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101 Cards in this Set
- Front
- Back
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What is the largest organ of the body?
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The skin
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What percent of body weight is the skin?
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16%
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The skin is continuous with what?
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The mucous membranes of the digestive, respiratory and reproductive systems
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What are the appendages of the integumentary system?
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sweat glands, sebaceous glands, hair and nails
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What are the functions of the skin?
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Protection
Thermoregulation reception/sensation excretion/secretion absorption immunity |
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The hypodermis is also called what?
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The superficial fascia
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Hypodermis is composed of what types of tissue?
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areolar (loose fibrous CT) and adipose
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What is the role of adipose tissue in the hypodermis
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storage of energy, insulator and shock absorber
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The hypodermis is rich in what?
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Blood vessles, lymph vessles and nerve fibers.
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What layer of the skin are the coiled ducts of sweat glands and the base of the hair follicles present?
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hypodermis
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What is dermis derived from?
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mesoderm (true skin)
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What kind of connective tissue is the dermis formed from?
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dense irregular collagenous CT
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What are the raised ridges of the dermis called?
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dermal ridges or papillae
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What do the dermal papillae interdigitate with?
What is the entire structure called? |
The epidermal ridges
rete apparatus |
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The dermis makes up how much of the dry weight of skin?
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70%
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What layer of the skin gives it strength, form and flexibility?
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the dermis
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What are the 2 layers of the dermis?
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Reticular layer and papillary layer
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What connective tissue form the reticular layer?
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dense, irregular CT with collagen and elastic fibers, adipose tissue and derivatives
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The papillary layer is formed from what connective tissue?
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Areolar CT with fine elastic fibers
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What layer of the skin are capillary loop and meissner's corpuscles found?
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papillary layer of the dermis
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Where are free nerves found in the skin?
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everywhere
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What do Pacinian corpuscles detect?
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Pressure and vibrations
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What do Meissners corpuscles detect? Where are they mostly found?
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light touch
In the feet and finger tips |
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What are merkel receptors?
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slowly adapting touch receptors.
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What is the epidermis derived from?
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The ectoderm which comes from the epiblast.
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What type of epithelium is found in the epidermis?
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stratified squamous keratinized
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Is the epidermis vascularized?
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no
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Keratinocytes make up ___% of what layer of the skin?
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90% of the epidermis
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Melanocytes makeup _____% of what layer of the skin?
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8% of the epidermis
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What is the role of the langerhans cells in the epidermis? And where do they come from?
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They come from the bone marrow. They aid helper T cells in immunmity.
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Where are Merkel cells located and what is their function?
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located in the deepest layer of the epidermis and function with tactile discs in the deepest layer to sense touch
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What cell differs in its morphology as it ages and allowes for the 5 layer of the epidermis.
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The keratinocytes
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What are the layers of the epidermis from superficial to deep?
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Stratum Corneum
Stratum Lucidum Stratum Granulosum Stratum Spinosum Stratum Basale |
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What layer of the epidermis is supported by the basement membrane?
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stratum basale
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What type of epithelium makes up the basale layer?
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simple cuboidal epithelium
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Stem cells, melanocytes and Merkel cells are found in what layer of the epithelium?
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Basale
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What do stem cells become in the basale layer?
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keratinocytes
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Stratum Basale is also called what?
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Stratum germinativum
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What attaches the cells of the stratum basale together?
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Desmosomes
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What attaches cells of the stratum basale to the basal lamina?
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Hemidesmosomes
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What intracellular structures are numberous in the cells of the stratum basale?
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free ribosomes, tonofibrils and tonofilaments
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Where is Melanin made?
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in melanosomes within melanocytes
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Melanin is made from what?
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tyrosine by tyrosinase
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What induces tyrosinase?
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UV light
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What type of secretion occurs with melanin granules?
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Cytocrine - contents passed directly to another cell
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Where are Melanocytes derived from?
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The neural crest
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The stratum spinosum is how many rows of cells thick? And what are the cells shape?
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8-10 layers and they have a polyhedral shape
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What attches cells in the spinosum together?
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desmosomes
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What does spinosum mean?
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prickly
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What organells are present in the cells of the stratum spinosum?
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same organelles as in basal cells, but more tonofilaments
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What are bundles of tonofilaments called? And what do they do to the cytoplasm? Which layer?
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Tonofibrils. They make the cytoplasm eosinophilic.
The spinosum layer |
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What cytoplasmic secretory granules do the cells of the stratum spinosum have?
What are in these granules? |
membrane-coating granules or lamellar bodies
gylcolipids |
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How many layers of cells does the stratum granulosum have?
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3-5
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How are the nuclei in the stratum granulosum?
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in various stages of degeneration
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What granules are found in the cells of stratum granulosum?
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basophilic, non membrane bound, keratohyalin
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Relative number of tonofibrils in stratum granulosum?
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increased amount compared to the other deeper layers
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What is the process of keratinization?
