The BrainThe Brain

DivisionsDivisions

• Cerebrum

• Diencephalon

• Brainstem

• Cerebellum

CerebrumCerebrum

• Cerebrum

• Largest area

• On top

• 4 lobes (frontal, parietel, temporal, occipital)

• Thinking, short and long term memory, voluntary movement, reasoning, level of consciousness

Cerebrum (cont)Cerebrum (cont)

• Structure• Ridges (convolutions/gyri)• Grooves (sulci)• Deep grooves (fissures)• 2 hemispheres (R and L)• Corpus callosum (connect two halves)• Cerebral cortex: thin layer of gray matter (mostly

dendrites an cell bodies) gray matter• White matter: inner cerebrum• Some inner gray:basal ganglia (automatic postures)

4 lobes4 lobes

• Frontal

• Parietal

• Temporal

• Occipital

Frontal LobeFrontal Lobe

• Prefrontal; conscious thought

• Broca’s area; motor speech

• Premotor area; muscle coordination

• Primary motor area; precise muscle control

• Central sulcus

Parietal LobeParietal Lobe

• Primary somatic sensory area; body sense perception

• Primary taste area

• Somatic sensory association area; body sense perception

• Wernicke’s area; sensory speech area

Temporal LobeTemporal Lobe

• Auditory association area

• Primary auditory area

Occipital LobeOccipital Lobe

• Visual association area

• Visual cortex

DiencephalonDiencephalon

• Thalamus: relay station for senses

• Hypothalamus:body temp., water balance, sleep cycle, appetite (mind-body connection)

• Pituitary gland: master gland (8 hormones)

BrainstemBrainstem

• Midbrain: relay for visual and auditory impulses

• Pons: relay station; influences respirations

• Medulla oblongata: life centers (cardiac and respiratory)

CerebellumCerebellum

• Balance and coordination

Spinal CordSpinal Cord

• Occipital bone to bottom of first lumbar vertebrae (17-18 inches)

• H-shaped

• Core made of gray matter (cell bodies and dendrites)

• Outer portion: white matter; bundles of myelinated axons: spinal tracts

Spinal TractsSpinal Tracts

• Ascending tracts: conduct impulses to the brain

• Descending tracts: conduct impulses from the brain

• Tracts are organized to carry different sensations

CNS Protective CoveringsCNS Protective Coverings

• Skull

• Vertebrae

• Cerebrospinal fluid (CSF)

• Meninges: dura mater: outer

arachnoid mater: middle

pia mater: inner

CdCdFlow of CSFFlow of CSF

• Filtered out from blood capillaries known as choroid plexus

• Two large spaces: lateral ventricles (R and L)• Flows down through aqueduct to third ventricle• Then to a fourth ventricle down to subarachnoid

space near cerebellum• Then to spinal cord• Purpose: protection