Anatomy

Question 1

Layers of the eyeball

Answer 1

Outside in

1. Fibrous coat/outer layer
2. Vascular coat/middle layer
3. Nervous coat/inner layer

Question 2

Segments of the eyeball

Answer 2

1. Anterior segment

2. Posterior segment

Question 3

Characteristics & Function of Cornea

Answer 3

• Transparent
• Centrally positioned at the front of the eye
• Makes up anterior 1/6th of fibrous coat
• Light refraction

Question 4

Sclera’s functions

Answer 4

• Provides shape to the eye

- Provides attachment to extraocular muscles

Question 5

Components of fibrous coat

Answer 5

• Sclera

- Cornea

Question 6

Junction where sclera ends and cornea begins

Answer 6

Limbus

Question 7

Components of vascular coat

Answer 7

Anterior -> Posterior

• Iris
• Ciliary body
• Choroid

Question 8

Function of fibrous coat

Answer 8

Protects intraocular contents

Question 9

Function of vascular coat

Answer 9

Supplies nutrition to various structures of the eyeball (Cornea and lens are avascular)

Question 10

Describe sclera

Answer 10

• White part of the eye
• Makes up posterior 5/6th of the fibrous coat
• Several vessels penetrate through the sclera including the optic nerve

Question 11

Another name for vascular coat

Answer 11

Uvea

Question 12

What is choroid?

Answer 12

A layer of connective tissue and blood vessels

Question 13

Function of choroid

Answer 13

Provides nourishment to the outer layer of the retina

Question 14

Parts of the ciliary body

Answer 14

1. Ciliary muscle

2. Ciliary processes

Question 15

What is ciliary muscle made of?

Answer 15

A collection of smooth muscle fibres arranged in 3 orientation (radial, circular, longitudinal)

Question 16

Briefly explain the role of ciliary muscle in accommodation reflex

Answer 16

Accommodation reflex : adjusting lens for near vision

Ciliary muscle contracts -> Circular ciliary body reduces in size -> Zonnular fibres/suspensory ligament of lens slack -> Lens become more rounded

Question 17

What are ciliary processes?

Function?

Answer 17

Ciliary processes project from the surface of the ciliary body

Attach the lens to the ciliary body via zonnular fibres/suspensory ligament of lens

Question 18

What is iris?

Answer 18

• Circular structure with an aperture in the center called the pupil
• Gives the eye colour as iris is strongly pigmented

Question 19

Function of iris

Answer 19

• give the iris colour

- has a two fiber arrangement which help control the pupil size

Question 20

Explain the layers of fibres in the iris

Answer 20

1. Circular fibres give rise to sphincter pupillae
   - Under parasympathetic control -> miosis
2. Radial fibres give rise to dilator pupillae
   - Under sympathetic control -> mydriasis

Question 21

Name the layers of the nervous coat

Answer 21

2 cellular layers

• neural
• pigmented

Question 22

Location of pigment cell layer of retina

Answer 22

• Beneath the neural layer

- Attached to the choroid layer

Question 23

What is optic disc?

Answer 23

• Optic nerve head
• Retinal ganglion cell axons exit the eye to become optic nerve
• Site of entry of central retinal artery into the retina
• Blind spot (no light detecting cells)

Question 24

Name the two chambers of the anterior segment

Answer 24

• Anterior chamber

- Posterior chamber

Question 25

Boundary of anterior segment

Answer 25

Cornea -> Lens (included)

Question 26

Boundary of posterior segment

Answer 26

Lens -> Retina

Question 27

Boundary of anterior chamber

Answer 27

- Anterior boundary : Back of cornea | - Posterior boundary : Anterior surface of iris and part of ciliary body

Question 28

Depth of anterior chamber in hypermetropes and myopes

Answer 28

Hypermetropes : Slightly shallower than normal Myopes : Deeper than normal Almost equal in both eyes of the same individual in any case

Question 29

Secretion of aqueous humour

Answer 29

By ciliary body in the posterior chamber

Question 30

Function of aqueous humour

Answer 30

- Nourishes and protects the eye (cornea and lens are avascular)

Question 31

Boundaries of posterior chamber

Answer 31

Anterior boundary - posterior of surface of iris and part of ciliary body Posterior boundary - crystalline lens Lateral body - ciliary body