brain

By: Dr. Pamela Josefina T. Fabie

BRAIN

o Part of the CNS contained within the skullo Most complex and largest mass of nervous tissue in the body

and contains billions of nerve cells

MALE1380 g

FEMALE1250 g

Grows frombirth up to 5th year

Weightdecreases with

old age

PARTS OF THE BRAIN

Largest portion

7/8 of the total weight

Cerebral surface –cerebral cortex, composed of graymatter

Fold- gyrus (gyri)

Intervening furrows-sulcus (if shallow); fissures (if deep)

Innermost part –white matter

CEREBRUM

Parts of the Brain : Cerebrum

Seat of Mental Activities

(attributed to higher centers)

•Memory

•Thinking

•Reasoning

•Moral sense

•Learning

•Sense of responsibility

Sensory Perception

•Pain

•Temperature

•Touch

•Special senses

Initiation and

Control of

Voluntary Muscular

Coordination

FUNCTIONS:

LOBES:

1. FRONTAL – motor functions and personality

2. PARIETAL – sensory functions

3. TEMPORAL – hearing and smell

4. OCCIPITAL – vision

5. ISLAND OF REIL – libido (sexual desires of man)


“Little Brain”

Oval in shape

DIVISIONS:

Ant. Lobe – posture

Post. Lobe –coordination of movements

Flocculonodular lobe - equilibrium

CEREBELLUM

Found between the forebrain and the hindbrain

Concerned with motor coordination

Connects the pons and the cerebellum with the cerebrum

MIDBRAIN

Parts of the Brain : Midbrain

CEREBRAL PEDUNCLES – pair of cylindrical bodies made up of nerve fiber tracts which connect the forebrain with the hindbrain

CORPORA QUADRIGEMA – 4 rounded nuclear masses

a. SUPERIOR COLLICULI (Upper 2) – concerned with

visual reflexesb. INFERIOR COLLICULI

(Lower 2) – concerned with auditory reflexes

SYLVIAN OR CEREBRAL AQUEDUCT or ITER - canal which connects the 3rd and 4th

ventricles of the brain

Situated in front of the cerebellum between the midbrain and the medulla oblongata

Bridge-like structure composed entirely of white matter linking the various parts of the brain

Joins the two halves of the cerebellum

Contains pneumotaxiccanter – regulation of respiration

PONS VAROLLI

Extends from the pons above and is continuous with the spinal cord below

Pyramidal in shape, being broad above and narrow below

Nerve cells are grouped to form nuclei

Origin of CN 6,7,8,9,10,11,12

MEDULLA OBLONGATA

PARTS OF THE BRAIN: Medulla Oblongata

1. Organ of conduction for the passage of

impulses between brain and spinal cord

2. Contains center for control of bodily

functions

•Cardiac inhibitory center – holds heart rate to slower rate

through CN 10

•Vasoconsctrictor center – narrowing of lumen of the

arteries

•Respiratory center – controls rate of depth of respiration

•Reflex center – sneezing, coughing, vomiting, winking,

movements and secretions of the alimentary canal

FUNCTIONS:

brain

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