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Which of the following cutaneous receptors is specialized for the reception of touch or light pressure? |
Meissner’s corpuscles |
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Which of the following cells and their functions are correctly matched? |
dendritic cells active the immune system |
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The epidermis consists of five layers of cells, each layer with a distinct role to play in the health, well-being, and functioning of the skin. Which of the following layers is responsible for cell division and replacement? |
stratum basale |
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The integumentary system is protected by the action of cells that arise from bone marrow and migrate to the epidermis. Which of the following cells serve this function? |
macrophages called dendritic cells (Langerhans Cell) |
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Water loss through the epidermis could cause a serious threat to health and well-being. Which of the following protects us against excessive water loss through the skin? |
Lamellated granules of the cells of the stratum granulosum, a glycolipid that is secreted into extracellular spaces. |
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A dendritic or Langerhan cell is a specialized ________. |
phagocytic cell |
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T/F: The dense fibrous connective tissue portion of the skin is located in the reticular region of the dermis. |
true |
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Which glands produce ear wax? |
ceruminous glands |
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Sudoriferous (sweat) glands are categorized as two distinct types. Which of the following are the two types of sweat glands? |
eccrine and apocrine |
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Apocrine glands, which begin to function at puberty under hormonal influence, seem to play little role in thermoregulation. Where would we find these glands in the human body? |
in the axillary and anogenital area |
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In addition to protection (physical and chemical barrier), the skin serves other functions. Which of the following is another vital function of the skin? |
It converts modified epidermal cholesterol to a vitamin D precursor important to calcium metabolism. |
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Select the most correct statement concerning skin cancer. |
Melanomas are rare but must be removed quickly to prevent them from metastasizing. |
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Burns are devastating and debilitating because of loss of fluids and electrolytes from the body. How do physicians estimate the extent of burn damage associated with such dangerous fluid loss? |
by using the rule of nines |
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the skin is considered to be an_ and it is the_of the body |
organ largest organ |
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if the skin is not a tissue, what is the tissue of the skin? (3) |
It is made of multiple tissues like epidermis, dermis, hypodermis which have multiple tissues |
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The _and its_organs make up the intergumentary system |
skin derivative organs |
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integumentary system (what is it composed of, main function) |
skin and its derivatives (sweat and oil glands, hairs and nails) provides external protective covering of the body |
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hypodermis (what kind of tissue/ other name, membership, where found, what has in common with skin, consists mostly of_) |
-subcutaneous tissue/ superficial fascia -not part of skin -found just below the skin (deepst layer) -it shares some of the skin protective functions consist mostly of adipose tissue |
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dermis is composed of_ (layers) |
-papillary layer reticular layer |
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list the appendages of the skin (5) where they are found? what else can you find in this area? (3) |
1-eccrien sweat glands 2-arrector pili muscle 3-sebaceous (oil) gland 4-hair follicles 5-hair root -dermis -nervous structures: sensory nerve fibers with free endings; lamellar corpuscle; hair follicle receptor (root hair plexus) |
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the skin accounts for about _% of the body weight |
15% |
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the skin is composed of two distinct regions: |
-epidermis -dermis |
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epidermis (what has on it, what kind of tissue, what cells, where found) |
-keratinized stratified squamous epithelium -composed of epithelial cells -outermost protective shield of the body |
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dermis (made out of what, where found to respect to epidermis, makes the what of the skin, how it is, (2), it is composed mostly of what kind of tissue) |
-connective tissue layer -underlying to the epidermis -makes the bulk of the skin, is though, leathery layer composed mostly of fibrous connective tissue |
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which of the two regions of the skin is vascularized? |
only the dermis |
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If epidermis is not vascularized, how obtain nutrients? |
-Nutrients reach the epidermis by diffusing though the tissue fluid blood vessels in the dermis |
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why the hypodermis receives the name of superficial fascia? |
-because it is superficial to the tough connective tissue wrapping (fascia) of the skeletal muscles |
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the skin is consists of two layers, an outer_and an underlying_ |
-epidermis -dermis |
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Thickness of skin varies, normally_. _ may thicken, up to _. which layer increases and what its increase does? |
-normally 1-2 mm -dermis -6mm -stratum corneum layer increases -Produce the calluses on hands and feet |
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the deeper you go, how blood vessels change? |
the more and thicker the blood vessels are |
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what are the functions of hypodermis? (4) |
1. stores fat (shock absorber and insulator that reduces heat loss) 2. anchors skin to the underlying structures (mostly muscles), but loosely enough that the skin can slide relatively freely over those structures. Sliding skin protects us by ensuring that many blows just glance off our bodies |
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Functions of skin (6) |
Resistance to trauma and infection Barrier to ultraviolet light Vitamin D synthesis Sensory receptors Thermoreceptors through sweating Nonverbal communication |
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does keratin water proofs the skin? why? |
-keratin really does not water proof the skin -it help the other granules to do |
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what is the main function of keratin? |
helps against abrasion |
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why the skin is a great protective layer against pathogens> |
-due to many layers, it is difficult for pathogens to enter -the acid mantle helps in this. hypodermis produces it -certain pathogens do not like acidic -repeals them to enter the body |
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what within the skin protects against the UV light? how? |
melaning secreted by melanocytes protects the nucelus of cells of UV light to prevent cancer cells |
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what layer has sensory receptors? |
dermis |
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avascular (what it is and example) |
tissues that do not have blood supply ex: epidermis |
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what are the cells within epidermis? (5) |
stem cells keratinocytes melanocytes dendritic cells tactile cells |
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stem cells |
-undifferentiated cells in deepest layers -cells-produce new cells that take places of the cells that die off and renew skin |
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keratinocytes (what quantity found in epidermis, main role) |
