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106 Cards in this Set
- Front
- Back
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What is the largest system of the body and what percent of the body weight does it make up? |
-Integumentary system -16% -1.5-2m^2 in area |
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What two parts make up the integumentary system? |
1. Cutaneous membrane -Outer epidermis -Inner dermis 2. Accessory structures |
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What two parts make up the cutaneous membrane? |
1. Outer dermis 2. Inner dermis |
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What are the components of the outer epidermis of the cutaneous membrane? |
-Made up of superficial epithelium (stratified squamous epithelium) -Avascular -Thickness varies based on location on body -Thickest = hands, feet, and inner linings of mouth -Regulates permeability when it comes to materials moving in and out f the body |
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What are the components of the inner dermis of the cutaneous membrane |
-Made up of connective tissues i.e areolar, dense irregular -Where all accessory structures originate -Vascular -Has specialized sensory neurons |
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What accessory structures are present in the integumentary system |
-Hair -Nails -Glands -Touch receptors -Multicellular exocrine glands -Originate in the inner dermis -Extend through the epidermis |
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How is the integumentary system connected to the cardiovascular system? |
-Blood vessels in the dermis -Allows for exchange of gases and nutrients |
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How is the integumentary system connected to the nervous system? |
-Sensory receptors are found within the dermis for pain, touch, and temperature -Allow for recognition of vibration, soft/sharp, shape of objects, etc. -Abundance of receptors varies depending on location of the body |
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Where on the body would many touch receptors be found? |
-Hands and fingers have many touch receptors |
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Where on the body would fewer touch receptors be found? |
-Back of leg or small of back has less receptors |
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What is located beneath the dermis? |
-Hypodermis |
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What is the hypodermis made up of? |
-Loose connective tissue (adipose & areolar) -Larger blood vessels -Adipose tissue creates insulation |
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What does the hypodermis create a loose connection to? |
-Muscle -Too tight of a connection would restrict motion |
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What is the benefit of hypodermic injections? |
-Diffusion of injection is more gradual -Injections into the bloodstream create faster & more dramatic changes -Example: Insulin |
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What are the 8 functions of the skin? |
1. Protection of underlying tissues and organs 2. Excretion of salts, water, and organic wastes 3. Maintenance of body temperature 4. Production of melanin 5. Synthesis of vitamin D3 6. Storage of lipids 7. Production of keratin 8. Detection of touch, pressure, pain, and temperature |
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What's an example of the skin's excretory function? |
Sweating during exercise |
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What is a benefit of the skin's production of keratin? |
It helps create a strong barrier that prevents free diffusion of substances from the external environment |
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How does the epidermis receive nutrients and oxygen? |
Nutrients and oxygen diffuse across capillaries in the dermis |
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What happens to cells of the epidermis as they become more superficial? |
-They begin to die -Skin is always flaking off cells |
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What are the cells that are most abundant in the epidermis? |
-Keratinocytes -Create keratin -Stratified squamous |
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What does keratin do in the epidermis? |
-Keratin holds epithelial cells together with tight junctions -Creates a tighter barrier |
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What two types of skin are there? |
-Thin skin and thick skin |
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How many layers does thin skin have? What are they? |
-Four Layers 1. Stratum basale (deepest layer) 2. Stratum spinosum 3. Stratum granulosum 4. Stratum corneum (superficial layer) |
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What type of skin covers most of the body? |
Thin skin |
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How many layers does thick skin have? What are they? |
-Five layers 1. Stratum basale (deepest layer) 2. Stratum spinosum 3. Stratum granulosum 4. Stratum lucidum 5. Stratum corneum |
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Where on the body is thick skin found? |
Palm of hands and soles of feet |
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What are the five strata of keratinocytes |
