Term
| What is 40% of the cerebral cortex involved in? |
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Definition
| processing visual information |
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Term
| How much of the eye's surface is visible? |
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Definition
| anterior 1/6th the rest is deep in orbit |
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Term
| What does the internal cavity of the eye contain? |
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Definition
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Term
| What are the external walls of the eye composed of? |
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Definition
3 tunics:
-fibrous tunic
-vascular tunic
-sensory tunic |
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Term
| What is the fibrous tunic? |
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Definition
most external layer of the eyeball
-2 regions of connective tissue |
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Term
| What are the fibrous tunic's two regions of connective tissue? |
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Definition
1. Sclera- posterior 5/6th of tubic
-white, opaque region
-provides shape and anchor for eye muscles
-Scleral venous sinus allows aqueous humor to drain; returned to blood
2. Cornea- anterior 1/6th of fibrous tunic; transparent |
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Term
| What is the vascular tunic? |
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Definition
the middle coat of the eyeball
composed of chorid ciliary body and iris |
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Term
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Definition
in the vascular tunic:
-vascular, darkly pigmented membrane
Forms posterior 5/6ths of vascular tunic
-Brown color from melaocytes
-Prevents scattering of light rays within eye |
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Term
| What is the ciliary body? |
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Definition
thickened ring of tissue-encircles the lens
Composed of ciliary muscle:
-Ciliary processes- anterior part of the ciliary body, ciliary zonule ragiate from processes
-Ciliary zonules (suspensory ligaments) attach to lens
--Attached around entire circumference of lens |
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Term
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Definition
visible colored part of eye
-attached to ciliary body
-composed of smooth muscle
-pupil: round central opening
--sphincter pupillae muscle constricts
--Dilator pupillae muscle dilates
Both act to vary size of pupil |
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Term
| What is the sensory tunic |
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Definition
aka retina
deepest tunic
2 layers: pigmented and neural |
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Term
| What is the pigmented layer of the retina? |
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Definition
single layer of melanocytes
-absorbs stray light along w/choroid pigment |
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Term
| What is the neural layer of the retina? |
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Definition
sheet of nervous tissue
-contains 3 types of neurons:
1. Photoreceptor cells
2. Bipolar Cells
3. Ganglion Cells |
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Term
| What are the types of photoreceptors? |
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Definition
1. rod cells- sensitive to light, allows vision in low light
2. Cone cells0 operate best in bright light
-enable-high acuity, color vision |
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Term
| What are the regional specializations in retina? |
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Definition
mascula lutea- mostly cones
fovea centralis- contains only cones
Optic disc- blind spot, where blood vessels leave/enter, axons of ganglion cells leave to form optic nerves |
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Term
| What region of the retina has the highest visual acuity? |
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Definition
| fovea centralis bc it contains only cones |
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Term
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Definition
| Lens and ciliary zonules divide eye |
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Term
| What fills the posterior segment (cavity) |
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Definition
Vitreous humor
-clear, jelly like
transmits light
supports the posterior surface of the lens |
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Term
| What is the the anterior segment of the eye filled with? What is it divided into? |
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Definition
Filled w/aqueous humor- supplies nutrients to the lens and cornea
Anterior chamber of the anterior segment of eye is between cornea and iris
Posterior Chamber is between iris and lens |
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Term
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Definition
| receptor organs for hearing and equilibrium |
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Term
| What is the ear composed of? |
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Definition
outer ear- functions in hearing
middle ear- hearing
inner ear- hearing and equilibrium |
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Term
| What is the outer ear composed of? |
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Definition
auricle (pinna) -directs sound
external acoustic meatus- lined w/skin, contains hairs, sebaceous glands, and ceruminous glands
Tympanic membrane- eardrum, forms the boundary between external and middle ear |
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Term
| What is in the Middle ear? |
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Definition
Tympanic Cavity- small air filled space, in petrous portion of the temporal bone
medial wall is penetrated by:
-oval window: entrance to cochlea
-round window: exit from choclea
Pharyngotympanic tube (auditory or eustachian tube) -links the middle ear and pharynx, equilibrate pressure across tympanic membrane |
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Term
What does the middle ear?
How? |
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Definition
amplify sound
Ear ossicles: smallest bones in body
-Malleus (hammer): attach to ear drum
-Incus(axe)-between malleus and stapes
-Stapes(diamond ring) -vibrates against oval window |
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Term
Inner ear is aka?
WHere is it?
Consists of: |
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Definition
labyrinth
petrous portion of temporal bone
Boney labyrinth- a cavity consisting of three parts |
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Term
| What are the 3 parts of the bony labyrinth? |
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Definition
semicircular canals
vestibule
cochlea |
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Term
| What fills the bony labyrinth? |
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Definition
Membranous laybrinth
- series of membrane-walled sacs and ducts
- filled w/ clear fluid endolymph (confined to membranous labyrinth, not bony laby) |
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Term
| What fluid fills the bony labyrinth? Membranous labyrinth? |
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Definition
Bony- perilymph continuous w/CSF
Membranous- endolymph |
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Term
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Definition
| 2 egg shaped parts of the membranous labyrinth |
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Term
| What is the macula of utricle and saccule? |
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Definition
contains receptor cells, called hair cells
monitors head position, linear acceleration and tilting
-endolymph contains otoliths (calcium carbonate) to increase mass of endolymph |
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Term
Receptor Cells bend due to?
Synapse with? |
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Definition
bending of seriocilia on hair cells caused by movement of endolymph due to head motion, depolarizes cells
Synapase w/vestibular nerve |
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Term
| Where are the semicircular canals? What are there names? |
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Definition
lie posterior and lateral to vestibule
-Anterior, Posterior, Lateral Semicircular canal |
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Term
| What is the membranous ampulla? |
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Definition
located w/in the bony ampulla of each canal
-contain receptor celss of rotational acceleration |
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Term
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Definition
the cochlear duct (scala media) contains receptor for hearing
-lies between perilymph filled chambers of the bony labyrinth
-scala vestibuli and scala tympani
The vestibular membrane is the roof of the cochlear duct
-the basilar membrane is the floor of cochlear duct |
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Term
| What is the organ of corti? |
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Definition
receptor epithelium for hearing located on basilar membrane
Consists of supporting cells
Hair cells; seriocilia embedded in tectorial membrane
tectorial membrane-covers hair cells |
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