HIS - Integument Flashcards

HIS: Integument

1
Q

functions of the integument

A
  • protection
  • sensation
  • excretion
  • thermoregulation
  • synthesis of vitamin D
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2
Q

what is the integument composed of?

A
  • epidermis (epithelial layer - ectoderm)
  • dermis (CT layer - mesoderm)
  • hypodermis (loose CT layer)
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3
Q

functions of the hypodermis

A
  • binds skin to underlying tissue and corresponds to superficial fascia
  • contains epidermal derivatives
    • hair, nails, sebaceous, and sweat glands
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4
Q

epidermis epithelial cell type

A

stratified squamous keratinized epithelium made of keratinocytes

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5
Q

cell types of the epidermis

A
  • keratinocytes
  • melanocytes
  • Langerhans cells
  • Merkel cells
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6
Q

irregular projections at epidermal-dermal junction

A

dermal papillae

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7
Q

dermal papillae interdigitate with this structure to strengthen adhesion

A

epidermal ridges

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8
Q

thin skin

A
  • 75-150 microM
  • 4 layers
  • widespread on body
  • glands and hair. follicles
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9
Q

thick skin

A
  • 400-1400 microM
  • palms and soles, fingerprints
  • contain 5 layers
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10
Q

layers of the epidermis

A
  1. stratum corneum
  2. stratum lucidum (*only thick skin)
  3. stratum granulosum
  4. stratum spinosum
  5. stratum basale
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11
Q
  • predominant cell type of the epidermis
  • produce keratins (85% of cells)
  • participate in the epidermal water barrier
  • will produce “cornified” cells, full of keratin
    • undergo keratinization and desquamation
A

keratinocytes

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12
Q
  • single-layer of keratinocytes w/ stem cells interspersed
  • mitotically active
  • cuboidal/low columnar cells
  • contain melanin
  • bound apically by desmosomes
  • bound basally by hemidesmosomes
A

stratum basale

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13
Q
  • thickest layer
  • polyhedral cells w/ central nuclei and spiny processes
  • keratin filaments assemble here into microscipically visible bundles called tonofibrils
  • associated with desmosomes
    • spiny appearance = “prickle layer”
A

stratum spinosum

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14
Q
  • 3-5 layers of flattened cells
  • filled with keratohyaline granules
  • also include lamellar granules
  • keratinization + lipd-rich layer = almost impenetrable skin barrier
A

stratum granulosum

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15
Q
  • granules = tonofibrils + filaggrin (bundling protein)
  • undergoing terminal differentiation of keratinization
  • stain intensely basophilic
A

keratohyaline granules

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16
Q
  • small ovoid structures containing lipids and glycolipids
  • undergo exocytosis and produce lipid-rich, impermeable layer that protects against water loss
A

lamellar granules

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17
Q
  • 15-20 layers of squamous, keratinized cells filled with filamentous keratins
  • anucleated cells coated with extracellular layer of lipids
  • squames are continuously shed as desmosomes break down
A

stratum corneum

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18
Q

fully keratinized “cornified” cells

A

squames

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19
Q
  • found only on thick skin
  • thin, translucent layer of flattened eosinophilic keratinocytes
  • held together by desmosomes
  • nuclei and organelles lost
  • cytoplams exclusively keratin filaments
A

stratum lucidum

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20
Q
  • produce melanin and transfer it to keratinocytes
  • NCC derived
  • scattered along stratum basale
A

melanocytes

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21
Q

pigment protein that protects nuclei from UV radiation

A

melanin

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22
Q

one melanocyte maintains an assoiation with a specific number of keratinocytes (1:10)

A

epidermal-melanin unit

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23
Q

melanin production (reaction, location, and transport)

A
  • Production
  1. tyrosinase converts tyorsine to DOPA
  2. DOPA polymerizes into melanin
  • Location: membrane bound organelles called pre-melanosomes
  • As melanin increases, pre-melanosomes increase and form melanosome
  • Melanosomes transferred to keratinocytes via pigment donation
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24
Q

melanosome transfer to keratinocytes

A

pigment donation

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25
Q
  • APCs found in skin that provide defense against pathogens
    • develop from monocyte precursor
A

Langerhans cells

(Ag is phagocytosed, displaced on cell surface, migrated to nearby lymph node and activates lymphocytes)

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26
Q

what initiates epidermal cell replacement?

A

division of stem cells in the stratum basale

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27
Q

where do new cells undergo divisions?

A

stratum basale

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28
Q

how are new skin cells replaced?

A

new cells undergo division in the SB > move upward as they differentiate into keratinized cells > lost by exfoliation on skin surface

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29
Q

characteristics of the dermal-epidermal junction

A
  • uneven boundary with finger-like dermal papillae that project into epidermis
  • complemented by epidermal protrusions, epidermal ridges
  • increased in size/number at sites of mechanical stress
  • hemidesmosomes provide tight interface
  • focal adhesions are also present
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30
Q

2 layers of dermis (detail)

A
  • papillary layer
    • loose CT beneath epidermis
    • contain vasculature and nerve endings
  • reticular layer
    • deep to papillary layer
    • dense irregular CT wit coarse elastic fibers
    • form regular lines of tension (Langer’s lines)
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31
Q

lines of tension formed by the reticular layer

A

Langer’s lines

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32
Q

rich, nutritive capillary network located between papillary and reticular layers

A

subpapillary

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33
Q

lies near dermis-subcutaneous layer interface

A

deep plexus

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34
Q

name the 2 plexuses of the dermis

A
  • subpapillary plexus
  • deep plexus
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35
Q
  • loose CT that binds the skin loosely to the subjacent organs
  • adipocytes vary in number and size based on body regions/nutritional state
  • extensive vasculature promotes rapid uptake of insulin or drugs injected into this tissue
A

hypodermis (subcutaneous fascia)