1. Stratum basale (Deepest layer) 2. Stratum spinosum 3. Stratum granulosum 4. Stratum lucidum (only in thick skin) 4. Stratum corneum (Most superficial layer) |
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Components of the Stratum Basale |
-Single layer of cells -Attached to basement membrane by hemidesmosomes -Forms a strong bond between epidermis and dermis -Forms epidermal ridges -Has many basal cells (germinative cells) -Specialized cells = Merkel Cells and Melanocytes |
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What are basal cells and where are they found in the most abundance? |
-Found in the stratum basale -Have the ability to divide -Regeneration of epidermis |
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What specialized cells are found in the stratum basale? |
Merkel cells and melanocytes |
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What do Merkel cells specialize in and where are they found? |
-Respond to touch (trigger nervous system) -Fine touch receptors -Found in hairless skin (palms, finger tips) |
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What do melanocytes specialize in, and where are they found? |
-Contain the pigment melanin -Skin color -Produced in and scattered throughout stratum basale |
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Dermal Papillae |
-Found in the dermis -Increase surface area of basement membrane -Coincides with epidermal ridges to create a tight adhesion, and strong attachment between epidermis and dermis |
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Components of the stratum spinosum |
-"Spiny Layer" -Produced by division of stratum basale -8-10 layers of keratinocytes bound by spot desmosomes -Cells shrink until cytoskeletons stick out (spiny) -Continue to divide & increase thickness of epithelium -Contains dendritic (Langerhans) cells |
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What is the movement of the keratinocytes in the stratum spinosum? |
-Cells divide and move upwards -Cells dehydrate and flatten as they move upwards |
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What specialized cells are found in the stratum spinosum, and what is their function? |
-Dendritic (Langerhans) Cells
-Active in immune response and help remove pathogens -Help regulate the environment |
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Components of the stratum granulosum |
-"Grainy layer" -Cells stop dividing -Cells dehydrate and die -Cells produce protein fibers (Keratin and keratohyalin) -Create tightly interlocked layer of keratin surrounded by keratohyalin |
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Why do cells die and stop dividing in the stratum granulosum? |
They are unable to receive nutrients |
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What is Keratin, and what strata begins producing it first? |
-Tough, fibrous protein -Makes up hair and nails -Produced in stratum granulosum |
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What is Keratohyalin, and what strata begins producing it first? |
-Dense granules that cross-link keratin fibers -Increase density -Produced in stratum granulosum |
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Components of the stratum lucidum |
-"Clear layer" -Found only in thick skin -Covers stratum granulosum -All cells are dead by this point -Not a lot of function in this layer |
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Components of the stratum corneum |
-"Horny layer" -Exposed surface of skin -15-30 layers of keratinized cells -Skin is constantly sloughed off and replaced -Most amount of keratin -Dead cells remain tightly bound by desmosomes |
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What can cause the stratum corneum to have more than 30 layers? |
Mechanical stress i.e. calluses |
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What allows the stratum corneum to be water resistant? |
Keratin |
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How many days does it take for cells to move from stratum basale to stratum corneum? |
7-10 days |
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What strata contains the most amount of keratin? |
Stratum corneum |
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How long do cells remain in the stratum corneum before being shed? |
Two weeks |
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What is keratinization? |
-The formation of protective, superficial layers of cells filled with keratin -Takes place on all exposed skin surfaces except eyes |
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What are the two types of perspiration? |
1. Insensible perspiration 2. Sensible perspiration |
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Components of insensible perspiration |
-Interstitial fluid is lost by evaporation through the stratum corneum -Occurs through diffusion -Happens constantly without notice -Creates moisture of the skin |
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How does insensible perspiration occur? |
Diffusion |
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Components of sensible perspiration |
-Noticeable -Involves opening glands -Ex: water excreted by sweat glands |
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In which ways does dehydration occur? |
