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Chapter 4
Skin and Body
Membranes
BODY MEMBRANES
• _________________________cover
surfaces,line body cavities and forms
protective-sometimes lubricating –sheets
around organs
I.Classification of Body Membranes
•
A) EPITHELIAL MEMBRANES
–
–
Covering and lining membranes
All have an underlying sheet of connective
tissue
•
•
•
1) Cutaneous Membranes= skin
Superficial epidermis
is____________________________________
Underlying dermis is dense(fibrous) connective
tissue.The superficial tissue is exposed to air and
is a ________________________________
Composed of keratinizing
stratified squamous
epithelial
Dry membrane
•
•
2) Mucous Membranes-made of varying types of
epithelial tissue resting on a loose connective
tissue called ____________________ and lines
all membranes that open to the exterior(hallow
organs of respiratory tract,digestive,urinary and
reproductive…
Mucosa refers to location,not cellular
makeup….But most mucosa are stratified
squamous (mouth and esophagus) epithelium or
simple columnar (rest of digestive tract)----all wet
and bathed in secretions)
Lamina propria
3)Serous membranes(serosa)•
•
Areolar
connective
tissue
Has a layer of simple squamous epithelium
on a thin layer of
________________________________
Serosa are closed to the exterior (except for
dorsal body cavities and joint cavities)
• Occur in pairs…The __________________lines
a specific portion of the ventral body cavity
• Parietal layer folds in itself to form
________________-covers outside of the
organs in that cavity
• Serous layers separated
by___________________-secreted by both
membranes
Serous fluid
Parietal layer
Visceral layer
• Serous fluid allows organs to slide against
ea. Other and cavity w/o friction
SEROUS NAMES RELATED TO
LOCATION
peritoneum
pleural
– ______________________covers abdominal
cavity
– ____________________-surrounds lungs
– _______________________surrounds heart
pericardium
Connective Tissue membranes
• Composed of ______________________and
has NO epithelial cells-line capsules surrounding
joints
• Line small sacs of connective tissue called
bursae and the tubelike tendon sheath----all
cushioning organs against each other and
tendon across bone
Soft areolar connective
tissue
II.The Integumentary
Sysyem(skin)-cutaneous
membrane
• The Integumentary Sysyem(skin)-cutaneous
membrane
• functions –most importantly
protective….against mechanical
damage,chemical damage,
• bacterial damage,
• UV effects,thermal effects and
dessication(drying out)
• ---also aids in controlling body heat
• ---aids in excretion of urea and uric acid
• ----synthesizes Vitamin D
• The uppermost layer is full of _____________and is cornified or hardened-help prevent water
loss
• Capillaries and sweat glands work on thermal
control
• ____________sense
touch,pressure,temperature and pain
keratin
Cutaneous sensory
receptors
Structure of skin
–
–
–
–
Epidermis-stratified squamous epithelial
capable of keratinizing(hardening)
_________-underneath-mostly dense connective
tissue
Epidermis and dermis strongly connected,but
some abuse can cause them to separate—
interstitial fluid comes between layers making a
_____________
_____________is below dermis and mostly
adipose----not actually considered part of
skin,but attaches skin to organs beneath--works as “shock absorber” and insulates from
extreme temperatures
dermis
blister
Subcutane
ous tissue
1)Epidermis•
•
•
strata
has 5 layers or _______________.From inside
out they are stratum
basale,spinosum,granulosum,lucidum and
corneum
avascular
most cells are
______________________________which
make keratin
keratinocytes
• Stratum basale-closest to dermis and
connected along a wavy borderline.Contains
epidermal cells that that get the most
nourishment by diffusion from dermis;constant
cell division-MILLIONS OF NEW CELLS
DAILY(also called stratum
germanitivum),daughter cells pushed upward
• Stratum Spinosum and stratum granulosum
become flatter and increasingly full of keratin
• When the previous cells die,they form the clear
_________________________________-not in all skin
regions-only where skin is hairless and extra thickie.palms and soles;it secretes a water repellent
