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(^4) FINGERNAIL
Ideal for gripping objects and
scratching itches, fingernails are clear
plates that protect the sensitive
upper parts of the fingertips.
The cells that make nails
die, flatten, and fill
with keratin as
they are pushed
forward from
the nail’s root.
(^5) HAIR
Millions of hairs grow from the skin
covering most body areas. Scalp hairs
protect the skin from sunlight and
reduce heat loss. Finer, shorter body
hairs sense the presence of insects on
the skin before they can sting or bite us.
(^6) TOUCH RECEPTORS
The dermis contains a range of
receptors that respond to soft touch,
firmer pressure, and vibrations, and
send signals to the brain so we can
feel our surroundings. The dermis
also has receptors that detect pain,
heat, and cold.
Skin covering
the fingertips is
sensitive because
it contains many
touch receptors
4
5
6
Hair follicle is
a hollow space
in the skin
from which
a hair grows
Sebaceous gland
secretes oily sebum
that keeps hair and
skin flexible and soft
Hair bulb, deep
in the dermis,
contains living,
dividing hair cells
Hair shaft is
made of dead cells
packed with
keratin, pushed up
from the hair bulb
Fingernail is formed from
layers of dead, flattened
cells from the epidermis
074_075_Skin.indd 75 03/01/19 12:09 PM