Anatomy and Physiology Chapter 5

What is the first step in the process by which epidermal cells are replaced?Basal cells in the stratum germinativum divide, adding in new daughter cells and pushing the cells above upward through the layers
epidermal ridgeresponsible for increasing surface area to provide for the strength of attachment between the epidermis and dermis
how long do skin cells last before being shed or sloughed off21-24 days
the epidermal layer that consists almost entirely of keratinstratum corneum
4 functions of the integumentary systemprotection of underlying tissue
maintenance of body temp
excretion of salts and wastes
detection of sensations
two components of the integumentary system arecutaneous membrane
accessory structures
The type of cells that form the strata in the epidermis arekeratinocytes
The tough superficial layer of the epidermis is known as the stratumcorneum
Large quantities of keratin are found in the epidermal layer called thestratum corneum
The layer of the skin that provides a barrier against bacteria as well as chemical and mechanical injuries is theepidermis
________ are cells in the epidermis that are part of the immune systemdendritic cells
The epidermis of the skin is composed of what type of tissuekeratinized stratified squamous epithelium
The layer of stem cells that constantly divide to renew the epidermis is thestratum basale
melanocytesstore melanin in melanosomes
basal cell carcinomaskin cancer that is the most common but least dangerous
cancer’s key characteristics
an albino individual lacks the ability to producemelanin
melanin (4 things)is usually some shade of brown or black.
is produced from the amino acid tyrosine.
is produced by cells called melanocytes.
protects DNA from the damaging effects of UV radiation.
Cyanosis signifies that a patient hasoxygen-starved skin
Jaundice is indicated by a(n) ________ skin coloration.yellowish
Exposure to ultraviolet light (sunlight) causes the skin to darken by increasing the production ofmelanin
The pigment found in vegetables that can make the skin appear orange or yellow is calledcarotene
Melanin is produced by melanocytes within thestratum basale
The skin appearance that results from dark-red hemoglobin is calledcyanosis
what are 4 effects of ultraviolet radiation-chromosomal damage in melanocytes
-production of cholecalciferol within epidermal cells
-reduced amounts of elastic fibers in the dermis
-increased activity by melanocytes
vitamin Dformed in the skin when it is exposed to sunlight
3 types of skin cancersquamous cell carcinoma, malignant melanoma, and basal cell carcinoma
ricketsbone disorder that cause a bow in legs
prevented by vitamin D and sunlight
leads to weak bones
usually in children
Skin cancer that starts in the mitotically most active epidermal layer is calledbasal cell carcinoma
function of epidermal growth factor (EGF)stimulating synthetic activity
accelerating production of keratin
stimulating epidermal repair
stimulating secretion by epithelial glands
major layers of skin (top to bottom)Epidermis
Dermis (papillary then reticular)
Which layers of the skin hold compressed blood vesselsthe papillary and reticular layers of the dermis
reticular layerThe layer of the skin that contains bundles of collagen and elastic fibers responsible for the strength of the skin
elastinThe protein that permits stretching and recoiling of the skin
Skin inflammation that primarily involves the papillary layer is termeddematitis
A bruise turns “black and blue” because of ________ in the dermis.broken blood vessels
contusiona bruise
what layer is targeted by liposuctionhypodermis
The skin can move easily over the underlying muscles because of the loose connective tissue within the __________.hypodermis
cuticleThe layer of hard keratin that coats the hair
variations in hair color reflect differences in the piagment produced bymelanocytes
When the arrector pili muscles contract,“goose bumps” are formed
secretes oil into the hair folliclesebaceous
secrete a thick odorous secretion into the hair follicleapocrine
Cerumen is produced by glands located in the __________.ear canal
Merocrine sweat glands are most abundant in the __________.palms of the hands
if body temperature rises above normal blood flowto the skin increases
Merocrine sweat glandssecrete a watery fluid directly onto the surface of the skin
nail production occurs atnail root
steps to integument repairinflammatory phase
migratory phase
proliferation phase
scarring phase
inflammatory phase-bleeding occurs at the site of injury immediately after the injury
-mast cells in the region trigger an inflammatory response
migratory phase-a scab has formed and cells of the stratum basale are migrating along the edges of the wound
-phagoctic cells are removing debris
proliferation phase-the scab has been undermined by epidermal cells migrating over the collagen fiber meshwork produced by fibroblast activity
-phagoctic activity around site almost ended
scarring phase-the scab has been shed
-the epidermis is complete
-there may been a shallow depression still
abrasiondamage to skin caused by scraping;
In a penetrating wound, ________ divide to produce mobile cells that repair the dermis.fibroblasts
The type of burn that may require a skin graft is a ________ burn.third-degree
A fibrin clot that is formed over a skin wound is called ascab
Why are the elderly more prone to skin infections?-Tissue repairs take longer.
– they have a thinner epidermis.
-They have fewer dendritic cells
Which layer of the epidermis is responsible for water resistance?stratum corneum
structures of the epidermis (bottom to top)stratum basale
stratum spinosum
stratum grandulosum
stratum lucidum
stratum corneum