TEAS Integumentary System

epidermis

the thin, outermost, waterproof layer of the skin

dermis

the middle layer of the skin which contains sweat glands, oil glands, and hair follicles

subcutaneous layer

the inner layer of the skin. has connective tissue, adipose tissue, nerves, arteries, and veins

stratum basale

the deepest layer of the epidermis, containing a single layer of cuboidal or columnar cells that adhere to the basement membrane. this is the most nourished layer as it is closest to the capillaries of the dermis

stratum spinosum

the second deepest layer of the epidermis, consisting of 8 to 10 layers of spiny cells connected by desmosomes

stratum granulosum

2 to 5 layers of slightly flattened cells containing granules of keratohyalin. cells lose their nuclei here

stratum lucidum

2 to 5 layers of dead, flattened keratinocytes that is only present on the palms of the hands and soles of the feet. cells contain eleidin

eleidin

a translucent, water-resistant protein derived from keratinohyalin

stratum corneum

the most superficial layer, consisting of 15 to 30 layers of dead, keratin-containing squamous cells. this layer helps prevent water loss from the body

keratinocytes

the most common type of cell in the epidermis, arising from stem cells in the stratum basale. produce keratin, and flatten and die as they move up toward the surface of the skin

keratin

a fibrous protein that hardens the cell and helps make the skin water resistant

melanocytes

skin cells that produce melanin

melanin

a pigment that gives skin its color and protects against UV radiation

langerhans cells

antigen-presenting cells of the immune system. most common in the stratum spinosum

merkel cells

cutaneous receptors located in the stratum basale and detect light touch

fibroblasts

a dermis cell that secretes collagen, elastin, glycosaminoglycans, and other components of the extracellular matrix

adipocytes

fat cells of the dermis

macrophages

dermis cells that are phagocytic and engulf potential pathogens

mast cells

cells of the dermis that are antigen-presenting and play a role in inflammatory response (release histamine)

osmoregulation

the skin’s ability to prevent water loss from the underlying tissues, as well as uptake water from outside the body

arrector pilli

a small smooth muscle that contracts in the dermis when the body is cold. this muscle pulls on the hair follicle, causing the hair to stand erect

hypodermis

a layer of subcutaneous tissue that helps to anchor the skin to underlying organs and consists of mainly loose connective tissue, specifically adipose tissue

adipose tissue

a layer of fat cells that provide insulation from heat and cold

apocrine glands

sweat glands that have ducts that empty into hair follicles, activated by the onset of puberty and found only in certain regions of the body

eccrine glands

sweat glands that are found all over the body and play a role in thermoregulation by secreting sweat to help cool the body as sweat evaporates

hypothalamus

part of the brain that regulates the release of sweat

nails

dense plates of hardened keratinocytes that protect the distal ends of the fingers and toes

callus

a buildup of dead cells that forms a protective pad due to the stratum basale increasing the rate of mitosis, causing an overdevelopment in the stratum corneum (hyperkeratosis)

acid mantle

formed from the secretions of sweat and sebaceous glands mixed together on the surface of the skin. helps prevent infection because of its low pH and antimicrobial agents and enzymes