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38 Cards in this Set

  • Front
  • Back
The Skin
d
surface area
weight
thickness
how many layers?
Largest organ in body
Very large surface area 1-2 m2
Weight 5-11 lbs
averages 1-5 mm thck
2 main layers
General Functions of Skin
Protection
Penetration variables
TEmperature Regulation
Metabolism
Excretion
Sensory
Skin - Forms of Protection
Mechanical (physical barrier)
-holds everything in
-protects from bacteria,chemicals,h20
-keratin (specialized protein)
-glycolipids (carb lipid, waterproof)
Chemical
-acid mantle (makes skin acidic to
fend off bacteria/virus)
-sebum (bactericidal) oily
-normal flora (healthy bacteria)
Skin Functions - Penetration Variables
Skin is not protectant against:
lipid solubles: vitamins, steroids,
gases
organic solvents: alcohol, acetone
heavy metals: pb, hg
Penetration enhancers: DEET (bug repellant)
Function of Skin - Temperature Regulation
Sweat (helps lose heat through evaportn)
Vasodilaton (when blood vessels dilate
or expand to bring self to surface to
help cool body down
Vasoconstriction (when blood vessels
clamp down to conserve body heat)
Piloerection (goosebumps:erecting of
hair to perserve skin/ maintian heat)
Function of Skin - Metabolism
Examples
UV light conversion to Vitamin D
CYP 450 metabolism of arachidonic acid
by keratinocytes
Function of Skin - Exrection
Excretes amonia, urea, and uric acid

most of this is done by digestive tract,
urethra

some is done by the skin
Functions of Skin - Sensory
Senses
Pain
Tactile Sensations (touch, pressure,
vibration)
Provides tactile adaption
when your brain stops "firing" to you that your body is sensing clothing.
Layers of the Skin
Epidermis
Top layer(part you can see)
Specialized stratified squamous
Divided into several layers
Dermis
Bottom Layer(part you cant see)
Variety of connective tissue types

