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Anatomy & Physiology (Chapter 5-Integumentary)

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Integument
the largest system of the body
16 % of body weight
the integument is ____% of the body's weight
1.5 to 2 m^2 in area
the integument is: _____ to ______ m^2 in area
Cutaneous Membrane, Accessory Structures
The integument is made up of 2 parts:
Outer Epidermis
Superficial epithelium (epithelial tissues)
[one component of the cutaneous membrane]
Inner Dermis
Underlying area of connective tissues
[one component of the cutaneous membrane]
Accessory Structures
Hair, nails, & multicellular exocrine glands
-->located primarily in the DERMIS & protrude through the EPIDERMIS to the SKIN SURFACE
Dermis
An exensive network of blood vessels branches ( and sensory receptors that monitor touch, pressure, temperature, and pain provide valuable informaion to the CNS) through the _________
Hypodermis
-Deep to the Dermis
-Superficial fascia/SUBCUTANEOUS layer
Hypodermis
Seperates the integument from the deep fascia around other organs, such as muscles and bones
Protection, Excretion, Maintenance, Production, Production, Synthesis of Vitamin D3, Storage, & Detection
General functions of the skin & hypodermis:
Protection
The Skin & Hypodermis provide ________ of underlying tissues & organs against impact, abrasion, fluid loss, & chemical attack.
Excretion
The Skin & Hypodermis provide __________ of salts, water, & organic wastes by integumentary glands.
Maintenance
The Skin & Hypodermis provide ____________ of normal body temperature through either insulation of evaporative cooling, as needed.
Production
The Skin & Hypodermis provide ____________ of melanin, which protects underlying tissue from ultraviolet radiation.
Production
The Skin & Hypodermis provide ___________ of keratin, which protects against abrasion and serves as a water repellent.
Synthesis of Vitamin D3
The Skin & Hypodermis provide ____________ of ___________ ____, a steroid that is converted to calcitriol, a hormone important to normal calcium metabolism.
Storage
The Skin & Hypodermis provide _________ of lipids in adipose tissue in the subcutaneous layer.
Detection
The Skin & Hypodermis provide _________ of touch, pressure, pain, & temperature stimuli, & the relaying of that information to the nervous system.
Stratified Squamous Epithelium
The Epithelium consists of a: __________ __________ ___________
Keratinocytes
The epidermis is dominated by:
Keratinocytes
The body's most abundant epithelial cells:
Keratin
Keratinocytes contain large amounts of:
Thin skin
Covers most of the body surface; four layers of keratinocytes; about as thick as the wall of a plastic sandwich bag (about 0.08 mm)
Thick skin
Occurs in the palms of the hands and soles of the feet; contains a 5th layer (STRATUM LUCIDUM); has a much thicker superficial layer (STRATUM CORNEUM); is about as thick as a standard paper towel (about 0.5 mm)
Layer
Stratum means:
Stratum Basale, Stratum Spinosum, Stratum Granulosum, Stratum Lucidum, Stratum Corneum
The strata, in order from the basement membrane toward the free surface:
Stratum Basale
Innermost epidermal layer:
Stratum Germinativum
Another name for the Stratum Basale:
Hemidesmosomes
These attach the cells of the Stratum Basale (Germinativum) to the basement membrane that seperates the epidermis from the areolar tissue of the adjacent dermis:
Epidermal ridges
The Stratum Basale forms _________ ________, which extend into the Dermis (on the tips of fingers).
*Significant because the strength of the attachment is proportional to the surface area of the basement membrane (The more deeper the folds, the larger the surface area becomes.)
Dermal Papillae
Dermal projections that project into the Epidermis:
*Significant because the strength of the attachment is proportional to the surface area of the basement membrane (The more deeper the folds, the larger the surface area becomes.)
Ridge shapes; epidermal ridges
__________ __________ are genetically determined; the pattern of your __________ _________ is unique & does not change curing your lifetime.
