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38 Cards in this Set
- Front
- Back
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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 |
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General Functions of Skin
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Protection
Penetration variables TEmperature Regulation Metabolism Excretion Sensory |
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Skin - Forms of Protection
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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) |
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Skin Functions - Penetration Variables
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Skin is not protectant against:
lipid solubles: vitamins, steroids, gases organic solvents: alcohol, acetone heavy metals: pb, hg Penetration enhancers: DEET (bug repellant) |
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Function of Skin - Temperature Regulation
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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) |
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Function of Skin - Metabolism
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Examples
UV light conversion to Vitamin D CYP 450 metabolism of arachidonic acid by keratinocytes |
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Function of Skin - Exrection
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Excretes amonia, urea, and uric acid
most of this is done by digestive tract, urethra some is done by the skin |
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Functions of Skin - Sensory
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Senses
Pain Tactile Sensations (touch, pressure, vibration) Provides tactile adaption when your brain stops "firing" to you that your body is sensing clothing. |
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Layers of the Skin
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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 |
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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 |
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LAYERS OF THE EPIDERMIS
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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 |
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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 |
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APOPTOSIS
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programmed cellular death
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DERMIS: Layers
What are the layers called? |
Papillary
Reticular |
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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 |
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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 |
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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 |
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PIGMENTATION
Name them all |
Melanin
Hemoglobin Carotene Billirubin |
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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 |
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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. |
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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 |
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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 |
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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 |
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BILLIRUBIN
what is it? what can it produce? |
metabolic by-product heme synthesis
can produce jaundice |
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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 |
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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 |
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UNMILINATED
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Not covered in a protective sheath
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CELLS OF EPIDERMIS: Ruffini's
Respond to? |
Respond to stretch, spacial, overexten
tion |
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CELLS OF EPIDERMIS: Merkel's
Respond to? |
Respond to light touch
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CELLS OF EPIDERMIS: Pacinian Corpuscles
Respond to? |
Pressure/Vibration
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CELLS OF EPIDERMIS: Meisnners Corpuscles
respond to? |
Fine touch
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SWEAT GLANDS
What are the types |
Eccrine
Apocrine |
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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 |
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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 |
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GLANDS: Others
Name the 3 others |
Ceruminous
Mammary Sabacceous |
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GLANDS: Ceruminous
What is it? Where found? Secretes? |
Modified apocrine gland
Found in ear Secretes cerumen(wax) |
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GLANDS: Mammary
Secretes ** |
Secretes breast milk
**Males can get this too |
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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 |
