The Integumentary System: Lecture 11 Flashcards
integumentary system organs
skin, hair, nails, exocrine glands, sensory receptors, arrector pili muscles
layers of the cutaneous membrane
epidermis, dermis, hypodermis
integument functions
protection, sensation, thermoregulation, excretion, vitamin D synthesis
burn complications
infection and hypothermia (damage to thermoregulation and protective functions)
skin and body temp homeostasis
increase body temp: vasodilation, sweat secretion
decrease body temp: vasoconstriction
layers of the epidermis
corneum, lucidum, granulosum, spinosum, basale
stratum corneum
layer of dead keratinocytes; most superficial layers lose desmosomes, slough off
stratum lucidum
clear layer of dead keratinocytes (thick skin only)
stratum granulosum
numerous cytoplasmic granules containing keratin bundles or lipid based substance; secretes lipid based substance, waterproofs, cuts cells off from basal lamina
stratum spinosum
some mitotically active cells, starting to produce keratin components
stratum basale
single layer of stem cells (mitotically active), rests on basement membrane
epidermis cells
95% keratinocytes, 5% dendritic cells, merkel cells, melanocytes
dendritic cells
in stratum spinosum, phagocytes
melanocytes
in stratum basale, produce melanin pigment
merkel cell
in stratum basale, detect light touch and textures
layers of the dermis
papillary layer, reticular layer
papillary layer
loose CT, dermal papillae extend into epidermis; capillary networks and tactile corpuscles
reticular layer
dense irregular CT; strength and elasticity, hydration; contains blood vessels, sweat glands, sebaceous glands, lamellated corpuscles
fingerprints
prominent dermal papillae arranged into dermal ridges; sweat glands along ridges leave fingerprints
flexure lines
reticular layer bound tightly to deeper tissues; prominent around joints and palms
tension lines
gaps between collagen bundles in reticular layer indent epidermis to form tension lines; wound healing and scarring
melanin
orange-red to black pigment; protects DNA from UV radiation and produced by melanocytes in basale
carotene
yellow-orange pigment, vitamin A precursors, unsaturated lipids; obtained from diet and stored in adipose tissue
hemoglobin
red pigment (iron oxidation), binds oxygen, quaternary structure; protein synthesis in erythrocytes
freckles/moles
localized higher melanin production
albinism
melanocytes do not produce tyrosinase
erythema
reddening of skin (dilation of capillaries); hemoglobin bound to oxygen
pallor
decreased blood flow; pale or white appearance (collagen in dermis)
red lips
thin stratum corneum makes it appear more red
cyanosis
bluish skin, extremely low oxygen bound to hemoglobin
healthy tans
immediate response: oxidation causes melanin to quickly darken or turn red
delayed response: UV causes DNA damage, stimulates melanin production- lasts longer
secondary function of melanin
reduces synthesis of vitamin D
skin color
depends on number of melanocytes in particular body regions and differences in amount of tyrosinase activity and type
hair
derived from skin epithelium; protective and sensory functions
lanugo
thin, non-pigmented hair on fetus
terminal hair
scalp and around eyes; some body hair post-puberty
vellus hair
body hair
nails
derived from skin epithelium; protective and gripping functions
gland types
derived from skin epithelium; sweat and sebaceous glands with various functions
eccrine
merocrine secretion (exocytosis); most prevalent: water electrolytes, lactic acid
apocrine
merocrine secretion (exocytosis); release into hair follicle- armpits, anal area, areolae; protein causes odor
ceruminous gland
merocrine secretion (exocytosis); modified apocrine in ear-produce ear wax
mammary
merocrine secretion (exocytosis); produce milk
sebaceous
holocrine secretion (rupture and release); produce and secrete sebum
wounds
any disruption in skin integrity; lacerations, burns, skin cancers
first degree burns
minor, only damage epidermis; may develop erythema and mild pain
second degree burns
damage to epidermis and part or all of dermis; pain, blistering, and scarring
third degree burns
most damaging; epidermis, dermis, hypodermis, potentially deeper; destroys nerves, loss of hair follicles, diminished keratin production, massive fluid loss, risk of infection
skin cancer
unchecked cell division linked to UV radiation exposure
basal cell carcinoma
most common; arises from keratinocytes in basale, rarely metastasizes; can be resolved with surgical removal
squamous cell carcinoma
second most common, cancer of keratinocytes in spinosum; more likely to metastasize, surgical removal still useful
malignant melanoma
tendency to metastasize; critical early detection; extend into dermal blood vessels
hyperpigmentation
overproduction in melanin;
melasma: dark patches mainly on face can occur during pregnancy
hypopigmentation
decreased melanin production or destruction of melanocytes
vitiligo, tinea versicolor
