Skin Flashcards Preview

Histologia Junqueira's > Skin > Flashcards

Flashcards in Skin Deck (127)
Loading flashcards...
1
Q

Celulas de la epidermis

A

Queratenocitos
Melanocitos
Celulas de Langerhans
Celulas de Merkel

2
Q

Celula oval o cubica adherida a la lamina basal que conforme madura produce una proteina llamada queratina acumulándose dentro del citoplasma, una vez que llego al estrato más alto pierde sus organelas y el nucleo y lo único que queda es escamas de queratina

A

Queratenocitos

3
Q

El más bajo y adherido a la lamina basal, mitoticamente activo, en esta estrato se acumula la melanina producida por el melanocito

A

Estrato basal

4
Q

Estrato con el mayor número de capas o niveles llegando a tener de 6 a 8 niveles de Queratenocitos en una piel normal, son las que van a producir polipeptidos (desmoplaquina y desmogleinas) que forman los desmosomas dandole el aspecto espinoso, entre mas pegado al estrato basal es poligonal mientras madura se alarga hacia los lados

A

Estrato esponjoso

5
Q

Formado por 1 a 3 niveles de Queratenocitos conteniendo granulos de queratohialina

A

Estrato granuloso

6
Q

Está formado por múltiples capas de celulas poliedricas que se disponen en un patrón de canasta, estas celulas pierden sus nucleos y organelas citoplasmaticas y se componen por filamentos de queratina, se observa como una capa rosada y en donde hay piel gruesa como la planta de los pies y palmas

A

Estrato lucido o cornificado

7
Q

Formado por todas las capas de queratina desprendidas por el estrato lucido que puede ser inexistente como en los párpados

A

Corneo

8
Q

El proceso de queratenizacion en condiciones normales

A

20 a 45 días

9
Q

Grosor del estrato lucido en las callosidades o plantas de los pies

A

1 cm

10
Q

Celulas dendriticas que derivan de la cresta neural, se ven vaculadas en su citoplasma y se ubican en la capa basal de la epidermis con nucleo ovoide y producen melanina

A

Melanocitos

11
Q

Diferentes tipos de melanina

A

Feomelanina cuando es rojo

Eumelanina Amarillo negruzco

12
Q

Función principal de la melanina

A

Protección de los rayos UV

13
Q

Personas que con defecto en la maquinaria enzimatica de la tirosinasa produciendo manchas blancas debido a la ausencia de Melanocitos

A

Vitiligo

14
Q

La cantidad de Melanocitos

A

1 melanocitos por cada 10 queratinocitos

15
Q

Celulas observables en los estratos espinoso y granuloso indistinguibles una de otra

A

Celulas de Merkel y Langerhans

16
Q

Se encuentran siempre en la capa basal con Queratenocitos teñidos de melanina observables como raíces color café

A

Melanocitos

17
Q

Función relacionada con el tacto, se localiza en los pulpejos, labios y cavidad oral de aspecto parecido a melanocito, se adhieren a Queratenocitos por desmosomas con una zona para nuclear densa formada por granulos formado por neuritas no mielinizadas

A

Celulas de Merkel

18
Q

Celulas dendriticas derivadas de monocitos, parecido a melanocito pero con nucleo con muescas generalmente presente en estrato espinoso y puede presentar cuerpos alargados que en ocasiones uno de sus extremos se dilata dando aspecto de raqueta llamados cuerpos raquetoides o granulos de Birbeck

