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Module 7:
Skin Structure, Growth and
Nutrition
Anatomy of the Skin
• Dermatology - The medical branch of science
that deals with the study of skin and its nature,
structure, functions, disease, and treatment
• Dermatologist – is a physician engaged in the
science of treating the skin, its structures,
functions and diseases.
• Esthetician – is a specialist in the cleansing,
preservation of health and beautification of the
skin and body.
Cosmetologists are not allowed:
• To diagnose
• Prescribe
• Provide treatments for :
• Abnormal conditions
• Illnesses
• Diseases
• Largest Organ of the body
– 3,000 square inches
– 6 - 9 lbs.
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Slightly moist
Soft
Flexible
Texture – ideally smooth and fine grained
Slightly acidic
• Immune responses react quickly to touch
• Appendages
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Hair
Nails
Sebaceous glands
Sudoriferous glands
Skin
• Thinnest - eyelids
• Thickest – soles of feet and palms of hands
• Callus – continued pressure can cause skin to
thicken
• Scalp – larger, deeper follicles to accommodate
longer hair
• Did you know boxes – page 157
Two Main Divisions
• Epidermis – Outer most layer
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Cuticle
Scarf skin
Thinnest layer
Protective covering for body
Contains no blood vessels
Has many nerve endings
Layers of Epidermis
• Stratum Corneum – outer layer –
– scale-like cells continuously shed and replaced by cells
coming to the surface from underneath
– Keratin – protein
– Cells combine with a thin layer of lipids (fats/oils) to make a
protective water-proof layer
• Stratum Lucidum- clear, transparent layer – small cells
through which light can pass
• Stratum Granulosum – cells that look like distinct
granules
– Cells die, pushed to surface, replace cells being shed from
stratum corneum
• Stratum Spinosum
– Spiny layer
– Beginning of process that causes skin cells to shed
• Stratum Germinativum – basal or Malpighian layer
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Deepest layer of Epidermis
Several layers of different-shaped cells
Live layer - Responsible for the growth of the Epidermis
Contains a dark skin pigment (melanin)
Melanocytes – produce melanin which determines skin color
• Did you know box – page 158
Dermis
• Underlying or innermost layer
– Derma, corium, cutis or true skin
• 25 times thicker than Epidermis
• Within its structure
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Blood vessels
- Nerves
Lymph vessels
- Sweat Glands
Oil glands
- Hair follicles
Arrector pili muscles – goose bumps
Papillae – small coned shaped projections of elastic tissue
that point upward into the epidermis
Two layers of Dermis
• Papillary Layer
– Outer layer, lies directly beneath the epidermis
– Papillae located here
– Tactile corpuscles – structures with nerve endings that are
sensitive to touch and pressure
– Melanin
– Joins the Epidermal – dermal Junction
• Reticular Layer
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Deeper layer that supplies the skin with oxygen and nutrients
Fat cells
Blood vessels
Lymph vessels
Oil glands
Sweat glands
Hair follicles
Arrector pili muscles
• Did you Know – page 159
Subcutaneous Layer
• Fatty layer found below the dermis
• Tissue called adipose or subcutis
• Varies in thickness according to
– Age
– Sex
– General health
• Gives smoothness and contour to the body
• Contains fat for use for energy
• Acts as a protective cushion for the outer skin
How the Skin is Nourished
• Blood and lymph supply nourishment to the skin
• Contribute essential materials for:
– Growth
– Nourishment
– Repair of skin, hair and nails
• Lymph
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Clear fluid
Colorless corpuscles
Bathe skin cells
Remove toxins and cellular waste
Immune functions help protect body and skin
Nerves of the Skin
• Motor Nerves –
– attached to the arrector pili muscles
– Carry impulses from brain to muscles
• Sensory Nerves –
– React to cold, touch, pressure, pain
– Receptors send messages to the brain
• Secretory Nerves – Distributes to oil and sweat glands
– Autonomic Nervous System
– Regulate the excretion of perspiration from the sweat glands
– Control the flow of sebum to the surface of the skin
• Sense of Touch
– Nerve endings register basic sensations – touch, pain, heat,
cold, pressure
– Nerve endings most abundant in the fingertips
Skin Color
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Melanin – tiny grains of coloring matter
Distinctive color of skin is a hereditary trait
Varies among nationalities and races
Pheomelanin – red – yellow
Eumelanin – dark brown - black
Melanin protects sensitive cells against strong
light rays
Strength and Flexibility of the Skin
• Skin gets its strength, form, flexibility from two specific
structures of flexible protein fibers
• Make up 70% of the dermis
• Collagen –
– Fibrous protein that gives skin form and strength
– Helps give structural support by holding together all the
structures found in this layer
– Allow skin to stretch and contract
– If fiber become weakened – lose its tone and suppleness
