Skin

From Iusmhistology

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==Skin==
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PFgvi4 Enjoyed every bit of your post. Great.
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*The skin is the heaviest, largest organ of the boyd.
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*Skin is involved in protection, temperature regulation, hydration, excretion, and production of hormones, cytokines, and growth hormones.
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===Describe the basic histological structure of the skin===
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*There are 2 + 1 layers to the skin: the epidermis, the dermis, and the hypodermis.
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**The '''epidermis originates from the ectoderm''' and is composed of epithelial cells.
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**The '''dermis originates from the mesoderm'''.
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**The hypodermis is not considered part of the skin proper and '''contains adipose tissue'''.
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http://www.lab.anhb.uwa.edu.au/mb140/corepages/integumentary/Images/skthick0021he.jpg
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http://apbrwww5.apsu.edu/thompsonj/Anatomy%20&%20Physiology/2010/2010%20Exam%20Reviews/Exam%202%20Review/epidermal_ridges1.gif
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===Identify the cell layers that constitute the epidermis===
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*The '''epidermis''' contains 4 layers in most locations and 5 layers on the hands and feet.
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**The epidermis of the hands and feet is called '''thick skin''' and is '''hairless''' and contains a '''fifth layer'''.
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**Also, the granulosa and corenum layers are thicker in "thick skin".
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*From deep to superficial, the 5 layers of thick skin are: basale, spinosum, granulosum, ''lucidum'', and corneum (BSGLC).
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*The epidermis is not vascularized so the cells must rely on diffusion of nutrients from deep to superficial.
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**Therefore, it makes sense that deeper cells are more alive and the shallower cells are more dead-like.
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**Cellular progression from deep to superficial is also why it makes sense to talk about the layers from deep to superficial.
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http://www.greenfoodsonline.co.nz/blog/wp-content/uploads/2009/07/epidermal-layers.jpg
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http://faculty.stcc.edu/AandP/AP/imagesAP1/skin/skin.jpg
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====Stratum basale====
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*The stratum basale is also called the stratum '''germinativum'''.
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*This base layer of epidermis is made of a single layer of '''mitotically active''' columnar or cuboidal cells.
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**Recall that many adult stem cells live on basement membranes.
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*The cells of the basal layer are connected to the basement membrane via '''hemidesmosomes'''.
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http://employee.lsc.edu/faculty/BrianBich/Picture%20Library/Anat-Phys%20I%20(Biol%201140)/Integument/Thick%20Skin%20-%20Tutorial/F%20-%20Thick%20Skin%2040X-3-Epidermal%20Layers.jpg
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====Stratum spinosa====
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*The '''spinosa''' appears as though there are a series of "spears" aligned within.
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*This spinous look results from several layers of of cells connected by desmosomes.
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http://www.mc.vanderbilt.edu/histology/labmanual2002/labsection2/Integumentarysystem03_files/image004.jpg
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https://lcsdanatomyphysiology.wikispaces.com/file/view/epidermis.png/194354678/epidermis.png
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http://lecannabiculteur.free.fr/SITES/UNIV%20W.AUSTRALIA/mb140/CorePages/Integumentary/Images/skn40he.jpg
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====Stratum granulosmum====
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*The stratum '''granulosum''' contains cells with '''granules''' which usually implies they have some specific role--and they do.
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*The granule-containing cells of the granulosum contain '''filaggrin, and intermediat filaments''' that help to form the '''tonofibrils''' along with '''keratin'''.
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**Note that these granules are called '''keratohyline granules'''.
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**Kertohyline granules have no membrane.
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*The cells of the granulosum are flattened polygonal cells--found in 3 to 5 layers.
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**Epidermal cells of the granulosum are generally '''basophilic'''.
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**Note that '''the granulosum is thickened in thick skin'''.
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*There is a second type of granule (called '''lamellar granules''') that contain lipids that are excreted into the connective tissue to provide a barrier to water-loss.
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**Just like "lamellae" in chloroblasts, lamellar granules have a sort of stacked-bags look
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**Labellar graunules cannot be seen in light microscopy.
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**http://www.bioone.org/na101/home/literatum/publisher/bioone/journals/content/bire/2000/00063363-63.6/biolreprod63.6.1706/production/images/small/i0006-3363-63-6-1706-f06.gif
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**http://biologiedelapeau.fr/IMG/jpg/lamellar-granules-3web.jpg
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http://bestofbothworldsaz.com/wp-content/uploads/2010/09/SkinLayers.jpg