-most of the skin cells (most epidermal cells) -role: produce keratin and stratified squamous epitehlium |
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keratin (what it is, produced by who, and how helps epidermis) |
fibrous protein produced by keratinocytes that helps give the epidermis its protective properties |
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the keratinocytes are tightly connected to one another by_ |
desosomes |
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where does keratynocytes come from? (layer) |
they arise in the deepest part of the epidermis from a cell layer called stratum basale |
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describe the process of manufacturation of keratinocytes |
-arise in the deepest part of the epidermis from a cell layer called stratum basale -These cells undergo continuous mitosis in response to prompting by epidermal growth factor -As these cells are pushed upward by teh production of new cells beneath them, they make the keratin that eventually dominates their cell contents -By the time keratinocytes reach the skin surface, they are dead, scalike structures that are little more than keratin-filled plasma membranes -dead keratinocytes rub off every day -cell production of keratin formation is accelerated in body areas regularly subjected to friction (hands and feet) |
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callus |
-persistent friction causes thickening of the epidermis called a callus |
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melanocytes (what do?, shape, what layer found) |
-synthesize pigment melanin that shield UV -spider-shaped epitehlial cells -found in deepest layers of epidermis |
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describe melanin (where made, what it does) |
-melanin is made, it accumulates in membrane=bound granules called melanosomes that motor proteins move along actin filaments to the ends of the malnocyte’s processess -from there they are transferred to a number of nearby keratinocytes |
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describe function of melanin (2) |
–the melanin granules accumulate on the superficial "the sunny" side of the keratinocyte nucleus. forming a pigment in the shell that protects the nucelus form the damaging of the ultraviolet (UV) radiation in sunlight -gives pigmentation to skin |
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what cell in the epidermis produces the melaning pigment? |
melanocyte |
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which layer is the living, reproducing layer? |
stratum basal |
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which layer is the dead, outermost layer and heavily keratinzed? |
stratum corneum |
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dendtdric cells (shape and what they form in conjunction, other name, where arise and where end up, main function) |
-star-shaped and forms continuous network -langherans cells -arise from bone marrow and migrate to epidermis -macrophages (like white blood cells) that guard against pathogens |
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what are the functions of dentritic cells (2) |
-ingest foreign substances -they are key activators of our immune system |
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Tactile cells (other name, what are them and related wi what, where present, shape) |
-merkel cells -receptor cells associated with nerve fibers -present at epidermis-dermal junction -shaped like a spiky hemisphere |
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functions of tactile cells (associated with what?) |
–receptor cells associated with nerve fibers -pick up lighter pressure -associated with a disclike sensory nerve ending -The combination is called tactile or merkel disc |
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variation in epidermal thickness determines if skin is_ |
-thick -skin |
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describe thick skin (what kind and where found in body (3)) |
-covers areas subject to abrasion –palms, fingertips, soles of feet |
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from deep to superficial list the epidermis layers (other name for layers)(5) |
-"strata" -stratum basale -stratum spinosum -stratum granulosum -stratum lucidum -stratum corneum |
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describe thin skin (describe, which layers apply) |
-cover the rest of the body -stratum lucidum appears to be absent and the other strata are thinner |
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where tactile cells found? |
are above receptor cells in the dermis |
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describe the most superficial cells in the skin |
The upper cells are death cells packed with keratin |
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epidermis is made out of _called_ |
-different layers -stratum |
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stratum basale (where found, attached to what, what it is mainly, other name and why?) |
-deepest epidermial layer -attached to underlying dermis along a wavy borderline that reminds one of corrugated cardboard -Single layer cells on basement membrane -stratum germinativum becuase rapid division of the cells |
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cell types in stratum basale (4) |
-For the most part consists of a single row of stem cells (continually renewing cell population -Keratinocytes -melanocytes -merkel (tactile) cells are touch receptors (form Merkel disc) |
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describe how generation of new cells happen. where? |
-stratum basale -each time of time one of the basal cells (stem cells) divides (mitosis), one daughter cell is pushed into the cell layers just above to begin to specialization into a mature keratinocyte -the other daughter cell remains in the basal layer to continue the process of producing new keratinocytes |
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stratum spinosum (how many layers made of what and how connected, where found, cells contain what) |
-Several layers of keratinocytes unified by desosomes -superficial to stratum basale and much thicker -cells contain thick bundles of intermediate filaments made of pre-keratin |
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what cell types the stratum spinosum contains? (4) (describe them, which are the most abundant in this epidermial layer) |
-Contains dendritic (Langerhans) cells: -keratinocytes in this layer appear to have spines, causing them to be called prickle cells -Scattered among the keratinocytes are melanin granules and dendritic cells, which are most abundant in this epidermial layer |
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describe the function of dendritic cells and where they come from |
*macrophages from bone marrow (come from dendritic) *help protect body against pathogens by "presenting" them to the immune system |
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stratum granulosum (how many layers, how thick, description of layer, what process begins, contains what (2)) |
-3 to 5 layers Flat keratinocytes -thin -granular layer -process of keratinization begins -contains kekratohyaline granules and lamellar granules (release lipids) |
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keratinization |
-in which the cells fill wit the protein keratin |
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what happens to cells when they started to be keratinized? in what layer? |
-stratum granulosum layer -these cells flatten, their nuceli and organelles begin to disintegrate, and they accumulate two types of granules: keratohyaline granules and lamellar granules |
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describe keratinohyalin granules (what layer, functions (2)) |
-within stratum granulosum -combine with filaments of cytoskeleton to form keratin -help form keratin in the upper layers |
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-lamellar granules (what produce, function, how affects surface strata, major function) |
-Produces lipid-filled vesicles that release a glycolipid by exocytosis to waterproof the skin: -forms a barrier between surface cells and deeper layers of the epidermis -cuts off surface strata from nutrient supply -water-proof glycolipid is spewed into extracellular space and is a major factor in slowing water loss across the epidermis |
