Interaction and coordination in living beings involves stimuli, receptors, coordination systems, and responsive organs. Stimuli are detected changes that provoke responses. Receptors receive stimuli and sense organs like eyes, nose, tongue, and ears function as receptors. Coordination involves the nervous system which receives information and transmits responses, and the endocrine system which regulates functions through hormone release. Responses can be motor movements through muscles and skeletal system or endocrine responses through hormone release from glands.

1. Interaction and coordination

2. What is interaction?
All living beings interact with their environment
and with other living beings to survive.
Interaction enables livings beings to recieve and
respond to a stimulus.
Interaction involves different elements...

3. Interaction is...
Stimuli
Receptors
Coordination systems
Responsive organs (effectors)

4. Stimuli are...
Detectable changes in the internal or external
environment which provoke responses.
They can be:
­ Physical: light, sound, temperature...
­ Chemical: substances like water, oxygen...
­ Biotic: other living beings

5. Receptors are...
Structures which receive stimuli from the external or
internal environment.
In animals, they are called sense organs.

6. How do receptors work ?
Sense Sense organ How do they work?
Sight Eyes They detect light
Smell Nose (vertebrates) They detect chemical substances dissolved in air or
Appendage water
(arthropods)
Taste Tongue It detects chemical substances dissolved in water.
It is covered with tiny taste buds.
Hearing Ears They detect sound.
Touch Skin (vertebrates) They detect pressure, touch, pain and temperature
Appendage changes.
(arthropods)

7. Activities
1.­ Test a classmate on sense organs.
A: Which sense organ detects chemical substances in air?
B: The nose.

8. Activities
2.­ Can you solve these sense organs riddles?
This organ is used by...
… arthropods to smell things.
… fish to detect temperature changes.
… most animals to detect pressure.
… some animals to distinguish sounds.

9. How does coordination work
in animals?
Coordination involves processing information
received from receptors and producing appropriate
responses.
Animals have two coordination systems:
Nervous system
Endocrine system

10. Nervous system
The nervous system receives information, interprets it, and
transmits a response to the responsive organs or effectors.
It includes:
The central nervous system. (CNS)
This consists of the brain and the spinal cord.
It analyses information and decides on a suitable response.
The peripheral nervous system (PNS): carries nerve impulses
from the nerve centres to all other parts of the body.

11. Activities
Indicate which coordination system is working in
each of these situations:
Putting your hand close to a flame and then taking away
quickly.
Maintaining an adequate level of sugar in the blood.
Stopping when a car comes when crossing the street.

12. How do the responsive
organs work?
There are two types of responses to stimuli:
Motor responses: the response is movement
Endocrine responses: response is the release of hormones

13. Motor responses in
vertebrates
Motor responses are controlled by organs in the motor
system, which consists of:
Skeletal system (internal): bones supports the body.
Muscular system: muscles are contractile organs
attached to the bones by tendons.

14. Endocrine responses
They are controlled by glands in the endocrine system.
Glands produce chemical substances called hormones.
Hormones:
Are released into the blood.
Control and coordinate activities throughout the body

15. Endoncrine system
Both vertebrates and invertebrates have endocrine
systems. It regulates functions which require
maintained responses. These include:
Metamorphosis of some animals
Growth
Production of milk in mammals
Metabolism (chemical processes in living things that
change food into energy and materials)

16. The pancreas
The pancreas is a gland
which controls insuline
secretion in order to
regulate glucose levels
in the blood.

17. Activities
Are these statements true or false?
Only vertebrates possess an endocrine system
Hormones are transported in the blood.
The pancreas is part of the motor system.
Responses from the endocrine system are immediate and
rapid.

18. Activities
Are the following responses controlled by the nervous
system or the endocrine system?
A child growing up
A dog chasing a cat
A cow producing milk
Dancing to music
A tadpole changing to a frog

19. Complete the chart:
Nervous system Endocrine system
Transmission by N_______ B______
Means of transmission Nerve impulses Hor______
Speed of response Rapid Sl___
Duration of response Brief Lo___
Regulation and coordination Functions which require Functions which require
of functions r____ responses, such a ma_______ed responses
locomotion such as g____,
dev____ent, metab_____.

20. Glossary
Living being Environment
Receive Respond
Stimuli Receptor
Effector Sight
Smell Taste
Touch Sense organs
Chemical substances Pressure
Nervous system Brain
Spinal cord Motor responses
Skeletal system Glands (produce
hormones)
Growth Mammals
Blood Metabolism

21. Ear

22. Ear

23. Ear

24. Eye

25. Nervous system

26. Nervous system

27. Nervous system

28. Muscular system