Eyes lecture Flashcards
Why isn’t the cornea ever rejected in a transplant.
The lack of vascularization mean then there is no immune response.
How does constricting the pupil to focus on close objects work?
It help keep light rays parallel to prevent divergence.
What is the function of the lens in focusing
It fine tunes the image between humors
Which types of cells in the eye send an action potential?
Ganglion Cells
What is the plate of protective connective tissues in the eyelids? and where is it locate?
The tarsal plate on both upper an lower eyelids.
Ho may bi-polar cells and ganglion cells are there per cone?
One bi-polar cells, One ganglion cells.
What muscle causes constriction of pupil? What system control its?
The circular muscles (pupil constrictor muscle). Controlled by the parasympathetic system.
What is the sclera made out? What is is function?
Dense irregular connective tissue. Keeps the shape of the eyeball.
How does the cornea get oxygen?
It diffuses in from outside air.
Can vitreous humor be regenerated?
No. You only have what you are born with
Median caruncle
.
What are the medial and lateral commissures of the eyes?
The place where the eyelids meet.
What are 4 functions of tears.
The acidity helps keep bacterial count down. They Contain lysosomes to break down bacteria and fungal wall. they Wash the eye clean, and they keep it wet allow the cornea to be oxygenated.
What causes the cornea to be cloudy?
Problems with the sodium pumps that changes the shape of the fibroblasts.
Where do the nutrients for the cornea come from?
The aqueous humor.
What is the cause of cataracts?
problems the regular arrangement of the lens. Sometimes modified and sometimes removed to correct the cataracts.
How many pigments are the for eye color? What are other causes of eye color?
The is one pigment for brown. Other colors are caused by melanin quantity and refraction.
What produces the Aqueous humor, and how much is produced per day?
The Ciliary process. It produces about 1/2 liter per day
Describe the location of the conjunctiva.
The conductiva is a membrane that covers the font of the slcera and the eyelids.
What kind of tissue composes the cornea and what make it so clear.
It is highly regularly arranged college fibers. The hexagonal arrangement make is clear.
What organ is of primary importance for focus and how does it work?
The cornea. It becomes more of less convex depending on the distance of the object to make sure that the light it still refracted onto the fovea
What muscle causes dilation of pupil? What system control its?
The radial muscles (pupil dilator muscle). Controlled by the sympathetic system.
What is accommodation and when does it occur?
When the lens increases its curvature to view near objects. At distance close than 6 feet
What is the function of tarsal glands (Meibomian Glands)
Produce and secrete an oil that helps keep the eyeball wet and coats particles to prevent scratching