Transcript Integument ppt PED

Integumentary System
Skin & its appendages (hair, nails, skin glands)
Integument = skin,
principle organ of
integumentary system
Functions of Skin (cutaneous membrane)
Protection
1st line of defense vs microbes. Tough cells of stratum
corneum (thick skin b/c stratified squamous epi’s)
protects vs. tears, cuts
Keratin (protein) H2O proof protects vs fluid loss,
keeps fluids in
Melanin in pigment layer prevents UV rays from
penetrating body
Vit D manufactured in skin w/ sunlight (uvB Rays)
helps Ca/P absorption  strong bones
Temp Regulation
Regulates sweat secretions
sweat evaporates  heat lost
Regulates flow of blood close to body surface
Blood vessels dilate close to surface heat lost by
radiation
Blood vessels constrict  heat conserved
Sense Organ
Millions of nerve endings, receivers for body,
keep it informed of environmental changes,
react to stimuli (pain, pressure, temp, etc)
Structure of the skin
Skin is cutaneous membrane: sheetlike organ
composed of 2 layers of distinct tissue
Epidermis: Outermost skin layer
Thin sheet of stratified squamous epi’s
Dermis: Deeper layer
Thicker than epidermis
Consists of mostly connective tissue
Subcutaneous Tissue
Loose connective tissue & fat
Not part of skin itself
Carries major blood vessels & nerves to skin above
Rapid, painfree absorption of injected material
Spongy, porous layer
Stratum Basale
Epidermis
Stratum corneum
Dead, flat cells full of keratin
Keratin is waterproof protein
Cells are shed/sloughed
Stratum lucidum
(lucid = clear↑ apparent in thick skin
3-5 layers of clear cells
“Thicker” areas
Soles of feet, palms
 prints
Stratum granulosum
3-5 layers
Keratinization begins here
Cytoplasm replaced w/ tough, H2O proof protein
Cells beginning to die
Stratum spinosum
8-10 layers
Keratinocytes take in keratin
Stratum basale (stratum germinativum)
Single layer of cuboidal to columnar cells
Stem cells that produce keratinocytes
Melanocytes - # the same for all races
Melanin produced in a melanosome
Basal cell to surface – about 2-4 weeks
Increased [melanocyte]  deeper skin color
Sun ↑ melanocytes w/ melanin  tan
↑ sun exposure  ↑melanin deposits in dermis
[melanin] in relation to blood vol or [O2]
blood flow to skin pink, flush, blush
blood flow to skin bluish gray - cyanosis
*Notice above more w/ less w/ [melanin]
When skin cells deprived of O2 Decubitus Ulcer
Bed Sores
Tissue breaks down
Decubitus Ulcer of Elbow
Cells of epidermis pkd tightly & held together by
“spot welds”
(junctions btwn membranes of adjacent cells.
If weakened/destroyed  skin falls apart)
Burns, friction, irritant exposure  blisters
(top layer raised fluid filled)
Merkel cells in deep in
epidermis hairless areas ?
Fx in touch sensation
90% of
epidermis
Contains
melanin  skin
color, absorbs
UV radiation
Fx in immune
response, damaged
by UV radiation
*
*Merkel cell in
deepest layer of
hairless skin ? Fx in
touch sensation
Dermal-Epidermal Junction: junction between thin
epidermal layer of skin above and thicker dermal
layer below
2. Dermis: Deeper of 2 primary layers
Much thicker,
Made mostly of connective tissue
Cells scattered w/ fibers in between, not
pkd like Epidermis
Fibers: some tough & strong
others stretchable, elastic
Upper Dermis: Dermal Papillae
// rows of peglike projections
Important part of dermal-epidermal junction
 helps bind 2 skin layers together
Forms ridges & grooves fingerprinting/ID
Epidermis follows contours of dermal papillae
Develop before birth, unique, individual, never changes
but to grow larger fingerprints & footprints (+ ID)
Deeper area of dermis filled w/ dense network of
interlacing fibers
 collagenous  giving toughness to skin
Elastic fibers also present  stretchable, elasticity
Age, ↓ # of elastic fibers in dermis, amt fat stored
in subcutaneous tissue
 wrinkles…loss of elasticity, sags, pliant
(botox, collagen injections, retinol, ↑ collagenous fibers 
↓ wrinkles!
