1. The diagram below illustrates a sensory organ in humans.

Study it carefully and use it to answer questions 4(a), (b), (c) and (d).

1. (i)          Identify the sensory organ illustrated in the diagram.                            [1 mark]

1. Name the parts labeled I, II, III, IV, V, Vi, VII and

     VIII.                                                                                             [4 marks]

1.   Mention two defects of the sensory organ illustrated in the diagram.  [2 marks]

                 (c)   State four ways of caring for the organ in the diagram.                        [4 marks]

                 (d)  List two diseases that could affect the structure illustrated

This question was attempted by many candidates and their performance was good.  In part (a)(i) candidates correctly identified the sensory organ illustrated in the diagram, in (a)(ii) candidates could not name the parts labelled I, II, III, IV, V, VI, VII and VIII.
In part (b), candidates could not correctly mention defects of the sensory organ illustrated in the diagram. 
In part (c), candidates correctly stated ways of caring for the illustrated organ in the diagram.
In part (d), candidates also correctly listed diseases that could affect the structure illustrated in the diagram.

The expected answers are as follows:

4 (a)(i)    IDENTIFICATION OF SENSORY ORGAN ILLUSTRATED IN THE
               DIAGRAM

•   human eye

                       (ii)     PARTS LABELLED
                           I        -        suspensory ligament
                          II       -        lens
                          III      -        pupil
                          IV      -        aqueous humour/fluid
                          V       -        iris
                         VI       -       vitreous humour/fluid
                         VII     -        optic nerve
                         VIII    -        retina
                               

(b) DEFECTS OF THE SENSORY ORGAN ILLUSTRATED IN THE    
DIAGRAM

                        -           far/long sightedness/hypermetropia
                        -           near/short sightedness/myopia
-           astigmatism
-           presbyopia
-           squint/cross-eye
-           glaucoma
-           cataract

    (c)    CARING FOR THE ILLUSTRATED ORGAN            
                        -         avoid using other people’s towel
                        -         wash the sensory organ with clean water
                        -         use protective glasses when working with inflammable/explosive or with
                                   acid/dangerous objects                  
                         -         avoid rubbing eyes with hand
                         -         read with good light/avoid too bright/too dim light
                         -         avoid reading in a moving vehicle
                         -         avoid reading while lying down
                         -         computer monitors/books should not be placed too close or too far to the
                                   eye
                         -         regular visit to optician
                         -         avoid eye irritants
                         -         take food rich in Vitamin A, B, C, E and K
                                    
 (d)      DISEASES THAT COULD AFFECT THE ILLUSTRATED ORGAN   
                          -        trachoma.
                          -         conjunctivitis/pink eye
                          -         river blindness/onchocerciasis
                          -         stye