Chapter 5: Integumentary System Flashcards
integument
skin, hair, nails, sweat glands, sebaceous glands
functions of integumentary system (7)
- protection: abrasion, chemicals, water loss
- temp regulation
- sense organ (pain, hot)
- create/store vitamin D
- shields UV rays
- diagnostic organ (excessive itching is diabetes)
- sexual attraction organ (phermones)
What are the 2 tissue layers of skin?
dermis
epidermis
epidermis
- epithelial surface layer (5 layers)
- stratified keratinized squamous
dermis
- deeper connective tissue
- binds epodermis to hypodermis
Hypodermis (subcutaneous layer)
- not skin
- loose CT (mostly adipose)
- attaches dermis to deeper tissues
4 cell types in epidermis
- keratinocytes
- melanocytes
- langerhans cells
- merkel cells
keratinocytes
produce keratin
melanocytes
produce melanin
langerhans cells
- part of immune system
- derived frm bone marrow
- show forein substances to lymphocytes
merkel cells
ends of sensory neurons
How many layers are in the epidermis?
- varied (4 or 5)
- depends on degree of friction + mechanical pressure applied
- thick skin-non hairy parts (soles of feet, palms)
- thin skin everywhere else
what are the layers of the epidermis (deep–>superficial)?
- stratum basale (germanitivum)
- stratum spinosum
- atratum granulosum
- stratem lucidum
- stratum corneum
Stratum basale
- cells:
- keratinocytes: rest on basal lamina of basement mem.
- melanocytes: use enzyme (tyrosinase) to produce melanin
- merkel cells: numerous in stratum basale of fingertips (rapid mitosis)
how do melanocytes produce and distribute melanin? What does melanin prevent?
- melanin granules accumulate in melanocyte and exit by pinching off
- they’re distributed through epidermis and surround nucleus
- protects DNA from genetic mutation
stratum spinosum
- cells:
- keratinocytes: 8-10 layers, cuboidal and held togeter by desmosomes, accumulate keratohyalin (protein)
- langerhans: immunologically active, dont separate in areas of friction, produce karatohyalin, provides flex + strength
stratum granulosum
cells:
- keratinocytes: 3-5 layers of dying with shrunken nucleus
- lamellar granules: secrete water repellent lipid sealant in cytoplasm
- keratohyalin granules are present in cytoplasm (condense and reffered to as lamelar granules for sealant)
stratum lucidum
cells:
- keratinocytes: flattened, dead (transparent)
- found in thick skin
- keratohyalin forms eledin that fills cells
stratum corneum
- cells:
- keratinocytes- flattened, dead, filled with keratin (formed from eledin)
- horny cells: dead karatinocytes that have dispersed all of their keratin at the upper surfaceof stratum corneum
- keratinization
how does keratinization of the stratum corneum occur?
replacement of cell contents with the protein keratin as the cells migrate to the skin surface over a 2-4 week period
callus
abnormal thinckening of stratum corneum
dermis
what is it made of?
- made of dense regular CT that has 2 regions
- highly vascular
- supports epidermis
what are the 2 regions of the dermis?
- papillary region
- reticular region
papillary layer
- areolar CT
- fine elastic fibers
- dermal papillae
- nerve endings for sensations
- pushes up into epidermis (fibrous extension) to strengthen dermal epidermal junction
what are the types of nerve endings?