glycolipid into extracellular space;distant from blood
supply,so little nutrients-doomed cells
Stratum lucidum
• OUTERMOST Stratum corneum—20-30 cells
layers thick and is ¾ of epidermal
thickness;cornified,shinglelike dad cells,filled
w/ keratin;protects lower cells;dandruff
sloughs off from here
• We have a totally new epidermis every 25-45
days
• ___________________pigment that ranges in color
from yellow to brown to black produced by
melanocytes(in stratum basale).When skin is
exposed to sun,this stimulates these cells tomake
more of the pigment---THUS tanning
melanin
• Melanin accumulates in membrane bound
granules called __________________.They
move to the end of the melanocytes and taken
up by keratinocytes .THERE,melanin froms a
pigment umbrella over superficial side of
nuclei-shielding DNA from UV
• _______________and moles are where melanin
are concentrated in one spot
melanosomes
freckles
2)dermis-‘hide
Papillary
layer
Dermal papillae
– strong,stretchy
– dense fibrous connective tissue
– ___________________upper dermal
region;______________-peglike
projections from superior surface-many
containing capillary loops-thus
nutrients;some have pain receptors___________________ or touch receptors_________________________________
Free-nerve
endings
Meissner’s corpuscles
• Has whorled rings on soles and
palms,increasing friction and gripping
ability----genetically
determined…..sweat pores provide for
fingerprints
Reticular layer
–
–
– 2)_______________________________deepest skin
layer w/blood vessels,sweat and oil glands and
_______________________________deep pressure
receptors;phagocytes act here at reticular layer
Collagen and elastic fibers found in dermis.collagen gives
toughness and attract water for hydration.Elasisic fibers
give elasticity that declines w/age
Many blood vessels help w/ body temp.homeostasis.skin
is red when hot due to engorging of blood
Pacinian
corpuscles
– ___________________________________
happen in bedridden patients not turned
regularily-pressure restricts blood supply and
redness when pressure is released
– Rich nerve supply
Decubitus
ulcers
C-Skin Color-3 pigments:
•
•
•
1-melanin in epidermis
2-carotene in stratum corneum and
subcutaneous tissue
• 3-O2-rich hemoglobin in dermis
----varying amounts of thr above
create the numerous skin colors.Which is showing
up more in
Caucasians?_________________________
• ________________________hemoglobin is
poorly oxygenated---can happen during heart
failure and severe bleeding
hemoglobin
cyanosis
What else affects skin color?:
• Emotions and various disease states:
– ___________________-rednessblushing,hypertension,inflammation,allergy
– ___________________-blanching-pale—fear,anger
also anemia,low blood pressure,impaired blood
flow
– ___________________-yellowness-liver disorder
– ____________-sites wher blood has escaped and
clotted in tissue spaces;can happen w/disese or
vitamin C deficiency
• _________________-clotted blood mass
erythema
pallor
bruises
jaundice
hematomas
D.Appendages of the Skin
Cutaneous glands
•
•
•
1-__________________________________exocrine glands-release secretions to skin’s
surface via ducts
a)Sebaceous glands-oil glands-excepts on palms
and soles—some open into hair follicle and some
to surface
________________-is product-clump of oil and
cells;keeps skin moist and prevents hair from
drying out
sebum
• ______________(sudoriferous glands)-many in the
skin-2 types:
1)eccrine glands-all over body and
make sweat(mostly water,NaCl,vitamin C and tarces
of metabolic wastes(ammonia, urea,uric acid and
lactic acid.It is acidic and inhibits bacteria….sweat
comes through a poer(not same as facial
pores);helps regulate temp.(37 C
Sweat glands
Apocrine glands
• 2)_____________________________mostly at axillary and genital areas;ducts
empty into hair follicles;contains fatty acids
and proteins—giving milky/yellowish
color.It is odorless,but that changes whe
bacteria use it as food:function at onset of
puberty regulated by androgens(male sex
hormones)----have been connected to
sexual foreplay
3-Hair and Hair Follicles
• .
