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Anat Exam 2--5
Hamster
51
Anatomy
Undergraduate 4
10/30/2010

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Cards

Term
Three parts of the ear
Definition
outer, middle, and inner
Term
Functions of the outer ear (4)
Definition
- funnel sound into the head
- collecting sound
- amplification
- locating sound on a vertical axis
Term
What separates the outer ear from the middle ear?
Definition
Tympanic membrane (aka eardrum)
Term
Middle ear: function
Definition
- contains three ossicles (bones) that transfer the vibration of the tympanic membrane to the inner ear
Term
What are the names of the three ossicles in the middle ear?
Definition
malleus, incus, stapes
-lever system, chain rxn
Term
Attachments and functions of tensor tympani muscle and stapedius muslce
Definition
tensor tympani: attaches to malleus
stapedius: attaches to stapes

*limit movement, help reduce sound intensities, reflex contraction in loud conditions
Term
Auditory tube
Definition
- the middle ear must be filled with air so the tympanic membrane can move properly
- the auditory/Eusachian tube: maintains air within the middle ear
Term
Otitis media
Definition
- middle ear infection
- fluid has built up so tympanic membrane can't move very well
Term
The inner ear: where sound energy is transduced into _______ energy
Definition
electrical
Term
Inner ear components
Definition
- cochlea for hearing
- semicircular ducts, utricle, saccule for balance
- vestibular and cochlea branches of CN VIII
Term
Path of sound waves
Definition
- stapes fits into oval window
- vibrations of the stapes transfer the sound wave into the fluid of the inner ear
- this stimulates sensory receptors in the cochlea
Term
Cochlea unrolled
Definition
- the sound wave causes the basilar membrane to vibrate
- vibrations of the basilar membrane determine which hair cells (receptors) are activated
- High frequency sounds cause the basilar membrane to vibrate near the base, low freq near the apex
Term
Once sound energy is converted to electrical energy where does the signal go? What nerve carries the information
Definition
cochlea --> through spiral ganglion --> medulla --> midbrain --> thalamus --> auditory cortex in temporal lobe
Term
Vestibular apparatus of the inner ear (for balance)-- 3 parts
Definition
1. Semicircular canals
2. Utricle
3. Saccule

