Week 2 Central Nervous System: Brain and Spinal Cord

what are the three major divisions of the brain?

forebrain, midbrain, and hindbrain

forebrain

• process sensory information, helps with reasoning and problem solving, and regulates autonomic, endocrine, and motor functions

• largest brain division

• lateral and third cerebral ventricles present

• two subdivisions: telencephalon and diencephalon

telencephalon

• cerebral cortex — frontal, parietal, occipital, temporal, fissures, sulci, and gyri

• basal ganglia

parietal lobe

• somatosensory association area

• primary somatosensory area

• primary taste area

frontal lobe

• primary motor area

• premotor area

• broca’s area — responsible for speech

• prefrontal area

temporal lobe

• auditory association area

• primary auditory area

• wernicke’s area — responsible for speech

occipital lobe

• visual association area

• primary visual area

diencephalon

• important centers for homeostasis

• thalamus

• hypothalamus— connected to the pituitary gland: releases hormones that help carry out body functions

• epithalamus

• pineal gland

midbrain

• helps to regulate movement and process auditory and visual information

• connects the forebrain to the hindbrain

• components— cerebral aqueduct, midbrain, tectum, cerebral peduncle, substantia nigra

• midbrain (within midbrain)— cerebral peduncle and substantia nigra

hindbrain

• helps to regulate autonomic functions, relay sensory information, coordinate movement, and maintain balance and equilibrium

• subregions: metencephalon (pons and cerebrum) and myencephalon (medulla)

limbic system

• several structures involved in emotions, olfaction, and memory

• located between diencephalon and cerebrum

• amygdala, hippocampus, cingulate gyrus, septal nuclei, dentate gyrus, fornix, mammillary body, medial olfactory striae, olfactory bulb

tectum

posterior side of midbrain that houses two structures (superior and inferior colliculi)

brain stem

• most primitive region of the brain

• essential for basic life

• includes the midbrain, pons, and medulla

cerebrum

• coordinates motor commands

• balance and posture

cerebrospinal fluid

• protects and supports the nervous system

• produced in the choroid plexuses by ependymal cells on ventricle walls

• circulates through ventricles, meninges, and spinal cord

• cushion for the brain

blood supply to the brain

• internal carotid, vertebral arteries to dural venous sinuses to internal jugular vein

• astrocytes join to capillary walls to form blood brain barrier

cranial protection of the brain

• bones of the cranium

• cranial meninges — dura matter, arachnoid mater, pia mater

• cerebrospinal fluid

spinal cord

• begins at the foramen magnum (big opening at the base of the skull)

• ends at the conus medullaris

• meninges are also found here

• total of 32 spinal nerve pairs

• plexus of the spinal chord: cervical, brachial, lumbar, sacral

• cauda equina- free nerves found at the base of the spinal cord

• cervical and lumbar enlargements

gray matter

• unmyelinated

• neural cell bodies, axon terminals, and dendrites

white matter

bundles of axons