A

Celulas de langerhans

19
Q

Marcador especial para Melanocitos

A

HMB 45

20
Q

Anticuerpo para marcar celulas de Langerhans

A

CD1a

21
Q

Anticuerpos para celulas de Merkel

A

Enolasa neurona especifica
Peptido intestinal vasoactivo
Encefalina

22
Q

La piel se divide en tres capas principales

A

Epidermis
Dermis
Hipodermis

23
Q

The largest single organ of the body

A

Skin

24
Q

Weight of the skin

A

15% to 20% of total weight body

25
Q

Skin surface of the external environment

A

1.5 to 2 m2

26
Q

Origin of epidermis

A

Ectodermal

27
Q

Origin of dermis

A

Mesoderm

28
Q

At the irregular junction between the dermis and epidermis projection called

A

Dermal papillae

29
Q

Dermal papillae interdigitate with invaginating

A

Epidermal ridges

30
Q

Specific function of the skin

A
Protection 
Sensory
Thermoregulatory
Metabolic
Sexual signaling
31
Q

Cells of skin through the local action of UV light on the vitamins precursor, that need calcium metabolism and proper bone formation, they synthesized

A

Vitamin D

32
Q

Excess electrolytes can be remove in

A

Sweat

33
Q

Subcutaneous layer stores a significant amount of …. In form of fats

A

Energy

34
Q

Dermal epidermal interdigitation forms ridges and grooves called

A

Dermatoglyphs, or fingerprint,

35
Q

Thickness od the epidermal layer

A

75 to 150 micrometers for thin skin

400 to 1400 micrometers or 1.4 mm for thick skin

36
Q

Full skin on the back is about

A

4 mm

37
Q

Join basal layer to the basal lamina by

A

Hemidesmosomes

38
Q

The human epidermis is renewed about every

A

15 to 30 days

39
Q

The cytoeskeletal keratins intermediate filaments about … In diameter

A

10 nm

40
Q

Is normal the thickest layer

A

Spinous layer

41
Q

Percentage of all cancers originate in the skin

A

One third

42
Q

Consist of 15 to 20 layers of squamous keratinized cells fill with keratins

A

Stratum corneum

43
Q

Dense non membrane bound masses of filaggrin and other proteins

A

Keratohyaline granules

44
Q

Keratocytes are typically produced and differentiate at accelerated rates causing at least slight thickening of the epidermal layers caused by overactive T lymphocytes that trigger An autoimmune reaction in the skin

A

Psoriasis

45
Q

Factors that give color to skin

A

Melanin and carotene

46
Q

Proportion of melanocytes

A

One melanocytes accumulate for every five or six basal keratinocytes
600 -1200 /mm2

47
Q

Tyrosinase activity converts tyrosine into

A

3,4 dihydroxyphenilalanine DOPA

48
Q

Melanin pigment is accumulated in granules called

A

Melanosomes

49
Q

Melanosomes are transported vía …. To the tips of the cytoplasmatic extensions

A

Kinesin

50
Q

Melanosomes are phagocytose by neighboring keratinocytes and transport by …. Toward their nuclei

A

Dynein

51
Q

Melanin depot

A

Keratinocytes

52
Q

One melanocytes ➕ keratinocytes where is transfer Melanosomes Make up

A

Epidermal melanin unit

53
Q

The density of such unit skin is

A

Similar for all individuals

54
Q

2-3 layers of anucleate dead cells seen only in thick skin

A

Stratum lucidum

55
Q

Langerhans cells present,several layers of keratinocytes all joined by desmosomes

A

Stratum spinosum

56
Q

Melanocytes and Merkel cells present

A

Basal layer

57
Q

Compose of areolar or loose connective tissue and adipose connective tissue

A

Subcutaneous layer

58
Q

Darkening of the skin, or tanning after exposure to solar radiation at wavelengths of …….. A physicochemical reaction darkens preexisting melanin

A

290 to 320 nm

59
Q

Los lunares son crecimientos sobre la piel. Se producen cuando las células productoras de pigmento de la piel, llamadas melanocitos, crecen en grupos

A

Lunares

60
Q

Numero de lunares que tiene una persona

A

La mayoría de las personas tiene entre 10 y 40 lunares.