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what events produce an epidermal water barrier and make the cells more resistant to destruction? |
-plasma membrane of cells thickens as cytosol proteins bind to the innder membrane face and lipids released by the lamellar granules coat their external surfaces |
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epidermis relies on what for nutrition? what happens to the most superficial layers? |
-epidermis relies on capillaries in their underlying connective tissue (dermis) for its nutrients -above the stratum granulosum the epidermial cells are too far form the dermal capillaries and the glycolipids coating their external surfaces cut them off from nutrients, so they die |
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what would be the final function of keratinohyaline? |
to make cells more resistant to abrasion by producing keratin |
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stratum lucidum (thickness?, where found?, how many rows? type of cells found here? what cells do not have? contains what?) |
-Very thin translucent zone seen only in thick skin -above stratum granulosum -2 to 3 rows fo clear, flat, dead keratinocytes -Cells have no nucleus or organelles -contains tonofilaments |
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tonofilaments (where found, what are they, how form) |
-found in stratum lucidum and corneum -the substance of keratohyaline granules clings to teh keratin filaments in the cells, causing them to aggregate in this large, cable-like, parallel arrays of intermediate filaments |
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stratum corenum (how many layers, made of what, what other name, what happen to them frequently, describe its cells, how thick) |
-Up to 30 layers of dead, scaly, keratinized cells (called horny cells) -surface cells flake off (exfoliate) -outer potion of skin -flatted anucelated cells (result of specialized form of apoptosis) -The thickest of all epidermial layers |
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function of the cells found in the stratum corneum (3) |
-keratin and thickened plasma membranes of the cells in this stratum protect the skin against abrasion and penetration and the glycolipids between its cells nearly waterproofs this layer -protect deeper cells from hostile external environment and from water loss |
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what epidermial layer feeds dust termites? |
stratum corneum |
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while walking barefoot in a barn, Jeremy stepped on a rusty nail that penetrated the epidermis on the sole of his foot. Name the layers the nail pierced from the superficial skin surface to the junction of the dermis |
1. stratum corneum 2. stratum lucidum 3. stratum granulosum 4. stratum spinosum 5. stratum basale |
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the stratum basale is also called the stratum germinativum, a name that refers to its major function. what is that function? |
-stratum basale undergoes almost continuous mitosis to replace cells lost by abrasion |
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why are they desmosomes connecting the keratinocytes so important? |
the skin is subjected to a lot of abrasion and trauma. The desosomes, which are connecting junctions, help to hold the cells together during such stress |
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Given the epithelial are avascular, which layer would you expect to have the best-nourished cells? |
the stratum basale, which abuts the dermis where the blood supply is, has the best nourished cells |
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describe the History of Keratinocytes |
-Produced by stem cells in stratum basale -New cells push others toward surface: cells grow flat and fill with vesicles -Cells filled with keratin: forms water barrier -Cells die and exfoliate |
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what is the composition of the dermis? (4) (fibers? cells?) |
-collagen, elastic and reticular fibers -fibroblasts |
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layers of dermis |
-papillary layer -reticular layer is deeper part of dermis |
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what kind of tissues are found in dermis? |
connective tissues |
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what is the thickest layer of the skin? |
dermis |
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what cells found in dermis? (4) |
-fibroblasts -mast cells -white blood cells -macrophages |
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dermis semifluid matrix with fibers _(function) |
binds the entire body together |
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dermis has a rich supply of_(3) |
-fibers -blood vessels -lymphatic vessels |
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describe papillary layer (type of connective tissue?, what fibers, what else contains, what cells found) |
-aeolar connective tissue -collagen and elastic fibers for strength and elasticity -small blood vessels -looseness of connective tissue allows phagocytes and defensive cells to patrol area for bacteria that have breached the skin |
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dermal papillae (where found, what it forms, what contains) |
-extensions of the dermis into the epidermis -found in papilary layer -forming the ridges of the fingerprints (friction ridges) -contains capillary loops or nerve endings (pain receptors) and touch receptors (tactile or Meissener’s corpuscles) |
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the touch receptors found in the dermal papillae are called_ |
Meissener’s corpuscles |
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friction ridges |
-made by dermal ridges of dermal papillare that form the epidermial ridges -enhance the dripping ability of the fingers and the feet |
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fingerprints |
-identifying films of seat due to sweat power along their friction ridge crests, irregularly arranged, |
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describe reticular layer (how much contributes to thickness, what type of tissue, where found blood vessels, what matrix contains: cells and fibers, how fibers run) |
-accounts for most of the thickness of dermis -dense fibrous tissue (irregular) -network of blood vessles that nourish this layer (cutaneous plexus) lies between this layer and the hypodermis -matrix contains adipose cells and thick bundles collagen fibers running in various planes (most parallel to skin surface) |
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cleavage (tension) lines (what is this, how run, why important for surgeons) |
-separation of less dense region in reticular layer -run longitudinally in the skin of the head and limbs -circular patterns around neck and trunk -important for surgeons to cut parallel so skin gapes less and heals more readily |
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_fibers of dermis give skin_that prevent most _ (what else does) |
-collage -strenght and resistance -jabs and scrabs from penetrating the dermis -binds water to hydrate dermis |
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_fibers in dermis provides_of skin |
-stretch-recoil properties |
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the dermis consists of_tissue with _(2)fibers within a _. This tissue _and_(characteristics due to fibers) dense contains _(5) |
-loose connective tissue -collagen and elastic -strongly binds the skin to the underlying tissues and yet makes the skin elastic that it snaps back in place when stretched -contains nerve fibers, sensosry fibers, hair follicles, sebaceous glands, and sweat glands |
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which layer f the dermis is responsible for producing the fingerprint patterns? |
papillary layer |
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which tissue of the hypodermis makes it a good shock absorber and physical trauma and insulator? |
adipose tissue (fatty tissue) |
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you have just gotten a paper cut. It is very painful, but it doesn’t bleed. Has the cut peentrated itnot he dermis or just the epidermis? |
Because there is no bleeding, the cut has penetrated into the avascular epidermis only |
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what are the functions of hypodermis? (2) |
