Download collagen and elastin - The Global Beauty Group

Welcome to Skin Physiology 101
Class Overview-SAL
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Skin Facts
Layers of the skin
Functions of the layers
Functions of the skin
SKIN FACTS
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The skin is the body’s largest
organ, it weighs (+ or –)7 lbs.
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It is the most sensitive organ of
the human body.
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Flattened, it would be the
approximately the size of a twin
bed sheet.
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In a square inch, it has 15 ft of
blood vessels, 12 ft of nerves,
650 sweat glands
(sudoriferous), and 100 sebum
(sebaceous) glands. It has 65
hairs, and 1300 nerve endings.
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The conventional body system
term for the skin is the
Integumentary System, which
includes the hair and nails as
well.
Other astonishing skin facts…
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The skin is approximately 15 percent of our body weight.
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The skin contains more than ½ to 2/3 of all of the blood in the body; and ½ of the
primarily immune cells.
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The study of the structure and composition of the tissue is called Histology.
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The study of the functions of the body is called Physiology.
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The skin is the thickest on the palms of the hands and the soles of the feet; and
the thinnest on the eyelids.
Main Idea
Knowledge of the structure, functions and conditions of the skin, are
essentials for understanding how to optimally serve our clients at every level.
Key Terms
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Integumentary System- (medical term for the type of body system for skin, hair and nails)
Histology-(study of structure and function of the tissue)
Physiology- (study of the functions of the body)
The skin has three layers…
(some schools of thought will say 2 layers)
1.
Epidermis-upper/outer most layer with 5 layers of its own. The epidermis is
made of tissue known as epithelium. Ninety-five percent of the epidermis is
made up of dead skin cells, which are continually being shed (average life
cycle 28 days…until we are older, then it could be as many as 42 + -)
2.
Dermis-middle layer where the skin’s factory is located. It is the live-layer of
which is 25 x’s thicker than the epidermis. This layer contains: 2 layers which
are known as the papillary and reticular layers respectively; and blood,
lymph; oil (sebaceous) and sweat (sudoriferous) glands, hair follicles,nerves
and the arrector pili muscles (those that create goose bumps) are all
located, here.
3.
Subcutaneous tissue (Hypodermis)-the deepest layer, which is mostly a
fatty cushion which protects the muscles and bones.
5 Layers of the Epidermis
1.
Stratum Corneum- also called the “horny layer” is the outer most layer
because of keratinocytes which resemble scales on the surface of the
skin have become hardened. Keratin is a protein which provides a
protective layer.
2.
Stratum Lucidum- is a transparent layer found throughout the body, but
is the thickest on the soles of the feet and palms of hands.
3.
Stratum Granulosum-is a layer of granular-looking cells which are dying
and on their way up to replace the existing stratum corneum. Large
quantities of keratin/protein is created in this layer as protection to the
lower layers of the skin.
Layers of the Epidermis Continued
4.
Stratum Spinosum- the “spiny” layer because of the intercellular
connections which are called desmosomes (dez-‘me-sōm)
that appears as these “spines” which provide support between the cells.
There are 8-10 cell layers in the Stratum Spinosum. The Langerhans
cells are located in this layer, they assist the lymphocytes in protecting
the body from infection. They act like the immune system’s radar alert to
the T-Cells (immune cells) that the body is being invaded/attacked.
5.
Stratum Germinativum- (jur-mih-nah-TIV-um)- is also called the basal
layer is the lowest layer of cells that make up the living stratum. Cell
division known as mitosis occurs in this layer, and it is where we find our
melanocytes which create the melanin in our skin.
The Dermis
• The dermis has two layers, the papillary and the
reticular.
• The Dermis is often referred to as the “true skin”
• Collagen, a protein gives the skin its strength, makes
up 70% of the dermis.
• Elastin is a fibrous protein, is also found in the dermis
and contributes to the skin’s stretch and elasticity.
