The Brain

The BrainThe central nervous system begins as the

neural tube which has a fluid-filled cavity called the neurocoel.

The cephalic portion of the tube enlarges creating 3 large divisions called the

primary brain vesicles:

the prosencephalon or the forebrain,

the mesencephalon or the midbrain,

and the rhombencephalon or the hindbrain.

The neurocoel will contain to develop within the major portions of the brain

and form ventricles lined by ependymal cells.

Develop continues until the brain is formed.

DevelopmentThe prosencephalonis also known as the

forebrain. Theanterior portion

develops into thecerebrum and basal

ganglia, and theposterior portiondevelops into the

diencephalon .

DevelopmentThe mesencephalonis also known as the

midbrain.

DevelopmentThe

rhombencephalonis also known as the

hindbrain. This gives rise to the cerebellum, the pons, and the

medulla oblongata.

Four Major Sections1. Cerebrum

2. Diencephalon3. Cerebellum4. Brain Stem

Cerebrum

Corpus Callosum

Gyri, Sulci, Fissures

Lobes of the Cerebrum

Frontal

Parietal

Temporal

Occipital

Broca’s Area

DopamineThe majority of cerebral tissue is white matter; however, there are some areas

of gray matter called basal ganglia which are largely regulated by the

neurotransmitter dopamine.

Dopamine & Parkinson’sDopamine regulates body movements

and facial expressions.

A lack of dopamine within the basal ganglia can result in Parkinson’s disease.

Treatments include L-Dopa, electrical stimulations, or fetal tissue transplants.

The DiencephaonThe diencephalon is located between the

cerebral hemispheres.

Its main function is to process sensory information.

The diencephalon contains the thalamus, the posterior pituitary gland, the

pineal gland, and the hypothalamus.

The thalamus functions as a relay station for sensory information.

The pituitary and pineal glands are a part of the endocrine system.

The hypothalamus has a variety of functions - emotions, hormone production, and

autonomic responses (bp or heart rate).

The CerebellumThe cerebellum is located beneath the

occipital lobe and is divided into two lateralhemispheres.

Similar to the cerebrum, the outer layer is athin layer of gray matter called the

cerebellular cortex.

This portion of the brain is involved in communicationcontrolling movements, balance, and posture.

The Brain StemThe brain stem is located at the base of

the base and contains the nerve fibers that connect to the spinal cord.

There are 3 major structures in the brain stem: the midbrain, the pons, and the

medulla oblongata.

The Brain StemThe midbrain relays impulses from the lower

parts of the brain stem and spinal cord to other parts of the brain.

The pons also relay impulses but the relay isbetween the cerebrum and the medulla

oblongata.

The Brain StemThe medulla oblongata is the elongated area

under the occipital lobe.

It has some involvement in communication, and it controls several visceral areas –

cardiac, blood pressure, and respiration.

The Limbic System

The Reticular Formation

Sleep Stages

ProtectionThe three layers of meninges are continuouswith the spinal meninges. The three layers

are the dura mater,the arachnoid mater, andthe pia mater.

The dura mater’s outside layer is attached to theperiosteum of the skull.

ProtectionThe arachnoid mater covers the brain and provides

a smooth surface unlike that of the brain.

The pia mater sticks to the surface of the brain and is anchored by astrocytes.

It extends into the fissures and accompanies the

blood vessels as they penetrate the surface of thebrain.

Cerebrospinal Fluid

Brain’s Blood Supply

• The circle of Willis encircles the stalk of the pituitary gland and provides important communications between the blood supply of the forebrain and hindbrain

Brain’s Blood Supply