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- 1. Seeley’s
ESSENTIALS OF
Anatomy &
Physiology
Tenth Edition
Cinnamon Vanputte
Jennifer Regan
Andrew Russo
See separate PowerPoint slides for all figures and tables
pre-inserted into PowerPoint without notes.
© 2019 McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw-Hill Education.
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Senses
Are the means by which the brain receives
information about the environment and the body.
Sensation
The process initiated by stimulating sensory
receptors.
PERCEPTION
conscious awareness of stimuli received by
sensory neurons
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Characteristic of Sensation
PROJECTION
The sensation seems to come from the area
where the receptors were stimulated, even
though it is the brain that truly feels the
sensation
INTENSITY
The degree to which the sensation is felt; a
strong stimulus affects more receptors and
more impulses are sent to the brain
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Characteristic of Sensation
CONTRAST
The effect of a previous or simultaneous
sensation on a current sensation as the brain
compares them.
ADAPTATION
Becoming aware of continuing stimulus
If the stimulus remains constant, there is no
change for the receptors to detect.
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Characteristic of Sensation
AFTER IMAGE
The sensation remains in the consciousness
after the stimulus has stopped.
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Types of Senses
General senses
• receptors over large part of body that sense touch,
pressure, pain, temperature, and itch
• somatic provide information about body and
environment
• visceral provide information about internal organs
Special senses
• smell, taste, sight, hearing, and balance
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Sensory receptors
are sensory nerve endings or specialized cells
respond to stimuli by developing action
potentials
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Types of Receptors1
Mechanoreceptors:
• detect movement
• Example, touch, pressure, vibration
Chemoreceptors:
• detect chemicals
• Example, Odors
Photoreceptors:
• detect light
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Types of Receptors2
Thermoreceptors:
• detect temp. changes
Nociceptors:
• detect pain
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Types of Touch Receptors1
Merkel’s disk:
• detect light touch and pressure
Hair follicle receptors:
• detect light touch
Meissner corpuscle:
• deep in epidermis
• localizing tactile sensations
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Types of Touch Receptors2
Ruffini corpuscle
deep tactile receptors
detects continuous pressure in skin
Pacinian corpuscle
deepest receptors
associated with tendons and joints
detect deep pressure, vibration, position
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Pain
an unpleasant perceptual and emotional
experience
can be localized or diffuse.
Localized
sharp, pricking, cutting pain
rapid action potential
Diffuse
burning, aching pain
slower action potentials
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Pain Control
Local anesthesia:
• action potentials suppressed from pain receptors in
local areas of the body
• chemicals are injected near sensory nerve
General anesthesia:
• loss of consciousness
• chemicals affect reticular formation
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Referred Pain
A visceral pain that is felt as a cutaneous pain
originates in a region that is not source of
pain stimulus
felt when internal organs are damaged or
inflamed
sensory neurons from superficial area and
neurons of source pain converge onto same
ascending neurons of spinal cord
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Olfaction
Olfaction
• sense of smell
• occurs in response to
odorants
• receptors are located in
nasal cavity and hard
palate
• we can detected 10,000
different smells
Figure 9.4a
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Olfaction Process
1. Nasal cavity contains a thin film of mucous
where odors become dissolved.
2. Olfactory neurons are located in mucous.
Dendrites of olfactory neurons are enlarged
and contain cilia.
3. Dendrites pick up odor, depolarize, and carry
odor to axons in olfactory bulb (cranial nerve I).
4. Frontal and temporal lobes process odor.
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Taste
Taste buds
sensory structures that detect taste
located on papillae on tongue, hard palate,
throat
Inside each taste bud are 40 taste cells
Each taste cell has taste hairs that
extend into taste pores
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Taste Process
1. Taste buds pick up taste and send it to taste
cells.
2. Taste cells send taste to taste hairs.
3. Taste hairs contain receptors that initiate an
action potential which is carried to parietal
lobe.