Main Idea
Each layer of the skin has a distinctly different purpose and function.
Key Terms
•Collagen-(gives the skin strength)
•Elastin-(gives the skin it’s elasticity and it’s ability to stretch)
•Melanocytes-(are the skin’s pigment factories, and create color)
Skin Functions
The primary functions of the skin are:
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Protection-The skin is a protective barrier to outside elements and
microorganisms.
Sensation-Sensory nerve endings in the papillary layer in the dermis,
sense touch, pain, cold, heat and pain.
Heat regulation-(aka-Thermoregulation) With the body’s average
temperature at 98.6, skin will adjust itself to warm or cool the body.
Hair follicles and sweat glands dissipate heat to keep us from overheating. We cool by evaporation through the sweat glands, and by
blood vessel dilation, conversely our blood vessels constrict when we
are cold, thus decreasing the blood flow.
Excretion-Sweat glands (sudoriferous) excrete perspiration and
detoxify the body of excess salt and unwanted chemicals.
Secretion-Oil (sebum) protects the surface of the skin, and lubricates
skin and hair. Oil (sebum) is created to soften skin, slowing down H2O
evaporation, thus keeping more water in the cells.
Absorption-Water, O2, ingredients/chemicals and RX’s can all
penetrate the skin, for better or worse.
Review Assessment
1.
What is the medical term for
the skin?
2.
The skin has how many layers?
3.
How many layers are in the
epidermis…and what are they?
4.
How many layers to the dermis?
5.
Which layer is primarily made up of
fat?
Specific Functions of the Epidermis
The main function of the epidermis is to
act as a selective and protective
barrier. The term barrier function is a
key component to the health of the
skin.
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The epidermis functions as a
physical barrier to light and heat
waves, microorganisms (bacteria,
fungi, protozoa and viruses) and
most chemicals.
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The stratum germinativum is the
most important layer of the
epidermis be cause it is the only
layer in the epidermis that is capable
of renewing itself through mitosis,
as long as the skin as long as it
remains in tact.
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The stratum germinativum also
houses the melanocytes, which are
responsible for creating our pigment
called melanin. Melanin is our
primary source of protecting the
body from UV rays.
Specific Functions of the Dermis
The dermis serves as the skin’s “factory”,
supplying all necessary functions, energy
and nutrients for it’s survival. Within it’s two
layers (papillary and reticular) it is composed
of:
•Blood and it’s vessels
• transports O2 from the lungs to all of the
body’s cells for cell respiration and
metabolism which also feeds the skin
• move carbon dioxide and waste products to
the sweat glands for elimination/secretion
• regulates pH and body temperature
• protects from toxins and microbes by
sending out “combat-unit cells, known as
leukocytes.
Note: The dermal-epidermal
junction (DEJ) functions to serve
as the link between the dermis
and epidermis. The cells of the
epidermis receive their nutrients
from the blood vessels in the
dermis.
Specific Functions of the Dermis
sweat (sudoriferous) glands
• regulates body temperature (as sweat
evaporates off of the skin it cools the body)
• eccrine glands (major sweat glands) are
most prolific in the palm of the hand and
soles of the feet
•sweat glands also transport waste such as
uric acid (can cause gout and kidney stones)
and urea (spent protein) out of the body
Oil (sebaceous) glands
• lubricates epidermis and hair with
oil/sebum
•contains antibacterial and anti fungal
properties
•controlled by endocrine (hormone) system,
at ↑ during puberty and pregnancy, ↓ with
age.
