The integument The integument 1. 1. Skin and its main functions Skin and its main functions 2. 2. Structure of the skin: Structure of the skin: epidermis epidermis – – microscopic structure microscopic structure dermis dermis – – microscopic structure microscopic structure hypodermis (subcutaneous tissue) hypodermis (subcutaneous tissue) 3. 3. Appendages of the skin: Appendages of the skin: hairs and nails hairs and nails sebaceous and sweat glands sebaceous and sweat glands 4. 4. Mammary gland, mamma Mammary gland, mamma
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
The integumentThe integument1.1. Skin and its main functions Skin and its main functions 2.2. Structure of the skin:Structure of the skin:
3.3. Appendages of the skin:Appendages of the skin:�� hairs and nailshairs and nails�� sebaceous and sweat glandssebaceous and sweat glands
4.4. Mammary gland, mammaMammary gland, mamma
Prof. Dr. Nikolai LazarovProf. Dr. Nikolai Lazarov 2
Skin and skin functionsSkin and skin functions� the largest single organ of the body: ~16% (~4 kg) of the total body weight
�� majormajor rolerole –– a barrier between the organism and the environment:a barrier between the organism and the environment:
�� pprotectrotectionion of the body against pathogens and damage
� some other functionsother functions:� thermal insulation and heatheat regulationregulation
�� eexcretionxcretion by sweating � temperature regulation
�� ccontrol of evaporationontrol of evaporation and water resistanceand water resistance:�� prevents prevents excessive water loss and body dessication
�� sstorage and synthesistorage and synthesis::� storage center for lipids and water
� synthesis of vitamin D
�� absorptionabsorption –– oxygen, nitrogen and carbon dioxide, medicine
�� aaesthetics and communicationesthetics and communication
Human skinHuman skin
NB: NB: The adjective The adjective cutaneouscutaneous literally means literally means
““of the skin" (from Latin cutis, of the skin" (from Latin cutis, skinskin))
Prof. Dr. Nikolai LazarovProf. Dr. Nikolai Lazarov 3NB: NB: HumanHumanHumanHumanHumanHumanHumanHuman skin:skin:skin:skin:skin:skin:skin:skin: the most valuable 2 mthe most valuable 2 mthe most valuable 2 mthe most valuable 2 mthe most valuable 2 mthe most valuable 2 mthe most valuable 2 mthe most valuable 2 m22222222!!!!!!!!
Prof. Dr. Nikolai LazarovProf. Dr. Nikolai Lazarov 4
Structure of the skinStructure of the skin� two major layers major layers –– Gr. Gr. dermaderma, skin:, skin:
�� epidermisepidermis�� epithelial layerepithelial layer� derived from embryonic ectodermectoderm� generates skin appendagesskin appendages�� high capacity of regenerationhigh capacity of regeneration�� nonnon--vascular vascular but richly innervatedinnervated
�� hypodermishypodermis (subcutis)� loose irregular connective and fatty tissue, irregular connective and fatty tissue,
panniculus adiposuspanniculus adiposus
�� two skin typestwo skin types –– thickness of the epidermisthickness of the epidermis::�� thick (glabrous, hairless) skinthick (glabrous, hairless) skin
�� palms and soles palms and soles –– 1.5 mm1.5 mm�� thin (hairy) skin thin (hairy) skin –– 0.08 m0.08 mmm
�� elsewhere on the bodyelsewhere on the body�� thinnest on the eyelidsthinnest on the eyelids – 0.05 mm
Human skinHuman skin
Prof. Dr. Nikolai LazarovProf. Dr. Nikolai Lazarov 5
Prof. Dr. Nikolai LazarovProf. Dr. Nikolai Lazarov 6
DermatoglyphicsDermatoglyphics� dermatoglyphs are present on fingers, palms, toes, and soles� dermatoglyphic patterns give insight into a critical period of embryogenesis and
often relate to chromosomal abnormalities and genetic disorders
Gr. Gr. ddermaerma,, skin, skin, glyphglyph, , carvingcarving –– the scientific study of the scientific study of fingerprintsfingerprints
