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113 Cards in this Set
- Front
- Back
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what is the largest organ/
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skin is largest organ
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how much body weight does the skin account for?
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skin = 7% of body weight
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what are the two layers of the skin?
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dermis & epidermis are the 2 layers of the skin
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5 functions of the skin
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functions of the skin:
1. protection 2. regulation of body temp 3. excretion (urea, salts, water lost through sweat) 4. production of vitamin D 5. sensory reception |
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the epidermis develops from the
a. ectoderm b. mesoderm c. endoderm |
the epidermis develops from the ectoderm
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the dermis & hypodermis develop from the
a. ectoderm b. mesoderm c. endoderm |
the dermis & hypodermis develop from the mesoderm
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melanocytes develop from the __ which are ___ in origin
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melanocytes develop from the neural crest cells which are ectoderm in origin
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what layer of the skin is a keratinized stratified squamous epithelium?
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the epidermis is a keratinized stratified squamous epithelium
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what are the 4 distinct cell types of the epidermis?
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4 epidermis cell types:
1. keratinocytes 2. melanocytes 3. tactile epithelial cells 4. dendritic cells |
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which epidermis cell is the most common?
a. keratinocytes b. melanocytes c. tactile epithelial cells d. dendritic cells |
keratinocytes are the most abundant epidermis cells
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what are the 4 distinct cell types of the epidermis?
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4 epidermis cell types:
1. keratinocytes 2. melanocytes 3. tactile epithelial cells 4. dendritic cells |
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which eipdermis cell manufactures & secretes pigment
a. keratinocytes b. melanocytes c. tactile epithelial cells d. dendritic cells |
melanocytes manufacture and secret pigment
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which epidermis cell is attached to sensory nerve endings?
a. keratinocytes b. melanocytes c. tactile epithelial cells d. dendritic cells |
tactile epithelial cells are attached to sensory nerve endings
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which epidermis cell is part of the immune system & is macrophage like?
a. keratinocytes b. melanocytes c. tactile epithelial cells d. dendritic cells |
dendritic cells are part of the immune system and are macrophage-like
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which 2 epidermis cells are part of the basal layer?
a. keratinocytes b. melanocytes c. tactile epithelial cells d. dendritic cells |
melanocytes & tacticle epithelial cells are part of the basal layer of the epidermis
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keratinocytes produce what?
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keratinocytes produce antibodies, enzymes for chemical detoxification, and keratin
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what is keratin?
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a tough fibrous protein that gives the epidermis its protective properties
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kertinocytes are tightly connected by what?
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keratinocytes are tightly connected by desmosomes
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Keratinocytes are DEAD/ALIVE at the skin's surface.
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keratinocytes are dead on the skin's surface. millions of these dead cells rub off everyday
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how often does a new epidermis generate?
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every 35-45 days, a new epidermis generates
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in a lifetime the average person loses _ lbs of keratinocytes?
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40 lbs of keratinocytes slough off in a lifetime!
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what happens when the skin experiences friction? persistent? short term but severe?
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friction causes accelerated cell & keratin production, so thicker skin. persistent friction = callus. short term persistent friction = blister
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what is a blister
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blister occurs when there is short term severe friction and the epidermis and dermis are separated by a fluid filled pocket
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descirbe the stratum corneum
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stratum corneum
-most superficial layer of epidermis -20-30 layers of dead cells -flat sacs filled with keratin -glycolipids in extracellular space |
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desribce the stratum granulosum
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stratum granulosum (2nd layer deep)
-3 to 5 layers of flattened cells -organelles deteriorating |
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describe the stratum spinosum
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stratum spinosum (3rd layer deep)
-several layers of keratinocytes unified by desmosomes -contain thick bundles of intermediate filaments made of pre-keratin |
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describe the stratum basale
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stratum basal (stratum geminativum)
-deepest epidermal layer -one row of mitotic stem cell activity -attached to dermis & relies on its capillaries for nutrients |
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desribe the stratum lucidum
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-layer in epidermis
-only in thick skin |
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what are merkel cells?
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merkel cells AKA tactile epithelial cells
-associated with sensory nerve endings sparsely distributed among keratinocytes in stratum basale |
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what are tactile epithelial cells?
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merkel cells AKA tactile epithelial cells
-associated with sensory nerve endings sparsely distributed among keratinocytes in stratum basale |
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which layer of the epidermis are melanocytes found?
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melanocytes are spider shaped and found in the stratum basale
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what do melanocytes produce?
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melanocytes produce melanin
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melanocytes make up what percentage of the stratum basale?
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10-25% of stratum basale is melanocytes
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what is the purpose of melanin?
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melanin shields the cell nuclei from UV radition
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T/F darker skinned people have darker melanin & less pigment in each melanocyte
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FALSE. darker skin = darker melanin AND more pigment in each melanocyte
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how does one get a sun tan?