Sweat and Oil Glands
(sudoriferous and sebaceous)
Specific Functions of the Dermis
Nerves
•serve as body’s communication in perception,
interaction, and is in constant contact with the
brain and the environment
•over 1 million sensory bodies on the skin, detecting
touch, heat, pain, pressure, and many other functions
•Meissner’s “touch” corpuscles on the dermalepidermal junction (border)
Hair and hair follicles
•hair follicle (pilosebaceous follicle) acts as
Touch receptor (nerve endings wrapped at base)
•helps the body to retain heat and fluids
•protects the body from invaders (i.e. insects, dust)
•lessons friction between some body parts (axillary's,
groin)
•insulates against cold by conserving body heat
•aids in wound healing (Early Responders: Hair Follicle Stem
Cells Contribute to Wound Healing, According to New Penn Study )
Specific Functions of the Dermis
Collagen and elastin
•collagen gives the skin strength and
support
•lack of collagen and elastin is a major factor
in the development of wrinkles
•collagen and elastin is created by
specialized cells called fibroblasts which
supply’s the cells of the dermis for both
extracellular and intercellular matrix
(composed of tissue fluid, collagen,
hyaluronic acid)
•mesh-work structure of connective tissue
provides uniform elasticity to the skin
•essential in wound repair and healing
Specific Functions of the Subcutaneous
Layer
(AKA Hypodermis)
•as skin’s innermost and thickest layer, the “subcu” acts as a heat insulator as it constantly
accumulates and stores fat.
•fat cells are known as adipocytes, and can be
reused and “re-gifted”
•“sub-cu” acts as an energy reserve and when we
hear the term “burning calories, we are really
burning fat cells
•fat cells are grouped together in “clumps” and are
separated by connective tissue (collagen and
elastin)
Review/Assessment
1. _________ __________ is the term
for the key component to the health
of the skin
2. Which of the three layers of the skin
functions as a physical barrier to
light, heat, microorganisms?
3. The _________ _________ is capable
of renewing itself through mitosis.
4. What is the term for the area that
serves a link between the epidermis
and dermis?
5. What does the sudoriferous gland
produce?
Breakout Session: Let’s talk tissue…
There are 4 Primary Types of Tissue
Connective Tissue
Allows movement and provides
support
Muscle Tissue
Can shorten and thicken or
contract
Epithelial Tissue
Absorbs and Protects
Nervous Tissue
Transmits impulses
Connective Tissue
Connective tissue is the most abundant tissue in the body.
Loose connective tissue supports other tissues and organs and
surrounds blood vessels and nerves
Three types of loose connective tissue:
Connective Cell Tissues
Connective tissues include bone, cartilage, fat,
•adipose (add-i-pohz)- loaded with fat cells-these cells are so
full of fat that can easily protect organs, muscles, nerves and
blood vessels
•areola (arh-e–oh-la)-easily stretched-contains fibroblasts(ability to form fibrils collagen and elastin), are irregular in shape,
and additionally help in tissue repair
•reticular (reh-TIK-you-lar)-it’s fibers form framework of the liver,
bone marrow and lymph (oid) organs such as spleen and lymph nodes
•Cells are scattered in an extracellular
matrix composed of cells (collagen and/or elastin fibers)
and are secreted by fibroblasts in a polysaccharide (group of polymers
from sugar molecules-of the carbohydrate family-aka glycans)
ground substance.
ligaments, and tendons.
↓
Extracellular Matrix
It serves to:
A complex network of structural proteins
(collagen and elastin) and specialized
proteins (fibrillin and fibronectin),
interwoven in hydrated polysaccharide
ground substance (including
glycosaminoglycans (GAG’s)
such as hyaluronic acid).
•provides a meshwork for cells to migrate on and
interact with one another
•form the "glue" between cells in connective
tissues and hold cells and tissues together
•influences cell development, migration,
proliferation, shape and metabolic functions.
Includes the interstitial matrix and the basement
membrane
•interstitial matrix- is present between
various cells, it contains gels of
polysaccharides and fibrous proteins to act
as a stress buffer for the ECM
•basement membrane-The basement
membrane is a structure that supports
overlying epithelial cells
Collagen and Elastin
The collagen fibres account for 70 % of the proteins
in the dermis and make it resistant to tension and
traction, while
elastine fibres supply its elastic properties
The reticular dermis makes up the greater part of the dermis. Here elastin
and collagen fibres run in
all directions whereas in the papillary dermis
the elastin fibres are mainly perpendicular to the surface of the skin.
