Download Skin Explorers

Exploring the body’s biggest organ
• An organ is a portion of the body that has
special functions to perform for the entire body.
• When you think of an organ you may think of the
heart, brain, or liver but the skin is also an organ
and in fact is the largest organ.
• The skin is connected to the rest of the body and
it functions and communicates through nerves
and three kinds of vessels, arteries, veins and
lymphatics.
What the skin does
• Protection
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Against larger organisms - Lice, worms
Against smaller organisms - bacteria, viruses
Against powers and fluids - dirt, water, chemicals
Ultraviolet light
Controls body temperature
Makes Vitamin D for the body
Heals itself
Lasts for your entire life but changes with age
– Acne, wrinkles, hair changes
Organisms that affect the skin
come in different sizes• Look in the louse box-and pick some
lice (don’t worry not real – just celery
seeds) and put on your skin. Use the
surface microscope and compare the
size of the “louse” with that of a hair.
On the scalp lice lay eggs on hairs.
These are the small grey nits that
infected people may have.
• The fake lice on your skin are
approximately the same as a real
louse that can be spread from person
to person and causes infections and
severe itching.
• A bacterium is about 1/1000 the size
of the louse and a large virus is
about 1/10,000 the size of the louse.
Find sweat glands on the palms
• Where on the palm can you see sweat glands
must easily?
• Their opening is seen along the ridges that
form the fingerprints• Use higher power-to see small glistening
drops of sweat.
• How regular is the distance between sweat
glands on the skin ridges?
• Do you see openings in the depressed
portions between the ridges?
• Try to see sweat glands on other parts of the
body.
• What are the functions that the ridges might
have-think about the ridged soles on some
sports shoes?
• Sweat contains amino acids, the building
blocks of proteins, and can be stained with
special chemicals - this is used by crime
scene intelligence agents.
Skin is essential for controlling the
body’s temperature
• Sweat glands, blood vessels and nerves for a system to
control temperature.
• Sweat glands deliver a watery fluid (‘sweat’) with small
amounts of salt and amino acids to the skin surface.
• The heat brought to the skin by large and small blood
vessel evaporates the sweat on the skin surface and
lowers the body temperature.
• If sweat glands are lacking because of genetic diseases
children get very hot and sick during a fever or exercise.
Certain drugs can block sweating. Some drugs leave the
body in the sweat.
• Botox, a drug to decrease skin wrinkling is sometimes
used when people have excess sweating on their hands,
feet, or armpits.
Body Temperature
• Sweats glands are over
entire body except for
special locations like the
lips.
• Sweat is formed in a
coiled portion of the
gland in the fatty layer
from the glands that are
close to small blood
vessels.
• Nerves near the blood •Sweat glands lie deep in the skin in the
vessels control blood
fatty layer-the subcutaneous layer, each
flow and also release gland has a duct that carries the sweat
across the dermis of the skin and the duct
small chemicals that
crosses the epidermis to exit on the skin
control sweating.
surface.
Figure from: http://www.nature.com/milestones/skinbio/subjects/index.html
Sunlight• Sunlight and the skin have important
relationships– The skin is the only part of the body that uses sunlight
to make Vitamin D from a cholesterol-like chemical
– Too much sunlight, or suntan beds, causes redness
and pain in the skin, scaling, darkening of the skin
color, wrinkling, aging and skin cancer.
• The epidermis blocks the most dangerous
shorter UV rays but longer UV enters the dermis
(Layer II) and damaged the molecules collagen
and elastin that form the bulk of the dermis and
give skin its characteristic feel. These molecules
require special electron microscopes to be seen.
Sunlight
• Look at the skin the with scope on the outside
and inside portions of the upper arm.
– Which side is darker?
– What might the reasons be?
• Look at some freckles and see if someone has a
mole.
– What do you see in the mole?
– Different structures such as globules and a netlike
pattern are often seen.
Hair
• Hair follicles are over the entire skin except for special
locations like the lips and the palms and soles.
• People used to think that hair on the palms was the skin
of a werewolf.
• Look at the hair under high magnification and look for an
overlapping patterns of cells on the outside cuticle layer
of the hair.
• The hair is dead - what will happen if the hair is exposed
to too damage or chemicals.
• Look at the very fine hairs that are on the face. Acne
starts when these hair follicles get blocked.
• Hair follicles, if completely lost can not regrow, See if
someone in your group has a scar and what that skin
looks like.
Conclusion
• Skin is the largest organ and serves many
functions
• You should now have a better
understanding of how the skin protects us
from bugs, the location and function of
sweat glands, sun damage spots, and hair.