*all three innervated by CN VIII (the Vestibular branch)
Term
Semicircular canals: stimulated by what kind of movements of the head?
Definition
- rotatory movements: nod your head, shake your head, tip your head from side to side
- angular acceleration
Term
Utricle and saccule: contain hair cells that are positioned to detect _______
Definition
linear acceleration
- forward/backward when accelerating or decelerating in a car
- up/down when riding in an elevator
Term
Vestibular reflexes
Definition
-this sensory info is used for reflexes
- Vestibulospinal reflex---ex: when you extend your arm and leg to prevent a fall
- Vestibuloocular reflex: turns eyes if head moves so you can fix your gaze
Term
Which cranial nerves innervate the extraocular muscles?
Definition
CN III, IV, and VI
Term
What are 4 surrounding structures that protect the eye?
Definition
bony orbit (bony socket), eyelids, conjunctiva, and lacrimal glands (secrete tears)
Term
Describe flow of tears from the lacrimal gland to the nasal cavity
Definition
-tears are secreted and then spread across the eye while blinking
- this washes debris from the eye and keeps it moist
- tears collect in the lacrimal sac and pass through the nasolacrimal duct into the nasal cavity
Term
What cranial nerve innervates the lacrimal gland?
Definition
VII-Facial nerve
Term
The three tunics/layers of the eye
Definition
1. Outer
2. Middle
3. Inner
Term
Outer layer of the eye: made up of? (2)
Definition
1. Sclera: tough, white layer that protects the eye
2. Cornea-- clear area on the anterior side that transmits light
Term
Conjunctiva: function, and what is it called if this gets infected?
Definition
-connects surface of eye ball to the eyelid
- lines eyelid
- infection= "pinkeye"
Term
Middle layer of eye (3)
Definition
1. Choroid: vascular layer
2. Ciliary body: sm muscle that controls the shape of the lens, secretes fluid contained in the eye
3. Iris: contains two muscles that control the size of the pupil
Term
Inner layer/tunic of the eye
Definition
Retina: contains sensory receptors and neurons
Term
Eye chambers: posterior and anterior segments (positions and what they contain)
Definition
- Behind the lens = posterior segment: vitreous chamber, contains vitreous body which holds the retina in place
- in front of lens = anterior segment: has an anterior and posterior chamber (in front of and behind the iris); contains aqueous humor (watery fluid)
Term
Aqueous humor: secreted by? direction of flow? and define glaucoma
Definition
-secreted by: ciliary bodies
- flows from posterior chamber to anterior chamber where it is reabsorbed into the scleral venous sinus
-glaucoma: abnormalities of flow of aqueous humor(accumulation)
Term
What structure supports the lens?
Definition
suspensory ligamentm which is connected to the ciliary muscle
Term
What happens to suspensory ligaments and lens when ciliary muscles contract?
Definition
- tension is reduced insuspensory ligaments and lens thickens to focus on near-by objects
Term
Emmetropia
Definition
normal vision: light is focused exactly on the retina
Term
Myopia
Definition
-near sightedness
-eyeball is too long, the image is focused in front of the retina
- corrected by a concave lens
Term
Hyperopia
Definition
far-sightedness
- eyeball is too short, image is focused behind the retina
- a convex lens bends the light more and brings the focal point to the retina
Term
How does the ability to focus the lens change with age?
Definition
- lens stiffens and cannot change shape as easily
- need bifocals
- called Presbyopia
Term
The Retina: light passes through ___ layers of the retina before reaching the receptors at the back
Definition
all
Term
The sensory receptors that detect light
Definition
photoreceptors: rods and cones
Term
Ganglion cells in the retina
Definition
axons form the optic nerve
Term
the pigmented layer of the retina ____ light
Definition
absorbs
Term
Cones (features): low or hight sensitivity to light? good or poor acuity?
Definition
-color vision
- detail
- low sensitivity to light
- bright conditions
- best acuity
Term
Rods (features): low or high sensitivity to light? good or poor acuity?
Definition
- low acuity
- no color sensitivity
- high sensitivity to light
Term
Duplicity theory
Definition
- it is necessary to have two different types of photoreceptors: one for low resolution, night vision and another for high resolution, day vision
Term
Circuits of rods and cones: convergence and divergence
Definition
-Rods: many rods converge onto a single ganglion cell
- Cones: each cone communicates with its own ganglion cell
Term
One reason why different regions of the retina have different degrees of visual acuity
Definition
Rods and Cones are not distributed equally throughout the retina
Term
Macula lutea (aka: fovea)
Definition
spot on back of the eye, directly behind the lens: when you look directly at something
- contains only cones
- best visual acuity
Term
Why is macular degeneration so devastating?
Definition
-you'll have no vision at the center of your visual field, and things will be blurry out from there
Term
Distribution of rods as cones: as you move away from the fovea
Definition
- # of cones decreases and # of rods increases
- result: higher sensitivity to light but poor visual acuity
Term
What forms the optic disc?
Definition
-where the ganglion cells' axons exit the eye to form the optic nerve
- no photoreceptors in this part of the retina: so it is a blind spot
Term
What forms the optic nerve?
Definition
axons of ganglion cells as they exit the eye
Term
Visual fields: Monocular and Biocular vision
Definition
-Monocular: visible to only one eye
- Biocular: visible to both eyes, so you get two slightly different views of the same area--> gives you depth perception
Term
Visual pathway
Definition
- visual info projects to the contralateral occipital lobe cortex
- some ganglia remain ipsilateral, some contralateral
Term
Legions to the Visual pathways
Definition
- Lesion to Optic nerve: blind in one eye
- Lesion to Optic Tract, Thalamus, or visual cortex: blind in contralateral visual field
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