�� keratinocyteskeratinocytes –– 8585--95% of all epidermal cells95% of all epidermal cells�� keratinkeratin--producing cellsproducing cells
�� melanocytesmelanocytes�� neural crest cellsneural crest cells�� production and storage of melaninproduction and storage of melanin�� darkening of the skin (tanning)darkening of the skin (tanning)
�� Merkel cellsMerkel cells� present in the thick skinin the thick skin� "touch cells" � mechanoreceptorsmechanoreceptors�� APUD cellsAPUD cells �� neuroendocrine functionneuroendocrine function
Human skinHuman skin
Prof. Dr. Nikolai LazarovProf. Dr. Nikolai Lazarov 8
Epidermis Epidermis –– microscopic structuremicroscopic structure�� 5 layers of keratinocytes:5 layers of keratinocytes:
�� stratum basale (germinativum)stratum basale (germinativum)�� single layer of columnar cellssingle layer of columnar cells�� renewal of the epidermisrenewal of the epidermis
�� stratum spinosum stratum spinosum �� several layers of polygonal spiny cellsseveral layers of polygonal spiny cells
�� keratinization:keratinization:�� every 15every 15--30 days30 days�� due to mitotic activity of the malpighian layerdue to mitotic activity of the malpighian layer
Human skinHuman skin
NB: NB: Mnemonics Mnemonics Mnemonics Mnemonics Mnemonics Mnemonics Mnemonics Mnemonics for remembering the layers of the skinfor remembering the layers of the skinfor remembering the layers of the skinfor remembering the layers of the skinfor remembering the layers of the skinfor remembering the layers of the skinfor remembering the layers of the skinfor remembering the layers of the skin::::
"Cher Likes Getting Skin Botoxed" (from superficial to deep) "Cher Likes Getting Skin Botoxed" (from superficial to deep) "Cher Likes Getting Skin Botoxed" (from superficial to deep) "Cher Likes Getting Skin Botoxed" (from superficial to deep) "Cher Likes Getting Skin Botoxed" (from superficial to deep) "Cher Likes Getting Skin Botoxed" (from superficial to deep) "Cher Likes Getting Skin Botoxed" (from superficial to deep) "Cher Likes Getting Skin Botoxed" (from superficial to deep)
"Before Signing, Get Legal Counsel" (from deep to superficial)"Before Signing, Get Legal Counsel" (from deep to superficial)"Before Signing, Get Legal Counsel" (from deep to superficial)"Before Signing, Get Legal Counsel" (from deep to superficial)"Before Signing, Get Legal Counsel" (from deep to superficial)"Before Signing, Get Legal Counsel" (from deep to superficial)"Before Signing, Get Legal Counsel" (from deep to superficial)"Before Signing, Get Legal Counsel" (from deep to superficial)
Prof. Dr. Nikolai LazarovProf. Dr. Nikolai Lazarov 9
Dermis, coriumDermis, corium�� connective tissueconnective tissue –– though, flexible and elasticthough, flexible and elastic
�� variable thicknessvariable thickness –– max. 4 mm on the backmax. 4 mm on the back
�� two layers:two layers:�� papillary layerpapillary layer –– thin andthin and superficial:superficial:
�� sweat glands sweat glands – function:�� produce sweat to help keep the body coolproduce sweat to help keep the body cool�� secreted with strong odour (apocrine)secreted with strong odour (apocrine), ,
with a faint odour (eccrine)with a faint odour (eccrine)
�� arrector pilli muscle arrector pilli muscle – function:�� smooth muscle that pullsmooth muscle that pullss hairs straighthairs straight
Human skinHuman skin
Prof. Dr. Nikolai LazarovProf. Dr. Nikolai Lazarov 13
Hairs and their embryogenesisHairs and their embryogenesis�� Lat. Lat. pillipilli, Gr. , Gr. thryx, thrychosthryx, thrychos� elongated keratinized structures::
�� found everywhere with exception offound everywhere with exception of:� palms and soles� lips and eyelids � glans penis� glans clitoridis and labia minora
�� arise from an epidermal invagination, arise from an epidermal invagination, hair folliclehair follicle
