Chapter 5: The Integumentary System Flashcards
What is the integumentary system?
The skin along with its accessory organs (hair, nails, glands); skin is the largest organ in the body.
Accessory organs of the integumentary system:
Hair, nails, glands.
Androgen
Genetic term for agent (usually testosterone or androsterone) that stimulates the development of male characteristics.
Ductule
Very small duct
Homeostasis
State of equilibrium of the internal environment of the body despite changes in the external environment.
Synthsize
Forming a complex substance by the union of simpler compounds or elements.
Functions of the skin:
Protects underlying structures from injury.
Provides sensory info to the brain.
Protects the body from UV rays.
Regulates body temperature.
Prevents dehydration.
Acts as a reservoir for food and water.
Synthesizes Vitamin D when exposed to sunlight.
Epidermis
Outermost layer of the skin that’s thickest on the palms and soles. Separated into strata (different layers).
Strata of the epidermis:
Stratum corneum (top), basal layer (bottom); takes ~1 month for cells formed in the basal layer to slough off the stratum corneum.
Stratum corneum
Composed of dead, flat cells that lack blood supply and sensory receptors.
Basal layer
Only layer of the epidermis that contains living cells, where new cells are formed. These move toward the stratum corneum to replace the cells that have been sloughed off.
Keratin
Hardened skin cells with a waterproof characteristic that prevents evaporation of fluids and prevents moisture from entering the body.
Melanocytes
Cells that produce a black pigment called melanin
Melanin
Responsible for different skin colors; dark-skinned people have high melanin production, light skinned people have little-no melanin production. Provides a protective barrier from the Sun’s UV rays; moderate Sun exposure results in suntan, high exposure results in sunburn. Local accumulations of melanin result in freckles/moles.
Albino
An individual that has absence of pigment in the skin, hair and eyes as a result of an inherited inability to produce melanin.
Dermis
Second layer of the skin, also called the corium. Composed of living tissue and contains capillaries, lymphatic vessels, nerve endings, hair follicles, sebaceous (oil) glands, and sudoriferous (sweat) glands.
Subcutaneous layer
Also called the hypodermis, binds the dermis to underlying structures, stores fats, insulates/cushions the body, and regulates temperature. Is composed of connective and adipose tissue interlaced with blood vessels.
2 types of glands in the skin:
Sudoriferous (sweat)
Sebaceous (oil)
Both are exocrine glands because they secrete substances through ducts outside the body rather than into the bloodstream.
Sudoriferous glands
Secrete sweat onto the skin’s surface through pores, most plentiful on the palms, soles, forehead, and axillae. Main function is to cool the body by evaporation, excrete waste products, and moisten surface cells.
Sebaceous glands
Filled with cells, whose centers contain fatty droplets; when these disintegrate they release sebum. The acidic nature of sebum helps destroy harmful organisms on the skin and prevent infection. When the ductules of these glands get blocked, this forms acne. Present everywhere on the body except for the palms of hands/soles of feet.
Androgens
Hormone that regulates the production of sebum; increased during adolescence and decreased with age.
Hair
Found on all body parts except lips, nipples, palms, soles, and part of external genetalia.
Parts of a hair:
Hair shaft
Hair root (contains hair follicle)
Papilla
Hair shaft
visible part of the hair