Upload
blaise-summers
View
243
Download
2
Tags:
Embed Size (px)
Citation preview
Hole’s HumanAnatomy and Physiology
Tenth Edition
Shier Butler Lewis
Chapter
12
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 12-1
Chapter 12Somatic and Special Senses
Sensory Receptors• specialized cells or ____________ structures that collect information• stimulate neurons to send impulses along sensory fibers to the brain
12-2
Receptor Types
___________________• respond to changes in chemical concentrations
Pain receptors• respond to tissue damage
_________________• respond to changes in temperature
Mechanoreceptors• ________________________
Photoreceptors• respond to light 12-3
Sensory Impulses
• stimulation of receptor causes local change in its membrane• a graded electrical current is generated that reflects _________ of stimulation• if receptor is part of a neuron, the membrane potential may generate an action potential• if receptor is not part of a ________, the receptor potential must be transferred to a neuron to trigger an actin potential• peripheral nerves transmit impulses to CNS
___________• feeling that occurs when brain interprets sensory impulse
12-4
Sensory Adaptation
• adjustment of sensory receptors from continuous stimulation• stronger stimulus required to activate receptors• ____________ undergo sensory adaptation
12-1
Somatic Senses
• senses associated with skin, muscles, joints, and viscera
• three groups• ______________ senses – senses associated with body surface; touch, pressure, temperature, pain• _______________ senses – senses associated with changes in muscles and tendons• _________________ senses – senses associated with changes in viscera
12-6
Touch and Pressure Senses
Free nerve endings• common in epithelial tissues• ___________ touch and pressure
______________________• abundant in hairless portions of skin• detect light touch
__________________• common in deeper subcutaneous tissues, tendons, and ligaments• detect heavy pressure
12-7
Temperature Senses
Warm receptors• sensitive to temperatures above ____________• unresponsive to temperature above ______ (113oF)
______________• sensitive to temperature between 10oC (50oF) and 20oC (68oF)
Pain receptors• ________________________________• respond to temperatures above 45oC
12-9
Sense of Pain
• ______________________ • widely distributed • nervous tissue of brain lacks pain receptors• stimulated by tissue damage, chemical, mechanical forces, or extremes in temperature• ___________________
______________• may exhibit referred pain• _________________
12-10
Referred Pain
• may occur due to sensory impulses from two regions following a common nerve pathway to brain
12-11
Pain Nerve Fibers
___________________ thin, myelinated
• conduct impulses rapidly• associated with sharp pain• well localized
_________________• thin, unmyelinated• conduct impulses more slowly• associated with dull, aching pain• ________________
12-12
Regulation of Pain Impulses
Thalamus • allows person to be aware of pain
Cerebral Cortex • judges intensity of pain • locates source or pain• produces motor response to pain• produces emotions to pain
Pain Inhibiting Substances• ___________• __________• ____________
12-13
Stretch Receptors
• proprioceptors• send information to CNS concerning lengths and tensions of muscles• 2 main kinds of stretch receptors
• _________________ – in skeletal muscles• ________________ – in tendons
12-14
Special Senses
• sensory receptors are within large, complex sensory organs in the head• _________ in olfactory organs• _________ in taste buds• ______________________ in ears• sight in eyes
12-16
Smell
Olfactory Receptors• _________________• respond to chemicals dissolved in liquids
_________________• contain olfactory receptors and supporting epithelial cells• cover parts of nasal cavity, superior nasal conchae, and a portion of the nasal septum
12-17
Olfactory Nerve Pathways
Once olfactory receptors are stimulated, nerve impulses travel through
• ________________ • olfactory bulbs to • _________________ • limbic system (for emotions) and olfactory cortex (for interpretation)
12-19
Taste
________________• organs of taste• located on papillae of tongue, roof of mouth, linings of cheeks and walls of pharynx
_____________________• chemoreceptors• taste cells – modified epithelial cells that function as receptors• taste hairs –_________ that protrude from taste cells; sensitive parts of taste cells
12-20
Taste Sensations
Four Primary Taste Sensations• ________ – stimulated by carbohydrates• sour – stimulated by acids• _______ – stimulated by salts• bitter – stimulated by many organic compound
_________________________________
12-22
Taste Nerve Pathways
Sensory impulses from taste receptors travel along• cranial nerves to • _____________________• __________________ • gustatory cortex (for interpretation)
12-23
External Ear
• _____________• collects sounds waves
• external auditory meatus• lined with ceruminous glands• carries sound to tympanic membrane• _____________________ tympanic membrane
• tympanic membrane • _________ in response to sound waves
12-25
Middle Ear
• tympanic cavity• air-filled space in temporal bone• auditory ossicles
• vibrate in response to tympanic membrane• ________, ______, and stapes
• _____________ • opening in wall of tympanic cavity• stapes vibrates against it to move fluids in inner ear
12-26
Auditory Tube
• ________________ • connects middle ear to throat• helps maintain equal pressure on both sides of tympanic membrane• usually closed by valve-like flaps in throat
12-27
Inner Ear
• complex system of labyrinths• ____________________
• bony canal in temporal bone• filled with _________
• membranous labyrinth• tube within osseous labyrinth• filled with ____________
12-28
Inner Ear
3 Parts of Labyrinths• ________
• functions in hearing• _________________
• functions in equilibrium
