CHAPTER 1: The world through Our Senses

1.1 The Sensory Organs And Their Function

1. List our five senses.

2. State the types of senses, the sensory organs and the type of stimulus associated with the activities given.

Activity Sense Sensory organ Stimulus(a) Eating

burger(b) Watching

television(c) Listening to

radio(d) Touching

hot kettle(e) Smelling a

rose flower

1.2 Sense of Touch

3. By using the words given, complete the flow chart below to show the pathway from stimulus to response.

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Sense

Stimulus Response

Nerve Receptor Brain Effectors

4. Label the following diagram with the words given.

1.3 Sense of Smell5. Identify and label the following diagram with the words given.

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Heat receptors Pain receptors Dermis Cold receptors

Epidermis Pressure receptors Fatty layer Touch receptors

Nerve Brain Nasal cavity Sensory cell Nostril

Structure of the nose

6. Answer the following questions.(a) Where are the smell sensory cells located in the nose?

____________________________________________________________________________(b) Why the sensory cells are always covered with a mucous lining?

To enable the _____________ in the air to dissolve in it and stimulate the ________________(c) Why is our nose not able to function well when we have flu?

The passage in our nose is blocked due to __________________________________________

1.4 Sense of Taste7. Complete the flow map below to show the detection of taste at the tongue.

8. Answer the following questions.(a) Where is the taste receptors located on the tongue?

_____________________________________________________________________________(b) What is the role of saliva when we taste food?

Saliva enables ____________ in food to dissolve in it before the taste buds can detect the taste.(c) The taste buds on the tongue are sensitive to ________________________________________(d) The sense of taste is affected by____________________. When the sense of smell is not

functioning, our tongue cannot ______________ properly.(e) When a person has running hose, he finds his food tastes _____________. This is because his

sense of ______________ is not functioning.

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The brain __________ the taste

The _________ send the impulses to the brain

The taste receptors produces ____________

Stimulate the taste ___________

Dissolves in the __________

_____________in food

1.5 Sense of Hearing9. Label the parts of the human ear shown below.

10. By referring to the pathway of sound waves, fill in the blanks to explain the mechanism of hearing.(a) When a sound reaches the ear, the ear pinna ____________ the sound wave and

____________ it into the auditory canal.(b) The auditory canal ____________ the sound waves to the eardrum.(c) When the sound waves hit the eardrum, it ______________ at the same frequency of the sound

wave.(d) When the eardrum vibrates, the _______________ which are right next to it will also vibrate

and _____________ the vibration.(e) The oval window then ____________ the vibration from the ossicle bones to the cochlea.(f) The cochlea is filled with liquid which will change the vibration into ______________(g) The impulses are _____________ to the brain through the auditory nerve.(h) The brain ______________ the impulses and thus follow the hearer to understand and discern

the sound.

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Oval window Ossicles Eardrum

Auditory nerves Ear pinna Ear canal

Semicircular canal Cochlea Eustachian tube

1.6 Sense of sight11. Identify the parts and label the following diagram with the words given.

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Yellow spot Choroid Sclera Optic nerve Blind spot

Aqueous humour Cornea Retina Ciliary body Iris

Vitreous humour Pupil Eye lens Suspensory ligament

12. Match the following parts of the eye with their functions.

1.7 Light and Sight13. Tick (/) for the correct descriptions of vision defect.

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Part of the eye

a. Iris

e. Yellow spot

d. Retina

c. Vitreous humour

b. Eye lens

f. Optic nerve

Function

Send nerve impulse to the brain interpretation

Detect light or any image that falls on it

Controls the size of pupil

Detects light and generate nerve impulses

Focuses light onto the retina

Maintains the shape of the eyeball and helps to focus light

• Able to see close objects clearly

• Unable to see far objects clearly

14. Write True or False for the following statements of long-sightedness.

i. Experienced by old people because their eye lens become less elasticii. Cannot see near objects clearly

iii. Corrected by using convex lensiv. Image formed in front of retinav. Able to see far objects clearly

vi. The eyeball is too short or the lens is too thickvii. Caused by unevenly curved cornea

1.8 Sound and Hearing15. Write true for the correct statements and false for the incorrect statements.

i. Exposure to loud sounds for a long duration of time will cause hearing defects

ii. We cannot hear sound with a frequencies higher than 20 Hz

iii. Surgery can be done to repair a torn eardrum

iv. If the ossicles fuse together, a person will become deaf

v. A hearing aid is used to determine the direction of sound

vi. Earphones are used to make the sound louder

vii. The statoscope amplifies the heartbeatviii. Sound is absorbed when it hits hard

surfaces

16. Answer all the following questions to show the connection of stereoscopic vision and monocular vision with the survival of animals.

(a) State the type of vision animals X and Y have.X : ___________________________ Y : ____________________________

(b) State the animal that has a wider field of vision_______________________________________

(c) State one advantage of the type of vision possessed by animals X and Y.X : __________________________________________________________________________

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Y : __________________________________________________________________________(d) Draw the field of monocular vision and stereoscopic vision.

1.9 The Stimuli and Response in Plants17. Match the following diagrams with the correct types of response

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Diagram Type of response

Phototropism

Thigmotropism

Nastic movements

Hydrotropism

Geotropism

18. Diagram below shows an apparatus set up to study the response of plants to certain stimuli.

(a) Which part of the plant will grow towardsi. the moist cotton?

_______________________________________ii. the hole?

_______________________________________

(b) State one type of response in plant that is not observed in the diagram.__________________________________________________________

(c) What is the function of the silica gel?___________________________________________

(d) What is the function of the black box?_____________________________________ _______

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