Skin Integumentary system

Skin
Integumentary system
2009
Skin (cutis, derma)
The heaviest organ in the body - 16% of weight
Size: 1,2-2,3m2
Function: Protection (mechanic, from desiccation)
Thermoregulation
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Sweat glands (perspiratio insensibilis)
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Changes in blood flow
Excretion of salt (iron looses)
Nonspecific immunity
Metabolism- ergosterol-vit.D
Sensoric ending
Sexual signaling
(Endocrine gland – adipose tissue: leptin, adiponectin, estrogenes)
Development
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Ectoderm
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Periderm – 2 layers cuboidal and flat superficial
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Stratified squamous
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Glands, hair and nails – invagination of
ectoderm into dermis
Skin lines (lineae distractiones)
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Externally visible skin lines:
Wrinkle lines: lines of expression
Flexure (joint) lines
– sulcus mentolabialis, nasolabialis
– sulcus gluteus
Surface pattern lines - hand – Purkyně - chiromantia
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linea oppositionis pollicis (vitalis)
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linea manus clausae (cephalica, naturalis)
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linea occlusionis dig. trium ulnarium (mensalis)
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sulcus cutaneus intercarpalis (linea rasceta)
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linea restricta
Skin
• Grooves (sulci cutis)
• Papillary ridges (friction ridges) (cristae cutis) – dermatoglyphics - 9
types (according to Purkyně) → daktyloscopy – forensic importance
• Toruli tactiles – 10 in hand ( thenar)
• Lineae distractiones
• Retinacula cutis - (retinaculum caudale)
• Intristinc scarring - Striae cutaneae – rupture of lateral cohesion of
the collagen fibres -growth, pregnancy and obesity
Skin
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Epidermis
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Dermis
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Hypodermis (tela subcutanea – panniculus adiposus)
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Appendages:
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Hairs
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Nails
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Glands of the skin
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Mammary gland
Epidermis
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Stratified squamous keratinized epithelium +
melanocytes, Langerhans cells, Merkel´s
cells
Thick type: palms of hands and soles of the
feets
Thin type: rest of the body
Cell renewal in epidermis:15 – 30 days
EGF, Keratinocyte growth factor, retinoic acid (vit. A)
Epidermis
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Stratum basale (basophilic cuboid to columnar cells
on lamina basale – stem cells)
Stratum spinosum – polygonal cells, contain of
cytokeratin filament, desmosomes
Stratum granulosum – 3 – 5 layers of cells –
keratohyalin granules – basophilic; lamellar
granules – lipids (ceramids) – barrier – sheet
containing lipid
Stratum lucidum – in thick type -eosinophilic
Stratum corneum – cells filled by keratin filament
are packed together by filaggrin; desmosomes
Stem cells
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Stem cells in the bulb region of the hair follicle –
indepedent migration:
Bulb-hair stem pathway – at the apex of the dermal
papilla
Bulb-epidermis cell pathway – epidermis – stratum
basale
Sebaceous glands
Differentiation of a keratinocyte
Cells of stratum spinosum – synthesis of
acylglucosylceramide – RER + GA = membranecoating granules (or lamellar bodies)
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Bb. stratum granulosum – proteosynthesis =
keratohyaline granules, lamellar bodies release
ceramide into the intercellular spaces
Bb. stratum lucidum – intermediate layer eosinophilic
Bb. stratum corneum – without nuclei, keratin
croslinked by filaggrin, together with ceramide form
cell envelope, cells are joined by desmosomes
Melanocytes
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Development from neural crest
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Eumelanin, pheomelanin (contains cysteine) - red hair
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Tyrozine – dopa – dopaquinone – melanin (tyrozinase)
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Synthesis:vesicle with enzymatic activity, fine granular
material
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Melanosome – filaments with periodocity 10nm
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Dense granule
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Melanosome visible in LM, size 1x0,4 µm
Melanocytes
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Cytocrine secretion melanosomes transferred
to keratinocytes
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Function – protection from UV radiation
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Epidermal – melanin unit – about 1000/mm2
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Higher number in the skin of scrotum, circumanal region, areola mammae)
Merkel´s cells
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Present in thick skin in stratum basale
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Small dense granules (neurotransmiters)
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Nerve ending
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Sensoric mechanoreceptors
Langerhans´ cells
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Mainly in stratum spinosum
Bone marrow derived - antigen presenting cells
– in lymphatic nodes - they differentiate into
activated dendritic cells – (contain Birbeck´s or
vermiforms granules - rodlike)
Dermis
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Dense collagen connective tissue with elastic
fibres. Main glycosaminoglycane is dermatan
sulphate
Attachment to epidermis – hemidesmosomes and
anchoring filaments (laminin 5) and fibriles
(collagen VI) – blister, pemphigus
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Stratum papillare
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Stratum reticulare
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Skin appendages – glands, hairs, nails
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Sensoric ending (Vater-Paccini, Meissner etc.)
