Integumentary System Flashcards
Name and describe the two layers of the skin.
The epidermis is the top layer, composed of epithelial tissue.
The dermis is made of connective tissue and contains many blood vessels, nerve endings, and glands.
Describe the subcutaneous layer (a.k.a. hypodermis or the superficial fascia). What does it consist of?
Connective tissue membrane under the dermis. This layer connects the skin to the deep fascia covering the underlying muscles. Continuous bundles of elastic fibers connect the subcutaneous tissue with the dermis, so there is no clear boundary between the two.
It consists of areolar connective tissue and and adipose (fat) tissue.
Describe the steps in repair of skin wounds and the factors that affect healing.
- Blood brings nutrients and white blood cells to fight infection
- New vessels branch out from damaged capillaries
- Fibroblasts manufacture collagen
- Stem cells from undamaged skin produce new epidermal cells
- If both the epidermis and dermis are destroyed, skin grafts may be required
integumentary system
Blood vessels, nerves, sensory organs, skin, hair, nails
The deepest layer of the epidermis, where new epidermal cells are produced from stem cells
stratum basale
As the epidermal cells die from the gradual loss of nourishment, they undergo changes. Mainly, their cytoplasm is replaced by large amounts of this protein, which thickens and protects the skin
keratin
top layer of the epidermis
stratum corneum
A dark pigment that colors the skin and protects it from sunlight’s harmful rays
melanin
Babies are born with a covering produced by these glands that resembles cream cheese; this secretion is called the vernix caseosa (VER-niks ka-se-O-sah), which literally means “cheesy varnish.”
sebaceous glands
meibomian (mi-BO-me-an) glands
Modified sebaceous glands, are associated with the eyelashes and produce a secretion that lubricates the eyes
These smaller-sized sweat glands are widely distributed throughout the skin and function to cool the body
eccrine glands (EK-rin)
These sweat glands are located mainly in the armpits and groin area. They are always associated with hair follicles.
apocrine glands
The following are all classified as _____ glands:
These are the ceruminous (seh-RU-min-us) glands in the ear canal that produce ear wax, or cerumen; the ciliary (SIL-e-er-e) glands at the edges of the eyelids; and the mammary glands in the breasts.
apocrine
A sheath of epithelial and connective tissue that encloses the hair
hair follicle
The part of the hair that projects above the skin is the ___; the portion below the skin is the hair’s ____.
shaft; root
What are nails made of?
Hardened keratin formed by the epidermis
Keratin vs collagen
Keratin is an intracellular protein in epithelial cells, but collagen is an extracellular protein in connective tissue.
New cells develop continuously in a growth region (nail matrix) located under the nail’s proximal end, a portion called the nail ___. The remainder of the nail plate rests on a nail ___of epithelial tissue. The color of the dermis below the nail bed can be seen through the clear nail. The pale lunula (LU-nu-lah), literally “little moon,” at the nail’s proximal end appears lighter because it lies over the nail’s thicker growing region. The cuticle, an extension of the stratum corneum, seals the space between the nail plate and the skin above the root.
root
bed
Functions of the integumentary system
- Protection against infection
- Protection against dehydration (drying)
- Regulation of body temperature
- Collection of sensory information
iontophoresis
A recent advance in TD drug delivery. Based on the principle that like charges repel each other, this method uses a mild electric current to move ionic drugs through the skin. A small electrical device attached to the patch uses positive current to “push” positively charged drug molecules through the skin and a negative current to push negatively charged ones
Cicatrix
A scar
List four factors that affect wound healing
Nutrition—A complete and balanced diet will provide the nutrients needed for cell regeneration. All required vitamins and minerals are important, especially vitamins A and C, which are needed for collagen production.
Blood supply—The blood brings oxygen and nutrients to the tissues and also carries away waste materials and toxins (poisons) that might form during the healing process. White blood cells attack invading bacteria at the site of the injury.
Infection—Contamination prolongs inflammation and interferes with the formation of materials needed for wound repair.
Age—Healing is generally slower among the elderly reflecting their slower rate of cell replacement.
