A&P 5: The Integumentary System Flashcards Preview

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Flashcards in A&P 5: The Integumentary System Deck (67)
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1
Q

Integumentary system

A

skin & its derivatives (sweat/oil glands, hairs, nails) that make up a complex set of organs that serve several functions, mostly protective

2
Q

Hypodermis

A

subcutaneous tissue just deep to the skin; technically not part of the skin, but shares some of its protective functions

3
Q

Superficial fascia

A

another name for the hypodermis because it is superficial to the tough connective tissue wrapping of the skeletal muscles; consists mostly of adipose tissue

4
Q

Epidermis

A

keratinized stratified squamous epithelium consisting of 4 distinct cell types & 4-5 distinct layers

5
Q

Keratinocytes

A

chief role is to produce keratin

6
Q

Keratin

A

fibrous protein that helps give the epidermis its protective properties

7
Q

Melanocytes

A

spider-shaped epithelial cells that synthesize the pigment melanin; found in the deepest layer of the epidermis

8
Q

Dendritic cells

A

star-shaped cells that arise from bone marrow and migrate to the epidermis

9
Q

Langerhans cells

A

another name for Dendritic cells; named after a German anatomist; ingest foreign substances and are key activators of our immune system; their slender processes extend among the surrounding keratinocytes, forming a continuous network

10
Q

Tactile (Merkel) cells

A

occasionally present at the epidermal-dermal junction; shaped like a spiky hemisphere, each of these is intimately associated with a disclike sensory nerve ending; functions as a sensory receptor for touch

11
Q

Thick skin

A

covers areas subject to abrasion (palms, fingertips, soles of the feet); consists of 5 layers/strata - stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum

12
Q

Stratum basale

A

deepest epidermal layer; attached to the underlying dermis along a wavy borderline; consists of a single row of stem cells, a continually renewing cell population, representing the youngest keratinocytes; many mitotic nuclei (rapid division of cells)

13
Q

Stratum germinativum

A

another name for the stratum basale

14
Q

Stratum spinosum

A

several cell layers thick; contain a weblike system of intermediate filaments, mainly tension-resisting bundles of pre-keratin filaments, which span their cytosol to attach to desmosomes; a prickly layer - kerationocytes appear to have spines

15
Q

Stratum granulosum

A

a thin layer consisting of 4-6 cell layers in which a keratinocyte appearance changes drastically; process of keratinization begins

16
Q

Keratinization

A

process of cells filling with the protein keratin

17
Q

Stratum lucidum

A

clear layer; visible only in thick skin; a thin translucent band just above the stratum granulosum; considered by some to be a subdivision of the superficial stratum corneum, it consists of 2-3 rows of clear, flat, dead keratinocytes with indistinct boundaries

18
Q

Stratum corneum

A

horny layer; flattened anucleate cells of the outermost epidermal layer; broad zone of 20-30 cell layers that accounts for up to 3/4 of the epidermal thickness

19
Q

Dermis

A

2nd major skin region; strong, flexible connective tissue; “hide”; has a rich supply of nerve fibers, blood vessels and lymphatic vessels; major portion of hair follicles, oil/sweat glands reside here

20
Q

Papillary layer

A

thin, superficial layer of areolar connective in which fine interlacing collagen and elastic fibers form a loosely woven mat that is heavily invested with small blood vessels; allows phagocytes & other defensive cells to wander freely, patrolling the area for bacteria that have breached the skin

21
Q

Dermal papillae

A

peglike projections from the surface of the papillary layer, indenting the overlying epidermis; many contain papillary loops; others house free nerve endings & touch receptors (tactile/Meissner’s corpuscles)

22
Q

Friction ridges

A

skin ridges assumed to enhance the gripping ability of the fingers and feet; also contribute to our sense of touch by amplifying vibrations detected by the large lamellar corpuscles (receptors) in the dermis