Basal cells (Germinative cells)
Cells that dominate the Stratum Basale:
(Germinative cells)
Basal cells
Stem cells whose divisions replace the more superficial kertinocytes that are lost of shed at the epithelial surface:
Merkel cells
(Tactile cells) scattered among the cells of the stratum basale:
Tactile cells
Sensitive to touch; when compressed, they release chemicals that stimulate sensory nerve endings:
Melanocytes
The brown tones of the skin result from the synthetic activities of pigment cells called:
*Distributed throughout the stratum basale, with cells processes extending into more superficial layers
Stratum Spinosum
Each time a stem cells divides, one of the daughter cells is pushed superficial to the stratum basale into the ________ ________, which consists of 8 to 10 layers of keratinocytes bound together by DESMOSOMES
*Name means "spiny layer"
Dendritic (Langerhans) cells
The stratum spinosum also contains ____________ cells which participate in the immune response by stimulating a defense against (1) microorganisms that manage to penetrate the superficial layers of the epidermis and (2) superficial skin cancers.
Stratum granulosum
-region superficial to the stratum spinosum
-"grainy" layer
-consists of 3 to 5 layers of keratinocytes derived from the stratum spinosum
Keratin
A tough, fibrous protein, that is the basic structural component of hair and nails in humans:
*Protects against abrasion, and serves well as a water repellent
Melanin
Protects underlying tissue from ultraviolet radiation:
Vitamin D3
A steroid that is converted to calcitriol, a hormone important to normal calcium metabolism:
Keratohyalin
Forms dense cytoplasmic granules that promote dehydration of the cell as well as aggregation & cross-linking of the keratin fibers
Stratum Lucidum
In the thick skin of the palms and soles, a glassy __________ __________ ("clear layer") covers the stratum granulosum.
*The cells in this layer are flattened, densley packed, largely devoid of organelles, and filled with keratin.
Stratum Corneum
Layer usually at the exposed surface of thick and thin skin; Normally contains 15 to 30 layers of keratinized cells; cells in each layer are tightly interconnected by desmosomes:
Keratinization
(Cornification) The formation of protective, superficial layers of cells filled with keratin; process occurs on all exposed skin surfaces except the anterior surfaces of the eyes:
7 to 10
It takes ____ to ____ days for a cell to move from the stratum basale to the stratum corneum.
Interstitial fluids
Water from ________ ________ slowly penetrates to the surface , to be evaporated into the surrounding air. You lose about _____ mL (about 1 pint) of water in this way each day.
Insensible Perspiration
Process of water loss (perspiration) that we are unable to see or feel
Sensible Perspiration
Process of water loss (perspiration) produced by active sweat glands that we are usually very aware of
Blisters
When fluid accummulates into pockets, this forms:
Xerosis
A serious consequence of severe burns (If damage to the stratum corneum reduces its effectiveness as a water barrier, the rate of insensible perspiration skyrockets, & a potentially dangerous fluid loss occurs), and a complication in the condition known as:
*Excessively dry skin
Osmotic forces
When the skin is immersed in water, ______ forces may move water into or out of the epithelium
Osmotic flow
Swimming in the ocean reverses the ________ flow; because the ocean is a hypertonic solution, water leaves the body, crossing the epidermis from the underlying tissues.--> Long, slow process of dehydration.
Fresh water
Swimming or sitting in a bath of _______ water, causes the skin in the stratum corneum to swell due to the fact that this type of water is a hypotonic solution.
Carotene & melanin
Two main pigments of the epidermis:
Carotene
Orange-yellow pigment that normally accumulates in epidermal cells; most apparent in the cells of the stratum corneum of light-skinned individuals, but also accumulates in fatty tissues in the deep dermis and subcutaneous layer.
Carotene
Found in a variety of orange vegetables, such as carrots and squashes, and thus the skin of individuals who eat lots of carrots can actually turn orange from an overabundance of carotene.
