Chapter 5 Flashcards
MAKE SURE YOU KNOW THE DIAGRAM
LAYERS OF SKIN IS IMPORTANT
skin
the largest organ, varies from 1.5 to 4.0mm and two regions (epidermis and dermis)
functions of integumentary system
cushions and insulates the deeper organs protects entire body from trauma protect from harmful chemicals, heat/cold, and bacteria prevent water loss control temp eliminates waste blocks UV radiation
epidermis
keratinized stratified squamous epithelium
four types of cells of epidermis
keratinocytes, melanocytes, merkel cells, and langerhans
keratinocytes
produce keratin
melanocytes
produce melanin
merkel cells
associated with sensory receptors (amplify sensation)
langerhans
involved in immune response
layers of epidermis deepest to most superficial
stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum
stratum basale
basal layer, single row of mitotic keratincytes
stratum spinosum
spiny layer, “thorns” contains langerhans
stratum granulosum
granular layer, keratinization begins
stratum lucidum
clear layer, located only on thick skin, consists of rows of dead keratinocytes
stratum corneum
horny layer, most superficial, keratinocytes are dead
dermis
bulk of the skin, just deep to the epidermis, consists of CTP, and two layers (papillary and reticular)
papillary layer
superficial layer, 20% of the dermis, consists of areolar CT, contains dermal papillae and epidermal ridges
dermal papillae
fingerlike projections that project into the overlying epidermis
epidermal ridges
increase friction and enhance gripping
reticular layer
80% of the dermis, consists dense irregular CTP, thick collagen fibers giving skin its strength while elastic fibers allow the skin to stretch and recoil, and flexure lines
flexure lines
indicate where the dermis attaches tightly to underlying structures
hypodermis
fatty layer just deep to the skin,
contains both areolar and adipose tissue,
not truly part of the integumentary system,
helps anchor skin,
acts as insulator
what contributes to skin color?
melanin, carotene, and hemoglobin
melanin
yellow to reddish to brown to black
carotene
yellow-orange
hemoglobin
protein in blood that produces pinkish blue
appendages of the skin
derivatives of the epidermis that extend into the dermis
examples: hair, hair follicles, oil glands, sweat glands, nails
hair
flexible strand of dead keratinized cells
parts of hair
root: embedded in skin
shaft: projects above the skin surface
hair follicles
extend from the epidermal surface to the dermis
consist of epithelial layers and a CT layer
produce the cells that make a hair
serve to anchor the hair
associated with arrector pili (goosebumps)
sebaceous glands
oil glands associated with hair follicles secrete sebum that: collects dirt softens hair and skin prevent epidermis from cracking slow water loss provide antibacterial properties
sweat (sudoriferous) glands
2.5 million sweat glands, 500ml produced daily
serve to cool the body
eliminate waste (salt, urea, ammonia, uric acid)
inhibit growth of bacteria
four types of sweat glands
eccrine, apocrine, ceruminous, mammary
eccrine glands
most numerous type, response to heat and stress
apocrine glands
(armpit) confirmed to the axillary, anal, and genital
containing lipids and proteins
produce an odor when broken down by bacteria
ceruminous
earwax
mammary
milk
nails
scale-like modifications of the epidermis
help us pick up objects
composed of keratin
formation and structure is analogous to hairs
