Integumentary System and Body Temperature-Chapter 7. J oe Pistack MS/ED. Integumentary system includes: The skin Accessory structures:- sweat glands -oil glands - hair
Integumentary System and Body Temperature-Chapter 7
Joe Pistack MS/ED
Integumentary system includes:
Accessory structures:- sweat glands
Acts as a gland by synthesizing vitamin D. Vitamin D is necessary for absorption of calcium from the digestive tract.
Performs a sensory role by housing the sensory receptors for touch, pressure, pain, and temperature.
Plays an important role in the regulation of body temperature.
Considered an organ
Also called integument or cutaneous membrane
Skin has 2 layers:
Dermatology-the study of skin and skin disorders.
Epidermis-thin outer layer of skin.
Composed of stratified squamous epithelium.
Has no blood supply of it’s own, avascular.
Oxygen and nutrients diffuse into the epidermis from blood supply from the dermis.
The epidermis can be divided into 5 layers the two of interest here are the deeper stratum germinativum and the more superficial stratum corneum
-lies on top of the dermis.
-has access to a rich supply of blood.
-cells of this layer constantly divide, push old cells to the surface.
Changes take place as cells move away from surface: 1. cells begin to die
2. keratinization takes place
Keratinization-process whereby tough protein
called keratin is deposited within the cell, keratin hardens and flattens the cells as they move toward surface. This makes the skin water-resistant.
Insensible perspiration-500ml/day of perspiration that is lost through the skin.
Sensible perspiration-due to activity of the sweat glands.
If the epidermis is damaged, the rate of insensible perspiration increases. E.g. burns
22 to20 ga. 5/8 to 3/4 long
Skin color is determined by:
Melanocytes-skin cells within the epidermal layer.
Melanin-darkening pigment, stains the surrounding cells causing them to darken.
The more melanin, the darker the skin.
Amount of melanin secreted determines the skin color.
Exposure to ultraviolet sunlight increases the secretion of melanin=suntan.
Conditions involving malfunctioning melanocyte:
- melanocytes fail to secrete melanin.
- skin, hair, and iris (colored part of eye) are white.
-loss of pigment in certain areas of skin.
-creates patches of white skin.
Freckles and Moles:
-Areas in the skin where melanin is concentrated
-A mole that has changed in character and has become cancerous
Carotene-yellowish pigment to skin.
Cyanosis-blue look to skin, result of poorly oxygenated blood.
Blushing-dilation of the blood vessels.
Pallor-constriction of blood vessels, decrease in oxygenated blood.
Accessory structures include:
Hairless body parts: palms of hands, soles of feet, lips, nipples, and parts of the external reproductive organs.
Shaft-part above the surface of the skin.
Root-part that extends from the dermis to the surface.
Hair follicle-formed by downward extension of epithelial cells.
Eyelashes and eyebrows-protect the eyes from dust and perspiration.
Nasal hairs trap dust and prevent it from entering the lungs.
Hair of the scalp keeps us warm.
Hair growth-influenced by sex hormones.
Puberty-growth of hair in axillary and pubic areas in male and females.
Hirsutism-excessive hair growth in females, caused by too much testosterone.
Epidermal cells –receive blood supply from the dermal blood vessels.
Keratinization of cells- cells die as they move away from their source of nourishment.
Hair that we brush, blow dry, and curl is dead.
Genetically controlled by the amount of melanin.
Abundance of melanin-dark hair.
Less melanin-blond hair.
Absence of melanin-white hair.
Shape of the hair shaft:
Determines the appearance of hair.
Round shaft produces straight hair.
Oval shaft produces wavy hair.
Flat hair shafts produce curly and kinky hair.
Arrector Pili muscle- attached to the hair follicle.
Bundle of smooth muscle fibers, when these muscles contract, hair stands on end.
Contract when cold or frightened.
Also called goose bumps.
Thin plates of stratified squamous epithelial cells.
Contain a hard form of keratin.
Found on the distal end of the fingers and toes.
Protect structures from injury.
Nail growth-determined by half-moon shaped lunula located at the base of the nail.