Vitamin A
Carotene can be converted to Vitamin ____, which is required for both the normal maintenance of epithelia & the synthesis for photoreceptor pigments in the eye.
Melanin
A brown, yellow-brown, or black pigment produced by meloncytes (pigment cells):
Melanocytes
Involved in melanin production; located in the stratum basale; squeezed between or deep to the epithelial cells
Tyrosine
Melanocytes manufacture melanin from the amino acid ________
Melanosomes
Melanocytes package melanin in intracellular vesicles called _____________
Freckles
Small, pigmented areas on relatively pale skin; irregular borders; represent the areas serviced by melanocytes that are producing larger-than-average amounts of melanin; tend to be most abundant on surfaces such as the face (due to greater exposure to the sun)
Lentigos
Similar to freckles; regular borders; contain abnormal melanocytes
Senile Lentigos (Liver Spots)
Liver spots is most common name; variably pigmented areas that develop on sun-exposed skin; older individuals with pale skin
Ultraviolet (UV) Radiation
This can damage DNA, causing mutations and promoting the development of cancer; produce burns, etc.
Fibroblasts
Over time, cumulative damage to the integument by UV exposure can harm ___________, causing impaired maintenance of the dermis --> leads to premature wrinkling
Hemoglobin
Blood contains red blood cells filled with the PIGMENT ________, which binds and transports oxygen in the bloodstream.
When bound to oxygen, it is bright red, giving capillaries in the dermis a reddish tint that is most apparent in lightly pigmented individuals
Cyanosis
When the skin takes on a BLUISH coloration; most apparent in the areas of very thin skin, such as the lips or beneath the nails; canoccur in response to extreme cold or as a result of cardiovascular or respiratory disorders, such as heart failure or asthma
Jaundice
The liver is unable to excrete bile, so a YELLOWISH pigment accumulates in body fluids; advanced stages the skin and whites of the eyes turn yellow
Melanocyte-stimulating hormone
Some tumors affecting the pituitary gland secret large quantities of this; Hormone causes a darkening of the skin, as if the individual has an extremely deep bronze tan
Vitiligo
Individuals lose their melanocytes; condition develops in about 1% of the population, & its incidence increases among individuals w/ thyroid gland disorders; primary problem is cosmetic
Addison's disease
The pituitary gland secretes large amounts of adrenocorticotropic hormone (ACTH), which is structurally similar to MSH. The effect of ACTH on skin color is similar to that of MSH.
Cholecalciferol
When exposed to ultraviolet radiation, epidermal cells in the strattum spinosum and stratum basale convert a cholesterol-related steroid into:
Vitamin D3
Cholecalciferol is also called:
Liver
The _________ coverts cholecalciferol into an intermediary product used by the kidneys to synthesize the hormone CALCITRIOL
Calcitriol
______________ is essential for the normal absorption of calcium and phosphorus by the small intestine; an inadequate supply leads to impaired bone maintenance and growth.
Skin cancers
________ cancers are the more dangerous, most common form of cancer.
Acitinic Keratosis
A scaly area on sun-damaged skin; it is an indication that sun damage has occurred, but it is not a sign of skin cancer.
Basal Cell Carcinoma
A cancer that originates in the stratum basale; the MOST COMMON SKIN CANCER.
Squamous Cell Carcinoma
Less common skin cancer, but almost totally restricted to areas of sun-exposed skin.
Malignant Melanomas
Are extremely dangerous skin cancer; grow rapidly and metastasize through the lymphatic system.
Asymmetry, Border, Color, Diameter
ABCD mnemonic to remember cancer's key characteristics:
A/B/C/D:
Asymmetry
A is for _____________: Melanomas tend to be irregular in shape; they are raised; may also ooze or bleed
Border
B is for ___________: Generally irregular, and in some cases notched
Color
C is for ___________: Melanoma is generally mottled, with any combination of tan, brown, black, red, pink, white, and blue tones.
