LAB GUIDE ON SKIN 2005.PDF
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Transcript of LAB GUIDE ON SKIN 2005.PDF
SLIDES TO CONQUER
• 56a: Thin skin, H & E
• 56b: Thick skin, Masson, H & E
• 56e: Scalp
• 56f: Pacinian corpuscle
• 56g: Meissner corpuscle
KNOW THE HIERARCHY OF HISTOLOGIC ORGANIZATION
CELLS
TISSUEEpithelial tissue (= EPIDERMIS)
Connective tissue (=DERMIS/HYPODERMIS)Nervous tissue Muscle tissue Blood tissue
ORGANSkin
+ ECM
(Keratinocytes, etc.)
SKIN (Organ)
EPITHELIAL TISSUE(=Epidermis, glands, endothelium of blood vessels)
CONNECTIVE TISSUE(=Dermis, hypodermis)
NERVOUS TISSUE
(=Free nerve endings,
encapsulated receptors,
Merkel cell)
BLOOD TISSUE
MUSCLE TISSUE
(=Smooth muscle cells in blood vessel wall, platysma, Arrector pili)
• EPITHELIAL TISSUE
– CELLS CLOSELY PACKED TOGETHER W/ INTERCELLULAR JUNCTIONS
– SCANTY EXTRACELLULAR MATRIX
– AVASCULAR
– GLANDS
• CONNECTIVE TISSUE
– CELLS FEW AND FAR BETWEEN
– ABUNDANT EXTRACELLULAR MATRIX
• FIBERS
• GROUND SUBSTANCE
– VASCULAR
*INTIMATE RELATIONSHIP - ATTACHED TOGETHER BY A BASEMENT MEMBRANE
RECOGNIZE THE TISSUE COMPONENTS THAT MAKE UP THE SKIN
• EPIDERMIS– Stratified squamous
keratinized epithelium– Superficial– Thinner
• DERMIS– Dense irregular
connective tissue– Thicker
• EPIDERMAL-DERMAL INTERFACE– Wavy– Basement membrane not
visible w/ H & E
• HYPODERMIS– Loose connective tissue– May have abundant
adipose cells
IDENTIFY THE LAYERS
• EPIDERMIS– More deeply staining– Highly cellular (multiple
layers)
• DERMIS– Paler– Mostly Fibers (irregular
bundles) and some ground substance (poorly stained w/ H & E)
• S. corneum– Anucleate
– flattened layers
– “basketweave”
• S. granulosum– Diamond shaped
– Darkly staining cytoplasmic granules
• S. spinosum– Polygonal
– Rarely see “spines”
• S. basale– Single layer, cuboidal cells
– Crowded nuclei
– Occ. Mitotic figures
LAYERS OF THE DERMIS
• Papillary dermis– Contains dermal papilla
– Thin collagen fibers
– More cells (fibroblasts)
– Smaller blood vessels (capillaries)
• Reticular dermis– Thick collagen fibers
– Bigger blood vessels (arterioles/venules)
– *Elastic network NOT distinguished from collagen with H&E
VELLUS vs TERMINAL(most of body) (scalp)• Superficial
• Smaller
• Lightly pigmented
• Deeper
• Bigger
• Darkly pigmented
Slide 56e: Scalp
• HAIR FOLLICLES– Terminal (up to
hypodermis)
– Various planes of section
– Mostly anagen
– Oblique
– Continuous with the surface epidermis
LAYERS OF THE HAIR FOLLICLE: Longitudinal section
• Hair shaft
• Inner root sheath
• Outer root sheath
• Fibrous sheath
PILOSEBACEOUS UNIT(Longitudinal section)
• Arrector pili muscle
– Attaches to lower third of HF
• Sebaceous gland
– Duct enters into upper third of HF
SEBACEOUS GLAND
• CENTRAL: Vacuolated lipid-filled cells w/ scalloped nuclei
• eventually disintegrating together with sebum into duct
• PERIPHERAL: row of flattened germinative cells w/ large nuclei & basophilic cytoplasm
ECCRINE GLAND: Coiled portion in deep dermis (HPO)• SECRETORY PORTION
– Pale
– More cross sectional profiles, some tangential and bizarre-shaped (=tadpole)
• DUCTAL PORTION– Dark
– Fewer, more regularly rounded profiles
ECCRINE GLAND: Coiled basal portion
• Secretory portion
– Single layer
– Pale pyramidal cells
• Ductal portion
– 2 layers
– Eosinophilic cuboidal cells
– Hyaline lumenal lining
INTRAEPIDERMAL ECCRINE DUCT (=Acrosyringium)
• Corkscrew appearance
• Ductal cells are also keratinized