energy reservoir thermal insulation |
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hypodermic injections (abbreviation, reason injected there) |
-subQ -injected into hypodermis because it is highly vascular |
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what happens if you bleed: no bleeding? moderately? extensively? |
-no bleeding: cut up to epidermis -moderately: cut up to dermis -extensively: cut up to hypodermis |
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what are the 3 pigments that contribute to skin color? |
melanin carotene hemoglobin |
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hemoglobin pigment |
red pigment of red blood cells |
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carotene pigment |
yellow pigment |
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where pigments found in: melaning vs carotene vs hemoglobin |
-carotene: concentrates in stratum corneum and fat (hypodermis) -melanin: deeper layers of epidermis because it is disintegrated by lysosomes as go upward -hemoglobin found in blood cells circulating through the dermal capillaries |
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melaning pigment (3) |
yellow, brown, and black hues |
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synthesis of melanin is due to (2) |
1. pigment synthesis stimulated by UV radiation 2. keranocytes secrete chemicals to stimulate melanocytes |
|
melanin |
-melanocytes -passes from melanocytes to basal keratinocytes -found in deeper layers of epidermis |
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reason of production of melanin (where found in this process within the cell, reason cause of_) |
-prolonged sun exposure causes substantial melanin buildup, which helps protect the DNA of viable skin cells from UV radiation by absorbing the rays and dissipating the energy as heat -melanin builds up inside cells -reason tanning occurs |
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why there is a different colors of skin around the world? |
-due to melanin -all humans have the same amount of melanocytes, differences in skin coloring reflect the kind and amount of melanin made and retained -darked-skinned people tend to be found nearer the equator where greatest protection from the sun is needed. Their melanocytes produce many more and darker melanosomes. their keratynocytes retain longer -Light-skinned people are found closer to poles Their melanocytes tend to produce less and ligther melanocytes |
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what causes sunspots? |
a fungus, not the sun |
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carotene (where produced, found where in body, when have strongest color, converted to what and why needed) |
-found in plant products, like carrots -found in stratum corneum and fatty tissue of hypodermis -strongest color in palms and soles, where stratun corneum is thickest, and when consume large quantities of carotene-rich foods -converted to vitamin A: good for vision and epidermial health |
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why the blush of white skinned people looks more than in dark-skinned people? |
-because it contains small amounts of melanin, the epidermis is nearly transparent and allows hemoglobin color to show through |
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albino (determined by, what it is, they have greater chances to get_) |
-genetic condition -person that does not have melanocytes and does not produce melanin -more possible to get skin cancer |
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cyanosis |
blueness from deficiency of oxygen in the circulating blood (cold weather) |
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erythemia |
redness due to dilated cutaneous vessels (anger, sunburn, embarrassment) |
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Jaundice |
-yellowing of skin and sclera due to excess of bilirubin in blood (liver disease) -liver does not break down billirubin -reason some babies have it at the time they were born due to that their bodies do not completely function |
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Pallor |
pale color from lack of blood flow (anemia or low blood pressure) |
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bronzing |
-golden-brown color of Addison disease (deficiency of glucocorticoid hormone, which is a stress response hormone) |
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albinism |
gentic lack of melanin |
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hematoma |
a bruise (visible clotted blood) due to blood vessels that broke |
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president John F. Kennedy had which skin condition? |
Brozing (Addison’s disease) |
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how is hematoma in people with blood clotting problems? |
-If people have problems with blood clotting, their hematoma will be greter: greater and darker bruise -take minutes or 30 seconds longer to have process of blood clotting running |
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hypodermis is also called_ |
subcutaneous layer |
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melaning and carotene are two pigments that contribute to skin color, what is the third and where is it found? |
-hemoglobin -the pigment is contained in red blood cells found in blood vessels of the dermis |
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what is cyanosis and what does it indicates? |
Bluish cast of that indicates the hemoglobin in the red blood cells in the dermal capillaries is poorly oxygenated |
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which alteration in skin color may indicate a liver disorder? |
jaundice |
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along with skin, the intergumentary system includes_, called _. These include_ (5). Each play a unique role in_ |
-derivatives of the epidermis -skin appendages -hair, hair follicle, nail, sweat glands, and sebaceous (oil) glands -homeostasis of the body |
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a key step in beginning the formation of the skin appendages is formation of an_.how? |
-epithelial buds -stimulated by reduced production of cell adhesion factor (cadhein). Once cell-to-cell broke attractions, the cells can move about and rearrange themselves, allowing an epithelial bud to form |
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what parts of body does not have hair? (5) |
-palms -soles -lips -nipples -part of external genitalia (head of penis) |
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functions of hair (5) |
-Body hair (too thin to provide warmth): alert us to parasites crawling on skin -Scalp hair: heat retention and sunburn cover -Beard, pubic and axillary hair indicate sexual maturity and help distribute sexual scents -Guard hairs and eyelashes: prevent foreign objects from getting into nostrils, ear canals or eyes -Expression of emotions with eyebrows |
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What is hair composed of? |
filament of keratinized cells |
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what are hair parts and describe them? |
-shaft = above skin -root = within follicle |
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what would you see in a cross section of the hair? |
-in cross section: medulla (middle section area), cortex (around middle area) and cuticle |
|
follicle |
-"bag" -is oblique tube within the skin -fold down from the epidermal surface into the dermis (in scalp may extend into hypodermis) -structure with outer and inner root sheats extending from epidermial surface into dermis from which hair develops |
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where does hair originate? |
at the bulb |
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texture and shape of hair |
How oval or round it is determines the shape of hair: straight hair = round wavy = oval more oval=curly |
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what determines the hair color? |
pigment in cells of cortex |
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why brunette people have brown hair color? |
-Eumelanin pigment colors brown and black hair -more eumelanin=black -less emuelanin=brown |
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why blond people have yellow hair color? |
Blond hair contain pheomelanin pigment, but little eumelanin. |
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why red hair color? |