Diameter
D is for __________: Any skin growth more than about mm (0.2 in.) in diameter, or approximately the area covered by the eraser on a pencil, is dangerous.
Vitamin
Term usually reserved for essential organic nutrients that must be obtained from the diet because the body either cannot make them or makes them in sufficient amounts:
Vitamin D3
Alternative name for cholecalciferol:
*If cannot be produced by the skin and is not included in the diet, bone development is abnormal and bone maintenance is inadequate.
Rickets
__________ is a disease caused by Vitamin D3 deficiency, and results in the bending of abnormally weak and flexible bones under the weight of the body, plus other structural changes.
Epidermal Growth Factor
(EGF) One of the peptide growth factors; Stimulation of stem cell divisions and epithelial repairs; Targets the Epidermis; Sourced from the duodenal glands; Widespread effects on epithelia throughout the body
Salivary glands & glands of the duodenum
EGF (Epidermal Growth Factor) is produced by the ________ glands & glands of the __________ (part of the small intestine)
Roles of the EGF (Epidermal Growth Factor)
*Promote divisions of basal cells in the stratum basale and stratum spinosum
*Accelerate production of keratin in differentiating keratinocytes
*Stimulate eidermal development and epidermal repair after injury
*Stimulate synthetic activity and secretion by epithelial glands
Dermis
The _______ lies between the epidermis and the hypodermis.
Papillary & Reticular
The dermis has two major components:
(1) a superficial __________ layer
(2) a deeper ___________ layer
Papillary layer
________ layer of dermis: consists of areolar tissue, contains the capillaries, lymphatics, and sensory neurons that supply the surface of the skin.
*Derives its name from the dermal papillae that project between the epidermal ridges.
Reticular layer
___________ layer: deep to the papillary layer, consists of an interwoven meshwork of DENSE IRREGULAR CONNECTIVE TISSUE containing both COLLAGEN & ELASTIC fibers
Dermatitis
An inflammation of the skin that primarily involves the papillary layer; inflammation typically begins in a part of the skin exposed to infection or irritated by chemicals, radiation, or mechanical stimuli.
*May cause no discomfort, or it may produce an annoying itch, such as in poison ivy.
*Other forms of the condition can be quite painful, and the inflammation can spread rapidly across the entire integument.
Collagen fibers
Very strong and resist stretching, but are easily bent or twisted (fibers)
Elastic fibers
Permit stretching and then recoil to their original length (fibers)
Water content
The ______ content of skin also helps maintain its flexibiility and resilence, properties collectively known as SKIN INTIGOR.
Wrinkles and sagging skin
Aging, hormones, & the destructive effects of uultraviolet radiation result in: ________ and _______ skin
Stretch marks
The skin wrinkles and creases, resulting in _______ _______ over time.
Tretinon
(Retin-A) Derivative of vitamin A that can be applied to skin as a cream or gel; drug was originally developed to treat acne, but it also increases blood flow to the dermis and stimulates dermal repair.
Cleavage lines
(Tension lines) The resulting pattern of fiber bundles in the skin:
Cutaneous Plexus
Network of arteries supplying the skin in the hypodermis along its border with the reticular layer of the dermis
Papillary Plexus
Small arteries form another network called the ________ _______, of the papillary layer; provides arterial blood to capillary loops that follow the contours of the epidermis-dermis boundary; these empty into a network of small veins that form a venous plexus deep to the papillary plexus
Contusion
Alernative name for a bruise
Ulcer
Localized shedding of an epithelium
Decubitis uclers
(Bed sores) Affect patients whose circulation is restricted, especially when a splint, cast, or lying in bed continuously compresses superficial blood vessels; such sores commonly affect the skin covering joints or bony prominences, where dermal blood vessels are pressed against deeper structures..Chronic lack of circulation kills epidermal cells, removing a barrier to bacterial infection; eventually, dermal tissues deteriorate as well.
