This document provides an overview of the five senses and how they work. It discusses the main parts of the brain and their functions in processing sensory information and controlling voluntary and involuntary actions. The three main parts of the locomotor system that allow movement are also outlined. Additionally, the key parts and functions of the eye, ear, nose, tongue, and skin that enable sight, hearing, smell, taste, and touch are summarized. The process of a sense organ receiving a stimulus, sending the information to the brain, and the brain responding is explained.

1. NATURAL SCIENCE UNIT 1
5
SENSES
SIGHT
HEARING
SMELL
TOUCH
TASTE
EYE
SKIN(hands)
TONGUE
NOSE
EAR
STIMULUS
RESPONSE

2. BRAIN PARTS+ FUNCTIONS
The BRAIN has three parts:
CEREBRUM: It controls voluntary actions
(movements).
CEREBELLUM: It controls coordination and
balance.
BRAIN STEM:It controls involuntary actions (for
example the heart beats)

3. STIMULUS - RESPONSE
The BRAIN is the organ which controls everything we do. It is the control centre of
the NERVOUS SYSTEM.
Our sense organs (ear, eye, tongue, etc.) send
information=STIMULUS to our brain thanks to our
nerves.
The brain then sends information back= RESPONSE,
through the nerves, to different parts of the body

4. LOCOMOTOR SYSTEM
The LOCOMOTOR SYSTEM allows us to move. It has three main parts:
BONES: Are hard and rigid, they form our SKELETON.
MUSCLES:Are soft and elastic. They CONTRACT + EXPAND.
JOINTS: Are our bones’ connection to each other.(knee, shoulder, elbow,etc.)
joints

5. MUSCLES CONTRACT + EXPAND
Muscles EXPAND and CONTRACT
Some muscles move VOLUNTARY (I move my arm, because my Cerebrum orders it...)
Some other muscles move INVOLUNTARY (I can’t stop my heart moving...)

6. HEARING- EAR PARTS+FUNCTIONS
Our sense of HEARING allows to distinguish between different sounds

7. SENSE OF SIGHT-EYE PARTS
Our sense of SIGHT allows us to perceive:
SHAPES, DISTANCE, COLOUR, MOVEMENT.
1-EYEBROWS: protect the eyes from sweat.
2-EYELASHES: protect the eyes from sweat and dust.
3-IRIS: It provides color to our eyes.
4-PUPIL:It opens and closes to allow more or less light in.
5-SCLERA: It is white, “flexible” and protects the inner eye.
6-EYELID: a thin fold of skin that covers, protects and
hydrates an eye.

8. SENSE OF SIGHT
1-Light reflects off an object and enters the eye.
2-The light forms an upside-down image in the
RETINA.
3-The information is sent to the brain.
4-The brain reads the signal(STIMULUS) and
tells us what
are we seeing.(RESPONSE)

9. SENSE OF SMELL
Our senses of SMELL+TASTE are connected. These senses help us decide if we like
or we don’t like something…
SMELL
1-Air enters the nose through two holes
called NOSTRILS.
2-The OLFATORY NERVE detects the smell,
sitmulus, and sends the information to the brain
to elaborate a response.

10. SENSE OF TASTE
Our senses of SMELL+TASTE are connected. These senses help us decide if we
like or we don’t like something
TASTE
1-Tiny TASTE BUDS on the tongue
identify different tastes.
SWEET, SALTY, BITTER, SOUR.
2-This information, stimulus, is sent to the
BRAIN via the nerves to process a
response

11. SENSE OF TOUCH
Our body is covered in SKIN and our skin is the organ of TOUCH.
SENSORY NERVES below the skin send the
information, STIMULUS, to the brain when
we touch something to ellaborate
a RESPONSE . (HOT, COLD, WARM,
ROUGH, SOFT, HARD, RIGID, FLEXIBLE…).