chapter 5 Flashcards
what is the integument made up of?
cutaneous membrane and accessory structures
what are the functions of the skin?
protects, excretes (glands), maintains body temp, synthesizes vitamin D3 for absorption of Ca+, blood flow regulation (cold vs hot vessels), proprioception touch pain and temp
two components of the cutaneous membrane
outer epidermis (superficial epithelium) and inner dermis (connective tissues)
subcutaneous layer (hypodermis) is…
below the dermis, composed of loose CT, and location of hypodermis injections
epidermis
avascular, keritinized stratified squamous epithelium, nutrients and O2 diffuse from capaillaries in dermis
what are the types of cell of the epidermis?
keratinocytes (most abundant, strength and flexibility), langerhan cells (marcophages), melanocytes (stratum basale), merkel cells (sense of touch receptors)
“strata” means…
layers
structure of the epidermis (from most superficial to deepest)
apical
stratum corneum
stratum lucidum
stratum granulosum
stratum spinosum
stratum basale (geminativum)
stratum corneum
Outermost layer, consists of dead, toughened keratinocytes that provide a protective barrier and are continually shed
stratum lucidum
Transparent layer, present in thick skin, contains eleidin
stratum granulosum
Grainy layer, cells flatten and produce keratin and keratohyalin, nuclei disintegrate.
stratum spinosum
Spiny layer, contains keratinocytes that produce keratin and are held together by spiny projections
stratum basale (geminativum)
Deepest layer, contains actively dividing cells and melanocytes, stem cells, forms bond between dermis and epidermis, forms epidural ridges (fingerprints), dermal papillae
what is dermal papillae?
tiny mounds to increase surface area of basal lamina, strengthen attachment between dermis and epidermis
keratinization
formation of dead skin layer, occurs on all exposed skin
how long does it take for a cell to travel from basal lamina to stratum corneum?
15-30 days
vitamin D3
produced in epidural cells, aid absorption in Ca and Ph
what happens when insufficient vitamin D3?
rickets (softening of bone)
layers of the dermis
papillary and reticular layers
papillary layer
areolar tissue, dermal papillae projecting between epidural ridges
reticular layer
dense irregular CR, collagen and elastic fibers
what fibers help with dermal strength and elasticity (turgor)?
collagen- resist stretching, bend easily
elastic- permit stretching and recoil, limits flexibility of collagen fibers to prevent damage to tissue
what do nerve fibers in the skin control?
blood flow, gland secretions, sensory receptors,
hypodermis
elastic areolar and adipose tissues, dermis connected to reticular layer of skin, few capillaries, cutaneous injections
hemoglobin
pink skin color because oxygenated= red; not oxygenated= blue
melanin
melanocytes, protection against UV
carotene
found in stratum corneun, yellowish tint to skin
jaundice
buildup of bile produced by liver, yellow skin
addison disease
pituitary gland not working well, skin darkening to bronze
purpose of pituitary gland
secretion of hormones and control of the secretion from endocrine glands
albinism
defect of melanin production
vitiligo
melanocytes die or abnormal functions, autoimmune
nevi
birthmarks or moles
freckles
clusters of concentrated melanin
functions of hair
protects, insulates, guards openings, sensitive to very light touch
regions of hair
hair root (attached to integument) and hair shaft (no attachment)
arrector pilli muscle
involuntary smooth muscle, causes hair to stand up
hair follicle
root hair plexus surrounds base, deep in dermis
sebaceous gland
oils/sebum, lubricate hair, inhibit bacterial growth, attached to arrector pilli muscle
why does hair grow back when we pull it?
because we do not often pull the matrix out along with it
ceruminous glands
sweat gland of the external auditory canal, EARWAX
ABCDE’s of skin cancer
asymmetry, border, color, diameter, evolving
3 major types of skin cancer
basal cell carcinoma- most common, lease malignant, stratum basale cells proliferate and invase higher dermis and hypodermis
squamous cell carcinoma- arises from keratinocytes in stratum spinosum and goes to top layers
melanoma- most dangerous, highly metastatic, melanocytes
burns
first- epidermis damaged, no bleeding because epidermis is avascular
second- epidermis destroyed, part of dermis damaged, blistering and bleeding because dermis is vascular
third- epidermis and dermis destroyed, discolored, no pain because nerve endings burned off
tissue repair stages
inflammation and migratory phase- dialiation of blood vessels, mast cells release histamine, plasma with antibodies and clotting
granulation- proliferation of new blood vessels and connective tissue. fibroblasts lay new layers of collagen
maturation- restores normal function, scarring, surface of cut is regenerated
fibrosis
damaged tissue is repaired but normal function is not restored
parenchyma
functional repair and regenerated cellss
stroma
when fibroblast cells makes the tissue that causes fibrosis
keloid
excessive collagen from fibroblasts, repair exceeds boundary of wound
hypertrophic scar
excess collagen, growth does not exceed wound boundaries but still raised bump
