chapter 11 key terms 1 cerebrumsclera corneapineal gland hypothalamusstapes irislens corpus...
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1Chapter 11 Key Terms
CerebrumScleraCorneaPineal GlandHypothalamusStapesIris
LensCorpus Callosum RetinaOccipital LobeOlfactory SenseCerebellumPituitary GlandMedulla Oblongata Cerumen
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ANATOMY & PHYSIOLOGYCHAPTER 11: NERVOUS SYSTEM
BRAIN, CRANIAL NERVES, AUTONOMIC NERVOUS SYSTEM, SPECIAL SENSES
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Processing Words and Letters
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The Brain
On average weighs about 3 lbs Protection:
Cranial bonesMeningesCerebrospinal fluid
Acts as shock absorber and circulates nutrients
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The Brainstem
Connects brain to spinal cord Very delicate Medulla Oblongata
Contains all tracts going in and out of the brainControls 3 major reflex centers:
Vasomotor Center: regulates diameter of blood vesselsCardiac Center: regulates force of contraction and rate of
heartbeatMedullary Rhythmicity: adjusts basic rhythm of breathing
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The Brainstem
Pons“Bridge” between spinal cord and brainControls chewing, breathing, taste
MidbrainAlso called MesencephalonControls eyes and head movement in response to
visual stimulusControls head and trunk movement in response to
auditory
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Diencephalon
Above the midbrain and between the two cerebral hemispheres
Contains the thalamus and hypothalamus Thalamus
Relay station for sensory impulses Interpretation of pain and temp
Hypothalamus Controls many homeostatic functions and ANS Controls normal sleep-wake cycles
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Cerebrum
Bulk of the brain Surface is called cerebral cortex
Made up of gray matter White matter is found below the cortex Longitudinal fissure Gyri: folds on surface of hemispheres Sulci: grooves between folds Corpus Callossum: connects 2 hemispheres
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Cerebrum
FrontalControls voluntary muscle functions, moods,
aggression, smell Parietal
Evaluates touch, pain, balance, taste, temp Temporal
Evaluates hearing and smell, memory, abstract thoughts, judgment decisions
OccipitalReceives and interprets visual input
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Cerebellum
Also divided into two hemispheres connected by vermis
FunctionsTakes sensory information about position of body
parts to maintain posture and balanceCoordination of muscular movementsMaintains body postureKeeps body balanced
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Autonomic Nervous System
Functions without conscious effort (involuntary) Regulates functions of internal organs and regulates
homeostasis (heartbeat, blood pressure, breathing, temp)
2 partsSympathetic: prepares body for stressful situationParasympathetic: normal, non-stressful functions
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Cranial Nerves
12 pairs of cranial nerves, 10 originate out of brain stem Named according to two methods:
FunctionRoman numerals indicating order in which they arise from
brain Olfactory Nerve (I) – only sensory, smell Optic Nerve (II) – only sensory, sight Oculomotor Nerve (III) – controls movement of eye and eyelid Trochlear Nerve (IV) – controls eye movement (only 1
muscle)
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Cranial Nerves
Trigeminal Nerve (V) – largest cranial nerveControls chewing and delivers sensory impulses from
teeth and face Abducens Nerve (VI) – controls movement of eyeball (1
muscle) Facial Nerve (VII) – facial expression muscles, taste
sensation Vestibulocochlear Nerve (VIII) – equilibrium and
hearing Glossopharyngeal Nerve (IX) – swallowing and taste
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Cranial Nerves
Vagus Nerve (X) – controls viscera in thorax and abdomenControls movements of pharynx, larynx, palateSensory from larynx, viscera, ear
Accessory Nerve (XI) – swallowing and head movements
Hypoglossal Nerve (XII) – speech and swallowing See table 11-1 on page 258
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Special Senses
5 senses Taste Smell Sight: interaction of light and receptors Hearing Balance
Chemicals interact with receptors
Mechanical factors interact with sensory in the ear
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Sense of Smell
Known as the olfactory sense Chemicals enter nasal cavity and dissolve in mucous
epithelial lining of superior nasal conchae Olfactory neurons in lining and are in contact with
the olfactory receptor sites Receptors transmit smell to olfactory bulb which
transmits impulse to brain for interpretation Over time, receptors adapt so smell is not as strong
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Sense of Taste
Papillae: raised bumps on tongue that contain taste buds
Taste buds are made of taste cells which are the receptor sites for taste
Process:Saliva dissolves compound to be tastedHairs on taste cell absorb mixtureTaste cells bond chemicals to receptor sitesCranial nerves VIII, IX, and X take sensations to the brain
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Sense of Taste
Taste SensationsAll taste buds taste all sensations; some react more
stronglySweet: very tip of tongueSalty: side of tongue very close to the tipSour: side of tongue near the backBitter: back of tongue
Taste sensations are influenced by olfactory sensations
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Sense of Sight
3 layers of the eyeSclera: white, outermost layer of
the eyeCornea: transparent portion of
sclera that lets light enter the eye
Choroid: 2nd layer, contains blood vessels, absorbs light
Retina: innermost layer, contains rods and conesCones see 3 colors: blue, red,
green
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Sense of Sight
Ciliary Body: smooth muscle that holds the lens in place
Lens: changes shape to focus light as it enters eye
Iris: colored part of eyeDilates and constricts pupil
Pupil: opening that allows light to enter the eye
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Sense of Sight
Aqueous humor: bends light, source of nutrients for inner surface of eye, maintains ocular pressureProduced by ciliary body
Vitreous Humor: maintains ocular pressure, refracts light, holds lens and retina in place
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Sense of Sight
Optic Nerve: rods and cones connect to other neurons which come together hereTakes info from eye to brain
Optic Disk: blind spot, area where all nerve fibers meet and leave the eye
Fovea Centralis: depression on macula lutea that produces sharp vision
39Sense of Hearing and Equilibrium
Structure of the earOuter and middle ear are
involved in hearing Inner ear is involved with
hearing and balance External Ear
Auricle: flexible, visible part of ear
External Auditory Meatus: ear canal
Tympanic Membrane: ear drum
40Sense of Hearing and Equilibrium
External EarCeruminous glands: produce
cerumen Middle Ear
Malleus – “hammer” Incus – “anvil”Stapes – “Stirrup”Eustachian Tube: allows air
pressure to equalize