Title: Anatomy and Physiology by Rod R Seeley 6th edition chapter 15 power-point
1 Anatomy and Physiology, Sixth Edition
Rod R. SeeleyIdaho State University Trent D.
StephensIdaho State University Philip
TatePhoenix College
Chapter 15 Lecture Outline
See PowerPoint Image Slides for all figures and
tables pre-inserted into PowerPoint without notes.
Copyright The McGraw-Hill Companies, Inc.
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2Chapter 15
3Special Senses
- Olfaction
- Taste
- Visual system
- Hearing and balance
4Olfaction
- Sense of smell
- Olfactory neurons in this epithelium
- Bipolar neurons
- Olfactory hairs
- Cilia which lies in mucous
- Odors
- Odorants bind to chemoreceptor molecules
- Depolarize and initiate action potentials in
neurons - Low threshold for odor detection
5Neuronal Pathways of Olfaction
6Taste
- Detected by taste buds
- Papillae
- Vallate
- Fungiform
- Foliate
- Filiform
- Histology
- Support cells
- Gustatory cells
- Hairs
- Function
- Receptors on hairs detect dissolved substances
- Taste types
- Sour
- Salty
- Bitter
- Sweet
- Umami
7Papillae and Taste Buds
8Actions of Major Tastants
9Neuronal Pathways for Taste
10Visual System
- Eye
- Accessory structures
- Eyebrows, eyelids, eyelashes, tear glands
- Protect eyes from sunlight and damaging particles
- Optic nerve (II)
- Tracts
- Pathways
- Eyes respond to light and initiate afferent
action potentials
11Accessory Structures of Eye
- Eyebrows
- Prevent running perspiration into eyes
- Shade
- Eyelids or palpebrae
- Consist of 5 tissue layers
- Protect and lubricate
- Conjunctiva
- Covers inner eyelid and anterior part of eye
- Lacrimal apparatus
- Extrinsic eye muscles
12Lacrimal Apparatus
- Lacrimal apparatus
- Lacrimal Gland Produces tears to moisten,
lubricate, wash - Lacrimal Canaliculi
- Collects excess tears
- Punctum
- Lacrimal Sac
- Nasolacrimal duct
- Opens into nasal cavity
13Extrinsic Eye Muscles
14Anatomy of the Eye
- Three coats or tunics
- Fibrous Consists of sclera and cornea
- Vascular Consists of choroid, ciliary body, iris
- Nervous Consists of retina
15Anatomy of the Eye
- Retina Inner
- Contains neurons sensitive to light
- Macula lutea or fovea centralis Area of greatest
visual acuity - Optic disc Blind spot
- Compartments
- Anterior Aqueous humor
- Posterior Vitreous humor
- Lens
- Held by suspensory ligaments attached to ciliary
muscles - Transparent, biconvex
- Fibrous tunic Outer
- Sclera White outer layer, maintains shape,
protects internal structures, provides muscle
attachment point, continuous with cornea - Cornea Avascular, transparent, allows light to
enter eye and bends and refracts light - Vascular tunic Middle
- Iris Controls light entering pupil smooth
muscle - Ciliary muscles Control lens shape smooth muscle
16Functions of the Complete Eye
- Eye functions like a camera
- Iris allows light into eye
- Lens, cornea, humors focus light onto retina
- Light striking retina is converted into action
potentials relayed to brain
17Light
- Visible light Portion of electromagnetic
spectrum detected by human eye - Refraction Bending of light
- Divergence Light striking a concave surface
- Convergence Light striking a convex surface
- Focal point Point where light rays converge and
cross
18Focus and Accommodation
- Emmetropia Normal resting condition of lens
- Far vision 20 feet or more from eye
- Near vision Closer than 20 feet
- Accommodation
- Pupil constriction
- Convergence
19The Retina
- Provides black backdrop for increasing visual
acuity - Sensory retina and pigmented retina
- Photoreceptors
- Rods Noncolor vision
- Rhodopsin reduction Light adaptation
- Rhodopsin production Dark adaptation
- Cones Color vision
20Sensory Receptor Cells
21Rhodopsin Cycle
22Rod Cell Hyperpolarization
23Visual Pathways
24Eye Disorders
- Myopia Nearsightedness
- Focal point too near lens, image focused in front
of retina - Hyperopia Farsightedness
- Image focused behind retina
- Presbyopia
- Degeneration of accommodation, corrected by
reading glasses - Astigmatism Cornea or lens not uniformly curved
- Strabismus Lack of parallelism of light paths
through eyes
- Retinal detachment
- Can result in complete blindness
- Glaucoma
- Increased intraocular pressure by aqueous humor
buildup - Cataract
- Clouding of lens
- Macular degeneration
- Common in older people, loss in acute vision
- Diabetes
- Dysfunction of peripheral circulation
25The Ear
- External ear Hearing terminates at eardrum
- Middle ear Hearing contains auditory ossicles
- Inner ear Hearing and balance interconnecting
fluid-filled tunnels and chambers
26The Ear
- External ear
- Auricle or pinna elastic cartilage
- External auditory meatus
- Lined with hairs and ceruminous glands
- Tympanic membrane
- Vibrated by sound waves
- Middle ear
- Auditory or eustachian tube
- Opens into pharynx, equalizes pressure
- Ossicles malleus, incus, stapes transmit
vibrations - Oval window
27Inner Ear
- Labyrinth
- Bony
- Cochlea Hearing
- Vestibule Balance
- Semicircular canals Balance
- Membranous
- -Lymphs
- Endolymph
- In membranous labyrinth
- Perilymph
- Space between membranous and bony labyrinth
28Structure of Cochlea
29Auditory Function
- Vibrations produce sound waves
- Volume or loudness Function of wave amplitude
- Pitch Function of wave frequency
- Timbre Resonance quality or overtones of sound
30Effect of Sound Waves on Cochlear Structures
31CNS Pathways for Hearing
32Balance
- Static
- Evaluates position of head relative to gravity
- Detects linear acceleration and deceleration
- Utricle and saccule
- Maculae Consist of hairs embedded in gelatinous
mass containing otoliths
- Kinetic
- Evaluates movements of head
- 3 semicircular canals
- Ampulla
- Crista ampullaris
- Cupula endolymph moves when head moves
33Structure of the Macula
34Vestibule in Maintaining Balance
35Semicircular Canals
36CNS Pathways for Balance
37Ear Disorders
- Tinnitus
- Ringing, clicking, whistling in ear due to
disorders in middle or inner ear - Motion sickness
- Dysfunctions caused by stimulation of
semicircular canals during motion - Otitis Media
- Infections in the middle ear
- Earache
- Results from otitis media, dental abscesses, TMJ
pain
38Effects of Aging on the Special Senses
- Slight loss in ability to detect odors
- Decreased sense of taste
- Lenses of eyes lose flexibility
- Development of cataracts, macular degeneration,
glaucoma, diabetic retinopathy - Decline in visual acuity and color perception