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(^3) TASTE
Small projections on the
tongue, called papillae,
house taste receptors
called taste buds. Food
molecules dissolved in
saliva are detected by
the taste buds. These can
distinguish between five
basic tastes – sour, sweet,
salty, bitter, and umami
(savoury and meaty).
As well as helping us
to enjoy food, our sense
of taste enables us to
detect foods that may
be poisonous.
(^4) TOUCH
The skin acts like a sense organ. It contains several
different types of receptors that enable us to
“feel” our surroundings. Most are touch receptors
that send signals to the brain when the skin
comes into contact with objects. Some detect
light touch, some heavier pressure, and some
vibrations. Other receptors in the skin pick up
temperature changes or detect pain.
(^5) SMELL
The nose can detect more than 10,000 different smells.
When air is breathed into the nose, odour molecules
dissolve in watery mucus and are detected by odour
receptors high in the roof of the nasal cavity. Together,
the senses of smell and taste enable us to detect flavours.
Smell is more important, however, which explains why food
lacks flavour when we have a blocked nose. Some smells,
such as those produced by burning, can warn us of danger.
Fresh flowers
Lemons and most other
citrus fruits taste sour
Feathers feel
soft and ticklish
Cit
ru
s (^) fr
uits
Taste buds
housed in
mushroom-
shaped
papilla
Skin ridges in the
fingertips help us grip
the objects we touch
A cactus spine
puncturing the
skin stimulates a
pain receptor
Some
cheeses
emit a
strong
smell
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