Transcript PowerPoint to accompany

Hole’s Human
Anatomy and Physiology
Tenth Edition
Shier w Butler w Lewis
Chapter
12
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
12-1
Chapter 12
Somatic 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
Touch and Pressure Senses
12-8
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
Pain Inhibiting Substances
• ___________
• __________
• ____________
Cerebral Cortex
• judges intensity of pain
• locates source or pain
• produces motor response to
pain
• produces emotions to pain
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
Stretch Receptors
12-15
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 Receptors
12-18
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 Receptors
12-21
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
Hearing
Ear – organ of hearing
3 Sections
• ________
• Middle
• ________
12-24
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
Organ of Corti
12-33
Auditory Nerve Pathways
12-34
Summary of the Generation of
Sensory Impulses from the Ear
12-35
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
Crista Ampullaris
12-40
Sight
___________________
• eyelids
• lacrimal apparatus
• extrinsic eye muscles
12-41
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
Anterior Portion of Eye
• filled with ____________
12-49
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
Accommodation
• ____________________________
12-52
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
Rods
12-61
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 lightsensitive 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
Visual Pathway
12-64
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
Clinical Application
Refraction Disorders
• ___________________
nearsightedness
• ______________
farsightedness
12-66