�� single short duct:single short duct:�� in the upper portion of a hair folliclein the upper portion of a hair follicle
�� sebum sebum (Lat, (Lat, fatfat or or tallowtallow) ) – functions:�� complex mixture of lipids and waxes, complex mixture of lipids and waxes,
triglycerides, squalene and cholesteroltriglycerides, squalene and cholesterol�� natural lubricant ofnatural lubricant of the hairthe hair and skinand skin�� antibacterial and antifungal propertiesantibacterial and antifungal properties�� no importance in preventing water lossno importance in preventing water loss
Human skinHuman skin
Prof. Dr. Nikolai LazarovProf. Dr. Nikolai Lazarov 17
�� in in axillaeaxillae,, eyelids, eyelids, areola areola andand nipple, nipple, anal regionanal region, , embedded in the subcutaneous tissueembedded in the subcutaneous tissue
�� much larger (3much larger (3--5 mm in diameter)5 mm in diameter)� tubular with extensive coiled secretory portioncoiled secretory portion� cuboidal cells with secretory granules� straight ducts opened into hair folliclesducts opened into hair follicles� produce odorless viscous secretionodorless viscous secretion� innervated by adrenergic nerve endingsadrenergic nerve endings
�� structure:structure:�� matrixmatrix – the only living part of the nail�� eponychium (cuticle)eponychium (cuticle)�� paronychiumparonychium – the 'live' skin�� hyponychiumhyponychium�� nail platenail plate – layers of keratin�� nail badnail bad – pink colour of the nail�� lunulalunula – visible whitish crescent part of the matrix
�� nail foldnail fold – overlaps the base and sides of nails
�� nail groovenail groove – guide the direction of nail growth
Prof. Dr. Nikolai LazarovProf. Dr. Nikolai Lazarov 20
BreastBreast
Embryonic developmentEmbryonic development�� modified sudoriferous glandsmodified sudoriferous glands�� beginbegin – fourth week of gestationfourth week of gestation,
growth of a basic milk streakmilk streak
� formation of mmilk lines, ilk lines, "ventral epidermal ridges""ventral epidermal ridges" –sixth week of the embryo's "life"sixth week of the embryo's "life"
� persist of mammary ridges� polymastia (accessory breastsalong the milk line from axillae to groin)
polythelia (supernumerary nipple)
Prof. Dr. Nikolai LazarovProf. Dr. Nikolai Lazarov 21
BreastBreast
Embryonic developmentEmbryonic development�� modified sudoriferous glandsmodified sudoriferous glands�� beginbegin – fourth week of gestationfourth week of gestation,
growth of a basic milk streakmilk streak
� formation of mmilk lines, ilk lines, "ventral epidermal ridges""ventral epidermal ridges" –sixth week of the embryo's "life"sixth week of the embryo's "life"
� persist of mammary ridges� polymastia (accessory breastsalong the milk line from axillae to groin)
polythelia (supernumerary nipple)
Prof. Dr. Nikolai LazarovProf. Dr. Nikolai Lazarov 22
BreastBreast
Embryonic developmentEmbryonic development
Artemis of EphesusArtemis of Ephesus
with tier upon tier of breasts to highlight with tier upon tier of breasts to highlight her ability to nurtureher ability to nurture
�� modified sudoriferous glandsmodified sudoriferous glands�� beginbegin – fourth week of gestationfourth week of gestation,
growth of a basic milk streakmilk streak
� formation of mmilk lines, ilk lines, "ventral epidermal ridges""ventral epidermal ridges" –sixth week of the embryo's "life"sixth week of the embryo's "life"
GynecomastiaGr. γυνή gyne, "woman" and µαστός mastos, "breast"
Breast cancerPaget's disease Paget's disease (morbus Paget)(morbus Paget) – a special type of ductal carcinoma
Mammography
Prof. Dr. Nikolai LazarovProf. Dr. Nikolai Lazarov 30
� sympathetic fiberssympathetic fibers � along the blood vessels� sensory fiberssensory fibers � rami glandulares of rami perforantes of the intercostal nerves