Red hair contains little eumelanin but lots of pheomelanin. |
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why white/gray hair color? |
-White hair = air in medulla and lack of pigment in cortex. -Gray hair is a mixture of white and pigmented hairs. pigments are lost as hair grows and is cut |
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hairs or _(other name) are_ |
-pilli -flexible strands produced by hair follicles and consist largely of dead, keratinized cells |
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_keratin has 2 advantages for the hairs and nails than the _keratin in typical epithelial cells |
-hard -soft 1. it is tougher and more durable 2. its individual cells do not flake off |
|
shaft |
-above skin hair part -keratinization is complete -remainder of the hair deep within the follicle |
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root |
-below skin hair part -keratinization still ongoing |
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the textures of hair is determined by what part of the hair? explain |
-shaft -if shaft is flat and ribbonlike in cross-section, the hair is kinky -If shaft is oval, the hair is silky and wavy -If shaft is perfectly round, the hair is straight and tends to be coarse |
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what are the 3 concentric layers of keratinized cells within hair? (describe them) |
-medulla: center core, consisting of large cells and air space, it contains soft keratin -cortex: bulky layer surrounding medulla, consists of several layers of flattened cells -cuticle: outermost. Formed form a single layer of cells overlapping one another. Separate neighboring hairs. the most heavily keratinized part of the hair. provides strength and helps keep the inner layers tightly compacted. receives most of abrasion |
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where hair pigment is made? what cells within hair have it? |
at the base of follicle by melanocytes and transferred to cortical cells (pigment in cells of cortex) |
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deep end of follicle, expands and forms_ |
hair bulb |
|
hair follicle receptor |
-root hair plexus (hair nervous receptors) -wraps around each hair bulb -bending the hair stimulates these endings. Consequently, our hairs act as a sensitive touch receptor: feel tickle or can feel if a I pull my hair |
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associated with each hair follicle is a bundle of _cells called_ |
-smooth muscle cells -arrector pilli |
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arrector pilli (what it does, explain how works, what stimulates it do work, how usueful for animals) |
-raiser of hair -arrector pilli is attached in suhch a way that its contraction pulls the hair follicle upright and dimples the skin surface to produce goose bumps in response to col temperatures or fear -It is not as usual in humans, but in animals it is important for stay warm by trapping a layer of insulating air in their fur and a scared animal with its hair on end looks larger and more formidable to its enemy |
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what is the main role of arrector pilli in humans? |
its contractions force sebum out of hair follicles to the skin surface where it acts as a skin lubricant |
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what are the concentric regions of a hair shaft, from the outside in? |
-cuticle, cortex, and medulla |
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why is having cut your hair painless? |
There are no nerves in a hair |
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what is the role of the arrector pilli? |
the arrector pilli muscles pull the hair (normally slanted) to the upright position (when cold or scared) |
|
Nails |
-are protective coverings of heavily keratinized epithelial cells -scale-like modification of the epidermis that forms a clear protective covering on the dorsal surface of the distal part of a finger or toe -helpful to pick up small objects, or scratch an itch -contain hard keratin |
|
sweat glands are also called_ |
-sudoriferous glands |
|
sweat glands (where found, and types) |
-distributes over the entire skin surface except the nipples and parts of the external genitalia -2 types: eccrine and apocrine |
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function of sweat glands |
Filtrate of plasma and some waste products 500 ml of insensible perspiration/day |
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diaphoresis |
sweating with visible wetness is diaphoresis |
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myoepithelial (associated with what, what are they and function) |
-associated with the sweat glands: eccrine and apocrine -specialized cells that contract when stimulated by the nervous system -Their contraction forces the sweat into and through the gland’s duct system to the skin surface |
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merocrine glands (other name, shape, abundance, what they help to do, where found, describe where its parts lie, what secretes) |
-eccrine glands -is simple tubular gland -millions of them help cool the body (abundant) -abundant on the palms, soles of the feet, and forehead -secretory part lies coiled at dermis and duct extends to open in a funnel shaped pore at the skin surface -secretes sweat |
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sweat (what it is, how flows) |
-hypotonic filtrate of the blood that passes through the secretory cells of the sweat glands and is released by exocytosis |
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composition of sweat in merocrine glands (7) |
-99% water -salts -vitamin C -antibodies -microbe-killing peptide dubbed dermcidin -traces of metabolic waste -small amounts of drugs may also be excreted by this route |
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what is the pH of sweat? |
-pH between 4 and 6 |
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what controls sweating? what are some stimulus? (2) |
-the sympathetic division of the autonomic nervous system, over which we have little control, regulates sweating -heat-induced sweating and emotionally-induced sweating (cold sweat) brought on by fright and nervousness |
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what is the major role of sweat? |
-is to prevent the body from overheating |
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Apocrine glands (produces what containing what, where found, responds to what) |
-produce sweat containing fatty acids -found only near hair follicles and respond to stress and sex -not abundant |
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Bromhidrosis |
-bromhidrosis is body odor produced by bacterial action on fatty acids (sweat produced by apocrine glands) -basis of body odor |
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how appocrine glands are similar/different to eccrine/merocrine glands? |
-They are merocrine glands, which release their products by exocytosis like the eccrine sweat glands -Larger than eccrine glands -lie deeper into dermis or even in the hypodermis -their ducts empty into hair follicles |
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describe apocrine gland secretion |
-contains the basic components as true sweat, plus fatty substances and proteins |
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when apocrine glands start to function? who controls them? stimulus? may be the human equivalent_ |
-apocrine glands begin functioning in puberty under the influence of the male sex hormones (androgens) -play little role in maintaining a constant body temperature -They are active by sympathetic nerve fibers during pain and stress -sexual foreplay increases its activity and enlarge during menstrual cycle -MAY be human equivalent of sexual scent glands |
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other types of apocrine glands. Describe them |
-ceruminous glands: modified apocrine glands; found in the lining of the external ear canal (external auditory meatus); their secretion mixes with sebum produced by sebaceous glands to form sticky cerumen (earwax) -mammary glands |
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describe mammary glands (what are them and what they secrete, who have them, when have them, type of gland, what secretion does when produced) |