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http://www.dermpedia.org/files/u49/Epidermolytic_hyperkeratosis_stp5.jpg
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http://www.virtualmedicalcentre.com/uploads/VMC/Anatomy/oral_mucosa_450.jpg
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http://www.anatomyatlases.org/MicroscopicAnatomy/Images/plate136.jpg
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====Stratum lucidum====
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*The stratum lucidum is '''only present in thick skin'''.
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*The stratum lucidum contains only a few layers of very flattened eosinophilic epidermal cells.
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**The lucidum (ironically) stains darkly.
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http://ouhsc.edu/histology/Glass%20slides/43_09.jpg
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====Stratum corneum====
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*The stratum corneum contains 15-20 layers of very thin, highly keratinized cells.
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**These cells are called '''squames'''.
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*Note that corneum means ''horny''; think of a rhinocerus's horn--it is keratinized skin.
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http://employee.lsc.edu/faculty/BrianBich/Picture%20Library/Anat-Phys%20I%20(Biol%201140)/Integument/Thick%20Skin%20-%20Tutorial/D%20-%20Thick%20Skin%2040X-1-Epidermal%20Layers.JPG
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====Dermo-epidermal junction====
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*Recall that the stratum basal is the deepest layer of the epidermis and that the dermis is deep to the epidermis.
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**Recall, too, that the epidermal cells of the basal layer are connected to the basement membrane via hemidesmosomes.
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*Recall that the dermis contains lots of connective tissue.
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**The dermis contains lots of '''type 4 collagen'''.
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*The superficial aspect of the dermis that is attached to the basement membrane of the epidermis is the '''lamina densa'''.
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*The lamina densa of the dermis and the basement membrane of the epidermis are connected via '''anchoring filaments''' and '''anchoring fibrils'''.
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**Note that '''anchoring filaments are composed of type 7 collagen'''.
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https://steinbachs.org/download/attachments/4686497/Fig18-3c.jpg
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===Describe the cellular components of the epidermis and their functions===
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*There are four major cells of the epidermis: keratinocytes, melanocytes, langerhan cells, and merkel cells.
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https://lh6.googleusercontent.com/_WdFQawAlzZM/TaRKusxrDOI/AAAAAAAAAu4/yid3LHxB7Pw/s800/epidermal_cells.jpg
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====Keratinocytes====
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*Keratinocytes are the most numerous cell of the epidermis and primarily serve a structural role.
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**Keratinocytes produce the protein keratin.
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*Keratinocteys also help produce the '''water barrier''' with their tight junctions.
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*Keratinocytes are found in all layers of the epidermis and take many shapes depending on their location.
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http://www.nanogen.org/en/images/nano-skincell-life.gif
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====Melanocytes====
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*Melanocytes reside in and near the '''stratum basale''' and have dendritic projections that weave through neighboring keratinocytes.
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*Melanocytes are '''derived from neural crest cells''' and function to generate the pigment melanin which protects cells from UV damage.
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*Melanocytes generate melanin and pass it to neighboring cells via '''cytocrine secretion''' upon MSH signaling.
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**Note that '''melanin is produced from tyrosine''' via tyrosinase in a specialized intracellular organelle called a '''melanosome'''.
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***Melanosomes are said to "mature" as they are produced; they turn from a light, circular shape to a dense cucumber shape.
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***'''Eumalanosomes''' (black) and '''phaeomelanosomes''' (red / brown) give color to bird and dinosaur feathers.
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**Albino organisms often lack tyrosinase and thus cannot generate melanin.
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http://faculty.une.edu/com/abell/histo/thickskin1w.jpg
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http://autoimmune.pathology.jhmi.edu/images/Skin2.jpg
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http://www.ccs.k12.in.us/chsBS/kons/kons/images/Skin_tws_16_02.jpg
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http://skinipedia.org/images/photos/melanocyte2.jpg
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http://www.lab.anhb.uwa.edu.au/mb140/corepages/integumentary/Images/labmi040he.jpg
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http://www.ratbehavior.org/images/MyosinTravelBig.jpg
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http://www.nature.com/nrm/journal/v8/n10/images/nrm2258-f4.jpg
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====Langerhans cells====
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*Langerhans cells are derived from bone marrow and thus it makes sense that they serve an immunological role.
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**Langerhans cells bind, process, and present antigens to T cells with their star shaped cell bodies.