23
Q

Reticular layer

A

80% of the thickness of the dermis; coarse, irregularly arranged, dense fibrous connective tissue; cutaneous plexus = network of blood vessels that nourishes this layer

24
Q

Cleavage (tension) lines

A

less dense regions in between the thick bundles of interlacing collagen fibers; tend to run circularly around the trunk and longitudinally in the limbs

25
Q

Flexure lines

A

dermal folds that occur at or near joints, where the dermis is tightly secured to deeper structures

26
Q

Melanin

A

polymer made of tyrosine amino acids; two forms, ranging in color from reddish yellow to brownish black

27
Q

Carotene

A

yellow to orange pigment found in certain plant products (carrots); tends to accumulate in the stratum corneum and in fatty tissue of the hypodermis; color is most obvious in the palms/soles (where the stratum corneum is the thickest); most intense when large amounts of foods rich in this in pigment are eaten; can be converted into vitamin A in the body (essential for normal vision and epidermal health)

28
Q

Hemoglobin

A

oxygenated pigment in the red blood cells circulating through the dermal capillaries; pinkish hue of fair skin reflects the crimson color of this pigment

29
Q

Skin appendages

A

hair, hair follicles, nails, sweat glands, and sebaceous (oil) glands

30
Q

Hairs (pili)

A

flexible strands produced by hair follicles, consists largely of dead, keratinized cells

31
Q

Cuticle

A

outermost part of the hair formed from a single layer of cells overlapping one another; helps separate hairs so it does not mat

32
Q

Hair follicles

A

fold down from the epidermal surface into the dermis; in the scalp, may extend into the hypodermis

33
Q

Hair bulb

A

the deep end of the follicle (4mm below the skin surface) expands to form this

34
Q

Hair follicle receptor (root hair plexus)

A

knot of sensory nerve endings; wraps around each hair bulb; bending the hair stimulates these endings so hair acts as sensitive touch receptors

35
Q

Peripheral connective tissue sheath

A

wall of a hair follicle composed of this fibrous sheath derived from the dermis

36
Q

Epithelial root sheath

A

inner wall of a hair follicle, derived mainly from an invagination of the epidermis; has external and internal parts, thins as it approaches the hair bulb so only a single layer of epithelial cells covers the papilla

37
Q

Hair matrix

A

actively dividing area of the hair bulb that produces the hair; originates in a region called the hair bulge located a fraction of a mm above the hair bulb

38
Q

Arrector pili

A

bundle of smooth muscle cells associated with each hair follicle; attached in such a way that its contraction pulls the hair follicle upright and dimples the skin surface to produce goose bumps; contractions force sebum out of hair follicles to the skin surface, where it acts as a skin lubricant

39
Q

Vellus hair

A

body hair of children and adult females

40
Q

Terminal hair

A

coarser, longer hair of the eyebrows and scalp, which may also be darker than vellus hair

41
Q

Hirsutism

A

excessive hairiness; may result from an adrenal gland or ovarian tumor that secretes abnormally large amounts of androgens

42
Q

Alopecia

A

baldness

43
Q

Male pattern baldness

A

most common type of true/frank baldness; genetically-determined, sex-influenced condition

44
Q

Nail

A

scalelike modification of the epidermis that forms a clear protective covering on the dorsal surface of the distal part of a finger or toe; useful as tools to pick up small objects or to scratch

45
Q

Nail matrix

A

thickened proximal portion of the nail bed; responsible for nail growth

46
Q

Nail folds

A

proximal and lateral borders of the nail are overlapped by these skin folds

47
Q

Cuticle (eponychium)

A

proximal nail projects onto the nail body as this

48
Q

Hyponychium

A

thickened region beneath the free edge of the nail where dirt and debris tend to accumulate; “quick”; secures the free edge of the nail plate at the fingertip

49
Q

Sweat glands (sudoriferous glands)

A

distributed over the entire skin surface except the nipples and parts of the external genitalia; up to 3 million per person