-specialized sweat gland -secretes milk -Breasts of both sexes rarely contain glands -secondary sexual characteristic of females -found only during lactation and pregnancy -modified apocrine sweat gland -thicker secretion released by ducts open on the nipple |
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sebaceous glands (other name, shape and type of gland, secretion and what contains, shape) |
-oil glands -simple branched alveolar gland -Oily secretion called sebum that contains broken-down cells (accumulated lipids and cell fragments): lanolin in skin creams is sheep sebum -Flask-shaped gland with duct that opens into hair follicle |
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function of cerumen (include other name) (2) |
-earwax -waterproof keeps eardrum flexible -bitterness repel mites and other pests |
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where are the sebaceous glands located? |
-all over the body except in the thick skin of the palms and soles -large on face, neck,and upper chest |
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what kind of glands are sebaceous gland? why? |
-holocrine glands -the central cells of the alveoly accumulate oily lipids until they become so engorged that they burst |
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how are arrector pilli and sebacaous glands related? |
-arrector pilli contractions force sebum out of the hair follicles to the skin surface |
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what are the functions of sebum? |
-softens and lubricates the hair and skin -prevents the hair from becoming brittle -slows water loss form the skin when external humidity is low -works as a bactericidal (bacterium-killing) |
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what stimulates the secretion of sebum? when sebum is started to secrete? |
-androgens (hormone) -they are relatively inactive during childhood but are activated in both sexes during puberty, when androgen production begin to rise |
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which cutaneous glands are associated with hair follicles? |
-sebaceous (oil) glands and apocrine glands are associated with the hair follicles |
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when Anthony returned home from a run in 85 degree F weather, his face was dripping sweat. Why? |
His sympathetic nervous system activated his eccrine sweat glands and caused heat-induced sweating in order to cool his body |
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what is the difference between heat-induced sweating and a "cold sweat," and which variety of sweat gland is involved? |
-heat-induced sweating occurs allover the body when we are overheated -A cold sweat is emotionally induced sweating that begins on the palms, soles, and armpits and then spreads to other body areas -Both types of sweating are produced by the eccrine (merocrine) glands, but actively of apocrine sweat glands is also likely during a cold sweat |
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skin is composed of how many layers? |
3 epidermis dermis hypodermis |
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describe the type of tissues in the dermis |
-it is composed generally from loose connective tissue: -superficial part is composed of aeolar connective tissue -deeper part (80%) is composed of dense fibrous connective tissue |
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Sebaceous glands are not found in thick skin. why is their absence in those body regions desirable? |
the palms of the hands and the soles of the feet are thick skin areas. It would be dangerous to have oily soles, and oily palms would decrease the ability of the hands to hang onto things |
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what are the skin functions? (6) |
-protection -body temperature regulation -cutaneous sensation -metabolic functions -blood reservoir -excretion |
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what organ is the most vulnerable? why? (5) |
-given its superficial location, the skin is our most vulnerable organ system, exposed to microorganisms, abrasion, temperature, extremes, and harmful chemicals |
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the skin constitutes 3 type of barriers, which are_. (describe them) |
-chemical barriers: Skin secretions and melanin (chemical pigment to prevent UV damage to skin cells); low pH (acid mantle); demicidin of sweat and sebum; natural antibiotics defensins; Wounded skin releases cathelicidins -physical barriers: the continuity of the skin and the hardness of its keratinized cells; stratum corneum multiple layers of flat dead cells; water-resistant glycolipids -Biological barriers: dendritic cells of epidermis, macrophages in dermis, and DNA |
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the body works best under which temperature? |
-when its temperature remains within homeostatic limits (get right out of heat generated by internal reactions) |
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insensible perspiration (part of what, how many is secreted per day, why is called like this, what the body does) |
-part of body temperature regulation -sweat glands secrete about 500 mL of seat per day -It is unnoticeable sweating because the sweat evaporates -When body temperature rises, the nervous system stimulates dermal blood vessels to dilate and the sweat glands into vigorous secretory activity |
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sensible prespiration |
-when the day is hot -Loss of 12 L of body water in one day -visible output of sweat -Evaporation of sweat from the skin surface dissipates body heat and efficiently cools the body, preventing overheating |
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when the external environment is cold, what is the body response? |
-the dermal blood vessels constrict -the constriction causes the warm blood to bypass the skin temporarily and allow skin temperature to drop to that of the external environment -conserves body heat |
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cutaneous sensation includes (7) |
-cutaneous sensory receptors, which are part of the nervous system -respond to stimuli outside the body (extereceptors) -include tactile (Meissner’s) corpuscles and tactile discs (makes us aware of caress or the feel of things around us) lamellar corpuscles (alert us of bumps or contacts involving deep pressure. Hair follicle receptors (report on wind blowing through our hair) free nerve endings (painful stimuli) |
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metabolic functions of the skin (2) |
-chemical factory fueled by sun rays -cholesterol molecules are modified to vitamin D (calcium metabolism) |
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blood reservoir function of skin (1) |
-dermal vascular supply is extensive and cal hold about 5% of the body’s entire blood volume -If muscles require extra supply, nervous system constricts the dermal blood vessels, which cause more blood to shunt into general circulation |
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excretion function of skin (2) |
-the body eliminates amounts of nitrogen-containing wastes in sweat -Profuse sweating is an important avenue for water and salt loss |
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what epidermal cells play a role in body immunity? |
dendritic cells |
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how is sunlight important for bone health? |
-sunlight causes the skin to produce a precursor of vitamin D from cholesterol |
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how substances are secreted in: apocrine glands vs merocrine glands vs sebaceous glands |
Apocrine release products along the hair Merocrine secrete through pores (no hair-dependable) Sebaceum glands (travel along the hair) |
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why in humid places you are more aware that you are sweating? |
In humid places you are more aware because of humidity, does not let to dry (evaporate) |
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which places will have a greater amount of sebum? |
those that have a greater number of hair because sebaceous gland secretes through hair (reason head hairs becomes really oily) |
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what hormones have a key role in the functioning of mammary glands? |
Prolactin=hormone released by anterior pituitary gland to stimulate the production of milk Oxytocin causes the release of milk produced by posterior pituitary gland |
