Anatomy chapter 5: Integumentary

integument w urinary

U: excretes waste products and maintains normal body fluid pH and ion compostion -I: assists in elimination of water and solutes; keratinized epidermis limits fluid loss through skin

nail bed

covered by the nail body

1st degree burn

inflammed and tender; -killed: superficial cells of the epidermis -damaged: deeper layer of epidermis, papillary dermis

scar tissue

inflexible, noncellular, and noncellular tissue

squamous cell carcinomas

involve more superficial layers of epidermal cells.

dermis

lies beneath the epidermis. Has two major components: superficial papillary layer and a deeper reticular layer

medulla

makes up the core of the hair. contains flexible soft keratin; the cortex and cuticle contain thick layers of hard keratin, which give the hair its stiffness.

stratum spinosum

may continue to divide and add to the thickness of the epithelium. Spiny layer of stem cell daughters that undergo mitosis. desmosome junctions create the cells look.

Hair root

portion that anchors the hair into the skin.

nail root

production occurs here. an epithelial fold not visible to from the surface

hairs

project above the surface of the skin almost everywhere except the sides and soles of the feet, the palms of the hands, the sides of the fingers and toes, the lips, portions of the external genital organs. Hairs are nonliving structures produced in organs called hair follicles.

ultraviolet radiation

sunlight contains significant amounts of (UV radiation). A small amount of UV radiation is beneficial because it stimulates the synthesis of vitamin D3 in the epidermis. Too much UV can cause severe burns. Melanin helps prevent skin damage by absorbing UV radiation before it reaches the deep layers of the epidermis and dermis. Long-term damage can result from repeated exposure to sunlight.

cuticle (hair)

surface layer, is made up of an overlapping shingle-like layer of cells

cortex

underlying layer of the cuticle

nail body

visible, consists of a dense mass of dead, keratinized cells. the nail body is recessed beneath the level of the surrounding epithelium. the body of the nail covers an area of the epidermis called the nail bed

Integument w Digestive

D: provides nutrients for all cells and lipids for storage by adipocytes I: synthasizes VD3 needed for absorption of calcium and phosphorus

*effective healing depends on the depth and degree of the injury. Stem cells provide for regeneration. The larger the surface area involved, the more difficult the recovery

*note

Metastasis seldom occurs in either cancer and most people survive these cancers

*note

blood with abundant oxygen is bright red so blood vessels in the dermis normally give the skin a reddish tint that is most apparent in lightly pigmented individuals

*note

hair color reflects differences in the type and mount of pigment produced by melanocytes at the hair papilla. Different forms of melanin produce hair colors that can range from black to red. Pigments are genetically determined

*note

integumentary system (integument)

consists of the skin, hair, nails and various glands. Has two major components: the cutaneous membranes and accessory structures

stratum lucidum

covers the stratum granulosum. the cells in this layer are flattened, densely packed, and filled with keratin. flat, densely packed cell layer with increasing keratin content

Integument w Reproductive

-R: sex hormones affect hair distribution, adipose tissue distribution in subcutaneous layer, and mammary gland development I: covers external genitalia; provides sensations that stimulate sexual behaviors; mammary gland secretions provide nourishment for new born infant

integument w muscular

-contractions of skeletal muscle pull against skin of face, producing facial expressions important in communication -synthesized VD3 essential for normal calcium abosrption (plays role in muscle contraction)

Integument w nervous

-controls blood flow and sweat gland activity for thermo-regulation; stimulates contraction of arrector pili muscle to elevate hairs -receptors in dermis and deep epidermis provide sensations of touch, pressure, vibration, temp, and pain.

integument w skeletal

-provides structural support -synthesizes VD3, essential for calcium and phosphorus absorption

integument w lymphatic

L: assists in defending the integument by providing additional macrophages and mobilizing lymphocytes I: provides physical barriers that prevent pathogen entry; macrophages resist infection; mast cells trigger inflammation and initiate the immune responses

integument w respiratory

R: provides oxygen and eliminates carbon dioxide I: hairs guard entrance to nasal cavity

arrector pili

a bundle of smooth muscle cells from the arrector pili muscle, which extends from the papillary dermis to the CT sheath that surrounds each hair follicle. When stimulated, the arrector pili pulls on the follicle forcing the hair to stand up.

keloid

a flattened mass of scar tissue that begins at the injury site and grows intot he surrounding dermis. Thickened area of scar tissue

cuticle (nail)

a portion of the stratum corneum of the fold extends over the exposed nail nearest the root

Vitamin D3

a steroid building block for a hormone that aids calcium uptake.

