Term
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Definition
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Term
| Functions of the outer ear (4) |
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Definition
- funnel sound into the head
- collecting sound
- amplification
- locating sound on a vertical axis |
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Term
| What separates the outer ear from the middle ear? |
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Definition
| Tympanic membrane (aka eardrum) |
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Term
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Definition
| - contains three ossicles (bones) that transfer the vibration of the tympanic membrane to the inner ear |
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Term
| What are the names of the three ossicles in the middle ear? |
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Definition
malleus, incus, stapes
-lever system, chain rxn |
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Term
| Attachments and functions of tensor tympani muscle and stapedius muslce |
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Definition
tensor tympani: attaches to malleus
stapedius: attaches to stapes
*limit movement, help reduce sound intensities, reflex contraction in loud conditions |
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Term
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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 |
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Term
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Definition
- middle ear infection
- fluid has built up so tympanic membrane can't move very well |
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Term
| The inner ear: where sound energy is transduced into _______ energy |
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Definition
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Term
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Definition
- cochlea for hearing
- semicircular ducts, utricle, saccule for balance
- vestibular and cochlea branches of CN VIII |
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Term
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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 |
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Term
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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 |
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Term
| Once sound energy is converted to electrical energy where does the signal go? What nerve carries the information |
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Definition
| cochlea --> through spiral ganglion --> medulla --> midbrain --> thalamus --> auditory cortex in temporal lobe |
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Term
| Vestibular apparatus of the inner ear (for balance)-- 3 parts |
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Definition
1. Semicircular canals
2. Utricle
3. Saccule
*all three innervated by CN VIII (the Vestibular branch) |
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Term
| Semicircular canals: stimulated by what kind of movements of the head? |
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Definition
- rotatory movements: nod your head, shake your head, tip your head from side to side
- angular acceleration |
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Term
| Utricle and saccule: contain hair cells that are positioned to detect _______ |
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Definition
linear acceleration
- forward/backward when accelerating or decelerating in a car
- up/down when riding in an elevator |
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Term
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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 |
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Term
| Which cranial nerves innervate the extraocular muscles? |
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Definition
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Term
| What are 4 surrounding structures that protect the eye? |
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Definition
| bony orbit (bony socket), eyelids, conjunctiva, and lacrimal glands (secrete tears) |
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Term
| Describe flow of tears from the lacrimal gland to the nasal cavity |
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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 |
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Term
| What cranial nerve innervates the lacrimal gland? |
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Definition
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Term
| The three tunics/layers of the eye |
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Definition
1. Outer
2. Middle
3. Inner |
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Term
| Outer layer of the eye: made up of? (2) |
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Definition
1. Sclera: tough, white layer that protects the eye
2. Cornea-- clear area on the anterior side that transmits light |
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Term
| Conjunctiva: function, and what is it called if this gets infected? |
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Definition
-connects surface of eye ball to the eyelid
- lines eyelid
- infection= "pinkeye" |
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Term
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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 |
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Term
| Inner layer/tunic of the eye |
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Definition
| Retina: contains sensory receptors and neurons |
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Term
| Eye chambers: posterior and anterior segments (positions and what they contain) |
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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) |
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Term
| Aqueous humor: secreted by? direction of flow? and define glaucoma |
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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) |
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Term
| What structure supports the lens? |
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Definition
| suspensory ligamentm which is connected to the ciliary muscle |
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Term
| What happens to suspensory ligaments and lens when ciliary muscles contract? |
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Definition
| - tension is reduced insuspensory ligaments and lens thickens to focus on near-by objects |
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Term
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Definition
| normal vision: light is focused exactly on the retina |
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Term
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Definition
-near sightedness
-eyeball is too long, the image is focused in front of the retina
- corrected by a concave lens |
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Term
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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 |
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Term
| How does the ability to focus the lens change with age? |
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Definition
- lens stiffens and cannot change shape as easily
- need bifocals
- called Presbyopia |
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Term
| The Retina: light passes through ___ layers of the retina before reaching the receptors at the back |
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Definition
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Term
| The sensory receptors that detect light |
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Definition
| photoreceptors: rods and cones |
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Term
| Ganglion cells in the retina |
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Definition
| axons form the optic nerve |
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Term
| the pigmented layer of the retina ____ light |
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Definition
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Term
| Cones (features): low or hight sensitivity to light? good or poor acuity? |
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Definition
-color vision
- detail
- low sensitivity to light
- bright conditions
- best acuity |
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Term
| Rods (features): low or high sensitivity to light? good or poor acuity? |
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Definition
- low acuity
- no color sensitivity
- high sensitivity to light |
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Term
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Definition
| - it is necessary to have two different types of photoreceptors: one for low resolution, night vision and another for high resolution, day vision |
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Term
| Circuits of rods and cones: convergence and divergence |
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Definition
-Rods: many rods converge onto a single ganglion cell
- Cones: each cone communicates with its own ganglion cell |
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Term
| One reason why different regions of the retina have different degrees of visual acuity |
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Definition
| Rods and Cones are not distributed equally throughout the retina |
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Term
| Macula lutea (aka: fovea) |
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Definition
spot on back of the eye, directly behind the lens: when you look directly at something
- contains only cones
- best visual acuity |
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Term
| Why is macular degeneration so devastating? |
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Definition
| -you'll have no vision at the center of your visual field, and things will be blurry out from there |
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Term
| Distribution of rods as cones: as you move away from the fovea |
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Definition
- # of cones decreases and # of rods increases
- result: higher sensitivity to light but poor visual acuity |
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Term
| What forms the optic disc? |
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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 |
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Term
| What forms the optic nerve? |
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Definition
| axons of ganglion cells as they exit the eye |
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Term
| Visual fields: Monocular and Biocular vision |
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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 |
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Term
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Definition
- visual info projects to the contralateral occipital lobe cortex
- some ganglia remain ipsilateral, some contralateral |
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Term
| Legions to the Visual pathways |
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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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