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How skin cancer is obtained? (what damages that causes skin cancer? other factors (3)) |
-Induced by UV rays of the sun -the single most important risk factor for skin cancer is overexposure to the UV radiation in sunlight, which damages DNA bases -In limited number of cases, other factors are frequent irritation of skin by infections, chemicals, or physical trauma seems to be a predisposing factor |
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list the types of cancer, from least serious to most serious |
-basal cell carcinoma -squamos cell carcinoma -malignant melanoma |
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describe basal cell carcinoma (level of , how often occurs, and where is found, what part of body appears, shape) |
-least dangerous and most common -arises from stratum basale and invades dermis (stays at dermis -slow growing -appear on face and appear as shiny, dome-shaped nodules that later develop acentral ulcer with a pearly, beaded edge |
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describe squamos cell carcinoma level of dangerosness, commonness, where found, when becomes lethal, how looks, where in body appears, how fast grows) |
-medium dangerous -2nd most common -arises from keratinocytes in stratum spinosum -metastasis to the lymph nodes can be lethal -at lymph nodes can travel to the blood and then go to anywhere -scaly reddened papule (small round elevation) that arises most often on head (scalp, ears, and lower lip) and hands -tends to grow rapidly |
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describe malignant melanoma (level of dangerousness and why (2), where found, types, based on what to classify, what can increase chances of getting it in men, how survive from it) |
-most deadly (highly metastatic and resistant to chemotherapy) -arises from melanocytes of a preexisting mole (where is pigment) -ABCD–asymmetry, border irregular, color mixed and diameter over 6 mm (start to change shape and growing and change color instead of being symmetrical (oval in one side) and can get blue or red color) -Result of oncogene BRAF in men (BRAF is Gene found in males that will make somebody more susceptible to melanoma) -the key survival for melanoma is early detection |
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moles is made out of _ |
melanocytes |
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_(ratio) of Americans develops skin cancer at some point. Most tumors are_ |
-1 in 5 -benign and do not spread to other body parts |
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Is sunburn beneficial or contributing to skin cancer? |
-Sunburned skin accelerates its production of Fas, a protein that causes genetically damaged skin cells to commit suicide, reducing the risk of mutations that will cause sin-linked skin cancers |
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what about tans? are good? |
There is not such thing as "healthy tan" |
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How cure basal cell carcinoma, squamous carcinoma, and melanoma? |
-basal cell= excision -squamous= If caught early, remove surgically or by radiation therapy -melanoma= usual therapy is wide surgical excision accompanied by immunotherapy (immunizing the body against its cancer cells) |
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How can we identify melanoma? |
-regularly examine our skin for new moles or pigmented spots -ABCD rule -asymmetry: 2 sides of the pigmented spot or mole do not match -Border irregularity: the borders of the lesion exhibit indentations -color= the pigmented spot contains several colors (black, brown, tans, and sometimes blues and reds) -Diameter= the spot is larger than 6 mm in diameter -some add the E for evolution |
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what are causes of burns? (7) |
Hot water, sunlight, radiation, electric shock or acids and bases, fire |
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why is a reason a person dies from burn? |
-they do not actually die for the burn -Death from fluid loss and infection |
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how many degrees of burns there are? |
3 (possible a 4 one arose) |
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1st degree (where burn and degree of seriousness and why? symptoms (3)) |
-only the epidermis (red, painful and edema) -do not have blood supply so it is not so serious -symptoms: localize redness, swelling and pain |
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2nd degree (2) |
-epidermis and part of dermis (blistered) -epidermis regenerates from hair follicles and sweat glands |
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3rd degree (what burns and what requires to fix, quantity of_) |
-epidermis, dermis and more is destroyed (destroying a lot more of tissue) -often requires grafts or fibrosis and disfigurement may occur (does not regenerate very well so need skin grafts) -little or no edema at the beginning |
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possible treatment of burns is_ (4) why? |
-IV nutrition and fluid replacement, debridement and infection control -loss of body fluids containing proteins and electrolytes. Thus, to save the patient, the lost fluids must be replaced immediately via the intravenous (IV) route. In addition, supply extra food calories daily needed to replace the lost proteins and allow tissue repair |
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which degree of burn is the most painful? |
-2nd degree is the most painful because you have not destroyed the nerve endings -3rd degree does not have nerve endings (painful while burning) |
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debridement |
medical process that scrapes off the burned skin that is still attached to burned area or around |
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burn (definition) |
tissue damage inflicted by intense heat, electricity, radiation, or certain chemicals, all of which denature cell proteins and kill cells in the affected area |
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what is the process used to identify degree of burn? |
rules of nines |
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in the adults, the volume of_can be estimated by computing the_using_ |
-fluid lost -percentage of body surface burned -rule of nines |
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describe rule of nines |
-method to evaluate degree of burns -calculate the percentage of body surface burned -This method divides the body into 11 areas, each accounting for 9% of total body area |
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sunburn is considered to be what degree burn? |
1st degree |
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what are the partial thickness burns? what are the full thickness burns? |
-1st degree and 2nd degree -3rd degree (involving the entire thickness of the skin) |
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why the burned area is not painful in 3rd degree burn? when pain occurs? |
-because nerve endings and pain sensors have been destroyed the burned area is not painful -pain occurs in recovery and skin grafting |
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skin graft (describe steps) (5) |
-eschar or burned skin must firs be debirded (removed) -to prevent infection and fluid loss, the area is then flooded with antibiotics and covered temporarily with a synthetic membrane, animal (pig) skin, cadaver skin, or living bandage made form thin amniotic sac membrane that surrounds the fetus -Then healthy skin is transplanted to the burned site -Unless the graft is taken from the patient (autographt), however, there is a good chance that the patient’s immune system will reject it -Extensive scar tissue often forms in the burned areas |
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what exciting technique eliminates the problems of graft skin? (describe steps, advantage and disadvantage) |
-synthetic skin: silicon epidermis bound to spongy dermal layer composed of collagen and ground cartilage -applied to debrided area -In time, the patient’s own dermal tissue absorbs and replaces the artificial one. Then silicone sheet is peeled off and replaced with a network of epidermal cells cultured form the patient’s skin -Body does not reject graft, but more chances to become infected |
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which type of skin cancer develops from the youngest epidermal cells? |