• Elastin – interwoven with collagen
– Protein base similar to collagen that forms elastic tissue
– Gives skin its flexibility and elasticity
– Helps skin regain its shape
• Both fiber important to the overall health and
appearance of skin
• As we age, fibers naturally weaken, causing a kind of
wrinkling and sagging
• Most signs of aging are cause by sun exposure over a
lifetime
• Did You Know? pp.161 & 162
Glands of the Skin
• Sudoriferous Glands
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Sweat glands
Excrete perspiration
Detoxify body by excreting excess salt & unwanted chemicals
Fundus – secretary coiled base
Tube-like duct that ends on the skin surface to form sweat
pore
– Most numerous on palms of hands and soles of feet
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Regulates body temperature
Eliminates waste
Controlled by the nervous system
1 – 2 pints excreted daily
• Did You Know – pp. 163
• Sebaceous Glands
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Oil glands
Connected to the hair follicles
Little sacs with ducts that open into the follicles
Secrete sebum (oil)
Lubricates the skin
Preserves softness of the hair
On all parts of the body EXCEPT soles of feet and palms of
hands
• Comedo – a pore impaction – sebum hardens
and the duct becomes clogged
– Blackhead – a hair follicle filled with keratin and
sebum
Acne
• Acne Vulgaris
– Chronic inflammation of the sebaceous glands from
retained secretions and bacteria – Propionbacterium
acnes (p. acnes) – technical term for acne bacteria
• Pimple – a small elevation on the skin that
contains no fluid but may develop pus
• Pustule – raised, inflamed papule with a white or
yellow center containing pus in the top of the
lesion (head of pimple)
Functions of the Skin
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Protection: Protects the body from injury and bacterial infection
Sensation: By stimulating sensory nerve endings
Heat Regulation: Skin protects the body from the environment
Excretion: Perspiration from the sweat glands is excreted
through the skin
• Secretion: Sebum excreted. Lubricates the skin and keeps it soft
and pliable
• Absorption: Female hormones can enter the body through the
skin, and influence it to a minor degree, fatty materials are
absorbed largely through the air follicles and sebaceous gland
openings
Nutrition & Maintaining Skin Health
• “You are what you eat”
• Proper dietary choices
– Regulate hydration
– Oil production
– Overall function of the cells
• Can be caused by un healthful diet or improper
hydration
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Skin disorders
Fatigue
Stress
Depression
Some diseases
Essential Nutrients
• Eat foods from 3 basic groups
– Fats
– Carbohydrates
– proteins
• Must also have:
– Vitamins
– Minerals
– Water
USDA and USDH&HS
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FYI page 165
Grains
Milk
Vegetables
Fruits
Meat, poultry, fish, beans
– Page 166 – list
• Dietary Guidelines : Dietary Guidance : Food and
Nutrition Information Center
• Physical Health and Nutrition - The Office of
Adolescent Health
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Read food labels
Nutrition facts about serving size
Number of servings per container
Calories
Quantities of nutrients per serving
Vitamins and Dietary Supplements
• Aide in:
– Healing
– Softening
– Fighting diseases of the skin
• Taking vitamins internally (pill form)best way
Vitamin A
• Supports overall health of skin
– Health
– Function
– Repair of skin cells
• Antioxidant – prevents certain cancers (skin)
• Improve skin’s elasticity and thickness
• Topical form
– Prescription form
– Retinoic acid
– Retin-A®
• Treatment of acne
Vitamin C
• Ascorbic acid – topical form
• Proper repair of skin and various tissues
• Aides in and speeds up healing processes of the
body
• Vitally important in fighting :
– Aging process
– Promotes production of collagen
– Keeping skin healthy and firm
Vitamin D
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Promotes healthy and rapid healing of skin
Best source is sunlight
Fortified milk/orange juice
Supports bone development & maintenance
Vitamin E
• With vitamin A – helps fight against and protect
skin against harmful effects of sun’s rays
• Heals damage to skin’s tissues when used
internally & externally
• Topical – Heal structural damage
– Burns
– Stretch marks
• Strive to improve diet rather than take vitamins
/mineral supplements
• Clients might ask you about nutrition
• Ask about hair, skin,. Nail problems
Water and the Skin
• No person can live without it
• The body and skin both rely heavily on the
benefits of water
• Composes 50 – 70 % of the body’s weight
• Sustains the health of the cells, aids in the
elimination of toxins and waste, regulates the
body’s temperature and aids in proper digestion
Amount of water needed per person
• Take your body weight and divide by 16
• Resulting number approximates how many 8
ounces glasses of water you should drink every
day
• If intense physical activity is performed daily –
add 2 extra glasses of water to your final number
• Did You Know? (pp. 167)
• FYI – (pp. 166)