0:00
Hello, my
name is Glynis Scott.
I'm a professor of
dermatology and pathology
at the University of Rochester.
This talk will be on
pigmentation of skin
and will focus primarily on
pigmentation of human skin.
0:16
In this talk I'm going
to cover five main areas.
I'm first going to discuss
melanin, its basic molecular nature
and its secondary structure.
I'm then going to
discuss tyrosinase, which
is the enzyme that catalyzes the
rate-limiting step in melanin
synthesis and discuss, in some
detail, how tyrosinase is regulated.
In the third part of the talk, I'm
going to discuss melanocytes, which
are the cells that produce melanin.
And I'm going to go over
melanosomes, which are subcellular
organelles within melanocytes
in which melanin is synthesized.
In the fourth part of the talk,
I'm going to discuss the process
of tanning, which is
the response of the skin
to ultraviolet irradiation.
And finally, in the
last part of the talk,
I'm going to discuss the
evolutionary pressures that have
led to the distinctive
patterns of skin pigmentation
across the globe.
1:12
Before we get started,
I wanted to do
a brief review of the
architecture of the skin.
The skin has three main
layers, the epidermis,
the dermis, and the subcutis.
And the pigmentation of the
skin is almost exclusively
performed by the most
superficial layer of skin, which
is the epidermis, which
is the topmost layer.
The epidermis is composed of,
predominantly, keratinocytes, which
are the majority component, and
a minority component of cells,
called the melanocytes, which
are the pigment-producing cells.
The pigmentation of the skin--
one of its main functions
is to protect not only
keratinoctyes from phototoxic damage
and carcinogenic damage, but to
protect the underlying dermis,
which is directly
beneath the epidermis.
And then the other underlying
structures of the skin
are really not much affected
by ultraviolet irradiation
because they are too deep.
