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Histology > Exam2Lec3SkinandAppendages > Flashcards

Exam2Lec3SkinandAppendages Flashcards

1
Q

What is integument?

A

Your skin=epidermis +dermis

epidermis has strat sq epithelium

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2
Q

What covers skin?

A

Keratinized stratified squamous epithelium

epithelium->BM->loose CT (papillary layer)-> dense CT (reticular layer)

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3
Q

What are 6 fxns of skin?

A
  1. Barrier
  2. Homeostasis
  3. Immunologic (barrier)
  4. Sensory->nerve tissue (Pacinian +Meissner’s corpuscles)
  5. Endocrine
  6. Excretion-> glandular tissue (sweat + oil)
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4
Q

Is they hypodermis typically considered a layer of skin?

A

NO, it mostly has adipose tissue

also called superfiscial fascia or subcutanuos CT

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5
Q

What is the epidermis?

A

Epithelium derived from the ectoderm

consists of 5 layers (thick skin) and 4 layers (thin skin)

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6
Q

What are the 5 layers of the epidermis from outer to inner?

5 layers for thick. 4 for thin

A
  1. stratum Corneum
  2. stratum Lucidum (thick skin only)
  3. Stratum Granulosum
  4. Stratum Spinosum
  5. Stratum Basale (germinativum)

Come, Lets Gulp Some Beer

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7
Q

What can we find in the stratum corneum layer of the epidermis?

A

Dead, flattened keratinized cells=horny cells

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8
Q

What can we find in the stratum lucidum layer (thick skin only) of the epidermis?

A

Thin+ clear layer of dead, flattened keratinocytes

Acidophilic -> stains more pink/red

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9
Q

What can we find in the stratum granulosum layer of the epidermis?

A
  • H20 barrier
  • Keratohyalin granules (not mem bound) + membrane coating granules
  • Lamellar bodies-> lipid insoluble proteins=waterproof

basophilic -> stains more purple

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10
Q

What can we find in the stratum spinosum layer of the epidermis?

A
  • Polygonal cells w/desmosomes generates cohesion
  • Presence of mitotically active cells

they have spiny projections that form IC bridges which are now known as desmosomes

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11
Q

What can we find in the stratum basale (germinativum) layer of the epidermis?

A
  • single layer of cuboidal or Columnar cells w/desmosomes + hemidesmosomes
  • Most mitotically active layer-> replenish cell population

cuboidal or columanr cells rest on basal lamina

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12
Q

What is the layer of cell mitosis?

A

S. Germinativum/Basale

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13
Q

What is the malphigian layer?

A

S. Spinosum + Basale, its the most mitotically active region

region of keratinocyte proliferattion

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14
Q

1st degree burns
can the epidermis be repaired?
what layer of skin is damages and/or unharmed?

A
  • Patient can repair epidermis
  • Damage to S. Corneum +Lucidum +Granulosum +Spinosum
  • The S. Basale is unharmed & can restore the lost cell population
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15
Q

2nd degree burns
can the epidermis be repaired?
what layer of skin is damages and/or unharmed?

A
  • The pt can regenerate lost epidermis from dermis
  • Damage to all layers of the epidermis
  • Sweat glands + hair follicles in the dermis (derived from S. Basale of the epidermis) can regenerate epiderm
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16
Q

3rd degree burns
can the epidermis be repaired?
what layer of skin is damages and/or unharmed?

A
  • The pt has complete loss of the epidermis + dermis
  • Can only repair w/ skin grafts
  • Most dangerous burn b/c loss of H20 barrier can cause death
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17
Q

What type of cells can we find in the epidermis?

A

Keratinocytes, langerhans cells, melanocytes, merkel cells

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18
Q

What is the most abundant cells type?

A

keratinocytes

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19
Q

Explain keratinocytes
where is it produced?
where it prolif?
where they accumulate and die?
where it moves?
what does it store?

A
  • Produced in S. basale-> move to Spinosum + proliferate
  • As cells mature they accumulate keratin filaments (granules)
  • Start to die in the S. granulosum-> move to Corneum
  • Can store melanin produced by melanocytes
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20
Q

As keratinocytes mature and differentiate, what do they produce?