Below dermis lies subcutaneous area comprised of adipose(role in heat maint) and connective tiss(stores lipids
THE EPIDERMIS
What's in every layer?
What does this layer NOT contain?
Comprised of?
How are cells & layers id'd?
Comprised of 5 separate layers
-keratinocytes can be found in every
layer
Each layer possesses specialized cell
types
Cells & layers can be id'd histologicly
No blood vessels/nerve endings in this
layer
LAYERS OF THE EPIDERMIS
Corneum: surface layer, 20-30 cells
thick, dead cells, comprised mostly of
keratin and glycolipids.
Lucidum: dead skin/callous. only present
in thick skin. not present in all skin
Granulosum: 3-5 cell layers of dying
keratinocytes, some cells will accum.
granules of glycolipid and help prev.
water loss.
Spinosum: weblike system of filaments.
supportive func. may have keratinocytes
melanocytes, and langerhans cells
Basale: deepest layer, single layer of
newly formed keratinocytes
DERMIS
Location
How many layers?
What kind of cell types does it contain?
What else does it contain?
-Lies below epidermis
-Divided into 2 layers
-Richly supplied with nerves(tactile, pain etc), lymph(immune system), BV
-Contains variety of cell types
fibroblasts, macrphages, WBCs, mast
cells(chem. timebombs, make histamine), sensory receptors
APOPTOSIS
programmed cellular death
DERMIS: Layers
What are the layers called?
Papillary
Reticular
DERMIS: LAYERS: Papillary
D
Contains?
Superior surface?
Vascular/Avascular?
-Areolar connective tissue
-Has collagen & elastin
-Superior surface is ridged (Makes up ridges in fingerprints)
-Richly vascularized
-Contains free nerve endings & tactile receptors
DERMIS: LAYERS: Reticular
D
Comprised of?
What does it do?
Dense, irregular connective tissue
Mostly comprised of collagen
Collagen provides strength & resiliance
(like skin tares in old people due
to lack of collagen)
Binds water & helps maintain hydration
CELLS OF THE EPIDERMIS
Name all of them
Keratinocytes
Melanocytes
Langerhan Cells
Free Nerve Endings
Warm/Cold receptors
Nociceptors
Ruffini's
Merkel's
Pacinian Corpuscles
Meisnner's Corpuscles
PIGMENTATION
Name them all
Melanin
Hemoglobin
Carotene
Billirubin
CELLS OF EPIDERMIS: keratinocytes
What are they?
Greek meaning?
Location
Where are these cells produced?
What happends to the outer layers?
Keratin producing cells(fibrous protein)
Greek-horn
Located at the hair follicle
Cells produced in deepest part of
epidermis then migrate to surface
Outer layers die due to lack of nutrient
source
Constant cell turn-over
CELLS OF EPIDERMIS: melanocytes
What are they?
Greek meaning?
What is melanin? function?
What makes up diff colors of people?
Location?
Stimulated by?
Produced by?
What causes hyperpigmentation?
Pigment producing cells
Greek-black
Melanin is black amine polymer (pigment
colored molecule)
Provides protective shield against UV
Absorbs sunlight due to lg no. of H bond
Varying distribution = varying skin
color
Location -dendritic cells found in
basal layer
Stimulated by Melanocyte Stimulating
Hormone
Produced by Pituitary gland (endocrine
gland in brain)responds to uv expos.
Increases in ACTH can produce hyperpig.
MELANIN
Derivative of?
Where is it produced?
What's tyrosinase?
Where is it found?
Lack of tyrosinase leads to?
How does melanin cause vision probs?
Derivative of Amino Acid Tyrosine
Production in organelles called melano-
somes
Tyrosinase is enzyme that starts pathway
of tyrosine to melanin
Found on chromosome 11
Lack of Tyrosinase: albinism
Melanin: important for dev. of area in
retina called fovea. lack of melanin
results in vision problems
HEMOGLOBIN
What color does it give off?
What does it carry?
What is porphyria?
Gives pinkish blue
Can carry oxygen
Porphyria - disorder of heme synthesis
CAROTENE
what color does it give off?
location other than body?
where can it accumulate?
Yellow-orange pigment
Found in carotene plants
Can accumulate in corneum
BILLIRUBIN
what is it?
what can it produce?
metabolic by-product heme synthesis
can produce jaundice
CELLS OF THE EPIDERMIS: Langerhans Cells
Where are they derived?
Where do they migrate?
Function?
What happends during injury/exposure?
Derived in bone marrow
Migrate to epidermis
Have microphage like function (immunity)
During injury/exposure - travel to lymph
nodes and "display" the antigen for
T-Cells
CELLS OF EPIDERMIS: Free Nerve Endings
What is a free nerve ending?
What are they involved in?
What are nociceptors?
A nerve that does not have protective
coating around it.
Involved in sensations of pain, temp,
hot/cold
Nociceptors: pain receptors
UNMILINATED
Not covered in a protective sheath
CELLS OF EPIDERMIS: Ruffini's
Respond to?
Respond to stretch, spacial, overexten
tion
CELLS OF EPIDERMIS: Merkel's
Respond to?
Respond to light touch
CELLS OF EPIDERMIS: Pacinian Corpuscles
Respond to?
Pressure/Vibration
CELLS OF EPIDERMIS: Meisnners Corpuscles
respond to?
Fine touch
SWEAT GLANDS
What are the types
Eccrine
Apocrine
SWEAT GLANDS: Eccrine
Where do they lie?
What do they secrete?
What do they regulate?
What is the function of sweat?
Lie coiled in dermis, with ducts
extending to surface
secrete hypotonic solution of water,
vitamins, antibodies, and nitrogenous
waste
regulate SNS (sympathetic nervous sys)
function: thermoregulation, immunity,
waste removal
SWEAT GLANDS: Apocrine
Where found?
Secretes?
What & how does it produce?
What does it have a LIMITEd role in?
May also be involved in?
Found in axillary / genital areas
Secretes hypotonic solution of water,
vitamins, antibodies, nitrogenous
waste, proteins, and lipids
Degraded by surface bacteria to produce
odor
Limited role in thermoreg.
May be involved in pheromone release
GLANDS: Others
Name the 3 others
Ceruminous
Mammary
Sabacceous
GLANDS: Ceruminous
What is it?
Where found?
Secretes?
Modified apocrine gland
Found in ear
Secretes cerumen(wax)
GLANDS: Mammary
Secretes
**
Secretes breast milk
**Males can get this too
GLANDS: Sebaceous
Where found?
What size?
What isn't visible
What does it accumulate
Functions?
All over body
vary in size
no visible lumen
accumulate lipid then burst, secreted
along hair follicle
helps prevent water loss
immunity