integumentary system Flashcards
Integumentary
System
-The Integumentary
system includes:
◦Skin – largest organ
of the body
◦Accessory Organs:
Hair
Nails
-Serves to protect the
viscera (internal
organs) and regulate
temperature
Structure of the
Skin
1) epidermis
2) dermis
3) hypodermis
Epidermis
Outermost layer of skin
- Stratum Corneum– hard
outermost layer of epidermis
- Stratum Basale – produces new cells of epidermis
Stratum Corneum (epidermis)
hard outermost layer of epidermis
◦Produces a protein called keratin
◦Keratinization causes hardening of dead skin cells, making skin waterproof.
Stratum Basale (epidermis)
produces new cells of epidermis
◦Contains Langerhans cells (for immunity) and melanocytes (make pigment to give skin color)
Dermis
Thick layer of connective tissue containing the Dermal papillae and
collagen & elastic fibers- stretching & movement
◦Blood vessels
◦Sensory Nerves
◦Sebaceous Glands
◦Hair Follicles
Hypodermis (Subcutaneous
Layer)
Deepest layer of skin
Composed of loose
connective tissue and adipose tissue (fat)
◦Helps to store energy, insulate body, and provides protective padding
Five Functions of the
Skin
- Protection
- Regulates Water Loss
- Produces Vitamin D
- Gathers Sensory
Information - Regulates Body
Temperature
Functions of the
Skin- Protection
- Physical barrier to disease, dirt, and UV radiation
- Bacteria and other invaders are prevented entry by the top dead layer of skin and the acidic, oily secretion from sebaceous glands (sebum).
Functions of the
Skin- Regulates Water Loss
Keratinization of the dead skin outer layer also prevents water from entering or leaving the skin, even when immersed in water.
Skin works with the urinary
system to sweat off some excess water.
Functions of the
Skin- Produces Vitamin D
Melanocytes produce melanin to protect against harmful UV radiation from the sun and also to produce Vitamin D
Vitamin D helps regulate the
uptake of calcium by the digestive system.
Calcium is needed for strong bones.
Functions of the
Skin- Gathers Sensory
Information
Sensory receptors are linked to the nervous system
Receptors specialize in
sensing
◦Touch
◦Pressure
◦Pain
◦Temperature (hot & cold)
Many receptors in hands
Functions of the
Skin
When the body is too hot, the
skin will help to release heat
to cool the body temperature
back to 98.6°:
◦Sweat
◦Dilation of dermal blood vessels
When the body is too cold, the skin will help to raise body temperature back to 98.6° by generating heat:
◦Shivering (muscle contraction)
◦Goosebumps (contraction of
arector pili muscles attached to hair follicles) cause hair to trap heat
Hypothermia
Lower body temp. than normal interferes with the body’s normal functions and eventually ends in death
Hyperthermia
Higher body temp. than normal results in dehydration (from excess sweating) and heat stroke.
Skin Disorders
1. Chronic Disorders
2. Infectious
Disorders
3. Burns
4. Skin Cancers
Urticaria
(Hives)
◦Raised, often itchy,
red welts on skin surface
◦Usually due to an allergic reaction (to animal dander,
insect bites, pollen, shellfish, nuts, eggs, milk)
◦Also caused by caused by stress, extreme cold or hot, or illness
Eczema
Chronic skin disorder that
involves scaly and itchy rashes
Dry, flaky, blistering skin
appears red and inflamed
Intense itching and burning
sensations
Can be triggered by allergic
reactions to chemicals,
fabrics, heat, dryness
Dandruff (Seborrheic
dermatitis)
Caused by a yeast
White, flaky, inflammatory
skin condition
Often found on the scalp
Not contagious
Psoraiasis
-Flaky, silver-white patches called scales
-Redness and irritation
-Genetic
-The body produces too many new skin cells.
-Normally skin cell turn around is ~30 days, but with psoraiasis, turn over is around one week.
Albinism
Genetic disorder in which the body cannot produce melanin
Symptoms: absence of color in hair, skin, or iris; light
sensitivity; prone to sunburn
& skin cancer
Impetigo
◦Bacterial infection
◦Highly contagious
◦Causes blisters or sores on face and hands
◦Common among kids
Acne
Caused by an
overproduction of
sebum and oil, leading to clogging of the pores
Clogged pores trap
bacteria, dead skin
cells, and pus (white
blood cells)
Inflammation and swelling form red bumps
Pimples deep in the skin can form painful cysts
Other causes of acne
Genetics
Hormonal changes due to
menstrual cycles (females) or
stress
Greasy or oily cosmetic and hair products
Certain drugs (such as steroids, testosterone, estrogen)
High levels of humidity and
sweating
Diets high in refined sugars
