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I&D > Tuesday test Skin3 > Flashcards

Tuesday test Skin3 Flashcards

1
Q

Major functions of skin (7)?

A

Mechanical protection
Moisture barrier
Host defense
Thermoregulation
Excretion of salt
Synthesis of vitamin D & regulation of calcium absorption
Sensory organ

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2
Q

How big is skin as an organ?

A

15-20% of body weight
- 1.5 to 2 square meters of surface area

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3
Q

How thick is skin?

A

Thickness varies from 1 mm (eyelid) to 5 mm (upper back)

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4
Q

Cornified barrier is composed of __
What important things does it make?

A

Keratinocytes
Vitamin D production

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5
Q

Cells that protect agains ultraviolet radiation?

A

Melanin, melanocytes

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6
Q

Cells/structures that help with thermoregulation ?

A

Sweat glands, blood vessels

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7
Q

Sensory cells and structures?

A

Sensory dendrites, mechanoreceptors, thermoreceptors,
nociceptors

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8
Q

Leathery barrier is composed of __ and __

A

Fibroblasts and thick collagen fibers

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9
Q

primary barrier against pathogen access to deeper tissues?

A

Skin

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10
Q

Mucous membranes role in pathogenesis?

A

produce mucus (watery mix of the protein mucin and salts) → trap pathogens and can be expelled from the body

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11
Q

The first line of defense in innate immunity are ______, which block pathogen entry into the tissues of the body.

A

barrier defenses

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12
Q

Two main parts of the skin?

A

Epidermis (keratinocytes and non-keratinocytes) and dermis (Papillary layer, reticular layer).

CT is between them

Hypodermis isnt technically part of the skin

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13
Q

2 layers of dermis? major difference

A

Papillary (loose CT) and reticular (dense CT)

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14
Q

Two parts of Hypodermis?

A

Subcutis

Superficial fascia

I dont know if this is correct!

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15
Q

Name the 5 strata of epidermis

A

from deepest to superficial

Stratum basale

Stratum spinosum

Stratum granulosum

Stratum lucidum

Stratum corneum

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16
Q

Stratum basale - special things?

A

single cell layer between epidermis and dermis

• Germinative layer = high rate of mitosis - only one doing mitosis

• Keratin filaments form fibrils

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17
Q

What holds Stratum basale together?

A

Desmosomes

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18
Q

What does stratum spinosum produce?

A

membrane-coated granules

keratin fibrils

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19
Q

how is stratum spinosum hold together?

What does it contain?

A

desmosomes

Keratohyalin granules, Keratin fibrils, Membrane-coated granules

20
Q

Where are keratohyalin granules formed and what is their role?

A

Stratum granulosum. Hold keratin fibers together → cell stretches like a pancake

21
Q

Composition of Keratohyalin granules? 3

A

filaggrin, loricrin, involucrin

22
Q

what is the layer of the cells we only see in thick skin layer?

A

Stratum lucidum

23
Q

describe stratum lucidum

A

Extensive crosslinking of keratin fibrils, changes cell shape to squamous

24
Q

What does stratum lucidum do?

A

Glycolipids (from m-c granules) secreted into extracellular space seal the squamous layers.

25
Q

Cells of the stratum corneum form ___

A

Cornified envelope

26
Q

Difference of thick vs thin skin?

A
  • Named for different thicknesses of epidermis, not for thickness of entire skin.

Thin skin: almost all has hair; 14 days to turnover/replace.

Thick skin: only on palms and soles; hairless; 48 days to turnover.

27
Q

What are the non-keratinocytes cells? What do they originate from?

A

Melanocytes - originate from Neural crest cells and Merkel cells - originate from ectodermal basal cells

28
Q

Main functions of Melanocytes? How do they originate?

A

Contain pigment melanin -(Oxidation of tyrosine -> DOPA -> melanin), packaged into melanosomes. They are dendritic cells -> cytoplasmic extensions with over 30 keranocytes. bMelanin granules form a shield protecting stratum basale and nuclei from UV rad Originate from Neural crest cells -> migrate to epithelium and located between dermis and epidermis

29
Q

How do we visualise melanocytes?

A

Antibody to a protein, active early in melanin synthesis is used. In the basal layer of epithelium

30
Q

What are Langerhans cells? Where are they located? How does it do its job? How are they attached?

A
  • antigen presenting dendritic cell (derived from a bone marrow macrophages like all monocytes) Located in Stratum spinosum It’s motile and moves within the keratinocytes and bw epithelium and lymph vessels. Migrates regionally to lymph nodes and presents antigens to T cells. Langerhans cells aren’t attached with desmosomes to keratinocytes, but associated with E-cadherins
31
Q

Merkel cells job?

A

Slowly adapting mechanoreceptor (pressure) touch in thin skin. Sence of touch

32
Q

What do Merkel cells contain? How are they attached?

A

It’s ectodermal, desmosomal attachments to basal layers of epithelial cells Keratin tonofilaments Small granules presumably containing neurotransmitters

33
Q

What are the sensory innervations of epidermis?

A

Merkel cells - Tactile -touch to the skin. Unmyelinated nerve ending expands into plate like sensory ending Free nerve endings (Epidermis - Pain, temperature)

34
Q

What does the dermis contain?

A

Capillary network, AV shunts, Sensory nerve endings

35
Q

How do we prevent loosing heat during a cold day?

A

Blood supply to superficial capillaries is regulated through Shunts (pericapillary sphincter)

36
Q

What’s the sensory innervation of dermis?

A

1) Ruffini’s corpuscle (stretching)
2) Meisner’s corpuscle - fine sense of touch (papillary layer, Detects changes in “texture” • Vibrations around 50Hz • Fingertips, lips have increased innervation density (fine touch in thick skin)

37
Q

Sensory Innervation of Reticular layer? What does it sense?

A

Pacinian corpuscles

Rapidly adapting – Type II mechanoreceptor – Deep pressure & vibration

38
Q

At the base of the follicle, the ______ is surrounded by the hair bulb, whose keratinocytes proliferate, take up melanin granules and gain more keratin

A

dermal papilla (DP)

39
Q

What does Eccrine Sweat Gland secrete? How?

A

Reabsorbs sodium and chloride ions from the sweat, plus some of the water.

its continuous production

40
Q

Eccrine Sweat Gland - what types of cells?

A

Stratified cuboidal epithelium (two cell layers)

Excretory duct

41
Q

Excretory duct locations?

A

Big glands that lead to body odor; restricted to the arm pits, genital and anal regions

42
Q

What do apocrine sweat glands secrete?

A

Protein-rich secretion (odorless when secreted but bacteria like it, leading to body odor)

43
Q

Apocrine sweat gland - how does it secrete sweat?

A

Duct empties into canal of hair follicle, dont produce continuously

44
Q

Apocrine sweat gland structural difference?

A

Coiled tubular gland: lumen is larger than in eccrine sweat glands

45
Q

Sebaceous glands product? How is it secreted?

A

Oil (sebum) glands of the skin

Secrete into canal of hair shaft -Holocrine secretion: dying sebaceous gland cells…lots of lipids

46
Q

How do Sebaceous glands look like?

A

Branched acinar glands

The acini have no lumens.

47
Q

Describe wound healing process

A

Blood vessels clot → leukocytes clean the wound → blood vessels regrow and granulatio tissue forms→ stratum basale is restored → producing more keratinocytes

I&D (19 decks)

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