lecture 5 integumentary system Flashcards
-largest organ
-accounts for 7% body weight
-varies in thickness
-divided into 2 layers ;
epidermis & dermis
skin
- lies deep to the dermis
- also called superficial fascia
- composed of areolar and adipose tissue
- not part of the integumentary systems, but shares skins properties
- helps insulate the body
- different distribution in males and females
hypodermis
five important functions of skin
- protection
- body temperature regulation
- excretion
- production of vitamin D
- Sensory reception
cushions organs and protects from bumps, chemicals, water loss, UV radiation
protection
capillary network and sweat glands regulate heat loss
body temperature regulation
urea, salts, and water lost through sweat
excretion
epidermal cells use UV radiation to synthesize vitamin D
production of vitamin D
contains sense organs associated with nerve endings
sensory reception
4 layers of epidermis
- stratum basale
- stratum spinous
- stratum lucid
- stratum corneum
- deepest layer of epidermis
- attached to underlying dermis
- cells actively divide
- contains tactile epithelial cells and melanocytes
stratum basale
associated with sensory nerve ending
tactile epithelial cells
secrete the pigment melanin
melanocytes
- occurs only in thick skin
- location of thick skin ; palms and soles
- composed of a few rows of flat, dead keratinocytes
stratum lucidum
- second major region of the skin
- strong, flexible connective tissue
- richly supplied with blood vessels and nerves
- 2 layers ; papillary and reticular dermis
dermis
- includes dermal papillae
- increase surface area for exchange of gases, nutrients, and wastes
- dermal papillae on dermal ridges
papillary dermis
- elevations of dermal ridges
- fingerprints
- increase gripping ability of hands and feet
epidermal ridges
- accounts for 80% of dermal thickness
- dense irregular connective tissue
- cleavage lines
- collagen fibers give skin strength
- flexure lines
- rich nerve supply
- 2 vascular plexuses ; dermal and sub papillary plexus
- blood vessels play important role in temperature regulation
reticular dermis
separation between collagen fibers
-collagen fibers give skin strength
cleavage lines
deep crease in palms, wrists, soles, fingers, and toes
flexure lines
3 pigments that contribute to skin color
- melanin
- carotene
- hemoglobin
most important pigment ; made from tyrosine
melanin
yellowish pigment from carrots and tomatoes
carotene
- caucasian skin contains little melanin
- allows crimson color of blood to show through
hemoglobin
- flexible strand of dead, keratinized cells
- hard keratin- tough and durable
- parts ; root and shaft
hair
embedded in the skin
root
projects above skins surface
shaft
body hairs of women and children
vellus hairs
- hair of scalp
- axillary and pubic area (at puberty)
terminal hairs
- occur over entire body
- except palms and soles
- secrete sebum
sebaceous glands
-an oily substance
-simple areolar glands
-holocrine secretion
functions
-collects dirt; softens and lubricates hair and skin
sebum
entire cell breaks up to form secretion
-most associated with a hair follicle
holocrine secretion
- also called “sudoriferous glands”
- widely distributed on body
sweat glands
- a blood filtrate
- 99% water with some salts
- contains traces of metabolic wastes
- about 2% urea
sweat
classifications of burns
- first degree burn
- second degree burn
- 3rd degree burn
only upper dermis is damaged
first degree burn
- upper part of dermis is also damaged
- blisters appear
- skin heals with little scaring
second degree burn
- consumes thickness of skin
- burned area appears white, red, or blackened
third degree burn
-least malignant and most common kind of cancer
Basal cell carcinoma
arises from keratinocytes of stratum spinosum ; cancer
squamous cell carcinoma
- a cancer of melanocytes
- the most dangerous type of skin cancer
melanoma
any structure or prominence that assists in finding a structure that is not visible
anatomical guide
the points at where the structure in question is accessible
anatomical limits
an imaginary line drawn on the surface of the skin to represent a deeper lying structure or prominence
linear guide
made up of dead keratinized cells.
- hard keratin is different than soft keratin found throughout the skin.
- hard keratin is tougher and doesn’t flake off
nails
standard sweat gland
eccrine glands
axillary, anal, and genital
apocrine glands
ear gland
ceruminous
modified sweat glands
mammary glands