Carotene

an orange-yellow pigment that normally accumulates in epidermal cells. Carotene pigments are present in a variety of orange-colored vegetables. Ex) eating carrots and squash changes the color of your skin. The color change is less striking in the skin of darker individuals. Carotene can be converted to Vitamin A, which is required for the normal maintenance of epithelial tissues and the synthesis of photo receptor pigments in the eye.

cutaneous membrane (skin)

an organ composed of superficial epithelium, or epidermis, and the underlying connective tissues of the dermis.

skin contains two types of sweat glands (sudoriferous glands)

apocrine sweat glands merocrine swear glands

Sebaceous glands (oil glands)

are holocrine glands that discharge an oily lipid secretion into the hair follicles, or in some cases, onto the skin. the gland cells produce large quantities of lipids as they mature. the lipid is released through holocrine secretion, a process that involves the rupture and death of cells. The contraction of the arrector pili muscle that elevates the hair squeezes the sebaceous gland, forcing the oily secretion into the hair follicle and onto the surrounding skin. This secretion is called sebum. it lubricates the hair and skin and inhibits the growth of bacteria. Sebaceous follicles are large sebaceous glands that discharge sebum directly onto the skin.

structure of the integument

beneath the dermis, the loose connective tissue of the subcutaneous layer, or hypodermis, attaches the integument to deeper structures, such as muscle or bones.

2nd degree burn

blisters; very painful -killed: superficial and deeper cells of epidermis; dermis may be affected -injured: damage may extend into reticular layer of the dermis, but many accessory structures are unaffected

3rd degree burn

charred; no sensation at all killed: all epidermal and dermal cells injured: hypodermis and deeper tissues and organs

the color of skin is caused by the interaction between:

epidermal pigmentation and dermal blood supply

melanomas

extremely dangerous. A melanoma usually begins from a mole but may appear anywhere in the body. they grow rapidly and metastasize through the lymphatic system

keratin

extremely durable and water-resistant. coats the surface of skin by also forms the basic structure of hair, calluses, and nails.

nails

forms on the dorsal surface of the fingers and toes where they protect the exposed tips and help limit their distortion when they are subjected to mechanical stress.

thick skin

found on the palms of the hands and soles of the feet, contains five layers.

accessory structures include______

hair, nails, and a variety of exocrine glands

basal cell carcinoma

most common skin cancer which originates in the stratum germinativum layer

stratum corneum

most superficial layer, consisting of 15-30 layers of flattened and dead epithelial cells that have accumulated large amounts of keratin. tightly connected by desmosomes. takes 2-4 wees for a cell to go from the basale to the corneum

the papillary layer

named after the dermal papillae consists of loose connective tissue that supports and nourishes the epidermis. This region contains the capillaries and nerves supplying the surface of the skin

lunula

obscured blood vessels leaving a pale crescent

thin skin

only four layers make it up. covers the rest of the body

hair shaft

part that is seen on the surface. Each shaft consists of 3 layers of dead keratinized cells.

Hair follicles

project deep into the dermis and often extend into the underlying subcutaneous layer. the walls of each follicle contain all cell layers found in the epidermis. The epithelium at the base of a follicle forms a cap over the hair papilla, a peg of CT containing capillaries and nerves. hair is formed by the repeated division of epithelial stem cells surrounding the hair papilla. As the daughter cells are pushed toward the surface. the hair lengthens, and the cells undergo kertinization and die.

functions of hair

protect scalp from UV light, help cushion a light blow to the head, provide insulating benefits for the skull.

ance

sebaceous ducts become blocked and secretions accumulate, causing inflammation and a raised pimple. the trapped secretions provide a fertile environment for bacterial infection

apocrine sweat glands

secrete product into hair follicles in the armpits, around the nipple, and the groin. It relies on the merocrine secretion. at puberty these glands begin discharging a sticky, cloudy, and potentially odorous secretion. the sweat becomes odorous when bacteria break it down as a food source

things that are decreased with age

stem cell activity immune cell numbers VD production melanin production glandular activity hair follicle production bloody supply to the dermis

cyanosis

the blood in the skin loses oxygen and takes on a darker red tone. The skin then takes on bluish coloration. common around thin skin

granulation tissue

the combination of blood clot, fibroblasts, and extensive capillary network

The subcutaneous layer consists of loos CT with many fat cells. provide infants and small children with a layer of baby fat which helps them reduce heat loss, also serves as an energy reserve and shock absorber. as we grow older the distribution of subcutaneous fat changes during puberty. the hypodermis is quite elastic. it contains no vital organs and few capillaries. the lack of vital organs make subcutaneous injection a useful method for administering drugs using a hypodermic needle