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*Langerhans cells reside primarily in the '''spinosum''' layer (think "spines and chinese are for killing bad guys!''').
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http://www.technion.ac.il/~mdcourse/274203/slides/Skin/6-Langerhans%20Cells.jpg
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http://www.nature.com/nm/journal/v13/n3/images/nm0307-245-F2.gif
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====Merkel cells====
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*Merkel cells (like melanocytes) are found primarily in the basal layer, which makes sense because they are a sensation cell that needs to be near a nerve ending.
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**Note that '''Merkel cells are found primarily in thick skin''' where touch needs to be highly sensitive.
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*Merkel cells, along with the '''expanded terminal bulb''' of afferent, myelinated nerves, form the '''Merkel's corpuscle''' which detects touch as a '''mechanoreceptor'''.
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*The Merkel cells contain dense-cored '''neurotransmitter granules'''.
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http://neuromedia.neurobio.ucla.edu/campbell/skin/wp_images/cell%20types.jpg
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===Describe the structural organization of the dermis===
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*Recall that the dermis is a connective tissue layer (collagen 4) that connects the epidermis to the hypodermis.
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*The dermis has two layers (superficial to deep): papillary layers and reticular layer.
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====Papillary layer of the dermis====
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*The papillary layer is a delicate layer of connective tissue called ''papillary'' because of the papilla it forms as it protrudes up into the epidermis.
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**Connective tissue of the papillary layer is composed of '''type 1 collagen''', '''type 2 collagen''', and '''elastic fibers.
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**Recall that '''type 7 collagen binds the dermis to the basal lamina''' (the basement membrane) that separates the epidermis and dermis.
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**It is the papilla between the epidermis and papillary layer of the dermis that generate '''fingerprints (dermatoglyphics)'''.
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***When you think of fingerprints think of '''Mark Twain and Juan Vucetich'''.
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*The papillary layer '''contains nerves and vessels''' but they '''do not penetrate''' the epidermis.
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====Reticular layer of the dermis====
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*The reticular layer of the dermis is a sturdier connective tissue than the papillary layer and is '''less cellular'''.
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*The reticular layer is composed of '''type 1 collagen''' and '''regularly oriented elastic fibers (called Langer's lines)'''.
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*The reticular layer is always thicker than the papillary layer; though the thickness of the reticular layer can vary depending on the location.
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http://missinglink.ucsf.edu/lm/DermatologyGlossary/img/Dermatology%20Glossary/Glossary%20Histo%20Images/Papillary_vs_Reticular_Dermis_10x-208.jpg
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http://bestofbothworldsaz.com/wp-content/uploads/2010/09/SkinLayers.jpg
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http://www.biology-online.org/user_files/Image/Anatomy/AN-fibroblastF02.gif
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http://instruction.cvhs.okstate.edu/histology/HistologyReference/imagesco/dermis1.jpg
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http://www.bu.edu/histology/i/08203loa.jpg
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http://farm4.static.flickr.com/3412/3195805407_be3ba25e62_o.jpg
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===Identify other structures in the skin===
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====Vessels====
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*The vascular layout of the skin serves two functions: to provide nutrient and waste exchange and to regulate body temperature.
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*There are '''two plexuses of arteries''': between the two layers of the dermis (papillary and reticular) and between the dermis and hypodermis.
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*There are '''three plexuses of veins''': between the two layers of the dermis (papillary and reticular) and between the dermis and hypodermis (just like the arteries) and a '''third plexus in the middle of the dermis'''.
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**Recall that the reticular layer is thicker than the papillary layer so even though there is a vascular plexus between the two, there is also a veinous plexus deeper in the reticular layer.
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*'''Arteriovenous anastomoeses''' serve as the shunts that can be opened or closed for temperature reasons--cooling or conserving, respectively.
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http://www.netterimages.com/images/vpv/000/000/056/56826-0550x0475.jpg
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http://www.netterimages.com/images/vpv/000/000/056/56826-0550x0475.jpg
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====Sensory receptors====
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*There are four types of sensory receptors in the integumentary system (skin): free nerve endings, pacinian corpuscles, meissner's corpuscles, and ruffini's corpuscles.
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=====Free nerve endings=====
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*Free nerve endings are found in the '''stratum granulosum''' and detect '''fine touch, heat, and cold'''.
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*Free nerve endings are not surrounded by connective tissue or schwann cells.
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*http://library.thinkquest.org/05aug/00386/touch/freenerveendings.gif
