Page 46 - Biology_Form_3

Biology for Secondary Schools

Observation
(a) What did you observe to the volunteer?

(b) Write the observation of your experiment.

FOR ONLINE READING ONLY
Question
Explain the stimulus feelings before/after withdrawing the hand.

Conclusion
(a) Provide a conclusion for your experiment.
(b) Write a short report of the experiment.

body which have the ability of detecting the
Exercise 2.3
stimulus are known as sensory receptors.
1. Differentiate between the following:-
Sense organs are specialised organs
(a) Autonomic and somatic nervous composed of sensory receptors responsible
system
for receiving and responding to stimuli
(b) Simple and conditioned reflex action around us. These stimuli include touch,

2. Describe the neural pathway of the cold, heat, pressure, light, odor, taste and
reflex action. sound. In mammals, there are five major
sense organs namely; ear, eye, nose, tongue,
3. Explain the importance of simple and skin. Each sensory receptor responds
reflex actions in human body.
to only one specific stimulus. For example;
4. What types of neurones are involved the sense organ sensitive for smell will not
in a simple reflex arc? detect the stimulus of heat.

Sense organs Activity 2.5:
The body of a living organism gathers
information about its external and internal Observing sense organs in human
environment through sensory receptors or body
receptor cells. Receptors are the cells or Materials
nerve endings or groups of nerve endings Flat mirror
specialised for reception of stimuli and Procedure
change the stimuli into specific nerve 1. Hold the mirror in front of your face
impulse. The coordinated activity of an with one hand.
organism relies upon a continuous input 2. Look at the mirror while your
of information from internal and external
environments. The specialised cells of the mouth is open.

39 Student’s Book - Form Three

23/10/2025 11:52:35
BIOLOGY FORM 3 FINAL EDITED 16.09.2025.indd 39
BIOLOGY FORM 3 FINAL EDITED 16.09.2025.indd 39 KAMISHNA 23/10/2025 11:52:35 KAMISHNA