Layers of the eye ball

Question 1

what does the outer layer of the eye contain?

Answer 1

sclera in the posterior and cornea in the anterior

Question 2

what does the middle layer of the eye contain?

Answer 2

choroid in the posterior and cillary body in the anterior

Question 3

what does the inner layer of the eye contain?

Answer 3

retina

Question 4

describe the sclera and mention its functions

Answer 4

its a white opaque fibrous layer and functions as protecting the eye and allows attachment of muscles responsible for the movement of the eyeball

Question 5

describe the cornea and mention its function

Answer 5

it makes up 1/6 from the outer layer and its transparent. it allows light to pass through into the eye and have many nociceptive fibres which inn response to irritation triggers blinking and secretion of tears through lacrimal gland keeping cornea free of dust

Question 6

describe the choroid and mention its function

Answer 6

it lines the whole posterior segment of the eye except the optic disc. it is highly vascularized and have a brown membrane the color pigment is produced by retinal epithelium and absorbs light thats not detected by the retina, therefore prevents light form being reflected back to the retina and confusing the image

Question 7

what is the function of cillary muscles?

Answer 7

they are 3 sets of smooth muscles that are responsible for changing the shape of the lens during the process of focussing

Question 8

what is the function of cillary process?

Answer 8

it produces aqueous humours

Question 8

what is the function of cillary process?

Answer 8

it produces aqueous humour. it then flows out of the posterior chamber through the pupil into the anterior chamber where it drains into the venous blood through the canal of schlemm

Question 9

what happens if the canal of schlemm is blocked?

Answer 9

patient will develop glaucoma where the intraoptical pressure increase and reducing the blood flow through the retinal capillaries causing damage to the retina and eventually can cause blindness

Question 10

describe the iris and mention its function

Answer 10

it is the coloured part of the eye that extends from the cillary body across the front to the center of the lens leaving a gap which is the pupil and it has 2 types of muscles

Question 11

state the 2 types of muscles of the iris and mention its function

Answer 11

circular muscles narrows the pupil when contracted and the radial muscles widens the pupil when contracted

Question 12

describe the lens and mention its function

Answer 12

the lens is transparent at the junction of anterior and posterior segment. it contains a clear protein caleed CRYSTALINS. it focuses light onto the retina

Question 13

name the disease where the lens becomes opaque and mention its causes and treatment

Answer 13

its called cataract and caused in old age due to the oxidization and aggregation of crystallin and also high levels of uv light can cause cataract. its treatment is by removal the damaged lens and substituting it with a synthetic one

Question 14

what is vitreous humour and mention its function

Answer 14

its a transparent thick gelatinous fluid filling the posterior segment of the eye. it is composed of collagen and large amounts of water. it maintains the shape of the eyeball and contains phagocytic cells that remove any cell debris or anything that interferes with light transmission

Question 15

name the 2 layers of the retina?

Answer 15

outer pigment layer/ pigmented epithelial layer
inner neural layer

Question 16

what is the function of the outer pigmented layer?

Answer 16

prevents light scattering and provides a source of vitamin that is required by some photoreceptor cells

Question 17

vitamin A deficiency

Answer 17

leads to night blindness because the protein rhodopsin decreases which is required by some photoreceptor cells

Question 18

what is the content of the inner neural layer?

Answer 18

rhodes and cones and they are each divided into outer segment and inner segment

Question 19

the outer segment

Answer 19

in cones it contains many invaginations while in rhodes it contains multiple discs stacked on top of each other. the outer segment is specialized in photot transduction

Question 20

name all the layers of the eye starting from the bottom

Answer 20

1)pigmented cell layer
2)photoreceptors layer
3)outer nuclear layer
4)outer plexiform layer
5)inner nuclear layer
6)inner plexiform layer
7)ganglion cell layer

Question 21

what is the macula lutea

Answer 21

region at the centre of the retina where visual acuity is greatest and have fovea in its centre

Question 22

name the type of neuroglia that myelinates the optic nerve

Answer 22

oligodendrocytes

Question 23

what is retinal detachment

Answer 23

occurs when inner neural layer detaches from the outer pigmented layer this causes photoreceptors to die resulting in blurred vision.