Visual tracts and histo Flashcards
This functions to protect the eye
eyelid
The ______ ______ are special sebaceous glands. Secretion slows the evaporation of tears
Tarsal glands
What is the cause of a chalazion?
Inflammation of the tarsal gland
This is what gets infected when you have a sty
The Sebaceous (Zeis) gland
The _____ _____ produces tears, and is made up of tubuloacinar serous glands below the upper lid
Lacrimal gland
These line the space between the inner eyelid and ends lateral to the cornea
Palpebral and bulbar conjunctiva
This chamber of the eye is between the cornea and the iris
Anterior chamber
This chamber of the eye is between the posterior surface of the iris and the anterior surface of the lens
posterior chamber
This chamber of the eye is between the posterior surface of the lens and the neural retina
Vitreous chamber filled with vitreous humor, which is 99% water and proteins and hyaluronan
The ______ supports the eye shape, protects the delicate internal eye structures, and is the site for the EXTRINSIC muscles of the eye
Sclera
What is the tissue type found in the sclera?
Dense irregular connective tissue
The _____ protects the anterior surface of the eye and refracts incoming light
Cornea
This is characterized by two layers of epithelium with a layer of connective tissue in between
Cornea
What are the components of the fibrous layer of the eye?
Cornea and the Sclera
What is the function of the vascular tunic layer of the eye and what are its components?
Keeping things alive Choroid Ciliary body Iris
What is the portion of the vascular tunic that is highly vascularized?
Choroid
The ______ is what supplies nourishment to the retina
Choroid
This holds the suspensory ligament that attach to the lens and secretes aqueous humor
Ciliary body
What is the function of the iris?
To control the pupil diameter and the amount of light that enters the eye
This layer of the retina absorbs extraneous light and provides vitamin A to the photoreceptor cells
Pigmented layer
The _____ _______ detects incoming light rays and converts the nerve signals and transmitted to the brain
neural layer
List the 5 layers of the cornea
- Corneal epithelium 2. Bowmans membrane 3. Corneal stroma 4. Descemet membrane 5. Corneal endothelium
This is the inner vascular layer and is Bruch’s membrane
Choroid
What is the muscle that is in charge of accommodation of the eye
Ciliary muscle
Describe the process of accommodation
- Adjustments of the eye ciliary muscle 2. eye flattens and thickens 3. tension in the ciliary body 4. zonular fibers transmit the signal of tension to the lens 5. lens changes shape
What are the three components of the lens
- capsule 2. Subcapsular 3. Lens fibers
______ is the loss of elasticity of the lens that is common with age
Presbyopia
The ______ _______ _______ is a layer of simple cuboidal epithelial cells that rest on Bruch’s membrane of the choroid It serves as the blood neutral retinal barrier
Retinal pigmented layer
The ______ _______ is where the rods and cones lie
Neural retina
This is the area where the optic nerves from the ganglion layer exit the eye and cause a blind spot
Optic disc
The _______ _______ ________ is the apical boundary of the Muller cells
Outer limiting membrane
What is the innermost part of the retinal epithelium?
Retinal pigment epithelium
Where are the cell bodies of the photoreceptor cells?
In the outer nuclear layer
Where do the photoreceptors and non-photoreceptor cells connect?
Outer plexiform layer
Where are the processes of the interconnecting ganglion, amacrine, bipolar, and horizontal cells?
Inner plexiform layer
Where are the processes of the optic nerve fibers?
In the processes of the ganglion cells
What are the 3 main aspects of the general structure of the rods and cones?
Outer segment Connecting stalk Inner segment
Which portion of the rods and cones are the photosenstive parts with a series of plasma membrane discs that are connected to the inner segment via the modified cilium
outer segment
The _______ ______ is a portion of the rods and cones that contains the basal body of the cilium
Connecting stalk
Where are the major organelles in the rods and cones?
In the inner segment
True or False There are photoreceptors at the optic disc
False blind spot rmr
The ______ ______ has the highest concentration of cones and the sharpest visual acuity
Fovea centralis
This is the area that supports the fovea centralis
Macula lutea
Define a visual field
the area that a person is able to see when both eyes are fixed at one position light passes from the object through the pupil and creates a retinal field
Where is the object of attention focused in the visual field?
Fovea centralis and macula lutea
Where does the optic disc lie in relation to the macula?
Medially
What are the two zones that are in the visual field?
Binocular zone and the monocular zone
Describe the image that is formed on the retina from the corresponding visual field
The image is inverted in both lateral and vertical dimensions
This half of the visual field forms an image on the nasal half of the LEFT retina and the temporal half of the right
Left
This half of the visual field forms and image on the temporal half of the LEFT retina and the nasal half of the RIGHT
Right half of the visual field
Where is the right visual field going to hit? (which sides of the eyes)
On the left most sides of both of the eyes SO on the temporal part of the left eye and the nasal part of the right eye
Where is the left visual field going to hit? (which sides of the eyes)
On the right most sides of the eyes, so the temporal part of the right eye and the nasal part of the left eye
What travels to the left lateral geniculate nucleus?
The left most things; so the left temporal area and the right nasal area
What travels to the right lateral geniculate nucleus?
The right most things; so the right temporal area and the left nasal area
Describe the pathway that an image takes from the right visual field to the cortex
The image from the right visual field is projected onto the left temporal hemiretina and the right nasal hemiretina and then travels to the left lateral geniculate nucleus, down the left optic radiation, and into the visual cortex that is located in the occipital lobe
The ______ half of each retina decussate in the optic chiasm
nasal
The optic tract has fibers from the (IPSILATERAL/CONTRALATERAL) temporal fibers and (IPSILATERAL.CONTRALATERAL) nasal fibers
Ipsilateral temporal fibers and contralateral nasal fibers because they are the ones that cross in the chiasm
Why is the decussation of the retinal information important? Why does our brain want to have information from both retinas in the processing?
