Biology (9-1) - 0970 CIE

Sense Organs

Gbogbo ọrọ náà

Your eyes are remarkable light detectors. They bend incoming light, focus it onto a screen of light-sensitive cells, and adjust automatically to bright sunshine or a dim room, all without you noticing. The eye is the best-known example of a sense organ.

In this lesson you will learn what a sense organ is, name the parts of the eye and their jobs, and explain the pupil reflex. For the extended curriculum you will also master accommodation (how the lens changes shape to focus) and the roles of rods and cones in the retina.

Ebumnobi

Describe sense organs as groups of receptor cells responding to specific stimuli: light, sound, touch, temperature and chemicals
Identify in diagrams and images the structures of the eye, limited to: cornea, iris, pupil, lens, retina, optic nerve and blind spot
Describe the function of each part of the eye, limited to: (a) cornea - refracts light (b) iris - controls how much light enters the pupil (c) lens - focuses light on to the retina (d) retina - contains light receptors, some sensitive to light of different colours (e) optic nerve - carries impulses to the brain
Explain the pupil reflex, limited to changes in light intensity and pupil diameter
[Supplement] Explain the pupil reflex in terms of the antagonistic action of circular and radial muscles in the iris
[Supplement] Explain accommodation to view near and distant objects in terms of the contraction and relaxation of the ciliary muscles, tension in the suspensory ligaments, shape of the lens and refraction of light
[Supplement] Describe the distribution of rods and cones in the retina of a human
[Supplement] Outline the function of rods and cones, limited to: (a) greater sensitivity of rods for night vision (b) three different kinds of cones, absorbing light of different colours, for colour vision
[Supplement] Identify in diagrams and images the position of the fovea and state its function

Akọmọ Ojú-ẹkọ

Sense organs let an organism detect changes in its surroundings so the nervous system can coordinate a response. The eye shows beautifully how structure fits function, and examiners regularly ask you to label it, explain the pupil reflex, and (at Extended) describe accommodation.

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Ayẹwo Ẹkọ

Ekele diri gi maka imecha ihe karịrị na Sense Organs. Ugbu a na ị na-enyochakwa isi echiche na echiche ndị dị mkpa, ọ bụ oge iji nwalee ihe ị ma. Ngwa a na-enye ụdị ajụjụ ọmụmụ dị iche iche emebere iji kwado nghọta gị wee nyere gị aka ịmata otú ị ghọtara ihe ndị a kụziri.

Ị ga-ahụ ngwakọta nke ụdị ajụjụ dị iche iche, gụnyere ajụjụ chọrọ ịhọrọ otu n’ime ọtụtụ azịza, ajụjụ chọrọ mkpirisi azịza, na ajụjụ ede ede. A na-arụpụta ajụjụ ọ bụla nke ọma iji nwalee akụkụ dị iche iche nke ihe ọmụma gị na nkà nke ịtụgharị uche.

Jiri akụkụ a nke nyocha ka ohere iji kụziere ihe ị matara banyere isiokwu ahụ ma chọpụta ebe ọ bụla ị nwere ike ịchọ ọmụmụ ihe ọzọ. Ekwela ka nsogbu ọ bụla ị na-eche ihu mee ka ị daa mba; kama, lee ha anya dị ka ohere maka ịzụlite onwe gị na imeziwanye.

Which part of the eye refracts light as it enters? A. retina B. cornea C. optic nerve D. blind spot Answer: B
The part of the eye that controls how much light enters the pupil is the: A. lens B. retina C. iris D. cornea Answer: C
In bright light the pupil: A. gets larger B. gets smaller C. stays the same D. disappears Answer: B
To focus on a near object the lens becomes: A. thinner B. fatter C. flatter D. it does not change Answer: B
Cones in the retina are mainly responsible for: A. night vision B. colour vision C. detecting sound D. controlling the pupil Answer: B