A

Keratin hyaline granules and lamellar bodies

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21
Q

What goes through a very specialized differentiation to give rise to the protective dead cell layer, the stratum corneum

A

keratinocytes

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22
Q

Explain Langerhans cells
found in?
derived from?
act as?

A
  • Found in S. Spinosum
  • Derived from mesoderm
  • Act as immune cell (APC)= migrate into the dermis-> then lymph

NOT attached to adjacent keratinocytes by desmosomes, similar to dendritic cells seen in lymphoid tissues

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23
Q

What are langerhans cells responsible for?

A

responsoble for engulfing invading microorganisms in the epidermis and presenting antigens to lymphoid cells

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24
Q

Langerhans cells cannot be distinguised easily in H and E, what techniqe must be used to visualize it?

A

Gold impregnation techniques

25
Q

Explain Melanocytes
found in?
derived from?
contain?

A
  • Found in S. basale (germinativum) w/ hemidesmosomes
  • derived from neural crest cells which allows for migration
  • contains tyrosinase-> produces melanin-> gives skin color

melanin protects the keratinocytes from UV radiation
melanocytes are NOT conected to surrounding keratinocytes by desmosomes, but can be attatched to B. lamina by hemidesm

26
Q

Melanating granules are injected into keratinocytes by a process called ____ secretion

A

cytocrine

27
Q

Where do we find the most melanin?

A

Over nucleus in parts where mitotically active

above nuclei of keratinocytes in the S. Germinativum and spinosum

28
Q

If you have darker skin, what does this mean in terms of melanin?

A

Melanin is stored longer in keratin, it is not degraded by keratinocytes as fast

29
Q

Merkel cells
found in?
what type of cells are they?

A
  • Found in stratum basale (germinativum) of only thick skin
  • Specialized keratinocytes=mechanoreceptor (sensory) cells

they cant be distinguisged from keratonocytes in HE stain

30
Q

What is basal cell carcinoma?

A
  • Occurs only in thin skin (where seb glands are located)
  • Affects keratinocytes in the S. basale-> exceeds basal cells in areas they shouldnt be (like the dermis)
31
Q

What is squamous cell carcinoma?

A
  • Loss of normal (squamous) epithelium-> appearance of cuboidal or columnar cells
  • affects keratinocytes all throughout the epithelial layers
32
Q

What is malignant melanoma?

A
  • Most dangerous form of skin cancer
  • Affects melanocytes in the S. basale-> migrate into dermis-> invade blood + lymph vessels to spread cancer

2% of skin cancers
b/c of neural crest origin, they are metastatic

33
Q

Dermis is made of what 2 layers?

A

Upper loose CT (papillary layer) + Lower dense CT (reticular layer) underlying the epithelium

not a huge layern of immune cells bc stuff had to get through epidermis

34
Q

Upper loose CT layer=papillary layer
cellular layer or fibrous layer?
Cell populations?
considered a part of what?

A
  • cellular layer b/c loose CT= more cells than fibers
  • Cell populations: fibroblasts, mast cells, macrophages, etc
  • considered a part of the dermal papillae or pegs
35
Q

Lower dense CT=reticular layer
cellular or fibrous layer?
Made up of what type of fiber?
Contents?

A
  • Fibrous layer b/c dense CT has more fibers than cells
  • Made up of type 1 collagen fibers
  • Contents: sweat glands, seb glands (thin skin only), nerve fibers (pacinian and messners), arrector muscle (thin skin)
36
Q

The dermis in thick skin is the ____ as thick skin

A

same

exception is that thin skin has seb glands and arrector m. ( for hair)
structures in the dermis come from cells in the epidermis

37
Q

A distinction is made b/w thick and skin skin. What is it dependent on?

A

The distinction is dependent on the thickness of the EPIDERMIS only, nothing to do with dermis

38
Q

What type of skin is found in areas exposed to greater wear and abrasion?

A

Thick (glabrous) skin

ex: palms of hands and soles of feet, no hair, so seb glands

39
Q

What are the appendages of the skin?

