Podcast
Questions and Answers
What is the primary function of the retinal pigmented epithelium in relation to the rods and cones?
What is the primary function of the retinal pigmented epithelium in relation to the rods and cones?
Which type of photoreceptor is responsible for vision in bright lighting?
Which type of photoreceptor is responsible for vision in bright lighting?
What is the composition of the vitreous body?
What is the composition of the vitreous body?
What is the function of the zonular fibers?
What is the function of the zonular fibers?
Signup and view all the answers
What is the characteristic of the inner segment of rods?
What is the characteristic of the inner segment of rods?
Signup and view all the answers
What is the pigment present in the disks of rods?
What is the pigment present in the disks of rods?
Signup and view all the answers
What is the characteristic of the vitreous body?
What is the characteristic of the vitreous body?
Signup and view all the answers
What is the characteristic of the lens capsule?
What is the characteristic of the lens capsule?
Signup and view all the answers
What type of cells does the anterior epithelium consist of?
What type of cells does the anterior epithelium consist of?
Signup and view all the answers
What is the function of the third eyelid?
What is the function of the third eyelid?
Signup and view all the answers
What type of cartilage forms the third eyelid in horses, pigs, and cats?
What type of cartilage forms the third eyelid in horses, pigs, and cats?
Signup and view all the answers
What type of glands are the tarsal glands?
What type of glands are the tarsal glands?
Signup and view all the answers
What type of epithelium is the conjunctiva near the eyelid margin?
What type of epithelium is the conjunctiva near the eyelid margin?
Signup and view all the answers
What is unique to animals, but lacking in humans?
What is unique to animals, but lacking in humans?
Signup and view all the answers
What type of cells make up the lens fibers?
What type of cells make up the lens fibers?
Signup and view all the answers
Where are the aggregated lymphoid nodules located?
Where are the aggregated lymphoid nodules located?
Signup and view all the answers
What type of cells are more abundant in the retinas of animals active during the day?
What type of cells are more abundant in the retinas of animals active during the day?
Signup and view all the answers
Where is the fovea located in the eye?
Where is the fovea located in the eye?
Signup and view all the answers
What is the main purpose of a fundic exam?
What is the main purpose of a fundic exam?
Signup and view all the answers
What is anemia often detected by observing?
What is anemia often detected by observing?
Signup and view all the answers
Which is the correct statement, in regards to tear film layers?
Which is the correct statement, in regards to tear film layers?
Signup and view all the answers
What is unique about the eyes of birds?
What is unique about the eyes of birds?
Signup and view all the answers
What is the function of the pectin in birds and reptiles?
What is the function of the pectin in birds and reptiles?
Signup and view all the answers
In what order does light travel through the eye?
In what order does light travel through the eye?
Signup and view all the answers
What is number 1 referring to?
What is number 1 referring to?
Signup and view all the answers
What is number 2 referring to?
What is number 2 referring to?
Signup and view all the answers
What is number 3 referring to?
What is number 3 referring to?
Signup and view all the answers
What is number 1 referring to?
What is number 1 referring to?
Signup and view all the answers
What is number 2 referring to?
What is number 2 referring to?
Signup and view all the answers
What is this image primarily depicting?
What is this image primarily depicting?
Signup and view all the answers
What is number 1 referring to?
What is number 1 referring to?
Signup and view all the answers
What is number 1 referring to?
What is number 1 referring to?
Signup and view all the answers
What is number 2 referring to?
What is number 2 referring to?
Signup and view all the answers
What is number 3 referring to?
What is number 3 referring to?
Signup and view all the answers
What is number 1 referring to?
What is number 1 referring to?
Signup and view all the answers
What is number 2 referring to?
What is number 2 referring to?
Signup and view all the answers
What is number 3 referring to?
What is number 3 referring to?
Signup and view all the answers
What is number 1 referring to?
What is number 1 referring to?
Signup and view all the answers
What is number 2 referring to?
What is number 2 referring to?
Signup and view all the answers
What is number 3 referring to?
What is number 3 referring to?
Signup and view all the answers
What is number 4 referring to?
What is number 4 referring to?
Signup and view all the answers
What is number 1 referring to?
What is number 1 referring to?
Signup and view all the answers
What is number 2 referring to?
What is number 2 referring to?
Signup and view all the answers
What is number 3 referring to?