SO that there is depth perception and so that the brain is able to better understand the body’s location in space
Where is the lateral geniculate nucleus located?
Thalamus
Secondary neurons from the LGN extend a large bundle of myelinated fibers called _____ _______
optic radiations
Where is the primary visual cortex located?
On the upper and lower banks of the calcimine sulcus
Fibers from the _______ ________ of the contralateral hemifields target the superior bank and the calcimine sulcus on the cuneus
Lower quadrant
Fibers from the _______ ______ of the contra lateral hemifields arch rostrally into the temporal lobe and form the Meyer loop. They target the inferior bank of the calcimine sulcus on the lingual gyrus
Upper quadrant
Fibers with information from the ______ and ______ originate from eh central regions of the LGN and mass to caudal portions of the visual cortex
macula and fovea
The ______ is representing most posteriorly in the region of the occipital pole
macula
Upper halves of the visual field form images on the _____ halves of the retina
Lower and vice versa
Where do the fibers that represent the inferior portion of the visual field travel?
Course superiorly to terminate in the visual cortex above the calcimine sulcus
Where do the fibers that represent the superior part of the visual field travel?
Through meyers loop which is in the temporal lobe and terminate below the calcimine sulcus
Describe what it means to have vertical and lateral inversion of the projection of the retinal field in the visual cortex. (Use the left upper quadrant as an example)
The left upper quadrant will be projected in the right lower quadrant following the vertical and lateral inversions
Define hemianopia
blindness in one half of the visual field
Define quadrantanopia
blindness of a quadrant of the visual field
What are homonymous visual fields?
conditions on the visual field losses are similar in both eyes
What are heteronymous visual losses
conditions in which the two eyes have non-overlapping field losses
What is macular sparing
visual field loss that preserves the vision in the venter of the visual field
A deficit is ________ when the visual field loss of one eye can be superimposed on that of the other eye (symmetrical)
congruous
True or false The close that a lesion is to the visual field the more incongruent is is likely to be
FALSE The more close that a lesion is to the visual field the more CONGRUENT it is likely to be
If there is damage that is anterior to the chiasm, describe the loss
affects the IPSILATERAL eye
If there is damage at the chiasm, describe the loss
causes heteronymous deficits left temporal and right temporal
If there is damage behind the chiasm, describe the loss of vision
causes homonymous deficits: left temporal and right nasal
If there is a lesion at A, what is going to happen?
unilateral hemianopia on the temporal right eye
If there was a lesion at B what would happen?
Total loss of vision in the right eye
If there was a lesion at C what would happen?
non-homonymous bitemporal heminopia
If there was a lesion at D what would happen?
Contralateral (left) homonymous heminopia
If there was a lesion at E, what would happen?
Contralateral superior quadranopia: remember that the information that is carrying the superior portion of the image will swoop down into Meyers loop, which is what youre seeing at the site of the lesion
If there was a lesion at F what would happen?
Contralateral inferior quadranopia
If there were a lesion at G, what would occur?
Contralateral homonymous hemianopia
If there were a lesion at H, what would happen?
Contrallateral homonymous hemianopia
If there was a lesion in the upper bank of the calcarine fissure, what visual deficits would we expect to see?
Contralateral inferior quadranopia
If the posterior cerebral artery is occluded, what visual deficits would be expected?
left hemonymous hemianopia
If there were a lesion in the lower bank of the calcarine fissure, J, what would be expected to be the visual deficit?
Contralateral superior quadranopia
What are some acute reasons for lesions of the optic tract?
Infarcts or a CVA (stroke_
What are some chronic reasons for lesions in the visual tract?
Mass effect from tumors
What are causes of lesion in the optic nerve? What kind of deficit does this cause?
Inflammation, ischemia, and trauma can cause this
complete or partial unilateral vision loss
What are causes of lesion in the optic chiasm? What kind of deficit does this cause?
Neoplasms, trauma, inflammation, demyelination
can cause bitemporal hemianopia
What are causes of lesion in the optic tract? What kind of deficit does this cause?
Caused by: neoplasms, inflammation, ischemia, hemorrhagic infarcts, trauma, vascular malformations
If there is a temporal optic radiation lesion, what is the characteristic deficit?
Superior quadrantanopia
If there is a parietal optic radiation lesion, what is the characteristic deficit?
Inferior quadrantanopia
If there is a lesion in the occipital cortex, what are some of the causes of this and what is the characteristic deficit?
This can be caused by neoplasms, ischemia, hemmorhage, inflammation, infections, and trauma
The ________ cells form the dillator pupillae muscle
myoepithelial
The lens is covered on its anterior side by the _____ _____ and surrounded by a thick aceullar layer called the ______ ______
lens epithelium
lens capsule
What suspends the lens behind the iris and the pupil?
the ciliary zonule of the fibrilin fibers
What forms the ciliary zonule?
The epithelial cellst that are covering the ciliary body
Cells of the ______ _______ absord scattered light, form some of the blood retina barrier, and regenerate 11-cis retinal, phagocytose shed discs from rods, and support the rods and cones
pigmented epithelium
What do rod cells detect?
Cones
Light
color
Rods have stacked membrane discs that are densely packed with ______ and bound with ______
rhodopsin
retinal
Review slide 48, he starts using abbreviated letters and I dont get it. K thanks bye
Review 5 minutes
