Transcript Special Senses: Sight

Special Senses: Sight
Special Senses
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Smell
Taste
Sight
Hearing
Which of these is not a special
sense?
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Hearing
Breathing
Sight
Smell
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External structures of the Eye
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Eyelids
Eyelashes
Meibomian glands
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Sebaceous glands on eyelid edge lubricate
eye
Conjunctiva
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Membrane lining eyelids
Inflammation is called “pink eye”
External structures cont.
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Lacrimal glands
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Release tears
Helps clean eye surface and protect it
Muscles
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lateral rectus, medial rectus, superior rectus,
inferior rectus, inferior oblique, superior
oblique
Joe has a inflammation of the membrane lining the
eyelids, what may be his problem?
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Eye infection
Optic membroitis
Optic scleris
Conjunctiva
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Internal Structures
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Tunics- outer layers or coats
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Sclera- outermost tunic “white of the eye”
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Choroid- middle coat
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Cornea- central clear part of the sclera
Lens and iris opening of iris is the pupil
Retina- innermost coat
Contains photoreceptors (rods and cones)
 Blind spot- no rods and cones where optic nerve
connects
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Internal Structures cont
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Lens
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Divides eye into two segments
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Anterior Segment
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Filled with aqueous humor
Posterior Segment
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Filled with vitreous humor
Prevents eyeball from collapsing
While playing football George takes a finger to the
eye. Which portion of the eye is most likely hurt?
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Sclera
Retina
Lens
Choroid
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Binocular vision
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Right eye communicates with left brain
and vice versa
“binocular vision” means two-eyed vision
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3-D effect to vision
Close one eye and you will see in 2-D
Nearsighted vs Farsighted
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Emmetropic eye
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Nearsighted- myopia
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Normal vision
Cannot see distant images clearly
Eye is too long
Farsighted-Hyperopia
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Cannot see close images clearly\
Eyeball is too short
You have normal vision. If you put Cathy’s glasses
on and everything seems very large. What kind of
vision does Cathy have?
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Emmetropic vision
Myopia
Diopia
Hyperopia
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Sense of Smell and Taste
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Receptor for these senses are
chemoreceptors
Senses closely related
Four types of taste receptors
Many types of smell receptors
Taste buds
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Taste buds
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Receptors for taste
Papaille
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Four Types
6 tastes
Sweet, bitter, savory
 Salty, spicy, sour
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Which is not a type of taste
sensation?
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Bitter
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Olfactory Receptors
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Olfactory receptors
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Olfactory receptor cells
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Postage stamp area at top of nasal cavity
Hairs bathed in mucosa
Olfactory filaments (olfactory nerve)
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Stimulated by chemicals in mucus
Sense of Hearing
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Outer Ear
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Pinna (auricle)
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Outside of ear collects sound waves
External auditory canal
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Tube from pinna to ear drum
The mucosa in the nose is similar in
function to the _______ of the eye.
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Conjunctiva
Sclera
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Sense of Hearing
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Middle Ear (tympanic cavity)
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Eardrum
Ossicles
Hammer transfers vibration to anvil
 Anvil transfers vibration to stirrup
 Strirrup transfers vibration to oval window
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Oval Window
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Sets fluid in inner ear into motion
Sense of Hearing
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Inner Ear
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Bony labyrinth
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Cochlea
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Contains organ of Corti which contains hair cells
Vestibule
 Semicircular canals
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Which of these is not an ossicle
of the middle ear
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Stirrup
Hammer
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How Do We Hear
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Anvil transmits wave to oval window
Tectorial membrane moves bending or tweaking
the hairs in the organ of Corti
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Hairs closer to oval window stimulated by high pitch
Hairs further down cochlea stimulated by low pitch
Hairs send pulses to brain through cochlear
nerve
Equilibrium
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Sense of Balance
Depend on vestibule and semicircular
canals
Responds to movements of our head
Two parts
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Static and dynamic equilibrium
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Enter answer
text...
Static Equilibrium
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Maculae in vestibule report on changes in
position when at rest
Help tell which way is up
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Helps divers know which direction is surface
Dynamic Equilibrium
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Receptors are found in semicircular canals
Respond to angular or rotational
disturbances
Receptors orientated in all three planes to
sense any disturbance