Appendages of the skin
Hair: human body covered w/ hair
At birth, most follicles required for hair growth
present
Lanugo: newborn hair, fine & soft, lost &
replaced w/ new,
stronger & more pigmented hair
Lips, palms, soles hairless
Most body hair invisible
Most visible on scalp, eyelids, eyebrows
Pubic & Axillary (under arm) hairs
 develops w/ puberty (result of hormone secretions)
Cells of epidermis
grow ↓ into
Dermis forming
hair follicle
(sm tube)
Hair growth
begins from
cluster of cells
Hair Papilla
located at
follicle base
*
*
Papilla
nourished by a
dermal blood vessel
Root hidden in follicle
Shaft (dead cells)
visible part of hair
*
As long as cells in
Papilla alive, new
Hair replaces plucked
*
Neither makes hair
Grow faster of effects
*
epithelial cells
*
That form hairs b/c
they’re embedded in Depilliatories destroy protein in hair shaft
(Ex. Nair)
dermis
Arrector Pili
(Errects hair)
Smooth/involuntary
muscles
Attached at base of
dermal papilla
above & to side of follicle
Frightened or cold
 contract
Each muscle pulls
on 2 points of attachment
up on hair follicle,
down on part of skin
 goose bumps
*
Sensory Receptors: allows body surface to act as
sense organ
Relays messages to brain, sensations of pain, temp,
pressure
Meissners Corpuscle: dermis surface, light touch
Pacinian Corpuscle: deep dermis, detects pressure
Thermoreceptors: temp receptors in skin (detect
stimulus & send impulse to hypothalamus (control
center) in brain (Uses – feedback loop, like thermostat)
Nails: accessory organs of skin, produced by cells
in epidermis.
Epidermal cells over terminal ends of fingers/toes
fill w/ keratin (protein)  hard, plate like
Nail Plate/Body: visible part of nail
Root: lies in groove, hidden by fold (cuticle)
Luna: (little moon) crescent shaped white area near root
Nail Bed: under nail, thin layer of epithelium has blood
vessels pink & translucent
blood (O2)  cyanosis blue nail bed
free edge
Skin Glands
Sweat / Sudoriferous Glands: most numerous
eccrine sweat glands (most)
sm. distributed all over body surface
produce perspiration/sweat
eliminates wastes (NH3, UA, maintains BT)
1 sq inch = 3000 eccrine glands pores
(outlets of small ducts)
apocrine sweat glands 10 in armpit & pigmented
skin
@ genitals. (scent glands)
Lgr vs eccrine & secrete thicker, milky secretions, 
odor from contamination & decomposition of secretion
→
Most
numerous
Armpits,
pigmented
areas,
genital areas
Oil glands,
secrete sebum,
↑’s after puberty
(opens to hair
follicles)
Sebum ↑ during adolescence, stimulated by ↑ blood
levels of sex hormones
Sebum accumulates, enlarges duct of sebaceous gland
 white pimples  darkens  blackhead


Acne Adolescence overactive secretion of sebaceous
glands w/ blockage & inflammation of ducts
Ages 10-19…5x sebum secretion
 sebaceous gland ducts get plugged w/ skin
cells & sebum w/ bacteria  comedo (pus filled
pimples from 20 infection w/in or beneath
epidermis in hair follicle or sweat pore
Sebaceous Glands: Secrete oil (sebum) for hair & skin,
Found wherever hair grows
Tiny ducts open to hair follicles
Secretion: Sebum, lubricates hair/skin
Milia: sm white bumps on newborn, accumulation of
sebaceous gland material
Vernix Caeseosa: oily substance produced by fetus’s
sebaceous glands
Burns
fire, heat, UV light, chemicals, electrical
Burns, treatment & recovery depend on:
Total area involved
Severity of burn
… determined by depth of injury