What is number 3 referring to?
Signup and view all the answers
What is number 2 referring to?
What is number 2 referring to?
Signup and view all the answers
What is number 3 referring to?
What is number 3 referring to?
Signup and view all the answers
What is number 4 referring to?
What is number 4 referring to?
Signup and view all the answers
What is number 5 referring to?
What is number 5 referring to?
Signup and view all the answers
What is number 6 referring to?
What is number 6 referring to?
Signup and view all the answers
What is number 7 referring to?
What is number 7 referring to?
Signup and view all the answers
What is number 9 referring to?
What is number 9 referring to?
Signup and view all the answers
What is letter "A" referring to?
What is letter "A" referring to?
Signup and view all the answers
Study Notes
Eye: General Info
- Animals active at night have retinas with fewer cone cells than those active during the day.
- A fovea is a tiny pit in the macular region of the retina where light falls directly on cones.
- A fundic exam is a clinical method of evaluating the retina.
- Anemia is detected by observing mucous membranes, such as the conjunctiva and third eyelid.
Tears
- Tears have functions of protection, moistening, and nourishing.
- Tear films have three layers:
- Oily portion produced by Meibomian (tarsal) glands
- Aqueous portion consisting of sero-mucous material produced by lacrimal glands and glands of the third eyelid
- Mucous portion produced by goblet cells in the conjunctiva
Special Adaptations
- Some animals have special adaptations for their eyes, such as:
- Birds having cartilage in the sclera and occasionally ossicles
- Birds and reptiles having a pectin, which aids in nourishing the inner eye and retina
Path of Light and Visual Perception
- Light travels through the tear film, aqueous humor, pupil, lens, vitreous humor, and the first 8 layers of the retina
- Light stimulates the rods and cones, and then is absorbed by the retinal epithelium
- The visual impulse created then passes in the reverse order from rods and cones to the optic nerve and then to the brain
Retinal Pigmented Epithelium
- Retinal pigmented epithelium is the outermost layer of the retina, consisting of flat polygonal cells that rest on a basement membrane
- It is involved in the transport of nutrients and metabolites to the rods and cones
- It is also involved in light absorption and phagocytosis
Photoreceptor Layer
- The photoreceptor layer has neurons known as rods and cones
- Rods and cones have outer and inner segments that are connected through a cilium
Rods
- The inner segment of rods is long and thin
- Rods contain flattened membranous disks that contain the pigment Rhodopsin (vitamin A)
- Rods are responsible for vision in dim lighting and are more common in nocturnal animals
Cones
- The inner segment of cones has a broad base
- Cones have disks that contain lodopsin
- Cones are responsible for vision in bright lighting and color vision
Refractive Media
Vitreous Body
- The vitreous body is a gelatinous, colorless, viscous fluid
- It occupies the space between the lens and retina, making up 4/5 of the eyeball
- It is composed of 99% water, rich in hyaluronic acid, and has a cell cortex with a liquid center
- The vitreous body aids in maintaining the shape and retinal apposition
Lens
- The lens is entirely surrounded by a capsule and is thick on the anterior surface
- The capsule is thicker on the anterior lens surface than the posterior lens surface
- The lens is suspended by the zonular fibers from the ciliary processes
- The lens loses vascular supply after development
- The lens has an anterior epithelium and lens fibers
Anterior Epithelium
- The anterior epithelium is composed of simple cuboidal or columnar cells, apical towards lens fibers
- At the equator, it elongates and differentiates into lens fibers
- Anterior lens epithelium reflects onto the surface of the lens; cells elongate to form lens fibers that comprise the lens
Lens Fibers
- Lens fibers are composed of prism-shaped cells that lack a nucleus, interdigitate extensively, and have gap junctions which are transparent
- The differentiation and growth of the lens happen throughout life
Accessory Ocular Structures
Eyelid
- The eyelid contains:
- Conjunctiva, which is either a pseudostratified columnar or transitional epithelium that becomes stratified squamous near the eyelid margin
- Cilia (eyelashes)
- Tarsal (meibomian) glands, which are sebaceous
- Third eyelid (nictitating membrane), which is unique to animals and protects the eye and removes foreign material
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Learn about the structure and function of the human eye, including the retina, fovea, and macular region, as well as how to detect certain medical conditions.