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*http://webanatomy.net/histology/neural/free_nerves.jpg
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=====Pacinian corpuscles=====
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*Pacinian corpuscles are nerve endings surrounded by an oval encapsulation of connective tissue in the '''deeper dermis and hypodermis'''.
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*Pacinian corpuscles detect '''vibration'''.
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*Pacinian corpuscles are myelinated.
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*Think '''maraca shaped and all that vibration!'''
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*http://library.thinkquest.org/05aug/00386/touch/paciniancorpuscule.gif
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*http://www.siumed.edu/~dking2/intro/images/IN039b.jpg
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*http://kentsimmons.uwinnipeg.ca/cm1504/15lab42006/lb4pg9_files/image012.jpg
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*http://www.esg.montana.edu/esg/kla/ta/pacinian.jpg
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*http://download.videohelp.com/vitualis/med/pacinian_corpuscle.jpg
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*http://biology.clc.uc.edu/fankhauser/Labs/Anatomy_&_Physiology/A&P202/Special_Senses/Pacinian_corpuscles_PC271521lbd.JPG
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*http://www.sci.uidaho.edu/med532/images/receptor/pac_corp2.jpg
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=====Meissner's corpuscles=====
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*Meissner's corpuscles are found in the papillary layer of the dermis and are sensitive to '''low frequency stimuli'''.
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**Doesn't "meissner" sound like an old miser with a low, grumpy voice?
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*Meissner's corpuscles are shaped like tapered '''m'''itochondria and are oriented perpendicular to the skin.
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*http://library.thinkquest.org/05aug/00386/touch/meissnercorpuscule.gif
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*http://www.starsandseas.com/SAS_Images/SAS_Physiol_Images/SAS%20neuropics/Neurons_02.jpg
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*http://www.siumed.edu/~dking2/bluehist/BH011b.jpg
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*http://www.siumed.edu/~dking2/intro/images/IN038b.jpg
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*http://www.cytochemistry.net/microanatomy/nerve/nerve12.jpg
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*http://cmdi.medicine.dal.ca/Anat5217/Lab9/26LHMC.JPG
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*http://ouhsc.edu/histology/Glass%20slides/101_04.jpg
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*http://webanatomy.net/histology/neural/meissners.jpg
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*http://kcfac.kilgore.cc.tx.us/mobleypageap2/nerve%20tisues/Meissner%27s%20corpuscle%20400x%20fireworks.jpg
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=====Ruffini's corpuscles=====
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*Ruffini's corpuscles are simple mechanoreceptors and have an "elongated fusiform shape".
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*http://library.thinkquest.org/05aug/00386/touch/ruffiniending.gif
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=====Sensory receptor images=====
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http://www.neurobiography.info/teaching/images/somatosensory/cutaneous_receptors_hairy_vs_nonhairy_1.gif
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http://iupucbio2.iupui.edu/anatomy/images/Chapt18/FG18_03d-f.jpg
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http://alexandria.healthlibrary.ca/documents/notes/bom/unit_6/unit6.images/peripheral%20mech%20fig%201.jpg
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http://www.exploringnature.org/graphics/anatomy/sensory%20organs.jpg
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http://www.anatomyatlases.org/MicroscopicAnatomy/Images/Plate123.jpg
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http://www.karger.com/gazette/67/Elsner/images/skin.gif
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http://www.healthyheating.com/Thermal_Comfort_Working_Copy/Images/Nerve_endings_labeled.gif
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====Hair follicles====
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*The hair follicle is responsible for production of hair is a structure composed of epidermal and dermal structures and cell types.
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*Hair follicles originate from the invagination of epithelial cells downward to meet the papillary extension of dermal cells.
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*At the hair follicle a specialized layer called the '''glassy membrane''' (a type of basement membrane that is thickened and keratinized) separates the epidermis and the dermis.
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**Recall that a basement membrane separates the epidermis and dermis elsewhere, also, but that it is not keratinized.
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**Note that the glassy membrane is acellular, like all basement membrane.
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*During hair growth, the follicle has a bulbous end at the deepest part.
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**Vasculature that arises from the dermal layer up through the dermal papilla services the bulb of the hair follicle.
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**Surrounding the bulb (and originating from the epithelial layer) are melanoctyes which generate the melanin that dictates hair color.
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So, why is pubic hair always dark, even if head hair is light?  Do these melanocytes have more MSH receptors or some intracellular difference that generates a darker version of melanin?
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*There are two sections to the root sheath: inner and outer.
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**The inner root sheath runs from the bulb to the approximately the sabaceous gland.
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**The outer root sheath runs from the sabaceous gland to the surface of the skin.