Collagen and elastin fibers in Scanning electron microscopy
may be used for education purposes for presentation and for not-for-publication student papers!
Collagen and elastin are abundant fibrous proteins. (A) Collagen is a triple helix formed by three extended protein chains that
wrap around one another. Many rodlike collagen molecules are cross-linked together in the extracellular space to form collagen
fibrils (top) that have the tensile strength of steel. The striping on the collagen fibril is caused by the regular repeating arrangement
of the collagen molecules within the fibril. (B) Elastin polypeptide chains are cross-linked together to form rubberlike, elastic fibers.
Each elastin molecule uncoils into a more extended conformation when the fiber is stretched and will recoil spontaneously as soon as the
stretching force is relaxed.
-TaskLearning Opportunity
Write (essay), build (diagram) or
create a model that demonstrates
one of the following (could sing, act or write a
poem) :
•The 3 layers of the skin
•The primary functions of the skin
•The essential elements of the
connective tissue
REVIEW
1. Which tissue is the most abundant tissue
in the body?
2._________ _________ is so loaded
with fat cells-these cells are so full of fat
that can easily protect organs, muscles,
nerves and blood vessels.
Tissue
3. A complex network of structural proteins (collagen
and elastin) and specialized proteins (fibrillin and fibronectin), interwoven
in a ground substance ,such as hyaluronic acid is called the
___________ _________.
4. Which type of fiber gives the skin is stretch and elasticity?
The role of collagen and elastin in aging
Atrophy of the dermis
is largely due to loss
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There are two distinct types of
aging: intrinsic and extrinsic
aging which effect collagen and
elastin loss.
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Intrinsic aging factors are
determined by heredity and
genetics (fine wrinkling, loss of
fat).
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Extrinsic aging is determined by
external and environmental
factors such as sun exposure
and lifestyle (smoking, drinking
etc.). Scientist have determined
that 85% of all aging is
extrinsic.
of collagen, degeneration
in the elastic fiber
network, and
loss of hydration.
Fitzpatrick Skin Types
Factors affecting
intrinsic skin aging
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early expression lines-repetitive
movements
loss of elasticity (elastosis)
color (**Fitzpatrick Skin Types)
oil production
lack of oil (alipidic and or
dehydrated
illness or other bio chemical
changes
gravity-time on earth!
Skin Type
Skin Color
Characteristics
I
White; very fair;
red or blond
hair; blue eyes;
freckles
Always burns,
never tans
II
White; fair; red
or blond hair;
blue, hazel, or
green eyes
Usually burns,
tans with
difficulty
III
Cream white;
fair with any
eye or hair
color; very
common
Sometimes mild
burn, gradually
tans
IV
Brown; typical
Mediterranean
caucasian skin
Rarely burns,
tans with ease
V
Dark Brown;
mid-eastern
skin types
very rarely
burns, tans very
easily
VI
Black
Never burns,
tans very easily
INTRINSIC AGEING
Factors affecting extrinsic aging
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bad health habits (i.e. poor
nutrition, smoking, drinking)
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lack of proper skin care -impaired
barrier function due to lack of
hydration, proper protection
antioxidants (aka cell protectants)
sunscreens
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Over exposure to UVA/UVB rays
with repeated sunburns
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All other events that are under our
control
Earth is here ☺
UV Index Forecast Map
This graph was developed by the National Weather Service
(NWS) and the EPA. It predicts the next days UV radiation
levels. (Go to www.epa.gov/sunwise/uvindex.html to check
it out.)
