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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