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*Hair has three layers (from outside in): cuticle, cortex, and medulla.
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**The '''cuticle''' is the outer most and is comprised of '''squamous cells'''.
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**The '''cortex''' contains '''cuboidal cells''' that differentiate into '''keratinized cells'''.
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**The '''medulla''' contains large cells with '''vacuoles''' that are '''moderately keratinized'''.
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*Sebaceous glands are often associated with hair follicles and produce '''sebum''' as their secretion.
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**Sebum is released into the '''infundibulum''' which is a '''pilosebaceous canal''' that surrounds the base of the growing hair.
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**http://www.follicle.com/img/follicle.jpg
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http://elin.ttu.ee/mesel/Study/Subjects/0070BME/Content/BioElect/ProcPhen/7_kude_nahk_172-1x-Hair_follicle_labelled.jpg
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http://instruction.cvhs.okstate.edu/histology/HistologyReference/imagesco/hair4F.jpg
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http://education.vetmed.vt.edu/Curriculum/VM8054/Labs/Lab15/IMAGES/INTEGL16.jpg
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http://www.spencerclinic.co.uk/images/hair_pic2_large.jpg
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http://education.vetmed.vt.edu/Curriculum/VM8054/Labs/Lab15/IMAGES/DEEP%20HAIR%20FOLLICLE.jpg
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http://amakabeautycare.files.wordpress.com/2010/03/hair-follicle-2.gif
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http://www.raising-redheads.com/images/HairFollicleWikip.png
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http://www.nature.com/nbt/journal/v18/n1/images/nbt0100_20_F1.gif
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=====Phases of hair growth=====
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*There are three phases of hair growth: anagen, catagen, and telogen.
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**Anagen is active growth.
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**Catagen is apoptosis-driven involution
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**Telogen is the "resting phase" in which there is no more apoptosis but a new hair has yet to begin growing.
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*http://www.body-beauty-shop.com/images/hair-growth-cycle.jpg
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*https://lh6.googleusercontent.com/_WdFQawAlzZM/TaRf2b28PvI/AAAAAAAAAvI/mWnIfw18-Bg/s800/F1.large.jpg
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====Nails====
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*The nail (the nail plate) is a structure of '''specialized stratum corneum''' that has hard keratin that '''does not desquamate''' like the skin corneum layer.
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*The nail plate sit in the '''nail bed''' which is formed by the stratum basale and spinosum.
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**Recall that the layers of the skin are '''normally BSGLC''' and here we have corneum sitting on spinosum and basal--the granulosum is missing.
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*The nail bed is surrounded by the '''nail matrix''' which has a variety of cells: '''dividing cells that will cornify''' to become nail plate, '''melanocytes''', '''merkel cells''', '''langerhans cells''', and '''stem cells'''.
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**It makes sense that there are '''sensory cells in the nail matrix''' because sometimes you hit your nail plate just right and it hurts so bad!
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*The '''nail root''' is the '''proximal end of the nail plate''' to which cornified cells are added to generate nail growth.
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*The '''hyponichium''' is the point where the nail plate becomes free from the epidermis / nail bed.
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*The '''epinichium''' is the part of the epidermis that covers the proximal end of the nail plate.
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http://fungusfacts.com/wp-content/uploads/2009/10/nail-anatomy-diagram-cross-section.jpg
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http://eulep.pdn.cam.ac.uk/~skinbase/Annotated_anatomy_of_the_mouse_nail/nail_labelled.jpg
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http://classroom.sdmesa.edu/anatomy/Histologyphotos/Integument/Nail%201.jpg
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http://www.footdoc.ca/Websit1.jpg
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http://www.adiosnailfungus.com/images/anatomy_toenail.jpg
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====Glands====
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*There are two types of glands in the integument: sebaceous glands and sweat glands.
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**Sebaceous glands use an holocrine method of secretion; that is, they produce more and more of their secretion and then rupture their cell membrane and spill the contents of the lumen.
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-
**Sweat glands come in two forms: merocrine (eccrine) and apocrine.
+
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***Merocrine (eccrine) secretion is the dumping of vesiclular content.
+
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***Apocrine is the release of part of the cell by division of the cell membrane.
+
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+
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http://www.transtutors.com/Uploadfile/CMS_Images/21926_MODE-OF-SECRETION.JPG
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http://medicalsolutions.medi-health.info/pilsinl/348.gif
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+
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=====Sebaceous glands=====
+
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*Sebaceous glands use holocrine secretion: the release of the contents of the lumen.
+
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*Recall that sebaceous glands are often associated with hair follicles.
+
-
 
