Lecture #26: Integument System I Flashcards Preview

Histology -- Zach H. > Lecture #26: Integument System I > Flashcards

Flashcards in Lecture #26: Integument System I Deck (83)
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1
Q

True or False:

The dermis corresponds to lamina propria of a mucous membrane and is 0.5 to 3 mm thick.

A

TRUE

2
Q

Where are primary dermal ridge not found in the body?

A

Not found:

 - forehead
 - external ear
 - perineum 
 - scrotum
3
Q

During what months of fetal life are the primary dermal ridge formed?

A

Formed during 3rd to 4th months of fetal life.

4
Q

True or False:

The primary dermal ridge is subdivided into two secondary dermal ridges by interpapillary peg.

A

TRUE

5
Q

What is the interpapillary peg?

A

It is a downward growth of epidermis along crest.

6
Q

What is the dermal papillae and what does it function to do?

A

Upward projections from each secondary dermal ridge.

The dermal papillae keep the epidermis from sliding off or your dermis. It locks the epidermis down.

7
Q

What kind of fibers make up the secondary dermal ridges?

A

Thin collagenous, reticular, and elastic fibers.

8
Q

What are the functions of the integumentary system?

A
> protection from mechanical injury 
> prevents dessication 
> protects against foreign substances and microorganisms 
> protects against UV radiation 
> thermoregulation 
> regulation of blood pressure (via dermal capillary network)
> excretion of metabolic waste products 
synthesis of provitamin D
9
Q

Does thick skin display all five epidermal layers?

A

YES

10
Q

Where is the thickest thin skin and thinnest thin skin found in the body?

A

Thickest This Skin -> on the back

Thinnest Thin Skin -> is on eyelids

11
Q

Where are the only places in the body that thick skin occurs?

A

Thick skin occurs only on palms and soles and is hairless.

12
Q

Fill in the Blank:

_________ skin is thicker on extensor surfaces than flexor surfaces.

A

Thin Skin

13
Q

What stratum layer does thin skin lack?

A

epidermal layers less distinct and lacking stratum lucidum.

14
Q

What is stratified squamous epithelium derived from?

A

Embryonic Ectoderm

15
Q

What is the layers of stratum in the thick skin, starting with the deepest stratum?

A

Stratum basale (germinativum)

Stratum spinosum

Stratum granulosum

Stratum lucidum

Stratum corneum

16
Q

Which two stratum layers make up the stratum of Malpighi?

A

Stratum Basale and Stratum Spinosum

17
Q

What is the deepest stratum layer of the epidermis?

A

Stratum Basale

18
Q

What type of cells make up the stratum basale layer?

A

Columnar to high cuboidal keratinocytes

19
Q

True or False:

The stratum basale layer is multiple cell layers thick.

A

False - single layer of cells that are held together by desmosomes and hemidesmosomes hold the layer to the basal lamina.

20
Q

Are the keratinocytes of the stratum basale highly mitotic?

A

YES - mitotic activity produces stem cells differentiating keratinocytes.

Highly Mitotic

21
Q

What are 3 synonyms of subcutaneous tissue?

A

1) SubQ
2) Superficial fascia
3) Hypodermis

22
Q

True or False:

Secondary dermal ridges occur in double rows and are branched.

A

True

23
Q

Which 2 low-molecular weight keratins are produced by keratinocytes in the stratum basale layer?

A

Keratins 5 and 14

24
Q

What type of polyhedral-shaped cells make up the stratum spinosum?

A

prickle cells

25
Q

Which 2 high molecular weight keratins are found in the stratum spinosum?

A

Keratins 1 and 10

26
Q

What do the tonofibrils form in the stratum spinosum layer?

A

They form intercellular bridges.

**On slide 16 in the integument system 1 lecture there is a micrograph of tonofilaments in the stratum spinosum layer.

27
Q

True or False:

Keratohyalin granules develop in the stratum spinosum layer.

A

TRUE

28
Q

In the stratum spinosum layer of the epidermis membrane-coating granules first appear. What do these lamellar bodies contain?

A

Lipids
Carbohydrates
Hydrolytic Enzymes

29
Q

Is the stratum granulosum layer mutilayered or single cell layered?

A

Multilayered

30
Q

What type of keratins are produced in the stratum granulosum layer?

A

Keratins 2e and 9

31
Q

True or False:

The stratum granulosum layer is made up of flattened non-nucleated keratinocytes.

A

False - the stratum granulosum layer is made up of flattened nucleated keratinocytes.

32
Q

What protein induces the cross-linkage of keratin filaments by disulfide bonds in the stratum granulosum layer?

A

Fillagrin

**these are known as keratohyalin aggregates.

33
Q

Refer to Figure 11-6 for keratinization process. You should study this thoroughly.

A

Need to know the keratinization process for exam 3.

34
Q

True or False:

There are no tonofilaments found in the stratum granulosum layer.

A

False - there are tonofilaments

35
Q

Is the stratum lucidum found in thick or thin skin?

A

Thick Skin

36
Q

What is the difference between the stratum lucidum and stratum granulosum when comparing the layer of flat keratinocytes?

A

Stratum Lucidum -> flat keratinocytes laking nuclei and organelles.

Stratum Granulosum -> flattened nucleated keratinocytes

37
Q

True or False:

The stratum lucidum layer contains eleiden.

A

True

38
Q

What does the cytoplasm of dead, flattened, enucleated keratinocytes in the stratum corneum contain?

A

Keratin cross-linked with filaggrin -> cornified cell envelope.

The cytoplasm is replaced by keratin.

39
Q

Describe the extracellular component of the cornified cell envelope that is constructed of keratin cross-linked with filaggrin?

A

It is a multi-lamellar lipid layer covalently linked to involucrine.