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36
Q

types of sensory receptors of the skin

A

non-encapsulated and encapsulated receptors

37
Q
  • epithelial tactile cells that function as low-threshold meechanoreceptors essential for sensing gentle touch
  • abundant in highly sensitive skin (fingertips, hair follicles)
  • resemble keratinocytes but do not contain melanosomes
  • contain small, Golgi-derived granules concentrated near basolateral surface
A

Merkel cells

38
Q
  • type of cancer from Merkel cells
  • rare, aggressive, and difficult to treat
  • 40x less common than malignant melanoma, but 2x mortality rate
A

Merkel cell carcinoma

39
Q
  • located in the papillary dermis, extending into the lower epidermal layers
  • respond primarily to high and low temperatures, pain, and itching
  • may function as tactile receptors
A

free nerve endings

40
Q
  • encapsulated receptors
  • responsive to light-touch or low-frequency stimuli
  • perpendicular to the epidermis in the dermal papillae
  • numerous in the fingertips, palms, and soles
A

Meissner’s corpuscle

41
Q
  • large encapsulated, oval structures found deep in the reticular dermis and hypodermis
  • specialized for sensing coarse touch, pressure (sustained touch), and vibration
  • found in the CT of visceral organs, wall of the rectum, and urinary bladder
  • produce pressure sensations when distorted
A

Lamellated (Pacinian corpuscle)

42
Q

3 types of glands

A
  • merocrine
  • holocrine
  • apocrine
43
Q

merocrine gland

A

secreion delivered via membrane-bound vesicles and undergo exocytosis

44
Q

holocrine gland

A

secretion accumulates within cell > apopotisis > secretion and cell debris are released

45
Q

apocrine gland

A

release of apical portion of the cell, surrounded by cytoplasm within a plasma membrane

46
Q
  • several glands per follicle
  • abundant on face and scalp
  • produce lipid mixture (sebum) via holocrine secretion
  • waxy mix of triglycerides and cholesterol
    • lubricates and softens skin
    • waterproofs skin
  • sebum discharged into hair follicle
A

sebaceous glands

47
Q
  • simple coiled glands found extensively throughout the skin
  • duct is stratified cuboidal
  • myoepithelial cells facilitate expulsion of secretions
  • temperature regulation via cooling
    • evaporation of H2O from sweat on body surface
A

eccrine sweat glands

48
Q

sweat components

A
  • H2O
  • salt
  • ammonia
  • uric acid
  • mucinogen granules
49
Q
  • large lumen, tubular glands
  • duct = stratified cuboidal
  • myoepithelial cells facilitate expulsion of secretions
  • use merocrine secretion
A

apocrine sweat glands

50
Q
  • protein, carbohydrate, and ammonia-rich secretion
  • odorless until mixed with bacteria
  • become functional at pubertymero
A

merocrine secretion

51
Q

terminal dilation of hair follicle

A

hair bulb

52
Q

inserts into hair bulb and provides nutrients via capillaries

A

dermal papilla

53
Q

hair matrix is formed by ______

A

keratinocytes

  • continuous with epidermis
  • divide and differention = hair growth
54
Q

contains epidermal stem cells near insertion of thearrectorpili m.

A

follicular bulge

55
Q

small bundle of smooth muscle extending from midpoint of hair root to papillary layer

A

arrector pili muscle

56
Q

contracting muscle distorts attached dermis

A

Goose bumps

57
Q

highly keratinized cells on a bed of epidermis

A

nails

58
Q

most proximal region of the nail covering the nail matrix

A

nail root

59
Q
  • from this structure, stem cells divide and form keratinocytes
  • nail plate remains attached to nail bed
  • pushed forward by continuosu growth
A

nail matrix

60
Q

crescent shaped white area near the nail matrix

A

lunula

61
Q

extension of skin covering nail root

A

cuticle

62
Q

label

A
63
Q

label

A
64
Q

label

A
65
Q

label

A
66
Q

type of cell

A

keratinocytes

67
Q

identify if thick or thin skin

A

thick skin

68
Q
  1. label
  2. idenfity if thick or thin skin
A
69
Q

identify layers

A
70
Q

type of cell

A

keratinocyte

71
Q

identify

A

stratum basale

72
Q

identify

A

stratum spinosum

73
Q

identify

A

stratum granulosum

74
Q

identify

A

startum corneum

75
Q

label

A
76
Q

type of cell

A

melanocytes

77
Q

type of cell

A

Langerhans cells

78
Q

label

A
79
Q

idenfity

A

hypodermis (subcutaneous fascia)

80
Q

type of cell

A

Merkel cell

81
Q

identify structure

A

free nerve endings

82
Q

identify

A

Meissner’s corpuscle

83
Q

Lamellated (Pacinian) corpuscle

A
84
Q

identify

A

eccrine gland

85
Q

identify

A

sebaceous gland

86
Q

idenfity

A

aprocrine sweat glands

87
Q

label

A
88
Q
A
89
Q

label

A