- meissners corpuscles
- ruffini receptors
function of arrector pilli muscle
no function in humans, protective in animals
reticular layer
- dense irregular CT
- bundles of collagen + elastic fibers
- spaces btwn fibers contain adipose cells, hair follicles, sebaceous glands, sudorifferous glands
sebaceous glands vs sudoriferous glands
sebaceous: secrete sebum into shaft
sudorifferous: secrete sweat through ducts
tatooing
permanent coloration of skin in which foreing pigment is injected into the dermis
epidermal ridges
increases friction for grasping and provides fingerprints and footprints
3 pigments in the dermis
- melanin
- carotene
- hemoglobin
albanism
- inherited inability to produce melanin
- have melanocytes without melanin production
- symptoms: pink eyes, white skin & hair, high sunburn & skin cancer risk
vitiligo
- complete or partial loss of melanocytes from patches f skin
- results in irregular white spots
- immunological disease or from thyroid disfunction or head trauma
accessory structures of the skin
hair, glands, nails
hairs or pilli
present on most skin surfaces except palms, palmar surfaces of fingers, soles and plantar surface of toes
what does hair consist of?
- shaft above the surface
- root that penetrates the dermis and subcutaneous layer, cuticle, hair follicle & arrecto pilli muscle
what does arrector pilli muscle do? how?
- connected to hair follicle
- rotates hair perpendicular through skin
- pushes skin and causes goose bumps
- smooth muscle
cuticle
description
function
- 1 cell thick
- heavy
- keratinized
- loo like clear interlocking shingles
- assist in anchoring hair in place
hair follicle
contains actively mitotic cells that will produce new hair or repair damaged hair
what is hair color due to?
amount and type of melanin
graying of hair occurs because?
progressive decline in enzyme tyrosinase
why is tyrosinase used?
melanocytes use tyrosinase to convert melanin to eledin
sebaceous glands
- connected to hair follicles and produce sebum
- keeps skin and hair soft/waterproof and inhibits bacterial growth
- ducts empty into neck of hair folliclle everywhere except lips, genitalia, nipples
acne
results when sebaceous glands become plugged with dirt or white blood cells
sudoriferous (sweat) glands
divided into eccrine and apocrine type to rpoduce sweat
persperation consists of
- water
- NaCl
- protein
- urea
- polysaccharides
perspire in response to what?
parasympathetic nervous system
eccrine sweat glands
have ducts that terminate at pores at the surface of the epidermis
apocrine sweat glands
location
description
- located in axilla, pubis, areola
- ducts open into hair follicles
- secretion is viscous causing odor
- simulated by sex hormones and emotional stress
- controlled by sympathetic nervous system
nails
hard plates of keratinized epidermal cells over the posterior surfaces of the terminal portions of fingers/toes
nails help to
grasp, mmanipulate small objects and provide protection against trauma to the ends of digits
nail conditions
cyanosis, spooning
cyanosis symptoms
- blue to purple discoloration of skin
- whites of eyes
- mucus mmebranes due to a lack of hemoglobin bound oxygen
emphisima COPD
nails take on shape of spoon
thin skin
- covers all parts of the body except palms and palmar surfaces of digits/toes
- lacks stratum lucidum and epidural ridges
thick skin
- covers palms, palmar surfaces of digits/soles
- contains stratum lucidum and thick epidural ridges
- lacks hair follicles, arrector pilli muscles, sebaceous glands
- contains more sweat glands than skin
when an injury to tissues extends deep into the epidermis
the repair process results in scar tissues formation or fibrosis
inflammatory phase
- blood clot unites the wound edges
- epithelial cells migrate across the wound
- vasodilation and increased permeability of blood vessels deliver phagocytes & fibroblasts
migratory phase
- epithelial cells beneath the scab bridge the wound
- fibroblasts begin scar tissue
- damaged blood vessels begin to grow
- tissue filling wound is granulation tissue
proliferation phase
events of the migratory phase intensify
maturation phase
- scab sloughs off
- epidermis is restored to normal thickness
- collagen fibers become more organized
- fibroblasts begin to disappear
- blood vessels are resored to normal
decubitus ulcer (pressure sore)
cause
constant deficiency of blood to the tissues over a bony projection that has been subjected to prolonged pressure against an object such as a bed, cast, splint
where do you get pressure sores?
most susceptible tissues: sacrum, ischia (pelvis), femurs, bumps on ankle (malleoli)