4. Brain processes taste.
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Types of Tastes
1. Sweet
2. Sour
3. Salty
4. Bitter
5. Umami/savory
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Vision
Accessory Structures
Eyebrow:
protects from sweat
shade from sun
Eyelid/Eyelashes:
protects from foreign objects
lubricates by blinking
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The Eye and Accessory Structures1
Figure 6.7a
(a) ©Eric Wise
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The Eye and Accessory Structures2
Conjunctiva
thin membrane that covers inner surface
of eyelid
Lacrimal Gland
produces tears
Extrinsic eye muscles
help move eyeball
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Anatomy of Eye
Hollow, fluid filled sphere
Composed of 3 layers (tunics)
Divided into chambers
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LAYERS OF THE EYE
1. Fibrous Tunic layer
Outermost Tunic
Sclera:
• firm, white outer part
• helps maintain eye shape, provides attachment
sites, protects internal structures
Cornea:
• transparent structure that covers iris and pupil
• allows light to enter and focuses light
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2. Vascular Tunic
Middle tunic that contains blood supply
Choroid- black part (melanin), delivers O2 and
nutrients to retina
Ciliary body helps hold lens in place
Suspensory ligaments help to hold lens in
place
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Vascular Tunic2
Lens
flexible disk
focuses light onto retina
Iris
colored part
surrounds and regulates pupil
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Vascular Tunic3
Pupil
regulates amount of light entering
lots of light = constricted
little light = dilated
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3. Nervous Tunic1
Innermost tunic and consist of retina.
Retina
covers posterior 5/6 of eye
contains 2 layers
Pigmented retina
outer layer
keeps light from reflecting back in eye
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Nervous Tunic2
Sensory retina
contains photoreceptors (Rods and
Cones)
contains interneurons
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Rods
photoreceptor sensitive to light
20 times more rods than cones
can function in dim light
Cones
photoreceptor provide color vision
3 types blue, green, red
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Pigments and Pigment Protein
Rhodopsin:
• photosensitive pigment in rod cells
Opsin:
• colorless protein in rhodopsin
Retinal:
• yellow pigment in rhodopsin
• requires vitamin A
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Effects of Light on Rhodopsin1
1. Light strikes rod cell
2. Retinal changes shape
3. Opsin changes shape
4. Retinal dissociates from opsin
5. Change rhodopsin shape stimulates response in rod
cell which results in vision
6. Retinal detaches from opsin
7. ATP required to reattach retinal to opsin and return
rhodopsin to original shape
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Posterior Region of Retina3
Macula
• small spot near center of retina
Fovea centralis
Center of macula
The light is focused when looking directly at an
object
Cnly cones
Ability to discriminate fine images
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Posterior Region of Retina 3
Optic disk
white spot medial to macula
blood vessels enter eye and
spread over retina
no photoreceptors
called blind spot
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Chambers of the Eye1
Anterior chamber
located between cornea and lens
filled with Aqueous Humor (watery)
Aqueous humor helps maintain pressure,
refracts light, and provide nutrients to inner surface
of eye
Posterior chamber
located behind anterior chamber
contains aqueous humor
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Chambers of the Eye2
Vitreous chamber
located in retina region
filled with vitreous humor: jelly-like
substance
vitreous humor helps maintain
pressure, holds lens and retina in place,
refracts light
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Functions of the Eye
The eye functions much like a camera.
The iris allows light into the eye, which is
focused by the cornea, lens, and humors
onto the retina.
The light striking the retina produces action
potentials that are relayed to the brain.
Light refraction and image focusing are two
important processes in establishing vision.