*note

melanocytes

cells whose cytoplasmic processes extend between epithelial cells in the stratum basale layer, and receptors that provide information about objects touching the skin. Melanocytes synthesize melanin, a brown, yellow-brown, or black pigment that colors the epidermis. slowly increases in exposure to the sun. freckles represent areas of greater than average melanin production

merocrine sweat glands (eccrine)

coiled tubular glands that discharge their secretions directly onto the surface of the skin. far more numerous and widely distributed than apocrine glands. palms and soles have the highest numbers. the perspiration produced by merocrine glands is 99% water, also contains a mixture of electrolytes, organic nutrients, and waste products such as urea. the primary function of merocrine gland activity and persipiration is to cool the surface of the skin and lower body temp. sweat provides protection from environmental hazards. Sweat dilutes harmful chemicals in contact w the skin and flushes microorganisms from its surface.

stratum granulosum

consists of cells displaced from the stratum spinosum. cells are non-dividing but make many enzymes and proteins including the durable, water resistant keratin.

stratum germinativum

the deepest epidermal layer. the cells are firmly attached to the BM by hemidesmosomes. The BM separates the epidermis from the loose connective tissue. It forms epidermal ridges, which extend into the dermis, increasing the area of contact between the two regions extend upward between adjacent ridges. Because there are no blood vessels in the epidermis , epidermis cells must obtain nutrients delivered by dermal blood vessels. The combination of ridges and papillae increases the surface area for diffusion between the dermis and epidermis. superficial ridges on the palms and soles increase the surface area of the skin and increase friction, ensuring a secure grip. Stem cells (germinative cells) dominate the stratum germinativum, making it the layer where new cells are generated and begin to grow. Also contains melanocytes

subcutaneous layer an extensive network of CT fibers attaches the dermis to the subcutaneous layer (hypodermis). The boundary between the two is indistinct. the hypodermis is important in stablizing the position of the skin relative to underlying tissues, such as skeletal muscles or other organs, while permitting independent movement.

*note

when exposed to sunlight, epidermal cells in the stratum spinosum and stratum germinativum convert a cholesterol-related steriod into VD3. This product is absorbed, modified, and released by the liver and then converted by the kidneys into calcitriol, a hormone essential for the absorption of calcium and phosphorus by the small intestine. an inadequate supply of VD3 leads to abnormal bone growth

*note

integument w Cardiovascular

-C: provides oxygen and nutrients; delivers hormones and cells of immune systems; carries away carbon Dioxide, waste products, and toxins, provides heat to maintain normal kin temp. -I: stimulation of mast cells produce localized changes in blood flow and capillary permeability

Skin repair process

-involves the inflammatory responses due to bleeding and mast cell involvement -increased circulation and phagocyte activity, collting isolate the area and you have the formation of granulation tissue and scab - the clot dissolves, fibroblast cells form fibers - the scab is shed and the epidermis is complete.

integument w endocrine

-sex hormones stimulate sebaceous gland activity; male and female sex hormones influence hair growth, distribution of fat, and apocrine sweat gland activity -synthesizes VD3, precursor of calitriol

the integument contains two types of exocrine glands

1) sebaceous glands 2) sweat glands

layers (strata) of the integument (from BM up)

1) stratum germinativum (or basale) 2) stratum spinosum 3) stratum granulosum 4) stratum lucidum 5) stratum corneum

five major functions of the integument

1)protection- the skin covers and protects underlying tissues and organs from impacts, chemicals, and infections, and it prevents the loss of body fluid. 2) temp. maintainence- the skin maintains normal body temp by regulating heat exchange with the environment 3) synthesis and storage of nutrients- the epidermis sythesizes VD3. the dermis stores large reserves of lipids and adipose tissue 4) sensory reception- receptors detect touch, pressure, pain, and temp stimuli 5)excretion and secretion- glands excrete salts,water, and organic wastes. mammary glands secrete milk

classification of burns

1st, 2nd, and 3rd degree based on the layers of skin killed or damaged

deeper reticular layer

consists of an interwoven meshwork of dense, irregular connective tissue. Both elastic fibers and collagen fibers are present. the elastic fibers provide flexibility, and the collagen fibers limit that flexibility to prevent tissue damage. also contains the mixed cell populations of connective tissue proper. epidermal accessory organs such as hair follicles and sweat glands, extend into the dermis.