-Damage to stratum corneum -Ex: Burns and blisters [insensible perspiration] -Immersion in hypertonic solution -Ex: Sea water [osmosis] |
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How does hydration of the epidermis result? |
-Immersion in a hypotonic solution -Ex: Freshwater [osmosis] -Causes swelling of epithelial cells, which is evident in palms of hands and soles of feet |
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What two pigments influence skin color? |
1. Carotene 2. Melanin |
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What influences skin color other then pigments? |
-Blood circulation (red blood cells) -Occurs especially in lighter colored skin -More blood flow to skin = greater redness of skin and vice versa |
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Components of carotene |
-Fat-soluble vitamin stored in adipose tissue -Orange-yellow pigment -Found in orange vegetables -Accumulates in epidermal cells and fatty tissues of the dermis -Can be converted to vitamin A |
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Components of melanin |
-Yellow-brown or black pigment -Produced by melanocytes in stratum basale -Melanin is transported to keratinocytes in vesicles called melanosomes -Color the keratinocytes temporarily |
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What are the functions of Melanocytes? |
-Protects skin from sun damage by absorbing some of the light |
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What causes some people to have darker skin? |
-Melanosomes are larger and more numerous -Melanosomes move to more superficial layers i.e. stratum granulosum |
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What are the effects of Ultraviolet (UV) radiation? |
-Causes DNA mutations and burns that lead to wrinkles and cancer |
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What do epidermal cells produce in the presence of UV radiation? |
-Cholecalciferol (Vitamin D3) |
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What happens to cholecalciferol (Vitamin D3) once it is produced? |
-Liver and kidneys convert vitamin D3 into calcitriol -Aids in absorption of calcium and phosphorus |
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What condition can insufficient vitamin D3 cause? |
-Rickets -Often occurs in children -Causes bowed legs |
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Where is the dermis located? |
Between the epidermis and subcutaneous layer |
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What does the dermis do in regards to accessory structures? |
The dermis anchors epidermal accessory structures i.e. hair follicles and sweat glands |
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What are the two layers of the dermis? |
1. Outer Papillary layer 2. Inner Reticular layer |
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What is the function of the Papillary layer? |
-Binds the dermis to the epidermis with dermal papillae |
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What kind of tissue makes up the papillary layer of the dermis? |
Areolar tissue |
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What are the components of the papillary layer of the dermis? |
-Areolar tissue -Capillaries, lymphatics, and sensory neurons |
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What makes up the Reticular layer of the dermis? |
-Dense irregular connective tissue -Larger blood vessels, lymphatic vessels, and nerve fibers -Contains collagen and elastic fibers -Contains connective tissue proper -Where accessory structure originate |
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In what layer of the dermis do accessory structures originate? |
Reticular layer |
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What fibers are present in the reticular layer of the dermis? |
Collagen and elastic fibers |
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How do collagen fibers and elastic fibers differ? |
-Collagen fibers resist stretching but bend easily (provide flexibility) -Elastic fibers permit stretching and then recoil to original length (limit flexibility of collagen fibers) |
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Skin Turgor |
-Properties of flexibility and resilience are known as skin turgor -Ability to maintain strength |
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What causes skin damage? What are the results? |
-Dehydration -Age -Hormonal changes -UV exposure -Causes reduced skin elasticity i.e. sagging and wrinkling |
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What are cleavage lines? What is their significance? |
-Collagen and elastic fibers in the dermis arrange in parallel bundles that resist force in a specific direction -Establish important patterns: -A parallel cut remains shut & heals well -A cut at a right angle pulls open and scars |
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What three networks make up the dermal blood supply? |
1. Cutaneous plexus 2. Papillary plexus 3. Venous plexus |
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Components of the Cutaneous plexus |
-Network of arteries along the reticular layer -Larger vessels for transport of nutrients and gases |
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Components of the Papillary plexus |
-Capillary network from small arteries to papillary layer -Smaller thinner vessels for exchange/diffusion of gases and nutrients |
