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Histo > Skin > Flashcards

Skin Flashcards

1
Q

Keratinocytes are of what embryological tissue origin? What are they?

A

Ectoderm

They are keratinizing epidermal cells (they produce keratin) that are the main cells in all 5 layers of the skin

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2
Q

What do keratinocytes produce?

A
  • In spinosum - keratin
  • Blue & in stratum granulosum
    • Keratohyalin granules (filaggrin), which organize keratin into keratin-filaggrin protein complexes
    • Lipid-rich lamellar bodies/granules
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3
Q

Keratohyalin granules turn the cell what color on an h&e stain?

A

Blue!

Recall: Hematoxylin is a basic dye that stains acidic structures (nucleus, keratohyalin granules, calcified material)

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4
Q

Formation of a water-protective layer of skin requires

A
  • Cells undergo apoptosis and extrude their nucleus as well as their lipid-rich lamellar granules, creating the water-protective barrier
  • The cells become stratified squamous (keratinized) epithelium: flattened bags of keratin-filaggrin complexes surrounded by a cell membrane

In stratum granulosum

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5
Q

Stratum spinosum holds the cells that

A

Are filled with keratin bundles called tonofilaments that converge into small, spiny cellular extensions and insert on desmosomes to strengthen cell-to-cell adhesion

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6
Q

Stratum granulosum cells make

A

Keratohyaline granules and Lamellar granules ; purplish-blue

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7
Q

Stratum corneum cells

A

have no organelles; they are cornified (filled with keratin, extruded organelles, and flattened)

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8
Q

Stratum basale

A

One-cell thick layer of cells bound to the basement membrane below by hemidesmosomes

Contains stem cells

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9
Q

Melanocytes are from neural crest cells. Where are they? How do you recognize them?

A

Sits on the basal layer alongside keratinocytes; have a pale cytoplasm

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10
Q

Melanin funciton

A

Protect keratinocytes from UV radiation

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11
Q

Langerhans cells - what is their function and where are they? Origin?

A
  • What: Engulfs foreign antigens, goes to lymph nodes, and presents antigen to an active lymphocyte
  • Where: Stratum spinosum
  • Origin: monocytes in bone marrow
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12
Q

Merkel corpuscle

A
  • Merkel cell + nerve ending
  • Tactile discrimination
  • In the stratum basale, but not seen in an H& E
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13
Q

Epidermolysis Bullosa is a dysfunction in what cell junciton?

A

Hemidesmosomes anchor basal cells to the basal lamina

Friction can cause the epidermis to separate and fluid builds up between the dermis & epidermis –> blister

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14
Q

Keratin tonofibrils made by stratum spinosum keratinocytes insert onto..

A

Desmosomes

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15
Q

Outer layer of the dermis

A

Papillary layer: sticks up with dermal papillae into the epidermal ridge

  • Loose connective tissue, lots of collagen 3, blood vessels
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16
Q

Deeper layer of the dermis - what is it called? what type of tissue is it/describe its characteristics

A

Reticular layer

  • Dense irregular connective tissue
  • Fewer cells, more fibers such as collagen1 and elastic fibers
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17
Q

What are these wavy dark lines?

A

Elastic fibers of the reticular dermis

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18
Q

Hypodermis/subcutaneous tissue is made of what kind of connective tissue? What does it have a lot of?

A

Loose connective tissue that loosely binds skin to adjacent organs to allow for movement

Has a lot of blood vessels

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19
Q

Melanocyte produciton of melanin - what are the two steps and where does is occur?

A
  1. Tyrosinase oxidizes tyrosine to DOPA
  2. DOPA turns into melanin

Occurs in premelanosomes: membrane-bound structures derived from golgi

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20
Q

How do mealnocytes “donate” their melanin pigment to keratinocytes?

A

The premelanosomes mature into melanosomes, which eventually become colored pigments. They move to the tip of the melanocytes, where a keratinocyte will engulf it along with part of the cell membrane (cytocrine secretion)

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21
Q

Hair production is just like keratin production, it’s just a harder keratin.

Hair follicles are associated with what other two structures?

A
  • Sebaceous gland: Produces sebum to lubricate the skin and hair; protect against infections
  • Arrector pili: autonomically innervated smooth muscle; when cool, it causes the hair to stick straight up
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22
Q

Oblique and cross section of hair follicle - which part is continuous with teh surface of teh skin?

A

External root sheath is the only part continuous with the surface of the skin

Note the dermal papilla in the center giving the hair follicle nutrients

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23
Q

Nail matrix makes the keratin and then gets pushed out

A
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24
Q

Sebaceous gland

A

Holocrine secretion of sebum

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25
Q

Eccrine sweat glands

A
  • All over your body; note how the duct opens onto the skin’s surface
  • Innervated by cholinergic nerve endings
  • Small secretory portions & ducts
  • Can modify their products on their way to the surface of the skin (sebaceous & apocrine don’t)
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26
Q

How are apocrine sweat glands visibly different from eccrine sweat glands? Where are they? What do they produce? How are they innervated?

A
  • Bigger lumen
  • Only located in the skin of axillary and perineal regions
  • Produces pheromones
  • Innervated by adrenergic nerve endings
27
Q

Meissner corpuscles - location, composition, and detection

A

Location: Dermal papilla & papillary layer of fingertips, palms, soles

Composition: modified Schwann cells with a nerve axon exiting at its base

Detection: light touch

28
Q

Pacinian Corpuscles are where?

A

Look like onions in the hypodermis

Touch, pressure, vibration

29
Q

Free nerve endings are unencapsulated. Can you see them in an H&E stain?

