chapter 4 the integumentary system is a dynamic continuous body covering composed of: blood vessels...
TRANSCRIPT
The integumentary system is a dynamic continuous body covering composed of:
• Blood vessels• Connective tissue structures• Glands• Hair• Nails• Skin
Overview
Chapter 4 – The Skin and Its Parts
The skin has three distinct layers: the epidermis, the dermis, and the hypodermis (or subcutaneous layer).
The Integumentary System
Chapter 4 – The Skin and Its Parts
Epidermis:
Outermost layer, where new skin cells are continually produced
The Integumentary System
Chapter 4 – The Skin and Its Parts
Dermis:
Middle layer; composed mostly of connective tissue
The Integumentary System
Chapter 4 – The Skin and Its Parts
Hypodermis:
(also called the subcutaneous layer)
Innermost layer, composed of loosely arranged elastic fibers that anchor the skin to underlying tissue
The Integumentary System
Chapter 4 – The Skin and Its Parts
The four main functions of the integumentary system are:
• Protection against environmental damage
• Heat regulation – maintain a constant internal temperature
• Sensation – receiving stimuli from the environment
• Waste excretion
The Integumentary System
Chapter 4 – The Skin and Its Parts
3 types of glands commonly found in the skin:
1. Ceruminous glands
• Produces a waxy secretion called cerumen
• Found in the lining of the ear canal
2. Sebaceous glands
• Produce an oily secretion called sebum
• Secreted into hair follicles & moves to the surface of the skin
3. Sweat glands
GLANDS
Chapter 4 – The Skin and Its Parts
2 Types:
1. Apocrine sweat glands
Secrete odorous sweat into the hair follicles of the armpits, navel, and groin regions
Inactive until puberty
Usually tapers off in the elderly
SWEAT GLANDS
Chapter 4 – The Skin and Its Parts
Apocrine sweat glands contain chemicals called pheromones, which are believed to play a role in courtship and social behavior
ex.) dogs sniffing people
Why does your sweat smell so bad?
The secretions are easily broken down by bacteria, which creates body odors.
SWEAT GLANDS
Chapter 4 – The Skin and Its Parts
2. Eccrine Sweat Glands
Found mostly on the skin of armpits, forehead, palms, and soles
Eccrine sweat gland activity is genetically determined
Human eccrine sweat is composed primarily of water with various concentrations of salts, organic compounds, and wastes, including urea.
SWEAT GLANDS
Chapter 4 – The Skin and Its Parts
Antiperspirants can be used to reduce the amount of sweat (from both gland types), thereby reducing odors and dampness.
How do antiperspirants work?
There is an electrical repulsion between a negatively charged ingredient and the negatively charged sweat molecules.
Interesting Fact:
Chapter 4 – The Skin and Its Parts
• Fingernails & toenails are nothing more than a keratin secretion.
• Keratinocytes at the base of the nail root gradually move up to the surface of the skin.
• The cells closest to the surface die, flatten, press tightly together, & disintegrate to form the nail body.
• Fingernails of a healthy person typically grow 1/8th an inch per month (slightly faster than toenails)
NAILS
Chapter 4 – The Skin and Its Parts
Aging is due to:• Intrinsic factors
aging caused by the natural decline of cells
OR• Extrinsic factors
aging caused by environmental factors (disease, pollution, sun exposure)
One’s lifestyle can accelerate aging.
Wellness and Illness over the Life Span
Chapter 4 – The Skin and Its Parts
Pathology can be categorized as:• Degenerative
refers to diseases that progressively
deteriorate tissues
examples include skin cancer, moles,skin tags
• Genetic
includes acne, psoriasis, spider veins
• Infectious
diseases including impetigo, ringworm, warts
Wellness and Illness over the Life Span
DISORDERS: HOMEOSTATIC IMBALANCES
• Skin cancer can be caused by excessive exposure to sunlight.
• Risk factors for skin cancer include skin type, sun exposure, family history, age, and immunological status.
Skin disorders• Basal cell carcinoma
30% of Caucasians get this type of skin cancer. Does not metastasize.
• Squamous Cell carcinoma arises from the keratinocytes in the stratum spinosum. May metastasize (spread to other body parts).
• Melanoma arises in the melanocytes. Rapidly metastasizes.
Melanocytes
• Produces melanin for protection from UV radiation.
• Responsible for skin color.
• Melanoma.
Burns
• Denaturation of cell proteins.• Dehydration, protein loss, and infection.
• First degree burns only the epidermis (sunburn).
• Second degree burns epidermis and upper dermis. May include fluid-filled blisters that separate epidermis & dermis. Heals without grafting in 3 to 4 weeks & may scar
• Third degree burns = full thickness burns
– destroy epidermis, dermis & epidermal derivatives
– damaged area is numb (not painful at all) due to loss of sensory nerves
-- Skin grafting is almost always necessary.
Tattoos
• Tattooing is a permanent coloration of the skin in which a foreign pigment is injected into the dermis.