Module 4/Chapter 28/Sense Organs: The Eye and the Ear/Parts of the Eye
Terms
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- The eyeball fits into what?
- the orbital cavity
- What does the conjunctival membrane do?
- provides lubrication and protection
- What is the purpose of the lacrimal glands and ducts?
- produce and deliver tears
- orbital cavity
- The cavity or socket of the skull in which the eye and its appendages are situated
- ocular
- Of, pertaining to or affecting the eye.
- eyelids
- The lid or cover of the eye, a movable fold of skin and muscle that can be closed over the eyeball or opened at will. Each eye has an upper and a lower lid. An eyelid is also called a palpebra.
- The outer eye consists of what (5)?
-
1)orbital cavity
2)extrinsic ocular muscles
3)eyelids
4)conjunctuval membrane
5)lacrminal apparatus - What provides movement for the eyeball?
- ocular muscles
- What is the purpose of the eyelids (3)?
-
1)provides protection from light
2)provides protection from dust
3)provides protection from trauma - What does the lacrimal apparatus do?
- produces, delivers and drains tears from the eye
- extrinsic
- [L. extrinsecus situated on the outside] coming from or originating outside; having relation to parts outside the organ or limb in which found.
- extrinsic ocular muscles
- the muscles within the orbit but outside of eyeball; provide movement for the eyeball
- conjunctiva
- A clear membrane that coats the inner aspect of the eyelids and the outer surface of the eye.
- conjunctival membrane
- The mucous membrane which covers the external surface of the ball of the eye and the inner surface of the lids; the conjunctival membrane;provides lubrication and protection
- lacrminal apparatus
- The tear-forming and tear-conducting system which includes the lacrimal glands, eyelid margins, conjunctival sac, and the tear drainage system.
- lacrimal
- Pertaining to the tears.
- The inner eye (eyeball) consists of what 3 layers?
-
1)outer layer
2)middle layer
3)inner layer - sclera
- (part of the outer layer of the eyeball)-- tough,white,fibrous,connective tissue that maintains shape of the eye and protects the inner layers of tissue
- cornea
- (part of the outer layer of the eyeball)-- center for focusing;consists of 5 layers and is protected by tears.
- choroid
- (part of the middle layer of the eyeball)-- contains blood vessels that supply nutrients to the eye
- How many rods are in each eye?
- 120 million
- ciliary body
- (part of the middle layer of the eyeball) -- contains muscles that adjust the shape of the lens, produces aqueous humor
- aqueous humor
- It is a clear, watery fluid that flows between and nourishes the lens and the cornea; it is secreted by the ciliary processes
- iris
- (part of the middle layer of the eyeball) -- colored part of the eye; muscular diaphragm that controls the size of the pupil; it forms the colored portion of the eye
- pupil
- (part of the middle layer of the eyeball)-- opening in center of iris, regulating the amount of light coming into the eye
- The middle layer (one of the 3 layers of the inner eye) consists of what (4)?
-
1)choroid
2)ciliary body
3)iris
4)pupil - The outer layer (one of the 3 layers of the inner eye) of the eyeball consists of what (2)?
-
1)cornea
2)sclera - The inner layer (on of the 3 layers of the inner eye)consists of what (3)/
-
1)retina
2)rods
3)cones - retina
- (part if the inner layer of the eyeball) -- nerve layer of the eye containing rods and cones.
- rods
- (part of the inner layer of the eyeball)-- function in dim light--responsible for night vision
- cones
- (part of the inner layer of the eyeball) -- responsible for bright-light vision
- How many cones are in each eye?
- 6 million
- What is not considered to be a part of one of the layers of the eyeball (inner eye)?
- the lens
- refraction
- In ophthalmology, the bending of light that takes place within the human eye.
- What happens as light passes through the lens?
- it is bent (refraction)
- In order to focus light, the lens must do what?
- must change its shape
- accommodation
- the ability of the eye to change its focus from distant to near objects (and vice versa). This process is achieved by the lens changing its shape
- The changing of the shape of the lens is called what?
- accommodation
- With aging the lenses lose some elasticity. What can be used to provide additional refraction that the lenses can no longer provide.
- reading glasses