1 = low levels of radiation
11 + = extreme levels of radiation
SHADE
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Contains Essential UVA/UVB full
spectrum environmental protection
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Soothes with chamomile and
calendula and cucumber extract
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Vitamin E for antioxidant
benefits
Active Ingredients: Ethylhexyl
Methoxycinnamate, EthylHexyl
Salicylate, Benzophenone-3,
Butyl Methoxydibenzoylmethane
which are chemical sunscreen
absorbers…that’s what they
do…absorb UVA/UVA rays
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It’s also beneficial to have physical
sunscreen ingredients in the
sunscreen such as micronized
zinc oxide and titanium dioxide.
Environmental Protection
& Antioxidants
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Physical sunscreen ingredients
Chemical sunscreen ingredients
Antioxidants: Cell Protectants
REVIEW-ASSESSMENT
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What are the two distinct types of aging?
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Name a couple of factors in each of the two
distinct types of aging.
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Scientists have determine that 85% of
all aging is due to which of the two
types of aging?
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Early expression lines and repetitive
movements are examples of __________ aging?
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____________’s are types of Vitamins or amino acids that can help to
quiet free radicals.
What are: Antioxidants
Vitamin A & D
Lycopene
Vitamin C
Color on your plate…
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Antioxidants can be vitamins, amino acids (proteins), and other natural substances that help the cells
to cope with the effects of the environment.
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Nature knows…and has provided us with an abundance of protective fruits, vegetables, grains, and
cereals which are rich in the antioxidants.
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Antioxidants neutralize free radicals, which are wayward bad boy oxygen molecules that if left to their
own devices, will destroy cells.
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“Antioxidants scoop up free radicals , preventing the cellular degeneration and production of chemicals
within the body that cause further damage.” (Nikolas Perricone, M.D.)
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Free radicals are thought to cause cellular degeneration by means of a chemical process known as
oxidation. The
More on Antioxidants…
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Visualize antioxidants as nature's demolition teams that
neutralize the free radicals before they can do any damage.
(Putting oil on machinery to keep it from rusting, or by
keeping the apple in water thus keeping it from
turning brown are tangible examples of ways to
protect against oxidation).
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Antioxidants are any substances that prevent or slow the
oxidation process.
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Antioxidants work by donating an electron to a free
radical so it becomes a stable oxygen molecule.
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Free radicals cause oxidation - and antioxidants prevent oxidation.
A Closer Look at Free Radicals
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Free radicals are highly reactive molecules.
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Because electrons normally come in pairs, the free
radicals collide with other molecules in an attempt to
steal an electron, and may start a chain reaction,
damaging your DNA and cells.
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Free radicals also cause harm to lipids and proteins.
(*of course, such damage may lead to premature
aging and more serious consequences,
such as skin cancer.)
FREE RADICAL
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Their damaging potential may be
counteracted by antioxidative
Free Radical tamed by
Vitamin E
substances in the skin such as
the lipid-soluble vitamin E and the
water-soluble vitamin C.
Rejuvenated molecule
Vitamin E and vitamin C interact
with each other in the skin to
protect it from free radical attack
What causes Free Radicals?
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Our cells use oxygen to produce energy and they
generate free radicals as a byproduct of this and
many other metabolic functions like circulation
and digestion. (so our body systems naturally
produce free radicals, just being alive)
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Free radicals are also produced by sunlight,
toxins such as pesticides, cigarette smoke
and air pollution. Free radicals are without
question the central players in the aging process.
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Free radicals are thought to cause cellular degeneration by means of a
chemical process known as oxidation. Just like rust or a sliced apple, turning
brown, we are subject to that same process, and are more vulnerable to it as
we age.
Chemicals and Free Radicals
Legend:
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Free Radicals - Free radicals are atoms or molecules in your body
with an unpaired electron making them highly unstable. Emerging
science suggests this free radical damage may be linked to disease.
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2 Free radical scavengers, or antioxidants, bind with the free
radicals before they can do their damage.
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When we say damage is caused by oxidation, we could use the
modern buzzwords, free radicals. These are atoms or molecules in a
stage where an electron is "free" to link to an oxygen atom. Every
oxidative process, from rust to lung cancer and a lit match, has a
free radical as its very earliest step.