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sun tan comes from the melanocytes transfering more melanin to keratinocytes as a protective response to more UV
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vitamin D is found in which layers of the epidermis? purpose?
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vitamin D is found in the stratum basale and stratum spinosum. it is essential for uptake of Ca2+ from diet and the formation of healthy bones
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INVERSE relationship btwn amt of melanin in keratinocytes and the ability to produce vitamin D
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that's right. INVERSE relationship
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what is albinism?
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albino people lack the enzyme necessary to make melanin & hence are not very dark
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which pigments contribute to skin color?
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melanin, carotene & hemoglobin contribute to skin color
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describe melanin's contribution to skin color
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melanin is the most important pigment for skin color
-made from tyrosine -can vary in amount and type of melanin in ppl |
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what is carotene? which layers in skin have it?
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carotene is a pigment crucial for skin coloring.
-yellowish from carrots & tomatoes -accumulates in stratum corneum & in hypodermis |
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describe hemoglobin's role in skin color
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skin w/ little melanin allows the crimson of blood to show through the skin
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localized accumulations or concentrations of melanin in the skin result in what/
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FRECKLES & MOLES are localized accumulations of melanin in the skin
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moles form when clusters of melanocytes are transformed into _ aka _.
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moles form when clusters of melanocytes are transformed into melanin-containing cells AKA nervus cells
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what is the difference between freckles and moles? hint; think location
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freckles are only found in the basal layer of epidermis while moles are in the epidermis and dermis
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which is the least malignant?
a. basal cell carcinoma b. squamous cell carcinoma c. melanoma |
basal cell carcinoma is the least malignant
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which skin cancer arises from keratinocytes of stratum spinosum?
a. basal cell carcinoma b. squamous cell carcinoma c. melanoma |
squamous cell carcinoma arises from keratinocytes of stratum spinosum
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which is the cancer of melanocytes & the most dangerous?
a. basal cell carcinoma b. squamous cell carcinoma c. melanoma |
melanoma
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which layer of the epidermis has dendritic cells?
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the stratum spinosum (or spiny layer) has the dendritic cells
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what purpose do the dendritic cells serve in the epidermis?
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the dendritic cells are part of the immune system and detect foreign antigens that invade the epidermis
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which epidermal layers contains the intermediate filaments (tonofilaments)?
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the stratum granulosum has the intermediate filaments (tonofilaments)
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what are intermediate filaments AKA tonofilaments for?
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intermediate filaments AKA tonofilaments consist of tension resisting protein keratin
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which epidermal layer contains keratohyaline granules?
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keratohyaline granules are found in the stratum granulosum
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what are keratohyaline granules for?
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keratohyaline granules help form the keratin in the stratum granulosum
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which epidermal layer contains lamellated granules/
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the stratum granulosum has the lamellated granules
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what are lamellated granules for?
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lamellated granules contain waterproofing glycolipid which is secreted into the extracellular space
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what is the stratum lucidium?
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stratum lucidum AKA the clear layer occurs only in thick skin
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where on the body is a layer of stratum lucidum found?
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in the palms and soles
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what is the stratum lucidum composed of?
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stratum lucidum is composed of a few rows of flat, dead keratinocytes
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is the stratum corneum a THICK/THIN layer?
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stratum corneum is a THICK LAYER
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does the stratum corneum have live/dead cells?
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stratum corneum has dead kertinocytes
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what are dead keratinocytes filled with? which layer is abundant with them?
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dead kertinocytes are filled with keratin & are found in the stratum corneum
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what is the stratum corneum AKA?
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stratum corneum is also the horny layer
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what is the purpose of the stratum corneum or horny layer?
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the stratum corneum or horny layer protects the skin agains abrasion & penetration
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what makes the epidermis waterproof?
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intracellular glycolipids keep the skin waterproof
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what layers of the epidermis have intracellular glycolipids?
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stratum corneum & stratum granulosum have the waterproof characteristic from glycolipids
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which layer of the epidermis sheds keratinocytes?
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the stratum corneum sheds millions of dead keratinocytes everyday
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what is the second layer of skin?
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dermis = 2nd layer of skin
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describe the dermis (type of tissue, etc)
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dermis is strong, flexible connective tissue
-binds the body together |
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which layer of the skin is richly supplied with nerves & blood vessels?
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the dermis is richly supplied with nerves and blood vessels
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which plexus supplies the superficial dermal tissue, dermal papillae and epidermis with blood?
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the superficial subpapillary vascular plexus
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which plexus supplies the hypodermis and deep dermis with blood?
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the deep dermal vascular plexus nourishes the hypodermis & deep dermis
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blood running through which body part helps regulate body temperature?
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blood running through the hands plays a role in temperature regulation
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what are dermal ridges? where are they commonly found?
