Form 3 Chapter 1.2 Eye

Stimuli are (a)   in the surroundings that are detected by our sensory organs.

Answer explanation

Examples of stimuli:

Light, sound, touch, chemical substances.

Stimuli are detected by our sensory organs (i.e. skin, nose, eyes, ears, tongue).

Observe the picture.

Name the part of the eye that contains

photoreceptors which

detects light and produces

nerve impulses.

(a)  

Observe the picture.

Identify two parts of the eye that maintain the shape of the eyeball and focus light onto the retina.

• Retina

• Vitreous humour

• Ciliary muscle

• Suspensory ligaments

• Aqueous humour

Observe the picture.

Identify the part which is most sensitive to light as it has many photoreceptors.

• Retina

• Blind spot

• Lens

• Yellow spot

• Choroid

Observe the picture.

Identify the part which controls the size of the pupil.

(a)  

Observe the picture.

The functions of the choroid are to:

(a) prevent reflection of light in the eye

(b) supply (a)   and nutrients to the eye

Observe the image.

Part X controls the thickness of the eye lens. Identify part X.

(a)  

There are two types of photoreceptors: rod cells and cone cells.

Which photoreceptor is sensitive to the colours of light under bright conditions?

(a)  

Answer explanation

Rod cells are sensitive to different light intensities but are not sensitive

to the colours of light.

Fill in the blank.

(a)  

Answer explanation

Retina has photoreceptors which detects light (stimulus) and converts it to nervous impulse.

What happens at Y?

• The brain interprets nerve impulses and the image appears upright.

• The brain interprets nerve impulses and the image appears inverted.

• The brain carries out response.