Histology > Exam2Lec3SkinandAppendages > Flashcards

Exam2Lec3SkinandAppendages Flashcards

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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?

Study These Flashcards
A

Gold impregnation techniques

25
Explain Melanocytes found in? derived from? contain?
* Found in S. basale (germinativum) w/ hemidesmosomes * derived from neural crest cells which allows for migration * contains tyrosinase-> produces melanin-> gives skin color ## Footnote 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
Melanating granules are injected into keratinocytes by a process called ____ secretion
cytocrine
27
Where do we find the most melanin?
Over nucleus in parts where mitotically active ## Footnote above nuclei of keratinocytes in the S. Germinativum and spinosum
28
If you have darker skin, what does this mean in terms of melanin?
Melanin is stored longer in keratin, it is not degraded by keratinocytes as fast
29
Merkel cells found in? what type of cells are they?
* Found in stratum basale (germinativum) of only thick skin * Specialized keratinocytes=mechanoreceptor (sensory) cells ## Footnote they cant be distinguisged from keratonocytes in HE stain
30
What is basal cell carcinoma?
* 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
What is squamous cell carcinoma?
* Loss of normal (squamous) epithelium-> appearance of cuboidal or columnar cells * affects keratinocytes all throughout the epithelial layers
32
What is malignant melanoma?
* Most dangerous form of skin cancer * Affects melanocytes in the S. basale-> migrate into dermis-> invade blood + lymph vessels to spread cancer ## Footnote 2% of skin cancers b/c of neural crest origin, they are metastatic
33
Dermis is made of what 2 layers?
Upper loose CT (papillary layer) + Lower dense CT (reticular layer) underlying the epithelium ## Footnote not a huge layern of immune cells bc stuff had to get through epidermis
34
Upper loose CT layer=papillary layer cellular layer or fibrous layer? Cell populations? considered a part of what?
* 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
Lower dense CT=reticular layer cellular or fibrous layer? Made up of what type of fiber? Contents?
* 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
The dermis in thick skin is the ____ as thick skin
same ## Footnote exception is that thin skin has seb glands and arrector m. ( for hair) structures in the dermis come from cells in the epidermis
37
A distinction is made b/w thick and skin skin. What is it dependent on?
The distinction is dependent on the thickness of the EPIDERMIS only, nothing to do with dermis
38
What type of skin is found in areas exposed to greater wear and abrasion?
Thick (glabrous) skin ## Footnote ex: palms of hands and soles of feet, no hair, so seb glands
39
What are the appendages of the skin?
1. Hair follicales 2. sweat glands 3. seb glands 4. mammary glands 5. nails
40
Where do we find hair follicles? thick skin only thin skin only both
thin
41
Where do the hair follicles grow from and what is it usually near?
Downgroth (invagination) of epidermis into dermis. Usually near seb (oil) glands in the dermis ## Footnote also apocrine sweat glands in the armpits
42
The external and internal root sheaths of the hair follicle have what type of cells and what are they surrounded by?
basal cells and its surrounded by dense CT w/in the dermis
43
What is dermal papillae? lxn? contains?
* Hair bulb surrounded by root sheath * located at the bottom of the hair follicle (root) * contians vasculature to nourish the hair ## Footnote the cells of the hair bulb are like those of the S, germantivum
44
The hair itself has 2 layers, what are they?
Cortex + medulla
45
what is the most common sweat gland?
Eccrine sweat gland
46
Eccrine sweat gland what type of secretion? dervied from what type of cells? characterized by what type of epithelium?
* watery, non-viscous secretion * derived from epidermal cells (basal cells) invading down into dermis * characterized by simple cuboidal epthelium ## Footnote simple coiled tubular glands myoepithelial cells help to squeeze out secretions from the glans these cells stain dark pink + contains actin
47
What are myoepithelial cells?
specilaized cells that help to squeeze out secretions from the glands (sweat acini) these cells stain dark pink + contains actin ## Footnote they are epithelial, not smooth muscle cells they are acidophilic b/c they contain actin filaments
48
What is the less common sweat gland and why?
Apocrine sweat gland b/c it is only located in the axillary, areolar, & anal regions ## Footnote sexual fxn= phremones-> starts puberty
49
Apocrine sweat glands what type of secretion? glands secrete fluids where?
* protein rich, viscous odorless secretion * glands secrete fluid into ducts-> ducts open into the hair follicle + secrete fluid ## Footnote 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
What is an example of a modified apocrine sweat gland?
mammary glands
51
Sebaceous (oil) glands lxn? secrete what via what type of secretion? characterized by what type of cell? examples?
* 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 ## Footnote as cells swell + fill w/ oil, the large cell will lose its nuclei
52
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?
Seb glands
53
What are nails?
Plates of keratinized epithelial cells (nails are dead skin cells)
54
What are the nail layers from superficial to deep and note what is in it and/or what it does
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 ## Footnote The nail bed does not contribute to the nail plate
55
Where does the nail plate grow from?
It grows from the root of the nail and then it grows distally on top of the nail bed
56
What are free nerve endings?
Unmyelinated axons (nerve tissue) in the dermis penetrate up into the malphgian layer of epidermis. ## Footnote Temp and pain perception. and crude touch, only type of receptor found in cornea
57
What is meissner's corpuscle? present where? fxn?
Present in thick skin (most abundant) + thick skin-> identify in upper (papillary) layer of dermis fxn= discriminative touch /edge detection
58
What are pacinian corpuscles? present where? fxn?
present in thick skin + thin skin -> identify in lower (reticular) layer of dermis and hypodermis fxn= deep pressure + vibration ## Footnote responds to tuning fork placedd against skin
59
Where are Pacinian corpuscles most abundant?
skin of fingertips
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