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136 Cards in this Set
- Front
- Back
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5 accessory structures of the eye |
Eyebrows Eyelids Conjunctiva Lacrimal apparatus Extrinsic eye muscles |
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The _______ contain 70% of all sensory receptors in the body |
eye |
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Another name for eyelid |
palpebrae |
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The upper and lower _________ meet at the canthi |
Eyelids/palpebrae |
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4 parts of the eyelid |
Canthi Lacrimal caruncle Eyelashes Tarsal glands |
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Another name for canthi |
commissures |
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lateral and medial angles of the eye |
Canthi/commissures |
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the raised bump at the medial canthus where oil and sweat secrete |
lacramal carnucle |
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Eye sand is made of |
oil and sweat secretions from the lacramal carnucle |
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.... innervated at the root and provides reflexive blinking when stimulated |
eyelashes |
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Produce an oily secretion that lubricates surface of eye embedded in the tarsal plates with ducts that open at eyelid edge |
Tarsal glands |
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transparent mucus membrane that secrets mucus to protect eye surface and is well supplied with blood vessels |
Conjunctiva |
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Lacrimal gland plus ducts that drain into nasal cavity |
Lacrimal apparatus AKA tear gland |
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Function of tears |
clean, protect, moisten and lubricate |
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Contents of tears |
mucus, lysosomes, and antibodies |
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which direction do tears flow? |
from upper outer quadrant, flows across the eye surface to the inner inferior quadrant, out the punctum, drain into the canaliculus, then drain into the nasolacrimal duct, which causes runny nose |
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Does the conjunctiva cover the cornea? |
No, it stops at the corneal, scalar junction because the blood vessels would block vision |
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6 Extrinsic eye muscles that control the eyeball position |
Superior, inferior, lateral and medial Rectus muscles and Inferior, superior oblique muscles |
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Eyeball |
hollow sphere filled with fluid |
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Three tunics of the eye (AKA Coats) |
Fibrous tunic Vascular tunic Sensory tunic |
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The outermost avascular dense fibrous CT coat |
Fibrous tunic |
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2 main regions of the fibrous tunic |
Sclera Cornea |
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The white of the eye |
sclera |
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4 characteristics of the sclera |
Protects and maintains shape Covers optic nerve - contiuous with dura matter Posterior to cornea Avascular |
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Anterior clear part of the eyeball - contains many pain receptors |
Cornea |
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4 characteristics of the corneal structure |
- a modified transparent part of the fibrous tunic - stratified squamous - simple squamous - avascular |
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outer protective layer that join conjunctiva @ edge of cornea |
Stratified squamous |
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Lining of eye that contains sodium pumps for clairity located at the inner aspect of the cornea |
Simple squamous |
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part of eye not accessible to immune system because it is avascular |
cornea |
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What is the benefit of the cornea not being accessible to the immune system |
Can transplant without rejection |
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Middle coat of eye with three main regions |
Vascular tunic |
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3 regions of the vascular tunic |
Choroid Ciliary body Iris |
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Highly vascular, feeds the fibrous tunic - dark pigmented in humans to help prevent the scatter of light |
Choroid |
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Continues with the choroid anteriorly |
Ciliary body |
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when the ciliary body is tense the lens is ____________, |
fat |
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Comes off the choroid in the anterior portion of the eye |
Ciliary body |
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What kind of muscle is the ciliary body made up of? |
Mostly smooth muscle |
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____________ attache to the edge of the lens creating tension that controls the shape of the lens |
Ciliary zonules aka suspensory ligaments |
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Visible colored part of eye shaped like a doughnut |
Iris |
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The Iris divides what two fluids found in the eye? |
Anterior and posterior humor |
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The color of the iris is caused by.... |
the amount of dark brown pigment |
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babies have little eye pigment so when they are born their eyes are .... |
Blue |
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not pigment in the eye is known as.... |
Albino - pink eyes |
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What are the two types of smooth muscle that make up the multi unit smooth muscle control in the Iris. |
Radial Circular |
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Causes the iris to dilate |
A fight or flight response of the radial smooth muscle of the iris, triggered by the sympathetic nervous system |
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Causes the iris to constrict |
a response of the radial smooth circular smooth muscle triggered by the parasympathetic nervous system |
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Innermost tunic with 2 layers |
Sensory tunic (retina) |
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2 layers of the sensory tunic - Retina |
Pigmented layer Neural layer |
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absorbs light for image quality and is adjacent choroid |
Pigmented layer |
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Transparent layer - an out pocket of the brain |
neural layer |
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3 parts of the neural layer |
Photoreceptors Bipolar cells Ganglion cells |
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Photoreceptors aka...... |
Rods and Cones |
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Connect photoreceptors to the ganglion cell |
Bipolar cells |
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axons od _______ _________ converge and form optic nerve |
gangleion cells |
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Why is clarity of cones better than clarity of rods? |
Because cones have a 1/1 connection |
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The area where the optic nerve exits the eye |
Optic disc |
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why is the nasally located optic disc known as the blind spot? |
Because there are not photoreceptors there |
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lateral to the blind spot and straight back.... |
Macula lutea and fovea centralis |
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Small oval spot that mostly contains cones |
Macula lutea |
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True or false Cone density diminishes the further away from the macula lutea |
True |
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A pit in the center of the macula that contains cones only |
Fovea centralis |
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Tension of the suspensory ligaments makes the lens thick or thin? |
Thin |
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Internal cavities divided by the lens |
Posterior segment Anterior segment |
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Behind the lens filled with vitreous humor |
Posterior segment |
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a clear gel within the posterior segment that supports the eye and lens by keeping the retina pressed against the choroid |
Vitreous humor |
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2 chambers of the anterior segment |
Anterior chamber Posterior chamber |
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Chamber in front of iris |
Anterior chamber |
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behind the iris but in front of the lens |