+
-
http://blog.dearbornschools.org/renkom/files/2010/12/sebaceous-gland.jpg
+
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+
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http://education.vetmed.vt.edu/Curriculum/VM8054/Labs/Lab4/IMAGES/SEBACEOUS%20GLAND%20LABELED%20copy.JPG
+
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+
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http://www.nku.edu/~dempseyd/sebaceous%20gland%202%20good.jpg
+
-
 
+
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http://www.pgbeautygroomingscience.com/assets/images/wosc/Chapter%201/Special%20Skin%202.jpg
+
-
 
+
-
http://www.lab.anhb.uwa.edu.au/mb140/corepages/integumentary/Images/sebaceous011he.jpg
+
-
 
+
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http://apbrwww5.apsu.edu/thompsonj/Anatomy%20&%20Physiology/2010/2010%20Exam%20Reviews/Exam%202%20Review/ceruminous_gland.gif
+
-
 
+
-
=====Sweat glands=====
+
-
*Sweat glands come in two forms: merocrine (eccrine) and apocrine.
+
-
 
+
-
{|border="1"
+
-
|-
+
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!Attribute
+
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!Merocrine
+
-
!Apocrine
+
-
|-
+
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|Secretion method
+
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|Merocrine
+
-
|Apocrine '''and merocrine'''
+
-
|-
+
-
|Distribution
+
-
|Widely distributed
+
-
|Axillary and perineal regions only
+
-
|-
+
-
|Lumen size
+
-
|Small lumen
+
-
|Large lumen
+
-
|-
+
-
|Epithelial type
+
-
|Stratified cuboidal
+
-
|Simple cuboidal
+
-
|-
+
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|Innervation
+
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|Cholinergic fibers (ach)
+
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|Adrenergic (cats)
+
-
|}
+
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+
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+
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*Merocrine (eccrine):
+
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**Recall that eccrine (merocrine) secretion is the dumping of vesiclular content.
+
-
**'''Merocrine sweat glands are widely distributed'''
+
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**http://2.bp.blogspot.com/_o-Hb5F-QYCA/Sg1vjbjJ_pI/AAAAAAAABEs/ObmtIy1juXY/s400/180X10merocrine_sweat_gland.jpg
+
-
**http://www.technion.ac.il/~mdcourse/274203/slides/Skin/8-Eccrine%20Sweat%20Gland.jpg
+
-
 
+
-
 
+
-
*Apocrine:
+
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**Recall that apocrine secretion is the release of part of the cell by division of the cell membrane.
+
-
**'''Apocrine sweat glands are found in the armpits (axilla) and genital (perineal) regions only.'''
+
-
**http://faculty.une.edu/com/abell/histo/apocrinesgw.jpg
+
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**http://instruction.cvhs.okstate.edu/histology/HistologyReference/imagesco/skinglands3F.jpg
+
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+
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+
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*Visual differentiation:
+
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**Lumen size: small = merocirne, large = apocrine
+
-
**Density: denser = merocrine, lighter = apocrine
+
-
**Surrounding cells: myoepithelial cells surround merocrine to help secrete, apocrine don't necessarily have surrounding cells.
+
-
 