-basal cancer carcinoma |
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what name is given to the rule of recognizing the signs of melanoma? |
ABCD rule |
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the healing of burns and epidermial regeneration is usually uneventhful unless the burn is a 3rd degree burn. what accounts for this difference? |
-1st and 2nd degree burns can heal uneventfully by regeneration of epidermial cells as long as infection does not occur -3rd degree burns destroy the entire depth of skin and regeneration is not possible. Infection and loss of body fluid and proteins are problematic |
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the more _, the greater chances of of dying from dehydration or infection |
-parts burned |
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other way besides ABCD rule? |
-method in which takes into account sex of person (male and female) and age because this affects the percentages of the body |
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when you get over certain percentage, what will happen in the ABCD rule? |
you have greater chances of dying |
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what are the rays that affect the skin? What are the inappropriate names for each? why? |
UVA-tanning rays UVB-destroying rays -both thought to initiate skin cancer |
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what is the relation between the sales of sunscreen and amount of skin cancer incidents? why? (2) (3) |
-As sale of sunscreens has risen so has skin cancer -those who use have higher incidence of basal cell (more exposed to sun and do not replace the sunscreen that wears off) -chemical in sunscreen damage DNA and generate harmful free radicals: PABA, zinc oxide and titanium dioxide |
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why process of getting tan gets more chances to get cancer? |
-even if you produce more melanin due to exposure to sun, the way to produce melanin can cause cancer |
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can you get sunburned when is cloudy? why? |
yes because of the presence of UV light |
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what is the state with greatest skin cancer percentage? |
california |
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what is the relation of how deep is the cut with how much bleed? why? |
-the deeper the cut, the more you bleed -higher quantity of blood vessels as you go down the skin layers |
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How different is Grafted skin from normal skin? |
it has no hair follicles and does not have the typical structural layer of the epidermis, dermis, and hypodermis |
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what happens if skin graft has to be placed over a joint? how this refers to physical therapy? |
-when skin grafts cover a joint, movement of the joint is very painful -However, if patient does not move the joint, it becomes stiff and other problems develop -Physical therapists who work with burn patients have to get used to the idea that causing pain is helpful to the patient. It goes against the logic of physical therapy |
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the _ develops from embryonic ectoderm, and_ develops from mesoderm |
-epidermis -dermis and hypodermis |
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when damage the dermis, what will happen? Is this good or bad? why? |
-when damage skin into dermis, you are going to damage blood vessels and they will bleed -good thing: inside the blood has some cells that will regenerate the cut (ex: mast cells) |
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what will be secreted? (hormone) what it does? |
-Histamine: vessels dilator -to bring what is needed to cure through the blood -cause capillaries to dilate -wall become thinner, which have blood flow and capillary permeability |
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what makes the cloth? what forms over it? |
clotting factors scab |
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what happens after macrophages start to clean debris? |
Within dermis: new capillaries form to regenerate vessel capillaries to feed tissue and will regenerate that area -fibroblast come within blood: determine matrix |
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which strata is involved in mitosis? how this contributes to wound regeneration? |
-strata basale -it helps to regenerate and form new cells that substitute collagen fibers (fibrous connective tissue patch) that bridged the gap of the cut by slowly regenerating and filling up the space |
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what happens to wound that spread over a long distance? |
-cells cannot migrate that far of the epithelial tissue -get scar of the fibroblasts that were generate at the beginning |
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what layer of skin needs to be fixed first? why? |
-dermis -because the process needs to availability of nutrients, clotting factors, immune system cells, fibroblasts, and mast cells to regenerate the tissue. All of these are brought though the new formed blood vessels -to bring nutrients to basal layer though the new blood vessels (start mitosis and regenerate) |
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Blood vessels become _and more_enter the damage tissue. The tissue becomes_and_which is the body’s normal response to injury |
-dilated -blood -red and swallowen |
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why does an inflammatory response aid in healing? |
-It will increase the blood flow and capillary permeability because plasma carries antibodies, clotting factors, and White blood cells into wound required to fix and protect form infection within the cut |
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superficial cuts are filled in by reproducing _cells |
epithlial cells |
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deeper cuts damage blood vessels and form_clots. A _covers and protects underlying tissues. Fibroblasts produce_that bind the wound together. the what happens? |
-blood -scab -collagen fibers -Surface epithelium (basal layer) begins to regenerate (help by nutrients brought by blood vessels) growing under scab, which soon detaches. End result is fully regenerated epithelium |
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large wounds leave _and healing may be accompained by the formation of_ |
-scars -fibrous connective tissue |
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The healing of the dermis of the skin occurs in the following order: (4) |
1. bleeding 2. scab formation 3. granulation tissue 4. tissue fibrosis |
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Sudoriferous glands produce_ |
sweat |
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the stratum (layers) of the epidermis from superficial to deep are: (do not include lucidum) |
1. corneum 2. granulosum 3. spinosum 4. basale |
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the skin is composed of the following areas. From superficial to deep they are: |
1. epidermis 2. dermis 3. hypodermis |
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The least malignant of the skin carcinomas is_ |
-basal cell carcinoma |
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The reproducing cells of the epidermis are found in the_ |
stratum basale |
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The function of the melanin is to_ |
protect the cells of the skin from ultraviolet radiation |
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The portion of the dermis, which makes up approximately 20%, and contains Aeolar Connective Tissue is called_ |
paiplliary layer |
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Stratified squamous epithelium can be made waterproof and friction resistant by intercellular deposits _ |
keratin |
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Differences in skin color among human races is due primarily to the_ |
amount of melanin produced by melanocytes |
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T/F: Sweat is produced as a holocrine secretion, in which the cells themselves break up to form the product. |
False Sweat is produced as secretions pass through the secretory cells of the sweat glands by the process of exocytosis, leaving the secretory cells intact. |
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