40
Q

What is found in the intracellular portion of the cornified cell envelope of the stratum corneum layer?

A

> involucrine
small proline-rich proteins
loricrin
fillagrin and keratin complexes

41
Q

What are the 2 major keratin products of stratum basale keratinocytes?

A

Keratins 5 and 14

42
Q

Which 2 keratin types replace keratins 5 and 14 when basal keratinocytes migrate to the stratum spinosum layer?

A

Keratins 1 and 10

43
Q

What 2 keratin types are found in the stratum granulosum layer of the epidermis?

A

Keratins 2e and 9

44
Q

Which stratum layer has tight junctions?

A

Stratum granulosum

45
Q

What is the major product of keratinocytes in the stratum granulosum layer? What function does this protein have?

A

non-intermediate filament protein, filaggrin.

Function: Filaggrin induces the aggregation of keratins.

46
Q

What do hemidesmosomes hold together in the epidermis?

A

Found on the basal side of keratinocytes in the stratum basale and connect these cells to the basal lamina beneath.

47
Q

True or False:

Keratin filaments, aggregated by filaggrin, interact with the inner side of the plasma membrane to form the cell envelope.

A

True

48
Q

In which layer of the epidermis do you find tight junctions? Also, what are the 2 proteins that are contained in the tight junction that are components of the permeability barrier?

A

Stratum Granulosum

Contains claudin-1 and claudin-4, which are components of the permeability barrier.

49
Q

True or False:

Both the epidermis and dermis are derived from embryonic ectoderm.

A

False:

epidermis -> derived from embryonic ectoderm
dermis -> derived from embryonic mesoderm

50
Q

What are the characteristics of the dermis?

A

> dense fibrous irregular CT layer beneath epidermis

> derived from embryonic mesoderm

> induces development of epidermis and epidermal derivatives

> supports epidermis

51
Q

List some characteristics of the hypodermis?

A

> loose CT that underlies dermis

> corresponds to superficial fascia of gross anatomy

> technically not part of skin

> may contain fat cells that can form a thick layer called the panniculus adposus.

52
Q

What are the two layers of the dermis?

A

Papillary layer (closest to epidermis)

Reticular layer

53
Q

Is loose CT found in the reticular layer or papillary layer of the dermis?

A

Papillary layer

54
Q

What type of connective tissue is found in the reticular layer of the dermis?

A

dense irregular connective tissue

55
Q

What structure separates the papillary layer of the dermis and the deep layer of the epidermis, the stratum basale?

A

basal lamina

56
Q

Fill in the Blank:

Fibrocytes, macrophages, and adipocytes are found in the _________ layer of the dermis.

A

Reticular Layer

57
Q

True or False:

In the papillary layer of the dermis there’s a network of fine elastic fibers and abundant capillaries.

A

True

58
Q

What are Langerhans cells (dendritic cells) derived from?

A

monocytes

59
Q

True or False:

Langerhans cells are not antigen-presenting cells.

A

False - they’re antigen-presenting cells.

60
Q

In which layer of the epidermis are Langerhans cells primarily found?

A

Stratum Spinosum

61
Q

Where do Langerhans cells of the epidermis typically migrate to?

A

lymph nodes

62
Q

True or False:

Langerhans cells have Birbeck granules in their cytoplasm.

A

True

63
Q

What do Birbeck granules contain?

A

Contain the proteins langerin and CD1a, which are involved in the uptake and delivery of antigens.

64
Q

Langerhans cells leave the epidermis, enter the lymphatic system, and are transported to a regional lymph node. In the lymph node, what do Langerhans cells interact with and do?

A

Interact with T-cells in the deep cortex. The activated T-cell then re-enters the blood circulation, extravasate at the site where the epidermal antigen is present, and secrete proinflammatory cytokines.

65
Q

In which layer of the epidermis are merkel cells typically found?

A

Stratum Germinativum

66
Q

True or False:

Merkel cells may also act as diffuse neuroendocrine cells.

A

True

67
Q

Do Merkel cells contain catecholamine-like granules?

A

Yes

68
Q

What cell type act as mechanoreceptors in the epidermis?

A

Merkel cells.

69
Q

What are Merkel cells derived from?

A

Neural Crest Cells

70
Q

What type of cell are melanocytes derived from?

A

melanoblasts

71
Q

What cell type do melanocytes inject melanin into?

A

Keratinocytes

72
Q

True or False:

Melanocytes do not form desmosome attachments in epidermis.

A

True

73
Q

What is the pathway for melanin formation?

A

Tyrosine -> 3,4-dihydroxyphenylalanine (DOPA) -> dopaquinone -> melanin

requires tyrosinase

74
Q

True or False:

The epidermis starts as a single layer of ectodermal cells.

A

True

75
Q

What does the single layer of ectodermal cells divide into during week six of development?

A

Periderm

Inner cuboidal germinal layer

76
Q

What does the periderm slough off to form?

A

vernix caseosa

77
Q

The inner cuboidal germinal layer continues to proliferate to form adult layers of the epidermis and derivatives. What derivative is developed at week 10 and 12?

A

10 weeks -> fingernails

12 weeks -> hair buds and toenails

78
Q

What is the dermis derived from?

A

Embryonic Mesoderm

79
Q

True or False:

The epidermis starts as a single layer of ectodermal cells.

A

True

80
Q

What does the single layer of ectodermal cells divide into during week six of development?

A

Periderm

Inner cuboidal germinal layer

81
Q

What does the periderm slough off to form?

A

vernix caseosa

82
Q

The inner cuboidal germinal layer continues to proliferate to form adult layers of the epidermis and derivatives. What derivative is developed at week 10 and 12?

A

10 weeks -> fingernails

12 weeks -> hair buds and toenails

83
Q

What is the dermis derived from?

A

Embryonic Mesoderm