& amt of body surface affected
*Treatment  Prevent fluid loss & infection
Skin Grafts cultured
Estimating Body Surface: (% body surface burned)
Rule of 9’s to determine extent of burn injury
Body divided into 11 areas of 9% each + 1% genitals
Total = 100%
Head front 4.5%
back 4.5%
Arms front 4.5% (x2)
back 4.5% (x2)
9.0
9.0
Torso front 18%
back 18%
Legs front 9%
back 9%
genitals
1%
(x2)
(x2)
18.0
18.0
Burn Classification:
Based on # of tissue layers involved
1st degree: Sunburn, minor discomfort, skin red
surface layers of epidermis may peel 1-3d
No blistering
Minimal tissue destruction
2nd degree: Involves deep epidermal layers
Always causes injury to upper layer of
dermis
Damage sweat glands, hair follicles,
sebaceous glands, BUT NOT
complete dermis destruction
Blisters, severe pain, swelling, fluid loss,
scarring common
3rd degree: Complete destruction of epidermis/dermis,
tissue death extends below 10 skin layers
into subcutaneous tissue, muscle & bone.
Insensitive to pain
(destruction of nerve endings)
serious scarring
Types of Body Membranes
Membrane: Thin, sheet-like structure
Cover & protect body surface
Line body cavities
Cover inner surfaces of organs (dig, reprod, resp)
Anchor organs to each other or bones

Cover
internal organs
Some membranes secrete lubricating fluids to ↓ friction
during organ movements
(Ex. heart beating, lung expansion/contraction, in joints
between bone)
2 Main Types of Body Membranes
Epithelial Membranes
Connective Membranes
Cutaneous membranes
Skin (Integumentary)
Synovial membranes
Serous membranes
Mucous membranes
Epithelial Membranes
a. Cutaneous membranes: (Epidermis/Dermis) skin
10 organ of integumentary system
skin outer epidermis composed of stratified
squamous epithelial cells
underlying epidermis is dermis made of
connective tissue
subcutaneous
Epithelial Membranes cont’d
b. serous membranes: 2 distinct tissue layers
(secrete thin watery fluid helps ↓ friction  lubricant)
1. epithelial sheet: thin layer simple squamous epi’s
2. connective tissue layer: basement membrane
supports epi’s
2 Types of serous membranes
Parietal lines walls of body cavities
Visceral covers surface of organs in cavities
Pleura: Serous membrane of thoracic cavity
Peritoneum: Serous membrane of abdominal cavity
(lines cavities)
(covers organs)
parietal
& visceral pleura (of thoracic cavity)
parietal
& visceral peritoneum (of abdominal cavity)
pleurisy: inflammation of serous membranes (pleura)
lining chest cavity (parietal) and
covering lungs (visceral)
pain  friction of lungs rubbing vs. walls of chest cavity
peritonitis: inflammation of serous membranes
lining abdominal cavity (parietal) and
covering abdominal organs (visceral)
Sometimes from infected appendix
Epithelial Membranes cont’d
c. Mucous Membranes: Line body surfaces open to
outside
Structure depends on location
Most secrete mucus
moist, lubricate, protect
 keeps soft
Respiratory: Ciliated simple columnar epi’s  mucus
Digestive: Esophagus: stratified epi’s resist abrasion
Intestines: simple columnar epi’s
Urinary/Excretory: simple cuboidal  absorption
Reproductory
Connective Tissue Membranes
No Epithelial component
Synovial Membranes: Line joint spaces between bone
Smooth, slick
Secrete synovial fluid
Line bursae sacs (cushion)
between moving parts
 ↓ friction between joints
Now,
Brain Storm
and think of as many examples
of how structure dictates function
as you can,
then explain them!