Central Nervous System

Central Nervous System - Biol 121 Anatomy Physiology I...

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Nervous System #2 The Central Nervous System (Brain and Spinal Cord) II. The Brain Average adult male brain weighs 3.5 lbs Brain provides for voluntary movements, interpretation and integration of sensation, consciousness, and cognitive function. Four Regions of the Brain A. Cerebral Hemispheres B. Diencephalon C. Brain Stem D. Cerebellum A. Cerebral Hemispheres Superior portion comprising more than 60% of total brain weight Each hemisphere controls function of the opposite side of the body Left and right hemispheres each divided into four lobes. Lobes are named according to the overlying bones: frontal, parietal, temporal and occipital Three layers comprise each hemisphere 1. Cortex - outer grey, nerve cell bodies and unmyelinated fibers a) Surface features include: Fissures - prominent grooves, separate lobe Gyri - hills Sulci - furrows b) Cortex enables us to perceive, communicate, remember, understand, appreciate and initiate voluntary movement. c) Different areas of the cortex carry out different functions. Precentral gyrus - motor cortex, control movement of skeletal muscle Postcentral gyrus - sensory cortex, distinguish sensory information M Hopper 2010
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Broca's area - in frontal lobe, coordinates speech Visual cortex - occipital lobe, interprets visual stimuli Olfactory and auditory cortex's - temporal lobe, smell and hearing 2. White matter - just below the cortex. Contains nerve tracts between lobes that allow communication with other brain areas. 3. basal nuclei - islands of gray matter (cell bodies) deep within the white matter, connections to lower brain centers B. Diencephalon Below and surrounded by cerebral hemispheres. Consists of three structures: 1. Thalmus Egg shaped, Greek for "inner room" which describes this hidden region Serves as a relay station for sensory information, sorting-out and controlling input into the cortex 2. Hypothalmus Below the thalamus, caps the top of the brain stem Connects to the pituitary gland via the infundibulum Vitally important to overall body homeostasis. Roles: 1. Regulates the autonomic nervous system 2. Center for emotional response and behavior - involved in the perception of pain, pleasure, fear and rage as well as biological rhythms and drives. 3. Body temperature regulation - responds to changes in blood temperature 4. Regulation of food intake - monitors blood glucose and other nutrients. 5. Regulation of water balance and thirst - osmoreceptors activated when body fluids become too concentrated. Trigger release of antidiuretic hormone from the posterior pituitary. 6. Regulation of sleep-wake cycles
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This note was uploaded on 02/02/2011 for the course BIOL 121 taught by Professor Hopper during the Fall '10 term at University of Evansville.

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Central Nervous System - Biol 121 Anatomy Physiology I...

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