• 1)Hairs made by hair follicles and is flexible
epithelial structure;root in ________________and
shaft protrudes It is formed by mitosis of stratum
basale epithelial cells in matrix(growth zone)become keratinized and die as pushed forward--mostly hair contains protein
• Hair has central core called a medulla surrounded
by a cortex.This is covered by a cuticle(most
keratinized region)-gives strength
• Hair pigments made by melanocytes in hair bulb
Hair
follice
• Variety of shapes and sizes(eyebrows v. head then
skin hair).If shaft is flat and ribbonlike-hair curly or
kinky.If shaft is round-straight or coarse hair
• Hair all over except soles,palms,nipples and lips
• Fastest growing tissue in body
• Have hormonal control
• 2) hair follicles-contain inner epidermal sheath
that forms hair/outer dermal sheath is connective
tissue/papilla yield blood supply to matrix in hair
bulb
• ______________________________smooth
muscle that raise hair in response to temp
Errector pilli
Free edge
Nail matrix
• 3) Nails-scalelike product of dermis(corresponds to hoof
•
•
•
•
lunule
or nail)
Each nail has a _______________,a body(visible and a
root(imbedded in skin)
Nail bed in stratum basale and inner
____________________,responsible for growth-cells
become keratinized and die
Part appears pink due to vascularization in dermis
___________________ appears white
E.Homeostatic imbalances of skin
•
1) Infections and Allergies
–
–
___________________________-fungal,itchy red
,peeling skin(tinea pedis)
Boils and Carbuncles-inflammation of hair
follicles and sebaceous glands—often dorsal
neck.Carbuncles are caused by bacteria-esp.
Staphylococcus aureus
Athlete’s foot
– _____________________-small fluid
filled(fever blisters)-itch and sting –caused by
a herpes simplex virus-can be activated from
dormancy from emotions,fever,UV lightusually around lips or oral mucosa
– _____________________________itchy,red,swelling and turns into blistersexposure to chemicals like poison ivy
Cold sores
Contact
dermatitis
– ___________________-pink,water-filled
raised lesions around nose and
mouth;w/yellow crust;caused by
Staphylococcus
– _____________________-chronic
overproduction of cells w/ red epidermal
lesions—probably autoimmune
impetigo
psoriasis
2-burns-tissue damage and cell death caused intense
heat,electricity,UV light or certain chemicals---This can
have a domino effect on several organ systems
•
•
destroys cells
Life threatening from 1) loss of fluids as they seep
from burned surface-dehydrating and fluid
imbalance-could shut down kidneys and cause
circulatory shock
• ___________________________-divides body into 11
areas,ea. 9% of total body surface area+ area around
genitals-determines % burned
• 2) infection later is a leading cause of death-after 24
hrs.,pathogens invade the area and multiply quickly
RULE OF NINES
Classification:
• 1st degree-only epidermis is damaged-red and
swollen
• 2nd degree injury to epidermis and upper dermisregrowth will occur
• 1st and 2nd degree are
___________________________burns
• 3rd degree-destroys entire thickness of skin(fullthickness burns)
Partial-thickness burns
• Critical if a) over 25% covered w/ 2nd degree b)
over 10% 3rd degree OR c) 3rd on face ,hands or feet
3-Skin Cancer
– Most neoplasms benign(ex-wart)
– Affect 1/5 americans
– _________________________________-least
malignant and most common-affects stratum
basal so cannot form keratin;boundary between
epidermis and dermis lost;fairly slow growing
– _______________________________-from stratum
spinosum-scalp,ears,hands-grows rapidly,but if
caught early,prognosis is good
Basal cell
carcinoma
Squamous cell
carcinoma
•
•
•
•
– ____________________-cancer of
melanocytes(5%of skin cancers)-happen where
ever there is pigment and often deadly-50%
survival w/early detection
– ABCD RULE_
a)asymmetry
b)border irregularity
c)color-areas of different color
d)diameter-larger than 6 mm
Malignant
melanoma
Take notes p. 127 on
developmental aspects:
• Lanugo-downy hair covering on infant –shed by
birth
• Newborn has vernix caeosa-white and cheesy
and made by sebaceous glands-protection while
in womb
• Newborn skin thin-milia-accumulations in
sebaceous glands(nose and forehead)
• Skin and hair more oily during adolescenceacne occurs
• Dermatitis-inplammation
• During old age- subcutaneous tissue
decreases-less tolerance to cold/also drier
due to less oil/decreasing
elasticity/thinning of skin and more
bruising
• Good nutrition,fluids and cleanliness csn
slow loss of elasticity-aggravated by sun
and smoking
• Hair loses luster and less hair follicles
• ALOPECIA-hair thinning and baldness
• Male pattern baldness-has light vellus
hairs
• Graying hair
• Genetic factor-as gene is
expressed,melanin in hair decreases
• Also genetic factor in baldness