Fissionability lines
• Along the collagen fibres in dermis
• Important for cosmetic surgery and for cutting motion
podle Kraisla
Hypodermis
Tela subcutanea
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Loose collagen tissue and adipose tissue
Is not present in eyelids, clitoris and penis
Retinacula cutis
Panniculus adiposus
– Stratum musculorum
– Stratum fibrosum
• Stratum membranosum
• Textus connectivus laxus
• Bursae synoviales subcutaneae
Skin appendages
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Hair and hair follicle
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Sebaceous glands
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Sweat gland
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Apocrine glands
Hair
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Hair follicle
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Hair bulb (bulbus pili)
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Dermal papilla
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Hair (cuticle of hair, cortex, and medulla)
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Internal (epithelial) root sheat
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External (epithelial) root sheat
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Connective tissue sheat
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Arrector pili muscle
Nails
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Nail root hidden in nail groove
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Eponychium or cuticle
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Nail plate (stratum corneum) on the nail bed
(stratum basale and spinosum)
Nail plate arises from nail matrix (root and
lunula)
Glands of the skin
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Sebaceous glands – holocrine glands,
composed alveolar
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Duct – stratified squamous epithelium
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Not present in thick type
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Duct usually ends in the upper part of hair
follicle
Directly on surfacer: glans penis, clitoris,
labia minora, lips, areola mammae
Glands of the skin
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Sweat glands - eccrine (merocrine) – simple coiled
tubular gland
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Excretory duct opens at the skin surface
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Dark cells – glycoproteins
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Clear cells – glycogen, basolateral labyrinth –
secretion of water and ionts (Na, Cl)
Myoepithelial cells
Ducts - pseudostratified epithelium and space
between keratinocytes
Function - thermoregulation
Glands of the skin
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Apocrine glands – present in axilla, anal and
genitregion, areola mammae, modified in ear
(ceruminous) and eyelid (glands of Moll)
Secretory part is wider, ducts opens in hair
follicle, secretory activity starts at puberty
(merocrine secretion with changes of cell
size)
Adrenergic inervation
Mammary gland (glandula mammaria)
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The greatest gland of the skin
Lactation → newborn nutrition
Paired glands – sulcus intermammarius
From 3th – 6th ribs, parasternal ► anterion
axillar line
Upon the deep pectoral fascia
Retromammary space – loose connective tissue
11 cm x 12 cm
150g, during lactation 300-800g
Development
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Mammary ridge
Only in thoracal region
(Supernumerary breasts and nipples)
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Development of nipple and glands
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15-20 lobes epithelial buds – lactiferous ducts
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Before puberty lactiferous ducts and lactiferous sinuses,
only
Increase in size after puberty (influence of estrogens) terminal interlobular ducts + adipose tissue
Mammary gland (glandula mammae)
• Corpus mammae – glandular tissue - processus
axillaris
• 15-20 compound tubo-alveolar glands
• Ducts = lactiferous ducts → lactiferous sinuses →
nipple (mammary papilla) and areola
• Lobes → lobules →glandular alveoles surrounded
by dense connective tissue and adipose tissue
• Fibrous condensations of stromal tissue -to the
dermis suspensory ligaments (of Astley Cooper)
Retinaculum cutis mammae = ligg. suspensoria
mammaria Cooperi
Mamma
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Menstrual cycle Progesteron stimulates cyclic
changes – alveolar buds develop under the
influence of progesteron, old regress (apoptosis)
Pregnancy – Prolactin and placental lactogen –
development of secretory acini
Lactation
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Nerve stimulus – oxytocin – contraction of
myoepithelial cells – rejection of milk
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Prolactin – milk secretion
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Colostrum -první mléko
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Milk –
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Proteins – merocrine secretion
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Lipids -apocrine secretion
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Sugar (lactosa) production in GA
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Immunoglobulins (IgA) -plasma cells
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Decrease of prolactin level – apoptosis - regression
Mammary gland – arteries
Arcus aortae → a. subclavia → a. thoracica interna
Internal thoracic artery
aa. intercostales anteriores (I.-V./VI.) → rr. perforantes
Arcus aortae → a. subclavia → a. axillaris Axillary artery
→ a. thoracica superior
→ (r. pectoralis a. thoracoacromialis, a. thoracica lat., a.
subscapularis)
Aorta thoracica
aa. intercostales posteriores Intercostal arteries (II.V.) → rr. perforantes /II.
Mammary gland – veins
• Circular venous plexus Halleri – around
areaola
 v. axillaris
 v. internal thoracic
 vv. intercostal
Mammary gland - nerves
nn. intercostales IV.- VI.
 rami ant. + lat.
sensoric (T4) and sympathetic fibres
Mammary gland – lymph vessels
4 quadrants
Plexus subareolaris Sappeyi
• Contralateral breast and axilla
• Internal mammary lymph node chain
− nodi l. parasternales
− nodi. mediastinales ant.
− nodi epigastrici sup. + inf.
• Axillary lymph nodes
– Sorgius – The most cranial from nodi l.
pectorales,on 2./3. dens of m. serratus ant.
• nodi l. supraclaviculares
Carcinoma of mammary gland
The most frequent tumor in
females - 9% women suffer
from this illness
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Clinical signs – swelling -tumor,
skin pulling, ulcers
Examination – palpation,
sonography, mamography,
lymphatic nodes
• exstirpation
• mastectomy (parcial, total)
Carcinoma of mammary gland
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90% of carcinoma develop from ductal
epithelium, only 10% within lobular alveoloductal epithelium
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Ductal epithelium has estrogen receptors
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Paget carcinoma – in the nipple
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Intraductal– within lactiferous ducts
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Lobular carcinoma