Free Radicals
Legend:
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Symbol for highly reactive molecules
with free radical
Symbol for free radicals, which are
trapped by vitamin E
Symbol for regenerated molecules
without free radical
Aging and Antioxidants
You can't see them but they're there
, stealing the natural beauty and health
from your skin.
They're chemicals caused by too much sun,
air pollution, stress and other factors.
Dr. Marianne O'Donoghue says, "Free radicals are hyperactive molecules that act in the
skin to give us aging, to give us cancer, to break down DNA."
Fortunately nature has a secret weapon called antioxidants. Antioxidants can be found
in fruits and vegetables, and can also be absorbed through your skin.
"The two vitamins that are best for the skin are vitamin A and vitamin C.
They help the wound healing and they really will make
you a lot younger looking," says Dr. O'Donoghue.
• Humans and other organisms depend on oxygen to produce
the energy required for cells to carry out their normal
functions. A cell's engine, the mitochondria, converts oxygen
into energy. But this process also leaves a kind of exhaust
product known as free radicals. When free radicals are not
destroyed by antioxidants, they create oxidative stress. As
the body ages, it produces more and more free radicals and
its own antioxidants are unable to fight this process, which
results in the generation of highly reactive oxygen molecules
that inflict cellular damage by reacting with biomolecules
including DNA, proteins, and lipids. A lifetime of oxidative
stress leads to general cellular deterioration associated with
aging and degenerative diseases.
• "A common molecular denominator in aging
and many age-related diseases is oxidative
stress," says the study's lead author Azad
Bonni, MD, PhD, HMS associate professor
of pathology. The skin of a bitten apple will
brown because of its exposure to air, and in
some ways that is a good metaphor for the
damage that oxidative stress is causing to
neurons and other types of cells over time.
Case Study- Day and Night
bt Cocktail
Energy 1, 2, & 3
Protocol for
Saundra
AM
1. CLEANSE
2. TONE
3. Energy 1
4. Energy 2
5. Energy 3
5. Cream & Restore (eye)
7. Shade
8. Mineral Powder/Makeup
PM
1.
2.
3.
4.
5.
6.
CLEANSE
TONE
Energy 1
Energy 2
Energy 3
Cream & Restore
CLASS PRESENTATIONS
HOT from the Chemist!
Our formulations fall into a new
category…
called
“Eco Chic”
*This concept follows the Green Initiative trend which
explains that products may or may not be “Natural”
or “Organic” but are “Environmentally Aware”.
Preservative System for bt Cocktail™
Energy 1
•
0.1% Disodium EDTA- Acronym for ethy-lene-dia-mine-tetra-acetic acid, a
stabilizer used in cosmetics to prevent ingredients in a given formula from
binding with trace elements (particularly minerals) that can exist in water and
with other ingredients to cause unwanted product changes to the texture, the
odor, and the consistency. It also enhances the preservative delivery system. The
technical term for ingredients that perform this function is chelating agent (a
chemical that is added to cosmetics to improve the efficiency of the
preservative – M. Lees).
•
4.0% Pentylene Glycol- Polyvalent (can be used for many things/values)
alcohol with a humectant and antibacterial effect.
Preservative System for bt Cocktail™
Energy 2 1.0% Botanistat PF-64
(phenoxyethanol,
caprylyl glycol, ethylhexylglycerin, hexylene glycol)
Botanistat Is called the Ideal Alternative to Paraben Preservatives
•
•
•
•
•
•
•
•
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Paraben and formaldehyde-free preservative
Broad spectrum antimicrobial protection at low usage levels
Globally approved
Stable and effective over a wide pH range (3.0-10.0)
Easy and versatile to use in formulations
Compatible with essentially all cosmetic materials
Emolliency and skin-conditioning properties
Excellent safety and toxicological profile
Cost effective and readily available
Preservative System for bt Cocktail™
Energy 3
•
0.1% Disodium EDTA-0.1% Disodium EDTA- Acronym for ethy-lene-dia-mine-tetraacetic acid, a stabilizer used in cosmetics to prevent ingredients in a given formula from
binding with trace elements (particularly minerals) that can exist in water and with other
ingredients to cause unwanted product changes to the texture, the odor, and the
consistency. It also enhances the preservative delivery system. The technical term for
ingredients that perform this function is chelating agent (a chemical that is added to
cosmetics to improve the efficiency of the preservative – M. Lees).
