This document discusses coordination and response biology. It defines key terms like stimuli, receptors, effectors, and responses. It explains that organisms detect both external stimuli from the environment and internal stimuli within the body. The nervous and endocrine systems allow organisms to coordinate responses. Detection of a stimulus involves receptors sending a signal to an integrating center like the brain, which then triggers an effector like muscles or glands to produce an appropriate response. Negative feedback loops help regulate internal environments to maintain homeostasis. Examples illustrate how temperature, sound, and glucose levels trigger detection and coordinated responses.

1. 3.1COORDINATION
AND
RESPONSE
BIOLOGY
FORM 5

2. Learning outcomes :
1. List the changes in external and
internal environment faced by
organism
2. State why organisms have to be
sensitive to changes in internal and
external environment
3. Clarify through examples the
meaning of stimulus and response

3. Learning outcomes :
4. State the main components and pathways
involved in detecting and responding to
changes in external environment
5. State the main components and pathways
involved in detecting and responding to
changes in internal environment
6. Clarify through examples the meaning of
coordination

4.  The changes which response in the body called STIMULI
STIMULI
External
(outside the body)
Internal
(inside the body)
Light, smell, taste, temperature,
pressure, touch, sound
-Sugar level in the blood
-Osmotic pressure of blood
-Body temperature
-pH of tissue fluid

5. PLANT
RESPONSE
EXTERNAL
CHANGES
TROPISM
RESPONSE
NASTIC/TACTIC
RESPONSE
INTERNAL
CHANGES
OSMOTIC
PRESSURE / PH

6. Human / Animal
 To enable them to
move, feel pain & taste
for safety
 Adapt to environment
(ensure survival)
 To protect them from
harm / danger
 Regulate internal
environment
(homeostasis)
Plant
 Receive more sunlight
for photosynthesis
 Obtain better support
 Obtain enough water

7. NO ITEM DEFINITION
1 Receptors Group of cells that detect stimulus
2 Effector Produce response to stimuli
3 Response Way of an organism react after a stimulus is
detected
4 Coordination Response that appropriate towards the stimuli
Coordination
& Response
Nervous
system
Endocrine
system

8. 1: Receptor
(in sensory
organs)
3:Integrating
Centre
(Brain)
3: Effector
(muscles/glands)
causes
5: ResponseStimulus
Detected
by
Appropriate to

9. 1: RECEPTOR (in sensory organs)
detects the stimulus & triggers a nerve
impulse (NI) to be produced in
afferent neurone (AF)
2: AF carries the NI to the INTEGRATING
CENTRE ( in the brain)
3: Brain interprets the information &
send out another NI
4: Efferent neurone (EN) carries the NI
from brain to the EFFECTOR
(muscles/glands)
5: that reacts to RESPONSE to the
STIMULUS

10. Pathways Of Information Due To External Stimuli
Stimulus
(Sound of car horn)
Receptor in the ear
Integrating centre
(Brain)
Response
(Move away from the
incoming car)
Effector
(Muscles in leg)

11.  To regulate the internal environment so that it is at an
optimum condition.
 Homeostasis–regulation of the internal environmentso that
equilibrium is maintained.
 Involves negative feedback
 When a factor in the internal environment increase above
normal range, negative feedback will occur to lower it.

12. 1: Receptor
(in internal
organs)
3:Integrating
Centre
(Brain)
3: Effector
(muscles/glands)
causes
5: ResponseStimulus
Detected
by
Appropriate to

13. Stimulus
(High body temperature)
Temperature sensitive
cells in the
hypothalamus
Thermoregulatory centre
at hypothalamus
(Brain)
Response
(Increase heat loss)
Effectors
(Skin and endocrine
glands)

14. MECHANO
RECEPTOR
(in the ear)
INTEGRATING CENTRE
(BRAIN)
EFFECTOR
(Muscle in leg)
RESPONSE
(open the door)STIMULUS
Detected
by
Appropriate to
causes

15. Integrating centre
(Brain)
Receptors
(in hypothalamus)
Effector
(pancreatic glands)
Response
(activities to decrease
high glucose level)
Stimulus
(high glucose level
in the blood)
Normal glucose level
in the blood
A change in blood sugar
level is detected
By negative
feed back
Glucose level
is lowered

16.  Is a process involved in the detection of stimulus & the
subsequent response of the organism towards stimulus
 It involves both the nervous system & endocrine system