eye

Question 1

anatomy of orbit

Answer 1

Question 2

which wall of the orbit is most prone to fracture?

what is this fracture called?

Answer 2

floor (inferior wall) of the orbit,

which can occur following direct impact to the front of the eye e.g. by a ball or fist

(orbital blow-out fracture).

Question 3

which part of orbit has the foramina a fissures?

Answer 3

sphenoid bone

Question 4

shade the orbit of the skull

Answer 4

Question 5

Question 6

what covers the outer sclera?

describe the anatomy

Answer 6

Covering over the sclera is a thin transparent layer of cells called the conjunctivae

it extends up to the edge of the cornea (the limbus) and is reflected onto the inner surface of the upper and lower eyelids.

BV run through the conjunctivae.

Question 7

location of anterioir and posterioir chambers of eye

Answer 7

Question 8

choroid>> continues anteriorly as the _______&_______

Answer 8

choroid, which continues anteriorly as the ciliary body & iris.

The ciliary body, which is vascular and muscular (consisting of a ciliary process and muscle) connects the choroid with the iris.

Question 9

what is the uvea?

Answer 9

(“uvea” is a collective term for the choroid, ciliary process and iris)

Question 10

what is the inner layer?

Answer 10

retina!

Question 11

layers and cells of retina

Answer 11

• neurol part > photosensitive > neurosensory cell layer
• pigment layer> non-photosensitive > pigmented epithelial cell layer (containing melanin)

Question 12

fucntion of melanin in the pigmanted layer?

Answer 12

1. helping absorb scattered light that has passed into the eye
2. reducing reflection
3. allowing us to focus images appropriately on to the retina.

Question 13

neurosensory layer in retina and its functions

Answer 13

senses light and is where the photoreceptors (rods and cones)

Question 14

functions of cones and where r they mostly found?

Answer 14

The cones are responsible for high visual acuity and colour vision

concentrated in an area of the retina called the macula.

Question 15

what is the macula? location?

Answer 15

The macula is a yellowish avascular area of the retina upon which an object in your visual field falls if your gaze is directed to it (i.e. centre of your vision).

• depression in the centre called Fova centralis!>> light can pass directly there!> only cones r there
• lateral to the optic disk!

Question 16

how does the retinal layer receives its blood supply

Answer 16

from the underlying choroid layer

Question 17

function of rods

Answer 17

The rods (~20x more in number than cones) are responsible for vision in low intensity light (night vision) and do not discern colours. While some are found towards the central retina, they are more abundant in number towards the peripheral parts.

Question 18

what is known as the blind spot?

Answer 18

Optic disk

The optic disc actually represents the accumulation of retinal axons that leave the eye as the optic nerve; it is therefore devoid of photoreceptors. As such, the optic disc corresponds to what we colloquially know as the “blind spot”.