A&P Unit 4: Integumentary System

Integument

the skin

Largest organ in the body (16% of body weight)

What 4 tissues make up the skin?

stratified squamous

areolar

dense irregular

adipose

Functions of the skin

protection, homeostasis, energy storage, sensation, secretion

What layers make up the skin?

Epidermis, dermis, hypodermis

Epidermis

Cells divide in bottom layer and r gradually pushed upwards

has melanocytes

Pheomelanin vs Eumelanin?

pheomelanin- red/yellow and found in lips nipples, and some hair types (red hair)

Eumelanin- black/brown and most common type found in skin and hair

Rickets

softening of bone in children caused by vitamin D deficiency

Stratum spinosum

cells begin forming desmosomes to attach to e/o in layers

Stratum granulosum

cells begin producing large amounts of keratin and eventually die due to lack of oxygen from the dermis

Keratin

durable, water resistant protein found in hair, skin, and nails

Stratum lucidum

clear layer of dead, keratinized cells

only present in areas of the body w/ thick skin (palms and soles of feet)

Epidermal ridges

Increases surface area for oxygen diffusion from the dermis; found in thick skin epidermis

• causes fingerprints and footprints

Stratum corneum

oldest layer of cells; cells r dead, flattened and keratinized

Ceramides

type of intercellular lipid that seal the spaces between cells, creating a water resistant barrier

Cyanosis

bluing of the skin caused by poor circulation/ low oxygen levels

Jaundice

yellowing of skin due to liver not filtering bilirubin, a product of red blood cell metabolism

Albinism

genetic disorder that prevents the body from making melanin

harlequin ichthyosis

genetic disorder that results in thickened skin

skin doesnt produce lipids to maintain skin barrier so skin looks red, cracked, irritated

epidermolysis bullosa

genetic condition that result in easy blistering of the skin and mucous membranes. Blisters occur with minor trauma or friction and are painful. Its severity can range from mild to fatal

psoriasis

autoimmune disease in which skin cells build up and form scales and itchy, dry patches.

characteristics of cancerous cells (ABCDE rule)

asymmetrical, border irregularity, color change, diameter greater than 6mm, evolution/changes over time

Dermis

made of areolar tissue w/ nerves and blood vessels that deliver nutrients to epidermis

reticular layer made of dense connective tissue that gives skin its strength and flexibility

hypodermis

mostly made of adipose

provides insulation, shock absorption, and an energy reserve

hair papilla

contains nerves and blood vessels

hair matrix

contains stem cells that continuously divide

root sheath

extension of stratum spinosum that surrounds the hair root

arrector pili muscle

band of muscle that attaches each hair follicle to the epidermis

makes hair stand up right and sensation of goosebumps

hair root vs hair shaft?

hair root- living cells

hair shaft- dead cells

apocrine sweat glands

secrete an oily fluid

only found in armpits and genitals

degraded by bacteria, causing body odor

Merocrine sweat glands

secrete saltwater to cool the body down

nail bed

contains stratum basale and spinosum

nail matrix

has stem cells that continuously divide

male pattern baldness

genetic trait where hair follicles respond to testosterone by producingfiner, lighter hair

alopecia

autoimmune disorder that affects all hair follicles