Human Eye

Question 1

What are the 7 structures found at the front part of the eye?

(SIC PEET)

Answer 1

Sclera

Iris

Conjunctiva

Pupil

Eylashes

Eyelids

Tear Glands

Question 2

Sclera is the tough,white outer covering of the eyeball.

State the function of it.

Answer 2

Protects the eyeball from mechanical damage

Question 3

What are the 2 features of IRIS and what is the function of one of the features?

Answer 3

1. It contains a pigment which gives the eye its colour
2. It consists 2 sets of involuntary muscle called radial muscles and circular muscles.

Function of the 2 sets of muscles: Control the amount of light entering the eye.

Question 4

A thin transparent mucous membrane is found covering the sclera membrane. Name the feature and state its function.

Answer 4

Conjunctiva

-It secretes mucous to help keep the FRONT of the eyeball MOIST

Question 5

What does the pupil do?

Answer 5

It allows light to enter the eye

Question 6

What is the function of eyelashes?

Answer 6

Help shield the eyes from dust particles.

Question 7

What does the tear gland secrete and do?

Answer 7

Tear Glands secretes tears

• wash away dust particles
• Keep cornea moist so that atmospheric oxygen can dissolve and diffuse in cornea
• Lubricate conjuctiva to help reduce friction when eyelids move

Question 8

State one function of the eyelids and 2 actions it does to protect the eyes.

Answer 8

fx: Protect the cornea from mechanical damage
- Squinting : Prevents excessive light from entering the eys and damaging the light-sensitive cells tissues inside
- Blinking: spreads tears over cornea and conjunctiva and wipes dust particles off cornea

Question 9

State the 11 internal structures of the eye

ABC3 VS ROFL

Answer 9

Aqueous chamber

Blind spot

Cornea

Ciliary body

Choroid

Vitreous chamber

Suspensory ligament

Retina

Optic nerve

Fovea

Lens

Question 10

What muscle is found in the ciliary body and what does it control?

Answer 10

• Ciliary muscles

- It controls the curvature and thickness of the lens

Question 11

Identify the tissue that attaches the edge of the lens to the ciliary body.

Answer 11

Suspensory ligament

Question 12

What are the 2 functions of choroid?

Answer 12

1. It is pigmented black-to prevent internal reflection of light
2. Consist of blood vessels that bring o2 and nutrients to the eyes and remove metabolic waste products

Question 13

Vitreous chamber: What is this chamber filled with ? and state the 2 functions.

Answer 13

Vitreous humour.

• Keeps the eyeball firm
• Helps to reflect light onto the retina

Question 14

Identity the structure which is a small yellow depression in the retina situated directly behind lens.

Answer 14

Fovea

Question 15

What happens at the fovea? What’s so special about it and how does this affect the way a person sees things?

Answer 15

• It is where images are normally focused
• It has high concentration of cones but no rod
• Enables a person to have detailed coloured vision in bright light.

Question 16

Why is the blind spot not sensitive to light?

Answer 16

It does not contain any rods or cones. Hence, it is not sensitive to light

Question 17

What does the Optic nerve do?

Answer 17

Transmits nerve impulses to the brain when photoreceptors in retina are stimulated

Question 18

What can be found in the retina?

Answer 18

Light-sensitive cells//Photoreceptors which contains rods and cones

Question 19

What is the difference in terms of functions between rods and cones?

Answer 19

Cones allows us to see colours in bright light while Rods allows us to see in dim room in black and white

Question 20

What causes one to be diagnosed with night-blindness?

Answer 20

Vitamin A deficiency

-Vitamin A is reqwuired in order to form visual purple.

Question 21

Where can photoreceptors be found?

Answer 21

In the retina