Central Nervous System

Major Anatomic regions of Brain

CerebrumDiencephalonBrainstemCerebellum

Cerebrum

Cerebrum

Left and right cerebral hemispheres make up the cerebrum

Cerebral cortex (outer layer) is made of non-myelinated gray matter.

Internal tissue is white myelinated white matter with small interspersed regions of gray matter called basal nuclei.

Cerebrum

Surface of brain is convolutedGyrus – bump

Sulcus – shallow grooveFissure – deep groove

Sulci divide brain into 4 lobes FrontalParietalTemporalOccipital

Cerebrum

Longitudinal fissure divides brain into left and right halves

Left brain controls right side of bodyRight side controls left side of body

Cerebrum – Frontal Lobe

Frontal lobe is sectioned off from the brain by the central sulcus

Anterior to central sulcus is primary motor cortex – sends nerve impulses to control movement

This area has been mapped to show what body parts are controlled in each region of cortex (motor output)

Left frontal area also includes Broca’s area which controls tongue and lip movements required for speech

Cerebrum - Parietal

Posterior to frontal lobesIncludes primary somatic sensory cortex

which interprets incoming sensory impulsesThis has been mapped as well to show

sensory input

Cerebrum - Occipital

Posterior to parietal lobesResponsible for vision

Cerebrum - Temporal

Inferior to frontal and parietalInvolved in speech, hearing, vision, memory

and emotion

Diencephalon

Deep inside the brainIncludes thalamus, hypothalamus and

epithalamusThalamus: relay stationHypothalamus: key part of autonomic nervous system, regulating heart rate, etcEpithalamus: includes pineal gland that regulates sleep-cycle hormones

Brain Stem

Size of a thumbIncludes midbrain, pons and medulla

oblongataMidbrain: relay stationPons: helps regulate breathingMedulla oblongata: regulates heart rate,

blood pressure and breathing

Cerebellum

Below occipital lobe Coordinates body movements including

balance

Protection of Brain

SkullMeningesBlood-brain barrier

 The Meninges

= protective membranes located between bone and soft tissues of the nervous system

Dura mater - outermost

layer

Arachnoid mater  -  no blood vessels, in between layer (resembles a spider web)

Pia mater -inner membrane, contains nerves and blood vessels to nourish cells

Dura mater is being

peeled away in this

photo.

Blood Brain Barrier

Capillaries in brain are different from capillaries in other parts of the body.

Only certain substances are allowed to pass through to the brain

Spinal Cord

Goes from brainstem to beginning of lumbar region of spine

Major pathwayProtected by same mechanisms as brainExterior portion is myelinated white matterCentral area is butterfly shaped gray matter

containing neuron cell bodies and interneurons

Tips of butterfly are called horns