Flashcards in The Eye Deck (53)
2 things that occur in vision:
1) transforming light rays into an electrical impulse
2) forming a color image
2 Functions of the eye:
1) collects light rays
2) via the lens, all light rays need to be focused at the level of the retina
3 Layers of the Outer wall of the eye:
1) Fibrous tunic: clear & Cornea
2) vascular tunic: choroid & Iris (lots of blood vessels, regulates size of pupil)
3) Sensory Tunic: contains the retina (sensory layer) & pigmented layer
what is contained in the retina?
rods and cones
What is outside of the wall of the eyes, follows the surface of the cornea and then folds back and follows the side of the eyelid?
What can be caused as a result of the conjunctiva being swollen?
Conjuntivitis (pink eye)
Which layer covering the eye is the vascular tunic?
Choroid. The blood vessels get smaller and smaller as they spread forward to the front of the eye.
the only portion in the front of the eye that has blood vessels, restricting to form the iris
the sensory tunic. where rods and cones are located
different levels/intensity of light, greyscales
Entire area in front of the lens is called:
the anterior compartment
Entire area behind the lens is called:
the posterior compartment
Name of fluid in the posterior compartment?
Vitreous Humor: gelatinous mass. it does not move, does not change and remains the same.
Name of fluid in the anterior compartment:
Aqueous Humor: like water, very liquidy. Continuously being changed, cycled.
What is the term for the bending of light?
Refraction, helps us form a nice clear crisp image
Why is the Aqueous Humor continuous being cycled?
This is due to the cornea. It needs an oxygen supply. But most of it can diffuse across the conjunctiva. But it also needs a nutrient supply. Is a blood filtrate, containing glucose to feed the cornea.
What provides nutrients to the iris?
Blood vessels in the Iris most provide nutrients to the iris.
an eye disease in which the pressure (due to the liquid) inside the eye becomes too high. Tunnel vision can result, due to the constriction of tiny blood vessels. Peripheral vision will disappear.
Functions of the Accessory structures of the eye:
4) aid in eye function
Accessory structures of the eye:
Eyelids, eyelashes, eyebrows (the bone that forms the ridge) lacrimal apparatus, extrinsic eye muscles and conjunctiva.
Function of the eyebrow:
casts a shadow over the eye, since its easier to look from the dark to the light.
Function of the eyelid:
moveable protective coverings, blink 25x per minutes.
Function of blinking:
To keep the spreading of tears across the surface, and to keep a large object from entering eye
Keep out dust particles
How many muscles needed to move an eye?
Where are the collection/drain of debris from tears located?
in the puncta of the eye
Which two extrinsic eye muscles can you not contract at the same time?
the black matrix in which images are formed against.