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Functions of the Eye2
Light Refraction
• Bending of light
Focal point:
• point where light rays converge
• occurs anterior to retina
• object is inverted
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Focusing Images on Retina
Accommodation
Lens becomes less rounded and image can
be focused on retina
Enables eye to focus on images closer than
20 feet
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Visual Defects1
Myopia
nearsightedness
image is in front
of retina
Hyperopia
farsightedness
image is behind
retina
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Presbyopia:
lens becomes less elastic
reading glasses required
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Visual Defects
Diplopia
AKA Double vision
Misalignment of the two eyes
Due to weakness of the muscles
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Visual Defects2
Astigmatism
irregular curvature of lens or cornea
glasses or contacts required to correct
Color Blindness
absence or deficient cones
primarily in males
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Glaucoma
increased
pressure in eye
can lead to
blindness
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Visual Defects
CATARACT
Clouding or
opacity of
crystalline lens
that leads to
blurring of vision
and eventually
loss of sight
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Chart to Determine Color Blindness
Figure 6.16
(a) ©Steve Allen/Getty Images RF; (b) ©Prisma Bildagentur AG/Alamy
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The Ear
The organs of hearing and balance are located in
the ears.
Each ear is divided into three areas:
1. the external ear
2. the middle ear
3. the inner ear
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The External Ear
Auricle/Pinna
fleshy part on outside
External auditory meatus
canal that leads to eardrum
Tympanic membrane
Eardrum
thin membrane that separates external from the
middle ear
Sound waves reaching the TM cause it to vibrate
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Middle Ear
Air filled chamber with ossicles
Malleus (hammer)
bone attached to tympanic membrane
Incus (anvil)
bone that connects malleus to stapes
Stapes (stirrup)
bone located at base of oval window
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The Middle Ear2
Oval window:
• separates middle and inner ear
Eustachian or auditory tube:
• opens into pharynx
• equalizes air pressure between outside air and
middle ear
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Inner Ear
Set of fluid filled chambers
Bony labyrinth
tunnels filled with fluid
3 regions: cochlea, vestibule, semicircular canals
Membranous labyrinth
inside bony labyrinth
filled with endolymph
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The Inner Ear2
Endolymph:
• clear fluid in membranous labyrinth
Perilymph:
• fluid between membranous and bony labyrinth
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Cochlea
• snail-shell shaped structure
• where hearing takes place
• Has three channels
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Channels of Cochlea
Scala vestibuli
• Extends from the oval window to the apex of
cochlea; filled with perilymph
Scala tympani
• Extend in parallel; filled with perilymph
Cochlea duct
• Formed by the space between vestibular and basilar
membrane; filled with endolymph
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The Inner Ear5
Vestibular membrane
wall of membranous labyrinth that lines
scala vestibuli
Basilar membrane
wall of membranous labyrinth that lines
scala tympani
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The Inner Ear4
Spiral organ/Organ of Corti
• in cochlear duct
• contains hair cells
Tectorial membrane:
• in cochlea
• vibrates against hair cells
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Structure of the Inner Ear
Figure 6.19
(e) Courtesy of A. J. Hudspeth
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Effect of Sound Waves on Middle and
Inner Ear Structures
Figure 9.20
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Balance (Equilibrium)
Static equilibrium
associated with vestibule
evaluates position of head relative to gravity
Dynamic equilibrium
associated with semicircular canals
evaluates changes in direction and rate of head
movement
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Balance1
Vestibule:
• inner ear
• contains utricle and saccule
Maculae:
• specialized patches of epithelium in utricle and
saccule surround by endolymph
• contain hair cells
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Balance2
Otoliths:
• gelatinous substance that moves in response to
gravity
• attached to hair cell microvilli which initiate action
potentials
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Location and Structure of the Macula
Figure 6.22
(d) ©Susumu Nishinag/Science Source
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Function of the Vestibule in Maintaining
Balance
Figure 6.23
(d) ©Susumu Nishinag/Science Source
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Balance3
Semicircular canals:
• dynamic equilibrium
• sense movement if any direction
Ampulla:
• base of semicircular canal
Crista ampullaris:
• in ampulla
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Balance4
Cupula:
• gelatinous mass
• contains microvilli
• float that is displaced by endolymph movement
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Function of the Crista Ampullaris
Figure 6.25
(a) ©Julie Jacobson/AP Photo