61
Q

Represent 2% to 8% of the epidermal cells

A

Langerhans cells

62
Q

Are abundant in highly sensitive skin like fingertips and the basal of some hair folicles, essential for light touch sensation joined by desmosomes of the basal epidermal layer originate from stem cells as keratinocytes

A

Merkel cells

63
Q

Are very aggressive and difficult to treat and is 40 times less common than malignant melanoma but twice the mortality of that disease

A

Merkel cells carcinomas

64
Q

Stage of melanosome formation in which Accumulate of tyrosinase in vesicles and granular matrix proteins

A

Stage I Melanosomes

65
Q

Stage of melanosome formation matrix has Been organized into parallel filaments

A

Stage II

66
Q

Stage of melanosome formation melanin is deposited and accumulates

A

Stage III

67
Q

Stage of melanosome formation has lost tyrosinase and other activities and has the internal matrix completely filled with melanin

A

Stage IV

68
Q

Is a composite structure consisting of the basal lamina and the reticular lamina always occurs between the stratum basale and the dermis

A

Basement membrane

69
Q

Abnormalities of the dermal epidermal juntion

A

Bullous pemphigoid

70
Q

Includes the dermal papillae, consist of loose connective tissue with types I and III collagen fibers and achoring fibrils of type VII collagen insert in to the basal lamina helping to bind the dermis to the epidermis

A

Papillary layer

71
Q

Two sublayers with indistinct boundaries rich network of blood and lymphatic vessels

A

Papillary layers

Reticular layers

72
Q

Sublayer of dermis much thicker with dense connective tissue (collagen type I) with more fibers and elastic fibers abundant proteoglycans

A

Reticular layer

73
Q

Capillary branches extend into the dermal papillae forming a rich nutritive capillary network just below the epidermis

A

Subpapilary plexus

74
Q

Unencapsulated receptors includes

A

Merkel cells
Free nerve ending
Root hair plexuses

75
Q

Associated with expanded nerve ending function as tonic receptors for sustain light touch and for sensitive objects texture

A

Merkel cells

76
Q

In the papillary dermis and extended into lower epidermal layers which responds to high and low temperatures pain and itching and function as tactile receptor

A

Free ending receptors

77
Q

Encapsulated receptors that are seen in routine preparations

A

Meissner corpuscles and lamellated (pacinan) corpuscles

78
Q

Encapsulated receptors

A

Meissner corpuscles
lamellated (pacinan) corpuscles
Krause
Ruffini

79
Q

Loss of tactile corpuscles or reduction in their activity can also be detected in

A

Scleroderma

80
Q

Elliptical structures 30 to 75 micrometers by 50 to 150 micrometers within Shwann cells arranged initiate impulses when light touch or low frequency stimuli declining after puberty

A

Meissner corpuscles

81
Q

Large oval structures aproximately 0.5 mm by 1mm found deep in reticular dermis and hypodermis with An outer capsule and 15 -50 thin concentric lamellae of Shwann cells specialized for sensing coarse touch, pressure and vibration also located in organs like wall of rectum and urinary bladder producing sensation of pressure when is distored

A

Lamellated pacinian corpuscle

82
Q

Simpler encapsulated with extremely thin collagen capsule penetrated by a sensory fiber primary found on the penis and clitoris when they sense low frequency vibrations

A

Krause end bulb

83
Q

Have collagenous fusiform capsules with sensory stimulated by stretch (tension) or twisting (torque) in the skin

A

Ruffini corpuscles

84
Q

Glabrous skin

A
Palms
Soles,
Lips
Glans penis
Clitoris
And labia minora
85
Q

The face hair has about

A

600 hairs/cm2

86
Q

The remainder of the body has about

A

60/cm2

87
Q

The growing hair follicle has a terminal dilation called a

A

Hair bulb

88
Q

Inserts into the base of the hair bulb and contain a capillary network required to sustain the hair follicle

A

Dermal papilla

89
Q

Melanocytes in the hair bulb transfer Melanosomes into the epithelial cells that will later differentiate to form

