Integumentary System Flashcards Preview

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Flashcards in Integumentary System Deck (44)
1

Thick skin

Has thicker epidermal layer - two locations have this in the body - palms and soles of feet. Thin skin found everywhere else. No hair follicles with thick skin.

2

Thin Skin

4 layers:

Stratum Basale
Stratum Spinosum
Stratum granulosum
Stratum corneum

3

Stratum Basale

mitotically active layer. Stem cells give rise to new keratinocytes. As cells mature, they fill with more keratin. Adjacent to dermis. Comprised of a single layer of cuboidal cells (also stain very dark due to having a TON of ribosomes).

4

Stratum Spinosum

Have small cytoplasmic spines that attach to macula adherins (desmosomes), and fixing the tissue causes shrinkage that creates these "spines". Unlike stratum basale, this is extremely thick. Here intermediate filament production continues. These tonofilaments begin to be grouped into tonofibril bundles. Keratohyaline granules and lamellar body production begins in upper portion of this layer.

5

Stratum granulosum

1-3 cell layers thick. Granulosum - because of the presence of *keratohyaline granules*. Intermediate filaments of keratine filaments are tono filaments, which are produced in granulosum cells. Granulosum takes these and bundles them together to form totofibrils. This process of bundling keratin filaments into totofibrils is known as cornization.

6

Stratum corneum

no nuclei, completely dead.

7

Thick skin

5 layers - translucent layer called the stratum lucidum - between granulosum and corneum. It is like a white line.

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Keratinocytes

Predominate cell type in epidermis.

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Melanocyte

Epidermal cells - dendritic cells (rounded cell body with dendritic processes that extend up). Hang out in stratum basale and processes extend to spinosum. Produce melanin - protects melanocyte nucleus from the sun. Look for ring of cytoplasm around nucleus.

10

Langerhans cell

**look into how to examine this. check the slides.

11

Merkel's cell

Associated with acute sensory perception. Can descriminate in fine touch. Found in fingertips. Associated with sensory nerve. Combination of merkel's cell with afferent sensory neuron = merkel's corpuscle. Found in stratum basale. Have darkly staining secretory granules. Containing neurosecretory granules in cytoplasm.

12

Dermis layers

2 layers:
Papillary layer
Reticular layer - has fewer cells

13

Papillary layer

layer that is immediately adjacent to epidermis. Marked by protrusions into the epidermis known as dermal papillae. This is loose connective tissue - very cellular layer.

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Reticular layer

Dense irregular connective tissue.

15

Hypodermis

Has onion-like structures - sensory receptor known as pacinian corpuscle (axon with lamina/layers of connective tissue surrounding unmyelinated portion, innermost layer is layers of schwann cell. Senses deep pressure and vibration.

16

Meisner's Corpuscle

Oriented perpendicular to surface of skin. Involved in deep sensory reception.

17

Sebaceous gland

Empty into hair follicle. Secrete Sebum (lipid containing). Found in association with hair follicles. Holocrine secretion.

18

Arrector pili

Bands of smooth muscle that extend into papillary layer of dermis on hair follicle. Receives sympathetic innervation.

19

Sweat glands

Eccrine
Apocrine

20

Eccrine

Involved in thermoregulation. Duct leads to skin surface, not hair follicle - duct cells are darker. Duct is small cuboidal cells - strat. cuboidal. Smaller and darker. Duct has a more narrow outside diameter and lumen than secretory portion. These are simple coiled tubular glands. Secretory portion has lighter, larger cells - double layer in dermis/hypodermis. Merocrine secretion is what these do (exocytosis of products). Widely distributed.

21

Apocrine

Associated with hair follicles. Not functional at birth, become functional during puberty. Only located with arm and pubic hair. Products of these is protein rich. Odor is only the result of bacterial breakdown of these proteins. Coiled tubular. Develop from same epidermal downgrowths that form hair follicles.

Secretory portion- at apical surface you see cytoplasmic protusions. Merocrine glands** Usually in hypodermis or dermis. Simple cuboidal epithelium with eosinophilic cytoplasm.

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Sweat glands - another name

Sudoriferous glands

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Skin functions

Protective, immunologic (contains antigen affector cells), homeostasis, sensory, endocrine/exocrine.

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Epidermis

Avascular - receives nourishment from dermis.

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Dermis

Derived from mesoderm.

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Hypodermis

Subcutaneous layer/fascia

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"Thickest" skin

Skin on upper level of back - dermis and epidermis**

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Langerhan's Cells

Antigen presenting cell of the immune system.

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Merkels cell

mechanoreceptor cells associated with sensory nerve endings.

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Percentages

Keratinocytes: 85%
Melanocytes: 5%
Langerhan's Cells: 2-5%
Merkels cells: 6-10%

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Keratins form

Keratin filaments - classified as intermediate filaments, referred to as tonofilaments. Comprise 85% of a fully differentiated keratinocyte. Participates in forming epidermal water barrier - do this by producing tubular/ovoid shape organelles lamelar bodies (lipid containing).

32

lamelar bodies

Secreted in intercellular space between stratum granulosum and stratum corneum.

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Stratum Lucidum

between stratum corneum and granulosum. Essentially a transition between the two layers - where nuclei are lost, but cells are not quite full.

34

Melanosomes

Produce in melanocytes - travel to ends of dendritic processes, where they accumulate and transfer to adjacent cells.

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Melanin collects over

keratinocyte nuclei to shield DNA from UV.

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Langerhans cells

From bone marrow - migrate into epidermis from blood. Travel from epidermis to regional lymph node. H and E staining doesn't show these, immunostaining is a must.

37

Skin cancer

Basal cell carcinoma, squamous cell c., malignant melanoma

38

Basal cell carcinoma

Slow growing tumor that does not mestastisize - most common and least aggressive. Representes cells of basale- surgical treatment is removal of lesion

39

Squamous cell carcinoma

More aggressive - more prone to mestastisize. Characterized by atypical cells in varying levels with varying patterns.

40

Malignant melanoma

Originates from melanocytes - looks like an irregularly pigmented multicolor rough lesion. Surgery with chemo is needed.

41

Pacinian corpuscles

Encapsulated nerve endings (in connective tissue capsules) to detect pressure changes and vibrations across skin surface. ovoid in dermis and hypodermis

Myelinated nerve ending with concentric lamellae surrounding it. Inner core is a series of schwann cells tightly packed around unmyelinated axon.

42

Meisners Corpusles

Detect light touch. Tapered and cylindrical - in skin and lips. Perpendicular to skin surface. Unmyelinated nerve endings follow spiral path covered by unmyelinated schwann cells.

43

Epidermal skin appendages

Form from downgrowths of epidermis.

Hair follicles, apocrine, eccrine, sepaceous glands

44

Nails

Plates of keratinized cells that rest on nail beds. Difficult to sustain in histological sections.