ppt on Brain

By-Mr. ASHOK BISHNOI

Assist. Professor , JINR

The brain is the largest mass of nervous tissue in the body.

It lie in the cranial cavity

Weight of brain:-

In male is -1380 gm (48.6 oz)

In female is – 1250gm (44 oz)

Introduction:-

By carotid artery

Rt & lt anterior cerebral artery

Rt & lt posterior cerebral artery

Vertebral artery

Brain receive about 15% of the

cardiac output

Approximately 750 ml blood/mt

Blood supply to the brain;-

Cerebrum (Forebrain)

Mid brain

Pons

Medulla oblongata Brain steam

Cerebrum (Hindbrain)

Part of the brain:-

Structure:-

This is largest part of the brain

It is egg shaped organ.

It occupies the anterior & middle cranial faossa

Cerebrum (forebrain):-

Layers of the Cerebrum

Gray matter

Outer layer

Composed mostly of neuron cell bodies

White matter

Fiber tracts inside the gray matter

Example: corpus callosum connects hemispheres

Cerebral Hemispheres (Cerebrum)

Paired (left and right) superior parts of the brain

Include more than half of the brain mass

Each hemisphere of cerebrum divided in to lobs

Lobes of the Cerebrum:-

Frontal lobe

Parietal lobe

Occipital lobe

Temporal lobe

Frontal lobe:-Center of reasoning, Planning, Emotion, Speech, Problem solving.

Parietal lobe:-Receive sensory input from Skin (touch, pain, perception etc.)

Occipital lobe:- Receive input from eye.

Temporal lobe:- Hearing, Memory, Speech .

The boundaries of lobes are marked by deep sulci

These are Central, Lateral, Parietal , Occipital sulci

Functional Areas of the Cerebrum:-

Motor area ( Lie in frontal lobe)– sends impulses to skeletal muscles.

Broca’s area (motor speech) – Situated in frontal lobe (Control muscle movement necessary for speech)

Sensory area – receives impulses from the body’s sensory receptors

Sensory and Motor Areas of the

Cerebral Cortex

Slide 7.31

Figure 7.14

Sensory area:-

Slide 7.32a

Cerebral areas involved in special senses

Gustatory area (taste)

Visual area

Auditory area

Olfactory area

Gustatory area (taste):- Situated above the lateral sulcusimpulses from sensory receptor in taste buds are receive & perceive taste.

Visual area:- Situated in occipital lobe (optic nerve pass from the eye to this area.

Auditory area (Hearinf0:- Situated below the lateral sulcus in temporal bone. ( receive & interrupt impulse transmit from inner ear to auditory part)

Olfactory area (smell):-Situated in temporal lobe were impulse from nose transited through olfactory nerve are receive & interrupt.

Other areas:-

Thalamus:- Sensory input from skin or special sense.

Hypothalamus:- It is compose of number of nerve cell

It is situated front & below the thalamus.

Function:-

1. Appetite & satiety

2. Thirst & water balance

3. Regulate body temperature

4. Emotional reaction

Brain Stem

Attaches to the spinal cord

Parts of the brain stem

1. Midbrain

2. Pons

3. Medulla oblongata

4. Cerebrum (Hindbrain)

1. Mid brain:-

• It is the area of brain situated around the

cerebral aqueducts between cerebrum &

pons.

• It connect the cerebrum with lower part of brain & spinal cord

2. Pons:-

• I t is situated in front of the cerebellum.

• It consist of nerve fiber(white matter).

• Passing fiber from higher level of brain to spinal cord .

3. Medulla oblongata:-

• It extent from pons above &

• it continuous with spinal cord

below.

• About 2.5 cm long.

• Function:- ( the vital center)

• Cardiovascular center (HR control & BP regulation)

• Respiratory center

• Reflex center of Vomiting, Coughing, Sneezing, &

Swallowing

4. Cerebellum.:-

• It is situated behind the pons

• It occupying posterior cranial fossa

Function:-

• It help co-ordination of

voluntary muscular

movement, Posture

& balance.