As nail grows, it slides over the nailbed.
Underlying dermal layer contains blood vessels which give pink color to nail.
Cuticle-fold of stratum corneum-grows onto proximal portion of the nail body.
Assessment of the nails should include:
-adhesion to the nail bed
clubbing-condition that indicates fingertips have received an insufficient supply of oxygenated blood over a period of time.
Fingertips become large, nails become think, hard, shiny and curved at the free end.
Causes-chronic heart and lung disease.
Cyanosis-poor oxygenation makes the blood appear bluish, this in turn makes the nails appear bluish.
Nail abuse-trauma to the nail that causes the nail to thicken and hypertrophy.
Brittle- generally due to poor oxygenation or poor nutrition, or anemias.
Two major glands:
Sebaceous glands or oil glands-associated with the hair follicles, found in all body areas that have hair.
Sebum-oily substance that flows into hair follicle or onto surface of skin.
Sebum lubricates and helps waterproof skin and hair.
Inhibits bacteria on the surface of the skin.
Production decreases with aging, results in dry skin and brittle hair.
Vernix caseosa-cream cheese covering that babies are born with, secreted by sebaceous glands.
1) Apocrine glands-usually associated with the hair follicles, found in the axillary and genital areas.
Body odor- occurs when the substances in sweat are degraded by bacteria into chemicals with a strong unpleasant odor.
2) Eccrine glands-more numerous and widely distirubuted throughout the body. Especially numerous on the forehead, neck, back, upper lip, palms, and soles.
Normal body temperature is 98.6 degrees F .
Body temp. differs from one part of the body to another.
Core temperature-reflects the temperature of the inner parts of the body, (cranial, thoracic, and abdominal cavities).
Shell temperature-reflects the temperature of the skin and mouth.
Thermoregulation-the mechanism whereby the body balances heat production and heat loss.
Failure to regulate body temperature causes the body temperature to fluctuate.
Hypothermia-excessive decrease in body temperature.
Hyperthermia-excessive increase in body temperature.
Extreme changes in body temperature may be fatal.
80% of heat loss occurs through the skin.
20% is lost through the respiratory system and excretory products.
Heat loss occurs by four means:
Radiation-heat is lost from a warm object (the body) to the cooler air surrounding the warm object. Eg. Person loosing heat in a cold room.
Conduction-loss of heat from a warm body to a cooler object in contact with the warm body.
Eg. Warm person becomes cold when sitting on a block of ice.
Eg. Cooling blanket for hyperthermia-warm object (feverish patient) looses heat to the cooler object, the cooling blanket.
Convection-loss of heat by air currents moving over the surface of the skin. E.g. Fan moving across the surface of the skin.
Evaporation-heat may be lost through changing a liquid (sweat) to a gas.
E.g. during strenuous exercise, sweat on the surface of the skin evaporates and cools the body.
Normal body temperature is regulated by several mechanisms:
- Hypothalamus-thermostat of the body, located in the brain.
-senses changes in body temperature and sends information to the skin. (blood vessels, sweat glands and skeletal muscle).
Blood vessels dilate
Increased blood flow to the skin
Heat is transferred to deeper tissue surfaces
Sweat glands activate
Heat is lost as sweat evaporates
Body temperature lowers
Blood vessels constrict.
Traps blood and heat in the deeper tissues
(prevents heat loss)
Sweat glands become less active, preventing heat loss.
Skeletal muscles contract vigorously and involuntarily causing shivering and an increase
in the production of heat.
Contraction of the arrector pili muscles causes goose bumps indicating a decline in body temp.
Classified according to depth.
Classified as either partial-thickness burns or full-thickness burns.
Partial thickness are divided into first-degree and second-degree burns.
First degree burns:
Second degree burns:
Third degree burns:
(full thickness burns)
Rule of nines:
System used to measure the extent of burns.
Total body surface is divided into regions.
The assigned percentages are related to the number 9.
As we age:
Epidermis becomes thinner.
Skin is more translucent.
Dermis becomes thinner,
Decreased amount of collagen and elastin fibers.
Skin heals slower.