Chapter 2 Flashcards
What is the primary function of the medial rectus muscle?
Rotates the eye inward towards the nose.
Of the 6 muscles, the medial rectus is responsible for Adduction
In what order is visual information from the retina transmitted to the visual cortex?
Bipolar cells to ganglion cells to lateral geniculate body.
Light strikes the rods and cones on the retina that is transmitted through bipolar and ganglion cells to the cross the optic chiasm and reach the lateral geniculate bodies
The contraction of what muscle(s) affects globe rotation?
Superior oblique, inferior oblique, superior rectus, and inferior rectus.
The superior oblique performs incyclotorsion, the inferior oblique performs excyclotorsion, the superior rectus performs upward and incyclotorsion, and the inferior rectus performs downward and excyclotorsion
What membrane lies on the inner eyelid?
Palpebral conjunctiva.
The conjunctiva is a thin, translucent mucous membrane that lines the inner surface of the eyelids (palpebral) and outer surface if the front eye (bulbar), and where they meet is called the fornix
What separates an internal hordeolum (chalazion) from an external hordeolum (stye)?
The tarsal plate.
It is a dense, plate-like framework that separates the external from the internal eyelid
The contraction of what muscle results in enlargement of the pupil?
Dilator muscle.
Fibers stretch from the pupil to the Iris and contact to widen it in low light conditions. The sphincter is contracted to constrict the pupil
What structure is responsible for secreting the aqueous humor?
Ciliary body.
It is a band-like structure that has ridges called cilliary processes. These secrete the aqueous humor that fills the anterior and posterior chambers
What part of the eye is responsible for 2/3 of the eye’s focusing power?
Cornea.
The curvature and transparency of the cornea permit it to focus light rays. The tear film aids by providing a smooth surface over the Cornea
What is the process where the lens changes shape to allow an individual to focus on a near target?
Accommodation.
This is done with the help of the muscles of the ciliary body. When they contract, zonules relax, limiting the lens to become rounder and increasing its focusing power
What kind of vision loss is associated with injury or degeneration of the macula?
Detailed central vision.
Most of the cone cells are concentrated in the macula, so proper function of this area is crucial to detailed central vision
The crystalline lens comes in contact with what fluids and tissues?
Iris, Zonules, Aqueous humor, vitreous.
The Iris and aqueous humor lie in front of the lens, it is suspended by the zonules, and the vitreous lies behind it
What cells and glands of the eye and adnexa contribute to tear production?
Goblet cells, meibomian glands, and lacrimal gland.
The meibomian glands produce the outer layer of tear film that prevents evaporation of moisture from the middle layer, the lacrimal gland produces the middle layer that nourishes the cornea, and goblet cells produce the innermost layer that is comprised of mucinous fluid the promotes the even spread of tear film