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Components of the Venous plexus |
Capillary return deep to the papillary plexus |
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What is a contusion? |
-Damage to blood vessels that results in bruising -Pooling of blood -Can occur in papillary or cutaneous plexuses |
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What do nerve fibers in the skin control? |
1. Blood flow -Ex: dilate blood vessels to release heat 2. Grand secretions 3. Sensory receptors -Light touch (tactile corpuscles) -Deep pressure and vibration (lamellated corpusles) |
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Components of the Hypodermis (subcutaneous layer) |
-Elastic areolar and adipose tissue -Connected to reticular layer by tissue fibers -Few capillaries and no vital organs |
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Functions of the Hypodermis |
-Stabilizes skin -Allows for separate, independent movement of deeper structures i.e. muscle -Insulation and energy storage |
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What are the functions of hair? |
-Protects and insulates -Guards openings against particles and insects -Is sensitive to light touch |
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Components of the Hair Follicle |
-Located deep in dermis -Produces nonliving hairs -Wrapped in dense connective tissue sheath -Base is surrounded by sensory nerves |
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What are the accessory structures of hair? What do they do? |
1. Arrector Pili -Involuntary smooth muscle -Causes hair to stand up (goosebumps) -Provides heightened sensation (alarm reaction) 2. Sebacous glands -Only associated w/ hair follicles -Produce oil and lubricate hair -Antibacterial properties of oil control bacteria |
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What regions make up hair? |
1. Hair Root -Lower part of hair -Attached to integument (dermis) 2. Hair Shaft -Upper part of the hair -Cortex= outermost layer -Medulla = Innermost layer |
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How long does a hair in the scalp grow? |
Two to five years |
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Sebaceous (oil) Glands |
-Simple branched alveolar glands that are directly associated with hair follicles |
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Sebaceous Follicles |
-Discharge sebum directly onto surface of skin -Sebum: -Contains lipids and other ingredients -Lubricates and protects epidermis -Inhibits bacteria -Found all over body surface |
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Where are sebaceous follicles found and what are their purpose? |
-All over the body -Lubricates and protects epidermis -Inhibits bacteria |
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Where are sebaceous glands found and what are their purpose? |
-Found where there are hair follicles -Lubricate hair and maintain it's structure -Controls bacteria |
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Apocrine Sweat Glands |
-Found in armpits, around nipples, and groin -Secrete products into hair follicles -Produce sticky, cloudy secretions that break down and cause odor -Respond to hormonal or nervous signals |
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Where are apocrine sweat glands found? |
Armpits, around nipples, and groin |
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Merocrine Sweat Glands |
-Widely distributed across body surface (especially palms and soles) -Sensible perspiration -Coiled tubular glands -Discharge water, salts, and organic compounds directly on skin |
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What are the functions of merocrine sweat glands? |
-Cools skin -Excretes water and electrolytes -Flushes away microorganisms and harmful chemicals from skin |
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Mammary Glands |
Produce milk |
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Ceruminous Glands |
Produce earwax that protects ear drums |
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How are merocrine sweat glands controlled? |
-Controlled independently and sweating occurs locally -Ex: based on temperature of one area of the body |
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What glands does the ANS control? |
-Sebaceous glands and apocrine glands -Involuntary responses (sympathetic and parasympathetic) |
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Thermoregulation |
-Is the main purpose of sensible perspiration -Works with cardiovascular system to release or retain body heat -Regulates body temperature |
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Components of Nails |
-Dense dead cells packed with keratin protein -Protects fingers and toes -Metabolic disorders can change nail structure |
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Where does nail production occur? |
In deep epidermal fold near the bone called the nail root |
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What are the effects of aging? |
-Epidermal thinning -Decreased number of dendritic cells -Decreased vitamin D3 production -Decreased melanocyte activity -Decreased glandular activity (sweat and oil glands) -Reduced blood supply -Decreased function of hair follicles -Reduction in elastic fibers -Decreased hormone levels -Slower repair rate |