A

Hair

90
Q

In most thick hairs large, vacuolated, and moderately keratinized cells form the central

A

Medulla

91
Q

Densely packed cells Make un…. That surround the medulla

A

Cortex

92
Q

Thin layer of heavily queratinized squamous cells covers the cortex

A

Cuticle

93
Q

The outmost cells of the hair bulb are continous with epithelial root sheath

A

Internal and external root sheath

94
Q

Completely surrounds the initial part of the hair root but degenerates above the level of the attached sebaceous glands

A

Internal root sheath

95
Q

Extended all the way to the epidermis where it is continous with the basal and spinous layers

A

External root sheath

96
Q

Separating the hair follicle from the dermis is An acellular Hyaline layer called

A

Glassy membrane

97
Q

Hairs grow asynchronously, three major phases

A

Anagen
Catagen
Telogen

98
Q

A generally long period of mitotic activity and growth of hair

A

Anagen

99
Q

A brief period of arrested growth and regression of the hair bulb

A

Catagen

100
Q

A finally long period of inactivity of hair

A

Telogen

101
Q

Hair growth on the face and pubis is influenced by

A

Sex hormones, especially androgens and begins at puberty

102
Q

Loss of hair a complex combinations of genetic and hormonal factors

A

Alopecia

103
Q

Hard plates of keratin on the dorsal surface of distal phalanx

A

Nails

104
Q

Proximal part of the nail is the

A

Nail root

105
Q

Nail root is covered by a fold of skin from which the epidermal stratum corneum extend as the

A

Cuticle or eponychium

106
Q

Is bound to a bed of epidemis the nail bed which contains only the basal and spinous epidermal layers

A

Nail plate

107
Q

The nail root forms from the

A

Nail matrix

108
Q

Continuous growth in nail matrix in fingernails at a rate

A

3 mm/mo

109
Q

Continuous growth in nail matrix in toenails at a rate

A

1 mm/mo

110
Q

The distal end of the plate becomes free of the nail bed at the epidermal fold called

A

Hyponychium

111
Q

Average of glands per square centimeters of skin

A

100

112
Q

In the face and scalp sebaceous glands per square centimeters of skin

A

400 - 900/cm2

113
Q

A hair follicle and its sebaceous glands Make up a

A

Pilosebaceous unit

114
Q

Hairless regions, in which sebaceous ducts open directly onto the epidermal surface

A

Penis
Clitoris
Eyelids
Nipples

115
Q

Acini of sebaceous glands are

A

Holocrine secretion

116
Q

Flattened epithelial cells of holocrine glands on the basal lamina which proliferate and displace centrally called

A

Sebocytes

117
Q

Is a complex mixture of lipids that are hydrolyzed by bacterial enzymes after secretion

A

Sebum

118
Q

Sebaceous glands stimulated by

A

Testosterone men

Ovarian and adrenal androgens in women

119
Q

Two types of Sweat glands

A

Apocrine and eccrine

120
Q

Are the most numerous Sweat glands on the foot soles 620/cm2

A

Eccrine sweat glands

121
Q

The secretory part of eccrine Sweat glands has epithelium

A

Stratified cuboidal epithelium

122
Q

Three cell types on eccrine Sweat glands

A

Clear cells
Dark cells
Myoepithelial cells

123
Q

Produce the Sweat and the interstitial fluid comes from the capillary rich dermis

A

Clear cells

124
Q

Undergo merocrine secretion yo realease a poorly mixture of glycoprotein with bactericidal activity

A

Dark cells

125
Q

Absorbs Na ions from secreted water to prevent excessive loss of this electrolytes

A

Ducts

126
Q

Are largely confined to skin of the axilary and perineal regions, with much longer lumen, secretion in initially odorless but may acquire a distinctive odor as a result of bacterial activity and pheromones

A

Apocrine Sweat glands

127
Q

When the Sweat is often salty

A

Cystic fibrosis