Necrosis
Cell death and tissue destruction; can occur in any tissue deprived of adequate blood flow
Sensory receptors
The integument is filled with _______ _________
Nerve
_________ fibers in the skin control blood flow, adjust gland secretion rates, & monitor sensory receptors in the dermisand the deeper layers of the epidermis.
Tactile corpuscles
Receptors sensitive to light touch (located in the dermal papillae)
Lamellated corpuscles
Receptors sensitive to deep pressure and vibration (located in the reticular layer)
Hypodermis
The connective tissue fibers of the reticular layer are extensively interwoven with those of the ______________
Hypodermis
Consists of areolar and adipose tissue; quite elastic; superficial region contains larger arteries and veins; venous circulation of region contains substantial amount of blood-much of volume will shift to general circulation if these veins constrict
Blood reservoir
The skin is often desribed as a _______ reservoir.
Liposuction
(Lipoplasty) Sucutaneous adipose tissue is removed through a tube inserted deep into the skin ; relatively common and increasing in popularity
Subcutaneous; Hypodermic
____________ injection into the hypodermis by means of a ______ needle, is a useful way of adminstering drugs.
Hairs
project above the surface of the skin almost everywhere, except over the sides and soles of the feet, the palms of the hands, the sides of the fingers and toes, the lips, and portions of the external genetalia.
2.5 million
The human body has about _____ million hairs, and 75% of them are on the general body surface, not on the head.
Hair follicles
hairs are nonliving structures produced in organs called _____ _________
Dense connective tissue sheath
Deep to the epidermis, each follicle is wrapped in a ______ ___________ ______ _______
root hair plexus
a _____ _____ _______ of sensory nerves surrounds the base of each hair follicle; as a reslt, you can feel the movemet of the shaft of even a single hair
Hair root
The protion of hair that anchors the hair into the skin-begins a the base of the hair at the HAIR BULB, and extends distally to the point at which the internal organization of the hair is complete, about halfway to the skin surface.
Hair shaft
part of hair which we see on the surface of the skin, extends from this halfway point to the exposed tip of the hair
Hair bulb
(in hair) mass of epithelial cells that forms a cap, called the:
Hair papilla
hair bukb surrounds this; a peg of connective tissue containing capillaries and nerves
Hair matrix
superficial cells of the hair bulb are responsible for producing the hair; they form a layer called the:
Medulla
Basal cells near the center of the hair matrix divide, producing daughter cells that are gradually pushed toward the surface; daughter cells closest to the center of the matric form the:
Core
(medulla)
Cortex
Intermediate layer where daughter cells farther from the center of the hair matrix form
Cuticle
edges of the hair matrix form the _______, which will be the surface of the hair
hair growth cycle
hairs grow and are shed according to a ______ ______ _______
Club hair
at the end of the hair growth cycle, when the hair follicle become inactive, it is termed a _____ hair; the follcile gets smaller, and over time the connections between the hair matrix and _____ hair root break down; when another cycle begins, the follicle produces a new hair and the old hair is pushed to the surface and shed
100
Healthy adults with a full head of hair typically lose about _____ head hairs each day.
Lanugo
extremely fine and unpigmented hairs on a fetus
Vellus hairs
the fine "peach fuzz" hairs located over much of the body surface
Terminal hairs
heavy, more deeply pigmented and sometimes curly hairs-hairs on your head/eyebrows/eyelashes
Melanocytes
Hair color/pigment is determined by the production of:
Seaceous glands
(oil glands) Holocrine glands that discharge an oily lipid secretion into hair follicles; these glands that communicate with a single follicle share a duct and are called SIMPLE BRANCHED ALVEOLAR GLANDS
Sebum
secreted lipid product that contains tryglycerides, cholesterol, proteins, and elecrolytes; inhibits the growth of bacteria, lubricates abd protects keratin of the hair shaft, and conditions the surrounding skin.