•
0.7% Phenoxyethanol- a broad range preservative with fungicidal, bactericidal ,
insecticidal, and germicidal properties. It has a low sensitizing factor in leave on
cosmetics. (Skin Care & Cosmetic Ingredients Dictionary-Milady-Michalun)
•
0.2% Ethylhexylglycerin (Sensivia SC-50-C) Preservative derived from
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natural glycerin. www.theorganicbodycareshop.com
0.25% Potassium Sorbate-Used primarily against molds and yeast. Non-toxic.
The fibroblasts are the main cells in the dermis. They are essentially
located in the dermal papillae close to the epidermis,
and found only in very low numbers in the deep layers of the dermis
known as the reticular dermis. They are specialised in producing two types of
protein fibres, collagen and elastin fibres constituent of the
extra-cellular matrix. Collagen fibres, 70% of the proteins in the dermis, gives dermis
s resistance to strain and traction, while elastin supply its elastic properties.
The reticular dermis accounts for the greater part of the dermis.
On this level, the elastin and collagen fibres are multidirectional, whereas in the dermal
papillae the elastin fibres are mainly oriented perpendicular to the skin surface.
Dermal papilla in scanning electron microscopy
Langerhan cell
Zoom
Collagen and elastin fibers in Scanning electron microscopy
Fibroblasts
The fibroblasts are the main cells in the dermis.
They are essentially located in the dermal
papillae (papillary layer) close to the epidermis,
and found only in very low numbers in the deep
layers of the dermis known as the reticular
dermis.
Dermal papillae.
The fibroblasts are the principle cells of the dermis. They are mainly situated
in the papillary dermis close to the epidermis.
Only a few are found in the deep dermis, known as the reticular dermis. They specialise in
synthesising
two types of protein fibres: the collagen fibres and elastin fibres forming the extracellular matrix
The collagen fibres account for 70 % of the proteins in the dermis and
make it resistant to tension and traction,
while elastine fibres supply its elastic properties. The reticular dermis makes up the greater part of
the dermis. Here elastin and collagen fibres run in all directions whereas in the papillary dermis the
elastin fibres are mainly perpendicular to the surface of the skin.
Skin type
Unexposed skin color
Sun response
I
white
always burns, never tans
II
white
always burns, tans minimally
III
white
burns minimally, sometimes tans
IV
light brown
burns minimally, always tans well
V
brown
rarely burns, tans darkly (Asian skins)
VI
dark brown
never burns, tans darkly (African skins)
Both collagen and elastin fibres are made by cells called
fibroblasts, which are scattered through the dermis.
Special substances in the ground substance, called glycoproteins, can hold large amounts of water,
and are responsible for maintaining a mass of water in the dermis.
Hyaluronic acid is another important substance that forms part of the tissue that surrounds the
collagen and elastin fibres. It has the ability to attract and bind hundreds
of times its weight in water. In this way it acts as a natural moisturising ingredient responsible for the
skin's plumpness and moisture reserve. As we get older the amount of hyaluronic acid produced
in the skin naturally gets less. This is one reason why aging skin becomes less resilient and supple (pliable). Recently
Subcutaneous Layer
Fat=Adipose tissue
The subcutaneous or hypodermis acts as an energy reserve.
The fats contained in this area can be put back into circulation,
via the veins, when necessary. The subcutaneous layer plays a
role, although a passive one, in thermoregulation, as fat is a
heat insulator.
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