Posterior chamber |
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The chambers of the anterior segment are divided by... |
the iris |
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A watery fluid within the anterior segment produced continually by a capillary network of the ciliary body in the posterior chamber and circulates to anterior chamber thru the pupil |
Aqueous humor |
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Because it is a filtrate of blood it supplies O2 and nutrients to structures and drains out the scleral venus sinus |
Aqueous humor |
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A block in the scleral venus sinus is known as |
glaucoma |
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Biconvex, transparent, flexible disc composed of lens fibers |
Lens |
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Avascular and layered like and onion |
Lens |
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Describe lens epithelium |
Cuboidal on anterior surface |
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Contains densely packed proteins called crystallins, with no nuclei, that are continually produced and layered like an onion |
Lens fibers |
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True or false the continual production of crystallins causes the lens to thicken with age |
True |
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True or false lens fibers were formally cuboidal cells |
True |
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Visible light |
the 400-700 nm part of the electromagnetic spectrum |
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the bending of light |
refraction |
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2 ways light refracts |
1) Passing through different media densities (water, glasss, air) 2) hitting curved surfaces |
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transparent object curved on one or both sides |
lense |
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Convex lenses are curved ________ and when light hits it the rays _________ |
outward, converge |
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Concave lenses are curved ______ and when light hits it the rays ________ |
inward diverge |
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When focusing for distant vision the lenses are ______. Ciliary muscles are _____________ and ciliary zonules _______ tension. |
flat relaxed increase |
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When focusing for close vision lenses are ________. Ciliary muscles are _________ and ciliary zonules _______ tension |
thick/curved contracted decrease |
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process to increase refractory power of lens |
accommodation of the lens (focusing) |
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the closest point of focus |
Near point
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Near point |
Where we get excellent focussing on an object |
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T or F
Close point of focus depends on how easy the lens can become thick |
T |
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the loss of elasticity with age causes the near point to increase or decrease? |
Increase (becomes further away) |
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true or false the constriction of the pupils enhances the effect of accommodation by preventing excess light from blurring our vision |
True |
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Parasympathetic or Sympathetic? The sphincter pupillae muscle contraction decreases pupil size |
Para |
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Parasympathetic or Sympathetic? Dilator pupiliae muscle contraction increases pupil size |
Sympathetic |
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The ______________ of eyeballs is controlled by occulomotor nerve III and is required for _______ vision. |
Convergence, close |
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Emmertropia |
Normal vision |
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Nearsightedness |
Myopia |
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Can see up close |
nearsightedness |
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causes of myopia |
Eyeball too long or too thick |
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Correction for myopia |
lasic |
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Hyperopia |
Farsightedness |
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Farsightedness |
Can see in the distance |
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Eyeball too short or lens too thin |
Farsightedness |
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Focal point behind retina |
Hyperopia |
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Focal point in front of retina |
Myopia |
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Unequal curvatures in different parts of the cornea or lens |
Astigmatism |
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Possess and outer receptive region connected to an inner region by a thin neck |
Rods and Cones |
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The outer segments of rods and cones are embedded in the __________ _______ of the retina. |
Pigmented layer |
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a protein that forms part of the visual pigment rhodopsin and is released by the action of light
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Opsin |
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Photopigment in the dark means that photo receptors are constantly______________ |
depolarized |
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Photopigment in the light means that photoreceptors are _____________ |
Hyperpolarized |
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When we stimulate all photoreceptors all we see is _____________. |
White |
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When we stimulate no photoreceptors all we see is _______________. |
Black |
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Responsible for black/white (night) vision |
Rods |
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Photopigment of rods that is sensitive to low levels of light to stimulate. |
Rods |
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Is the visual acuity of rods good? Why? |
No, sharpness is not great, because 100 or more rods feed into each ganglion cell making them less precise |
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Responsible for color vision |
Cones |
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3 kinds of photopsins in cones |
Red Green blue |
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Do cones require high or low light intensity to stimulate? |
High |
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Do cones have high or low visual acuity? Why? |
high, because they have a 1 to 1 connection to ganglion cells |
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Are there rods in the fovea centralis? |
No |
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Rods ________________ toward the periphery of the retina. |
Increase |
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Part of the retina that is a cone only zone... |
fovea centralis |
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There are some ________ in the macula lutea, but once outside rod density _______________. |
Rods Increases |
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Rods see best in ________ light when not looking ___________ at the object. |
dim directly |
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Going into the light eyes go thru a process of _____________ |
light adaptation |
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Even a ________ amount of light can bleach rods |
tiny |
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Phenomena of light adaptation where rod photopigment breaking down and losing function and visual acuity improve over 5-10 min |
Photoreceptor bleaching |
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The opposite of light adaptation where rhodopsin needs to accumulate to hyperpolarize the cell. |
Dark adaptation |
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True or false each eye sees exactly the came image why or why not? |
False Each eye sees slightly different image (from different angels) because of binocular vision |
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area where fibers from each eye cross over to the opposite hemisphere, making an area where each half of the brain will have info of image from both eyes |
Optic chiasm |
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3D vision is aka___ |
Depth preception |
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True or false the distance between eyes is constant |
true |
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True or false An objects distance from eyes is constant |
false it varies |
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As an object gets closer eyes turn _____________ during focus |
medially |
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The brains ability to calculate distance is only possible due to ___________ ___________. |
Binocular vision |
