eye structure

Question 1

what are the 6 extra ocular muscle of the eye ?

Answer 1

. superior oblique
. inferior oblique
. medial rectus
. lateral rectus
. inferior rectus
. medial rectus

Question 2

what are the skeletal muscle involved in blinking?

Answer 2

. orbicularis oculi - one of the facial muscles which runs around the eye
its contraction closes the palpebral aperture
. the levator palpebrae superioris - runs along the top of eye ball and sends tendons into eyelid
contraction raises the upper eyelid

Question 3

why is there a lot of adipose tissue around the eye ?

Answer 3

. protection and acts as cushion and insulation

Question 4

what does ora serrata represent ?

Answer 4

. it’s the junction between the ciliary body and retina
. junction marks the transition zone between simple non-photosensitive area of photoreceptor to multi-layered photosensitive retina

Question 5

what type of tissue makes up vitreous humour ?

Answer 5

connective tissue made up of collagen and proteoglycan

Question 6

what is the function of vitreous humour ?

Answer 6

. helps maintain the shape of the eye
. vital role in protecting the eye
. transmit light to retina

Question 7

retina is involved in transduction - what is transduction ?

Answer 7

converts optical images into nervous potential

-turns photons of light into neurobiological activity.

Question 8

what is the function of tapetum lucidum ?

Answer 8

it reflects visible light back through the retina , increasing the light available to photoreceptors .
. enhancing visual sensitivity

Question 9

why is the tapetum lucidum unevenly distributed ?

Answer 9

its purpose is to reflect light to make image brighter so doesn’t have to be well placed

Question 10

what is the area that appears black because there is no tapetum on the posterior surface of the eye ?

Answer 10

choroid

Question 11

what is the function of the choroid ?

Answer 11

supplies the outer retina with nutrients

Question 12

how is the lens attached to the ciliary body ?

Answer 12

by suspensory ligaments

Question 13

which lens surface appears curved ?

Answer 13

cornea

Question 14

why does the lens appear hard ?

Answer 14

because of chemicals , in living animals the lens is softer

Question 15

what are the 3 layers of the lens ?

Answer 15

. an elastic capsule covering the entire surface
. a simple epithelium underneath this
. the bulk of the lens is made of elongated cells (lens fibres )

Question 16

what pathological condition results in a loss of transparency ?

Answer 16

cataract

Question 17

what is the ciliary body divided into ?

Answer 17

.anterior ridge pars plicata

. posterior , smooth , thinner pars plana

Question 18

what are the ridges in the pars plicata made off ?

Answer 18

series of ridges known as ciliary process

Question 19

what is the ciliary process covered ?

Answer 19

the ciliary process is covered by a 2 layered epithelium
. the pigmented epithelium - part of the eyes black box effect
.the un pigmented epithelium - produces aqueous humour

Question 20

what is the structure of iris ?

Answer 20

its posterior surface is covered by 2 layered epithelium containing melanin.
this ensures that the only light that enters the eye is through the pupil

Question 21

what is the function of ciliary body ?

Answer 21

. produces aqueous humour which supplies avascular cornea and lens with nutrients and oxygen
. ciliary muscle changes the shape of lens when your eyes focus near objects

Question 22

how is aqueous humour drained ?

Answer 22

into the canal of schlemm at the filtration angle

Question 23

what is the limbus ?

Answer 23

corneal scleral junction

Question 24

what pathological condition results from inadequate drainage ?

Answer 24

glaucoma

Question 25

What are the lens surtures?

Answer 25

The lens fibers that do not reach the poles form tight, interdigitating seams with neighboring fibers. These seams are readily visible and are termed sutures. The suture patterns become more complex as more layers of lens fibers are added to the outer portion of the lens.

Question 26

What happens when you peel off the outer layers of the lens?

Answer 26

fibrous composion

loss of translucency

Question 27

What is the lens nucleus?

Answer 27

The nucleus of the lens is made up of firm cortical substance, it is harder than the cortex because of its lower water content. There is no clear boundaries between the cortex and the nucleus of the lens.

Question 28

What is the size of the cornea?

Answer 28

11.5mm

Question 29

What is the cornea shape?

Answer 29

wider nasally.

Question 30

What colour is the fat and muscle?

Answer 30

fat= white

muscle=brown