Medulla
(core) of the hair contains a flexible SOFT KERATIN
Cortex
of hair contains thick layers of HARD KERATIN, which give the hair its stiffness
Cuticle
of hair, although thin, is very tough, & it contains HARD KERATIN
Internal Root Sheath
of hair surrounds the hair root and the deeper portion of the hair shaft; the cells of this sheath disentegrate quickly, and this layer does not extend the entire length of the hair follicle
External Root Sheath
of hair extends from the skin surface to the hair matrix
Glassy membrane
of hair is a thickened, clear layer wrapped in the dense connective tissue sheath of a follicle as a whole
Sebaceous follicles
large sebceous glands that are associated with hair follicles; ducts discharge directly onto epidermis; located on face, back, chest, nipples, & external genetalia
Vernix Caseosa
Secretions of sebaceous glands-mixed with shed epidermal cells, that form a protective superficial layer called the:
*coats the skin surface, and stops after birth
Seborrheic dermatitis
An inflammation around abnormally active sebaceous glands, most often those of the scalp.
Scalp becomes red, oily, and increased epidermic caling increases
*common cause of dandruff
Sudoriferous glands
sweat glands
merocrine and apocrine
2 types of sudoriferous (sweat) glands:
Apocrine sweat glands
(in the armits[axillae] and around nipples, and pubic region) sweat glands that secrete their products INTO hair follicles
--COILED, TUBULAR glands produce a sticky, cloudy, and potentially odorous secretion
Myoepithelial cells
in the apocrine swaet glands, surrounding the secretory cells, are special _____________ cells that contract and squeeze the gland, causing the accumulated swaet to discharge into the hair follicles
Merocrine sweat glands
(Eccrine sweat glands) COILED, TUBULAR glands that discharge their secretions directly onto the surface of the skin; far MORE NUMEROUS & WIDELY DISTRIBUTED then apocrine sweat glands
Cooling surface of skin, excreting water and electrolytes, providing protection from environmental hazards
Functions of merocrine glands: (3)
mammary glands
glands of breasts that are anatomically related to apocrine sweat glands
Ceruminous glands
modified sweat glands in the passageway of the external ear; produce cerumen (earwax)
Autonomic nervous system
(ANS) controls the activation and deactivation of sebaceous glands and apocrine sweat glands at the subcutaneous level
Thermoregulation
process of maintaining temperature homeostasis
Nails
protect the exosed dorsal surfaces of the tips of the fingers and toes; help limit distortion of the digits when they are subjected to mechanical stress-for example, when you run or grasp objects.
nail body
visible portion of the nail; recessed deep to the level of the surrounding epithelium
nail bed
area of epidermis covered by the nail body
Lateral nail grooves
(depressions) & lateral nail folds, that border the nail body
Free edge
distal part of nail that continues past the nail bed
Hypochonium
the free edge of the nail extends over the ____________, an area of thickened stratum corneum
nail root
where nail production occurs; epidermal fold not visible from the surface
eponychium
(cuticle) a portion of the stratum corneum of the nail root extends over the exposed nail, forming the:
lunula
pale crescent of nail, at root where vessels may be obsucred
keratin
the body of the nail consists of dead, tightly compressed cells packed with:
Scab
(blood clot) forms at the surface temporarily restores the integrity of the epidermis and restricts the entry of additional microorganisms into the area
granulation tissue
(tissue) combination of blood clot, fibroblasts, and an extensive capillary network
scar tissue
formation of rather inflexible, fibrous, noncellular ______ tissue completes te repair process but fails to restore the tissue to its original condition
keloid
thick, raised area of scar tissue covered by a shiny, smooth epidermal surface; most commonly develop on the upper back, shoulders, anterior chest, or earlobes.
Erythema
redness associated with a burn; painful; results form inflammation of the sun-damaged tissues
skin graft
areas of intact skin are transplanted to cover the site of the burn