LOBES OF BRAIN

1. AAKRITI DHAKAL
BPT

2. .The outer layer of gray matter of cerebrum is cerebral cortex.
The outer layer of cerebral cortex folds to create gyri and sulci.
The cerebrum or cortex is the largest part of brain,associated
with higher brain function such as thought and action.
 what is grey matter and white matter ???
The CNS has two kinds of tissue;grey matter and white
matter.
Grey matter is pinkish grey colour in the living brain containing
cell bodies,dendrites and axon terminals of neurons so it is
where all synapse are.
White matter is made of axons connecting different parts of grey
matter to each other.

4. Cerebrum is the principal and the most anterior part of the
brain in the vertebrates, located in the front part of the cranial
cavity.
It is made of two cerebral hemispheres which are incompletely
separated from each other by the median longitudinal fissures.
The two Rt and lft hemispheres are connected to each other
across the median plane by the corpus callosum which passes
messages betwn two halves of hemisphere.
The Rt half of the cerebrum controls the left side of the body
and vice versa.
Each hemisphere contains a cavity, called lateral ventrical.

6. 1. Sulci: A depression, sulcus in the surface area allows
for continued growth of brain thus allows for function of
brain to continue growing.
2. Gyri: elevated ridges “winding” around the brain
3. Fissures:
Types of fissures:
I. Longitudinal :divides two cerebral hemispheres
II. Transverse: separates cerebrum from cerebellum
III. Sylvian/lateral:divides temporal from parietal and
frontal lobes
4. Hemispheres – Rt and lft

8. Each cerebral hemispheres is divided into four lobes-
1.Frontal lobe
2.Parietal lobe
3.Occipital lobe
4.Temporal lobe

9. There are three basic functional divisions of cerebral
cortex:
1. Motor areas: the primary motor area, give rise to
contration of skeletal musculature.
2. Sensory areas: in these areas, electrical activity can
be recored if appropriate sensory stimulus is applied to
a particular part of the body .
3. Association areas: these areas integrate and analyse
the respones from various sources.

10. Surface/lobe Sulci Gyri
Superolateral surface:
1. Frontal lobe
A. Precentral
B. Superior frontal
C. Inferior frontal
a. Precentral
b. Superior frontal
c. Middle frontal
d. Inferior frontal
2. Parietal lobe A. Postcentral
B. Intraparietal
a. Postcentral
b. Superior parietal
lobule
c. Inferior parital lobule
i. The anterior,
supramarginal
ii. The middle, angular
iii. The posterior, over
the upturned end of
inferior temporal
sulcus

12. The frontal lobe forms one third of the cortical surface.
Frontal lobe of cerebral cortex is divided into two parts;
1.Precentral Cortex-
a.primary motor area(4,4s)
b.premotor area(6,8,44,45)
c.supplementary motor area
2.Prefrontal Cortex- (9,10,11)

14. FRONTA
L LOBE
AREA AREA NO. LOCATION FUNCTION EFFECT
OF
LESION
PRECEN
TRAL
CORTEX
1.primary
motor area
4
4s
Precentral
gyrus and
paracentral
lobule
Controls
voluntary
activities of
the
opposite
half of
body.
Suppresses
the extra
impulse
produced
by area 4
and
prevents
exaggeratio
n of
Contralater
al paralysis
and
Jacksonian
fits

15. Frontal
Lobe
Area Area
no.
Location Representation
of body parts
Function Effect
of
lesio
n
Precent
ral
cortex
2.Pre-
motor
area
6 Posterior
parts of
superior
middle
and
inferior
frontal gyri
_ Concerned
with
coordination
of
movements
initiated by
area 4.
Controls
extra-
pyramidal
system
Often
mixed
pyram
idal
effect

16. FRONTAL
LOBE
AREA AREA NO LOCATION FUNCTION EFFECT OF
LESION
Precentral
cortex
Premotor
area
(frontal
eye field)
8 - Concerned
with
conjugate
movement of
eyeballs
Conjugate
movements
of eyes are
lost.

17. Lobe Area Area
no.
Location Representation
of body parts
Function Effect
of
lesion
Precent
ral
cortex
Motor
speec
h area
(Broca’
s area)
44,
45
Para
triangularis
and pars
opercularis
_ Controls
the spoken
speech.Res
ponsible for
movements
of
tongue,lips
and larynx.
Aphasi
a
(motor)

18. • In association with premotor area provides attitudinal
movements,fixation movement of different segments of
the body and positional movements of head and eyes.

19. Lobe Area Area
no.
Location Representatio
n of body
parts
Function Effect
of
lesion
Frontal
lobe
5.Pre-
frontal
area
9,10,
11,
12,
13,
14,
23,
24,
29
and
32
The
remaining
large,
anterior
part of
frontal
lobe
_ Controls
emotion,
concentration
attention and
judgment
Loss of
orientat
ion,lack
of
initiatio
n and
mental
alertne
ss.

20. • The injury or ablation of prefrontal cortex leads to a condition
called frontal lobe syndrome.The features of this syndrome
are;
• 1.Emotional instability.
• 2.lack of concentration and fixing attention occur
• 3.lack of initiation and difficulty in planning any course of
action.
• 4.loss of moral and social science.
• 5.Failure to realize the seriousness of the condition.The
subject has the sense of well beingand also has flight of ideas.
• 6.Apart from mental disorders,other functional abnormalities
like;
i. Hyperphagia
ii.Incontinence
iii.slight tremor
iv.Disturbances in orientation

21. • The parietal lobe extends from central sulcus and merges
with occipital lobe behind and temporal lobe below.
• Parietal lobe is divided into 3 functional areas;
a.Somesthetic area I (1,2,3)
b.Somesthetic area II
c.Somesthetic association area (5,7)

22. Lobe Area Area
no.
Location Function Effect of
lesion
Parietal
lobe
Somesth
etic area
1
3, 1,
2
Postcentra
l gyrus
and
paracentra
l lobule
perception of
exteroceptive
(touch,
pain,pressure
and
temperature)
and
proprioceptive
impulses.Area 1
is concerned
with sensory
perception and
areas 2&3 are
involved in the
integration of
these
sensations.
Loss of
appreciati
on of the
impulses
received,l
oss of
sensation
s in the
opposite
side of
body.

23. SOMESTHETIC AREA II
It is situated in postcentral gyrus below the area of face of
somesthetic area I.
This area receives sensory impulses from somesthetic area I and from
thalamus.
Concerned with perception of sensation.
SOMESTHETIC ASSOCIATION AREA
It is situated posterior to postcentral gyrus.
It has two areas -5 & 7. Concerned with synthesis of various
sensations perceived by somesthetic area I.
The lesion of this area causes ASTEREOGNOSIS.