5.7 Structure of the eye
6 exam questions worth 15 marks. Write your answer, open the mark scheme, then give yourself the marks you earned. Your answers are saved on this device.
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The diagram shows a section through the eye.
Name the parts labelled C, E and H.
Mark scheme
- C: cornea (1)
- E: lens (1)
- H: retina (1)
Model answer
C is the cornea, E is the lens and H is the retina.
Which part of the eye contains the light receptor cells?
Choose one answer.
Correct Not quite: the answer is Retina
Mark scheme
C (retina)
Model answer
C: the retina.
Give the function of:
- the cornea
- the optic nerve
Mark scheme
- cornea: refracts / bends light (into the eye) (1)
- optic nerve: carries impulses from the retina to the brain (1)
Model answer
The cornea refracts light as it enters the eye. The optic nerve carries impulses from the retina to the brain.
A person walks from a dark room into bright sunlight.
Explain how and why the size of their pupils changes.
Mark scheme
- (light) receptors in the retina detect the bright light (1)
- circular muscles (in the iris) contract (1)
- radial muscles relax (1)
- pupil gets smaller / constricts (1)
- less light enters / prevents damage to the retina (1)
- it is a reflex / automatic (1)
Max 4
Model answer
Receptors in the retina detect the bright light, and in an automatic reflex the circular muscles of the iris contract while the radial muscles relax. This makes the pupil smaller, so less light enters the eye and the retina is protected from damage.
Compare rods and cones in the retina.
Mark scheme
- rods work in dim light / are sensitive to low light intensity (1)
- cones need bright light (1)
- cones detect colour / rods only black and white (1)
- cones are concentrated in the centre (fovea); rods around the edge (1)
Max 3
Model answer
Rods are sensitive to dim light but only see in black and white, and are found around the edge of the retina. Cones need bright light and detect colour; they are concentrated in the centre of the retina.
Describe the job of the suspensory ligaments and the sclera.
Mark scheme
- suspensory ligaments: hold the lens in place / connect the lens to the ciliary muscles (1)
- sclera: protects the eye / tough outer layer (1)
Model answer
The suspensory ligaments hold the lens in place and connect it to the ciliary muscles. The sclera is a tough outer layer that protects the eye.
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