50
Q

Eccrine sweat glands

A

AKA merocrine sweat glands; numerous; particularly abundant on the palms, soles of the feet, and forehead; each is a simple, coiled, tubular gland; secretory part lies coiled in the dermis; the duct extends to open in a funnel-shaped pore at the skin surface

51
Q

Apocrine sweat glands

A

approximately 2000; largely confined to the axillary and anogenital areas; merocrine glands which release their product by exocytosis; larger than the other type of sweat glands; lie deeper in the dermis or even in the hypodermis; ducts empty into hair follicles; viscous, sometimes with a milky/yellowish color; secretion is odorless but when bacteria on the skin decompose its organic molecules, it takes on a musky, unpleasant odor

52
Q

Ceruminous glands

A

modified apocrine glands found in the lining of the external ear canal; secretion mixes with sebum produced by nearby sebaceous glands to form a sticky, bitter substance (earwax), which is thought to deter insects and block entry of foreign material

53
Q

Mammary glands

A

specialized sweat glands that secrete milk

54
Q

Sebaceous glands (oil glands)

A

simple branched aveolar glands that are found all over the body except in the thick skin of the palms and soles; small on the body trunk and limbs, but quite large on the face, neck, and upper chest

55
Q

Sebum

A

oily substance secreted by sebaceous glands; functionally called holocrine glands

56
Q

Acid mantle

A

low pH of skin secretions retards the multiplication of skin’s bacteria

57
Q

Cutaneous sensory receptors

A

skin is richly supplied with these, which are actually part of the nervous system; classified as exteroceptors because they respond to stimuli arising outside the body

58
Q

Basal cell carcinoma

A

least malignant and most common type of skin cancer (80% of cases); stratum basale cells proliferate, invading the dermis and hypodermis; lesions appear most often on sun-exposed areas of the face that appear as shiny, dome-shaped nodules that later develop a central ulcer with a pearly, beaded edge; relatively slow-growing; metastasis seldom occurs before it is noticed; full cure by surgical excision in 99% of cases

59
Q

Squamous cell carcinoma

A

second most common skin cancer; arises from the keratinocytes of the stratum spinosum; lesion appears as a scaly reddened papule that arises most often on the head (scalp, ears, lower lip) and hands; tends to grow rapidly and metastasize if not removed; chance of complete cure good if caught early and removed

60
Q

Melanoma

A

cancer of melanocytes; most dangerous skin cancer; highly metastic, resistant to chemotherapy; accounts for 2-3% of skin cancers; can begin wherever there is a pigment; most appear spontaneously (1/3 from preexisting moles); metastasizes rapidly to surrounding lymph and blood vessels

61
Q

ABCD Rule

A

rule for recognizing melanoma: asymmetry, border irregularity, color, diameter; sometimes E added (elevation above the skin surface)

62
Q

Burn

A

tissue damage inflicted by intense heat, electricity, radiation, or certain chemicals, all of which denature cell proteins and kill cells in affected areas

63
Q

Rule of nines

A

approximating method that divides the body into 11 areas, each accounting for 9% of total body area, plus an additional area surrounding the genitals for 1% of body surface area

64
Q

First-degree burns

A

burn in which only the epidermis is damaged; symptoms include localized redness, swelling, and pain; tend to heal in 2-3 days without special attention; sunburn is an example

65
Q

Second-degree burns

A

injure the epidermis and the upper region of the dermis; symptoms mimic those of 1st degree burns, but blisters also appear; burned area is red and painful, but skin regeneration occurs with little or no scarring within 3-4 weeks if care is taken to prevent infection; along with 1st degree burns = partial-thickness burns

66
Q

Third-degree burns

A

involve the entire thickness of the skin; burned area appears gray-white, cherry red, or blackened; initially there is little or no edema; nerve endings have been destroyed, so the burned area is not painful; skin might eventually regenerate but skin grafting is advised

67
Q

Dermatitis

A

skin inflammation

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