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dermal ridges are the larger mounds that the dermal papillae lie atop. found in the palms and soles of feet. they elevate the epidermis and create finger prints!
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in which part of the skin is the reticular layer found?
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the reticular layer is found in the dermis. it makes up 80% of the thickness
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what kind of tissue does the reticular layer have?
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the reticular layer has dense irregular connective tissue
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what gives skin the stretchy, recoiling properties it has?
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the thick bundles of interlacing collagen and elastic fibers give the skin the stretch and recoil properties
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what are cleavage lines? why are they important?
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cleavage lines AKA tension lines run longitudinally in the skin of limbs and circularly around the neck and trunk, important for surgeons to cut parallel to these lines!
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how are cleavage lines formed?
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cleavage lines are formed from separations or less dense regions btwn collagen bundles in the dermis
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what happens to your reticular layer if you have extreme sustained stretching like if you're obese or pregnant?
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extreme sustained stretching tears the collagen in the reticular dermis which results in stretch marks
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what are striae?
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striae are stretch marks
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what are flexure lines & how do they form?
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flexure lines are from the deep part of the dermis and come from repeated folding (see palms of hands)
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what is the superficial fascia?
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superficial fascia AKA hypodermis is deep to the skin
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what kind of tissue does the superficial fascia have?
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the superficial fascia, or hypodermis, contains areolar and adipose connective tissue
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what is the purpose of the hypodermis?
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the hypodermis aka superficial fascia
-anchors skin to underlying structures -helps insulate the body |
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which kind of burn damages only the epidermis?
a. first degree b. second degree c. third degree |
a first degree burn damages only the epidermis
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which type of burn causes blisters?
a. first degree b. second degree c. third degree |
second degree burns cause blistering (fills with fluid to separate the epidermis from the dermis)
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which layers are damaged in a second degree burn?
a. epidermis b. upper dermis c. lower dermis d. only a and b e. all of the above |
the epidermis and upper dermis are damaged in a second degree burn
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which type of burn damage the entire thickness of the skin?
a. first degree b. second degree c. third degree |
a third degree burn damages the entire thickness of the skin
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does the skin heal in a third degree burn?
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yes, but with a permanent scar
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how does the skin heal with a second degree burn?
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with a second degree burn the skin heals with little or no scarring
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how do you estimate the extent of the burns?
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the rule of nines is used to estimate the amount of body surface burned.
head & arms are each 9% trunk back & front are 18% each legs are 18% each crotch/perineum is 1% |
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where do you find the sebaceous glands?
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sebaceous glands are everywhere except palms and soles
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what do the sebaceous glands secrete?
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sebaceous glands secrete sebum (oily substance)
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what is sebum?
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sebum is the oily substance secreted by the sebaceous glands
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what is holocrine secretion
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holocrine secretion
when sebaceous gland secretion breaks up entire cell to form secretion |
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what are the functions of the sebum?
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the sebum collects dirt, softens & lubricates hair & skin
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what are sudoriferous glands? & where are they found?
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sudoriferous glands
AKA sweat glands are found all over the body |
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what do sudoriferous glands secrete?
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sudoriferous glands secrete sweat, a blood filtrate
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what is sweat composed of?
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sweat is 99% water with some salts, it contains traces of metabolic wastes like urea & ammonia
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how much sweat do humans typically produce in a day
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500mL of sweat in a day
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what are the most numerous type of sweat gland?
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eccrine glands (merocrine) are the most numerous sweat glands. they produce true sweat in the palms, soles and forehead
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what are apocrine glands?
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apocrine glands are large sweat glands confined to axillary anal and genital areas
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what kind of sweat do apocrine glands secrete?
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apocrine glands secrete odorless sweat that has fats and proteins
-bacteria breaks down the organic compounds -> body odor -secretions act as a pheromone (Major Histocompatibility Complex) |
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what are nails made of?
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nails are scale-like modification of epidermis made or hard dead keratinized cells
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what is hair made of?
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hair is flexible, dead, keratinized cells; tough & durable
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what are the 2 main parts of a hair?
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hair
1. the root which is in the skin 2. shaft which projects above the skin's surface |
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a round cross-section of a hair shaft correpsonds with which type of hair?
a. straight hair b. wavy hair c. kinky hair |
round cross section of hair shaft = straight hair
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oval cross-section corresponds with
a. straight hair b. wavy hair c. kinky hair |
oval cross-section of hair shaft - wavy hair
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flattened cross-section of hair corresponds with
a. straight hair b. wavy hair c. kinky hair |
flattened cross-section of hair shaft = kinky hair
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hair lice has most difficulty attaching to
a. straight hair b. wavy hair c. kinky hair |
lice has most trouble attaching to kinky hair
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what determines hair pigment/color?
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the melanocytes at the base of the hair follicle transfer into the hair root & different proportions of black-brown and yellow-rust make hair color
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