A

NO.

30
Q

Ruffini corpuscles have ___ fibers sticking through it, so as collagen gets pulled it, it stimulates these to respond to stretch & torque.

Krause end bulbs can respond to low frequency vibration because they’re penetrated by a ___ fiber.

A

Ruffini, collagen fiber

Kraus, sensory fiber

31
Q

What layer of skin is this?

A

Hypodermis

32
Q
A

Reticular layer of dermis

33
Q

What is the region highlighted in yellow?

A

Stratum granulosum

34
Q

What’s the function of this structure?

A

Pacinian corpuscle - to respond to vibration stimuli

35
Q

What layer of the integument thas a decent amt of vasculature within the tissue (choose all that apply)?

  • Epidermis
  • Papillary layer of dermis
  • Reticular layer of dermis
  • Hypodermis
  • Subcutaneous tissue
A

Everything but the epidermis.

Epidermis is avascular

36
Q

The ducts of both eccrine and apocrine sweat glans use what kind of epithelial cells?

A

Stratified cuboidal .

(Note: myoepithelial cells are in the secretory part of only eccrine sweat glands)

37
Q

Identify the region indicated by the arrows

A

Granulosum

38
Q
A

Epidermal ridge

39
Q

Ehlers’ danos syndrome (defect in collagen production) would affect which the most?

  • Dermis
  • Hypodermis
  • Arteriovenous shunts
  • Hair follicles
  • Sweat glands
A

Dermis - connective tissue supporting epithelium; collagen, elastin, reticular fibers

40
Q
A

Bulb of hair follicle

41
Q

What gland is this?

A

Apocrine sweat gland, secretory portion; because it has a big lumen

42
Q

Decrease in tyrosinase would do what to your skin?

A

Decrease skin pigment becasue tyrosinaes is crucial for melanin produciton

43
Q

Which is most prevalent on the surface of a melanocyte?

  • Gapjunctions
  • hemidesmosomes
  • tight junctions
  • microvilli
  • cilia
A

Hemidesmosomes holds it down

44
Q

What sensation stimulate a ruffini corpuscle?

A

Stretch or torque

45
Q

What skin layer would most likely be to the origin of skin cancer?

A

Stratum basale

46
Q

What are the 3 components of the pilosebaceous unit?

A
  • Hair follicle: downgrowths of epidermal epithelium
  • Sebaceous glands: outgrowths of the external root sheath
  • Arrector pili: originates in the subcutaneous layer and contracts to expel sebaceous gland secretions
47
Q

What is this region?

A

Papillary dermis

48
Q

Ichthyosis

A

Filaggrin normally binds keratin fibers to create an effective water barrier.

Ichthyosis: filaggrin mutations causes scaly skin and hyperkeratosis from compensatory repair mechanisms causing increased cell proliferation

49
Q

Albinism

A

Genetic disorder that involves a defect in tyrosinase or in melanin production rate

50
Q

Which part o fthe hair follicle will become cornified (hard keratin)?

A

Internal root sheath

51
Q

What part of the hair follicle separates the connective tissue from the follicle?

A

Glassy membrane

52
Q

Which part of the nail gives rise to the nail

A
53
Q

The secretory part of the ECCRINE sweat gland vs the APOCRINE sweat gland is composed of what cell types?

A

Eccrine - clear, dark, myoepithelial cells

Apocrine- simple cuboidal or columnar cells

54
Q

Which sweat gland is more involved in the physiological response to increased body temp and stress?

A

Eccrine sweat glands

55
Q

Kraus end bulbs respond to what? Where are thye?

A

Low frequency vibration in skin of penis and clitorus

56
Q

Describe the transformation of keratinocytes from the basal to the superficial layers, ultimatelyr esulting in keratinization

A
  1. Stratum basale: Keratinocyte is a basal cell
  2. Stratum spinosum: Keratinocyte starts making keratin and are are attached to each other by desmosomes (looks spiny)
  3. Stratum granulosum: Filaggrin is released from keratohyalin granules and lipid rich organelles are extruded to form a water barrier
  4. Stratum corneum: Lost nuclei and desmosome attachments; “keratinized”
57
Q

Where in the body are melanocytes?

A

In the skin and the iris

58
Q

Cutis laxa

A

Impaired elastic recoil becuase elastic fibers don’t form properly

59
Q

hair follicles, hair, sweat glansd, sebaceous glands, nails, and mammary glands project from the dermis but

A

They are epidermal derivatives - they originate from ectoderm

60
Q

The outermost papillary layer has

____ anchoring the intermediate filaments to the basal lamina

____ anchoring actin to the basal lamina

A

Hemidesmosomes anchor IF to the basal lamina

Focal adhesions anchor actin to the basal lamina

61
Q

Panniculus carnasus

A

STriated muscle deep to the subcutaneous fascia

62
Q

Subutaneous tissue contains ___ and ___ so drugs are absorbed rapidly

A

Loose connective tissue of fat cells and numerous blood vessels (drugs absorbed quickly)

63
Q

Blood vessels that nourish teh skin come from two plexi where?

A

Between the hypodermis and dermis

64
Q

Papillary layer vs deeper reticular layer of the dermis contains what kind of tissue?

A
  • Papillary layer: Loost connective tissue (type 1 & 3 collagen)
    • Blood vessels, nerve processes, some elastic fibers
  • Reticular layer: Irregular dense connective tissue (type I collagen)
    • More fibers, fewer, cells and ELASTIC FIBERS

Histo (20 decks)

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