How long does it take? What is this keratin called? The process involved what? |
keritohyalin granules combine with tonofibrils to form keratin.
2-6 hours (the time it takes for the celss to leave the stratum granulosum and enter the stratum corneum Soft keratin breakdown of organelles and thickening of the plasma membrane |
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What happens to membrane-bound laminar bodies (glycolipids)?
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Thare are released by exocytosis into the extracellular space
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What do the membrane bound laminal bodies from the stratum granulosum do?
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They bind to the plasma membrane making it thicker and forming sheets of lipid-rich substance that are impermeable to water.
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How many cell layers is the stratum lucidum?
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3-5 rows of cells
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Describe the cells of the stratum lucidum?
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clear, flat, dead and filled with soft keratin
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How are the keratin filaments in the stratum lucidum oriented in relation to the skin?
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parallel
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How many rows of cells is the stratum cornium?
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25-80
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describe the cells of the stratum corneum
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very flat, dessicated, anuclear, cornified
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What layer loses its desmosomes as they become more superficial?
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stratum corneum
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What are squamous cells also called?
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horny
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How long does keratinization take?
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2-4 weeks
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How thick is thin skin? Thick?
Where is thin skin found? Thick? Which type of skin is hair found in? Which layer is lacking the stratum lucidum? |
thin =.08mm Thick = 6x thicker
thin = most of body Thick = palms and soles Thin |
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What pigments contribute to skin color? And what color do each contribute to?
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Melanin - yellow to reddish-brown to black
Carotene - yellow - orange (accumulates in the stratum corneum and adipose tissue in hypdermis) Hemoglobin - crimson |
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where are the skin appendages derived from?
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down growths of epidermal epithelium during development
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What are they types of glands found in the skin?
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- sebaceous
- sudoriferous (sweat glands) - ceruminous - mammary |
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What is the more common sudoriferous gland?
What is its secretion like? What type of gland is it? |
eccrin
more watery sweat than apocrine merocrine gland |
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What kind of sudoriferous gland is less common?
Where is it found Describe its secretion When does this secretion occur (age and environment) |
apocrine
armpit, pubic region, areolar region more viscus than eccrine during stress and sexual excitment beginning at puberty |
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What type of glands are sweat glands?
What kind of innervation do they have? |
simple coiled tubular
sympathetic, cholinergic |
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What is the secretory unit of the seat glands?
What helps squeeze the secretions out? |
Cuboidal to columnar
myoepithelial cells |
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Sebaceous glands undergo what type of secretion?
What does it secrete? What is its function? |
Holocrine
sebum keep hair from drying out, prevents evaporation of water, keeps skin soft and pliable, and inhibits certain bacteria |
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What are blackheads?
What are pimples? |
blocked sebaceous pores
Bacterial infection of sebaceous glands |
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What factors affect the growth and density of the hair?
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nutrition and hormones and increased local dermal blood flow
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What are the 2 types of hair?
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vellus - on women and childern
Terminal - darker, courser and longer |
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What is the function of hair?
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on scalp, eyelashes, nasal cavity, ear canal it is for protection.
On the body it is for sensation from touch receptors |
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What are the 3 parts of the hair?
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Shaft - above skin surface
Root - below skin Follicle - part the generates the hair |
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What are the layers of the hair shaft
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Medula (innermost) with pigment and soft keratin
Cortex - middle layer - pigment and hard keratin Cuticle - outer layer - heavly keratinized dead cells |
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What is the inner layer root sheath?
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a multi-layered cellular covering that surrounds the deep part of the hair
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What in the external root sheath?
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the outermost part of the hair follicle. It is a down growth of the epidermis
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Dermal papilla of hair follicle
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base of the bulb - areolar CT - provides nourishment
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What is the matrix of the hair follicle?
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surrounds papilla and consist of matrix cells
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What is the germinative layer in a growing hair follicle?
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the germinative layer (I know its redundant but I couldn't think of another way to put it!)
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What do the cells in the germinative layer of the hair follicle become?
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keratin producing cells
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What cells are scattered in the germinative layer of a hair follicle that contribute melanosomes?
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Melanocytes
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What type of muscle is the arrector pili?
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smooth
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What is the hair root plexuses? What is it sensitive to?
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nerve endings that surround the hair follicle.
The lightest touch |
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The nail consists of what 3 areas?
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free edge, nail body, and nail root
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The nail plate lies where?
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in the nail fold
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Where is the eponychium of the nail found?
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at the proximal part of the nail fold (cuticle)
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Where is the hyponychium part of the nail found?
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under the distal end of the nail plate
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Where does the nail plate lie?
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over the nail bed
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What does the nail matrix contain?
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cells that generate the nail plate
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The nail matrix is visable where?
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through the nail lunula (white crescent)
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Glands originate from what?
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epithelial cells
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Glands penitrate underlying connective tissue stroma forming what around themselves?
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basal lamina
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Vesicles secrete their products in vesicles called what?
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Secretory granules
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