activity through the
hypothesis cerebri

25. • Metathalmus:
• it consist of of
two medial 7
lateral geniculate
bodies,
• function’s as
relay stations for
auditory and
visual impulses

26. Epithalamus
• situated posterior to the
thalamus,consist of pineal
body and habenular nuclei.
• Pineal body is endocrine
gland,secretes
melatonin,regulate
development of
gonades,secondry sexual
characters.reduction of
malatonin secretion
precipitate puberty
• Habenular nuclei have
olfactory and limbic
connections,influenced by
smell and involved by
emotional and visceral
response

28. Subthelamus:
• it lies between
thalamus and
midbrain
• it is involved
controlling motor
function(inhibitor
y control on basal
nuclei and
cerebral motor
cortex

29. Mid Brain
• Is the small part of brain stem, is just superior to the pons and contain the
nuclei 3rd and 4th cranial nerves. It is traversed by the cerebral aqueduct.
• The part dorsal to the aqueduct, is called tectum, which consist of two
superior and two inferior colliculi, which in turn concerned with visual and
auditory reflexes
• Cerebral peduncles are ventral to the aqueduct,each consist of
tegmentum,substantia nigra,crus cerebri.space between the two crus
cerebri is called interpeduncular fossa
• Function: are ocular reflexes , postural reflexes .contain sensory and motor
tracts to and from cerebral cortex, basal nuclei
cerebellum,thalamus,spinal cord
•
• Contain 3rd ,4th cranial nuclei

31. Hind brain
Pons
cerebellum
medulla oblongata

32. Pons
• Middle Part of the brain stem.
• Pons mean bridge, it connect two
cerebellar hemispheres by middle
cerebellar peduncles
• The verticle median sulcus lodges
basilar artery
• Dorsal part (tegmentum) is the
direct upward continuation of
medulla oblongata(reticular
formation) contain motor and
sensory nuclei of 5th cr n.
• Function= contain vital centres
(circulatory,respiratory)

33. Medulla oblongata
• Lower part of brain stem, continuous
inferiorly with spinal cord at foramen
magnum
• On the ventral surface have two
pyramidal shaped elevations produced by
cortico- spinal tracts involved in
conscious control of skeletal muscles
• Lateral to pyramids oval elevations called
inferior olivary nuclei
• Dorsal to each olive is an inferior
cerebellar peduncle
• On the dorsal aspect have cuneate and
gracile tubercles,containg similarly
named nuclei
• Medulla contains various vital autonomic
centres responsible for several reflexes
such as thiose involved in regulation of
heart rate,blood vessels
diameter,breathing,swallowing
,vomiting,coughing,sneezing

35. Cerebellum (little brain)
• Lies dorsal to pons
&medulla.consist of 2
hemispheres and median
worm like part vermis
• Connected with mid-brain by
superior cerebellar
peduncle,with pons by
middle cerebellar
peduncle,with medulla by
inferior cerebellar peducle
• Surface has narrow
transverse ridges called
folia(leaf) separated by
fissures
• Function= involuntry control
of somatic motor
activities(maintenace of
equilibrium,muscle tone,and
posture)