• vestibule• __________ in equilibrium
12-29
Cochlea
______________• upper compartment• leads from oval window to apex of spiral• part of bony labyrinth
_____________• lower compartment• extends from apex of the cochlea to ___________• part of bony labyrinth
12-30
Cochlea
______________• portion of membranous labyrinth in cochlea
_________________• separates cochlear duct from scala vestibuli
Basilar membrane• separates cochlear duct from scala tympani
12-31
Organ of Corti
• group of hearing receptor cells (__________)• on upper surface of basilar membrane• different frequencies of vibration move different parts of basilar membrane• particular sound frequencies cause hairs of receptor cells to bend• nerve impulse generated
12-32
Equilibrium
Static Equilibrium• ____________• sense position of head when body is not moving
_________________• semicircular canals• sense rotation and movement of head and body
12-36
Vestibule
• ________• communicates with saccule and membranous portion of semicircular canals
• ________• communicates with cochlear duct
• ________• hair cells of utricle and saccule
12-37
Macula
• responds to changes in head position• bending of hairs results in generation of nerve impulse
12-38
Semicircular Canals
• three canals at right angles• __________
• swelling of membranous labyrinth that communicates with the vestibule
• ______________• sensory organ of ampulla• hair cells and supporting cells• rapid turns of head or body stimulate hair cells
12-39
Eyelid
• _____________• composed of four layers
• skin• muscle • connective tissue• conjunctiva
• _________________ - closes• levator palperbrae superioris – opens• ___________ – secrete oil onto eyelashes• _____________ – mucous membrane; lines eyelid and covers portion of eyeball
12-42
Lacrimal Apparatus
• lacrimal gland• lateral to eye• secretes tears
• ___________• collect tears
• lacrimal sac• collects from canaliculi
• ________________• collects from lacrimal sac• empties tears into nasal cavity
12-43
Extrinsic Eye Muscles
______________• rotates eye up and medially
_____________• rotates eye down and medially
Medial rectus• rotates eye medially
12-44
Extrinsic Eye Muscles
Lateral rectus• ________ eye laterally
______________• rotates eye down and laterally
Inferior oblique• rotates eye up and laterally
12-45
Structure of the Eye
• hollow• spherical• wall has 3 layers
• outer _____________• middle vascular tunic• inner ____________
12-46
Outer Tunic
_________• anterior portion• transparent• light transmission• light refraction
Sclera• posterior portion• opaque• ________
12-47
Middle Tunic
______ • anterior portion• pigmented• controls light intensity
____________• anterior portion• pigmented• holds lens• moves lens for focusing
Choroid coat• provides blood supply• pigments absorb extra light
12-48
Lens
• transparent• __________• ________________• largely composed of lens fibers• elastic• held in place by suspensory ligaments of ciliary body
12-50
Ciliary Body
• forms internal ring around front of eye• ____________ – radiating folds• _____________ – contract and relax to move lens
12-51
Iris
• composed of connective tissue and smooth muscle• _______________ in iris• dim light stimulates radial muscles and pupil dilates• bright light stimulates circular muscles and pupil constricts
12-53
Aqueous Humor
• ________________________• secreted by epithelium on inner surface of the ciliary body• provides nutrients• maintains shape of anterior portion of eye• _____________________________
12-54
Inner Tunic
• _________• contains visual receptors• continuous with optic nerve• ends just behind margin of the ciliary body• composed of several layers• ____________ – yellowish spot in retina• ______________ – center of macula lutea; produces sharpest vision• optic disc – blind spot; contains no visual receptors• ________________ – thick gel that holds retina flat against choroid coat
12-55
Layers of Retina
• ________________________________, and ganglion cells - provide pathway for impulses triggered by photoreceptors to reach the optic nerve• _______________________________ – modify impulses
12-56
Light Refraction
Refraction • __________________• occurs when light waves pass at an oblique angle into mediums of different densities
12-57
Types of Lenses
_________ lenses cause light waves to _________
_______ lenses cause light waves to _______
12-58
Focusing On Retina• as light enters eye, it is refracted by
• convex surface of cornea• _______________________
• image focused on retina is upside down and reversed from left to right
12-59
Visual Receptors
Rods• ______________• contain light sensitive pigment called rhodopsin• hundred times more sensitive to light than cones• _____________________• produce colorless vision• produce outlines of objects
Cones• short, blunt projections• contain light sensitive pigments called erythrolabe, chlorolabe, and cyanolabe• provide vision in bright light• produce sharp images• produce color vision
12-60
Visual Pigments
_____________• light-sensitive pigment in rods• decomposes in presence of light• triggers a complex series of reactions that initiate nerve impulses• impulses travel along optic nerve
Pigments on Cones• each set contains different light-sensitive pigment• each set is sensitive to different wavelengths• color perceived depends on which sets of cones are stimulated• ________ – responds to red• _______ – responds to green• ________ – responds to blue
12-62
Stereoscopic Vision• __________________________________• results from formation of two slightly different retinal images
12-63
Life-Span Changes
Age related hearing loss due to • ___________________________________• degeneration of nerve pathways to the brain• tinnitus
Age-related visual problems include• __________• floaters (crystals in vitreous humor)• loss of elasticity of lens• glaucoma• ___________• macular degeneration 12-65