A
  1. Hair follicales
  2. sweat glands
  3. seb glands
  4. mammary glands
  5. nails
40
Q

Where do we find hair follicles?
thick skin only
thin skin only
both

A

thin

41
Q

Where do the hair follicles grow from and what is it usually near?

A

Downgroth (invagination) of epidermis into dermis. Usually near seb (oil) glands in the dermis

also apocrine sweat glands in the armpits

42
Q

The external and internal root sheaths of the hair follicle have what type of cells and what are they surrounded by?

A

basal cells and its surrounded by dense CT w/in the dermis

43
Q

What is dermal papillae? lxn? contains?

A
  • Hair bulb surrounded by root sheath
  • located at the bottom of the hair follicle (root)
  • contians vasculature to nourish the hair

the cells of the hair bulb are like those of the S, germantivum

44
Q

The hair itself has 2 layers, what are they?

A

Cortex + medulla

45
Q

what is the most common sweat gland?

A

Eccrine sweat gland

46
Q

Eccrine sweat gland
what type of secretion?
dervied from what type of cells?
characterized by what type of epithelium?

A
  • watery, non-viscous secretion
  • derived from epidermal cells (basal cells) invading down into dermis
  • characterized by simple cuboidal epthelium

simple coiled tubular glands
myoepithelial cells help to squeeze out secretions from the glans these cells stain dark pink + contains actin

47
Q

What are myoepithelial cells?

A

specilaized cells that help to squeeze out secretions from the glands (sweat acini) these cells stain dark pink + contains actin

they are epithelial, not smooth muscle cells
they are acidophilic b/c they contain actin filaments

48
Q

What is the less common sweat gland and why?

A

Apocrine sweat gland b/c it is only located in the axillary, areolar, & anal regions

sexual fxn= phremones-> starts puberty

49
Q

Apocrine sweat glands
what type of secretion?
glands secrete fluids where?

A
  • protein rich, viscous odorless secretion
  • glands secrete fluid into ducts-> ducts open into the hair follicle + secrete fluid

active glands have lots of glandular tissue; inactive is mostly CT w/ scarce amount of glands
the secretions attains a distinctive ordor by the action of bacteria that reside on the skin

50
Q

What is an example of a modified apocrine sweat gland?

A

mammary glands

51
Q

Sebaceous (oil) glands
lxn?
secrete what via what type of secretion?
characterized by what type of cell?
examples?

A
  • located only in thin skin b/c they develop with hair follicles
  • secrete sebum (oil) via holocrine secretion-> more active after puberty
  • characterized by basal cells (from epidermis)
  • ex: lips, glans, clitoris

as cells swell + fill w/ oil, the large cell will lose its nuclei

52
Q

What type of glands becomes more active at puberty; i.e. respond to hormones and when clogged, they are an ideal site for bacterial growth?

A

Seb glands

53
Q

What are nails?

A

Plates of keratinized epithelial cells (nails are dead skin cells)

54
Q

What are the nail layers from superficial to deep and note what is in it and/or what it does

A
  1. Nail plate: keratanized epithelial cels
  2. Nail bed: epithelial cells of the S. Spinsom + Basale (malphigian layer)
  3. Nail matrix:
    generates the cells of the nail bed

The nail bed does not contribute to the nail plate

55
Q

Where does the nail plate grow from?

A

It grows from the root of the nail and then it grows distally on top of the nail bed

56
Q

What are free nerve endings?

A

Unmyelinated axons (nerve tissue) in the dermis penetrate up into the malphgian layer of epidermis.

Temp and pain perception. and crude touch, only type of receptor found in cornea

57
Q

What is meissner’s corpuscle?
present where?
fxn?

A

Present in thick skin (most abundant) + thick skin-> identify in upper (papillary) layer of dermis
fxn= discriminative touch /edge detection

58
Q

What are pacinian corpuscles?
present where?
fxn?

A

present in thick skin + thin skin -> identify in lower (reticular) layer of dermis and hypodermis
fxn= deep pressure + vibration

responds to tuning fork placedd against skin

59
Q

Where are Pacinian corpuscles most abundant?

A

skin of fingertips

Histology (39 decks)

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