+
-
===Understand the mechanism of skin repair===
+
-
*Repair of a wound to the epidermis / dermis requires proliferation at both layers and the contribution of clotting.
+
-
*Increased vascular flow at the site of wound contributes to formation of a clot known as a scab, made of fibrin, which generates an initial scaffold for epidermal and dermal cells to follow in remodeling the area.
+
-
*The dermis is responsible for cleaning up the damaged cartilage (via macrophages) and proliferating new fibroblasts to generate new connective tissue.
+
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*The epidermis contributes basal cells (recall that they are mitotically active) near the wound to migration and proliferation at the wound to generate new epithelial layers.
+
-
 
+
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+
-
*When the whole epidermis and dermis are damaged, cells from the base of the hair follicles and sabaceous glands can migrate and proliferate to regenerate the dermis and epidermis.
+
-
**Indeed, we can even '''generate iPSCs''' from these adult stem cells.
+
-
 
+
-
 
+
-
http://journals.cambridge.org/fulltext_content/ERM/ERM5_08/S1462399403005817sup005.gif
+
-
 
+
-
===Describe the histological findings in common skin diseases===
+
-
*We will look at the histology of three classes of integument ills: blistering, psoriasis, and skin cancer.
+
-
 
+
-
====Blistering====
+
-
*Blistering occurs because of intercellular connection loss or because of a loss of connection at the epidermis-dermis junction.
+
-
*Abnormalities at the '''epidermis-dermis junction''' are called '''bullous pemphigoid'''.
+
-
**http://www.dermpedia.org/files/images/Bullous_pemphigoid_3.jpg
+
-
*Abnormalities of intercellular junctions are called '''pemphigus'''.
+
-
**http://library.med.utah.edu/kw/derm/mml/24820016.jpg
+
-
 
+
-
====Psoraisis====
+
-
*Psoriasis occurs when cells of the basal and spinosum layers demonstrate '''excessive proliferation''' and decreased cycle time which leads to '''increased thickness'''.
+
-
*One can identify psoriasis by the presence of '''nuclei in the stratum corneum'''; this finding is called '''parakeratosis'''.
+
-
**Recall that cells of the stratum corneum do not usually have nuclei.
+
-
**Recall that we called the tongue epithelium '''perakeratinized''' because it had significant keratinization, differential staining, and yet the nuclei remained present.
+
-
 
+
-
http://www.drmihm.com/pictures/ACF1E7.jpg
+
-
 
+
-
http://www.webpathology.com/slides/slides/ExtGenitalia_Pagets1.jpg
+
-
 
+
-
http://dermatology.cdlib.org/126/unknown/eyelid/2.jpg
+
-
 
+
-
====Skin cancer====
+
-
*There are three major types of skin cancer, named for the origin of the tumor cells: basal cell carcinoma, squamous cell carcinoma, and malignant melanoma.
+
-
 
+
-
http://www.aafp.org/afp/2004/1015/afp20041015p1481-f1.gif
+
-
 
+
-
=====Basal cell carcinoma=====
+
-
*Note the excessive proliferation of the basal cells often drives them downward into the dermis.
+
-
 
+
-
http://skincancer-fact.com/wp-content/uploads/2009/10/Basal_cell_carcinoma_-skin_cancer-picture.jpg
+
-
 
+
-
http://www.orlandoskindoc.com/Basal-cell-carcinoma-large.jpg
+
-
 
+
-
http://www.trihealth.com/ser/cancer/images/Basal_cell_carcinoma.jpg
+
-
 
+
-
http://www.healthpm.com/wp-content/uploads/2010/09/basal_cell_carcinoma.jpg
+
-
 
+
-
http://missinglink.ucsf.edu/lm/DermatologyGlossary/img/Dermatology%20Glossary/Glossary%20Histo%20Images/basal_cell_carcinoma_high_power.jpg
+
-
 
+
-
=====Squamous cell carcinoma=====
+
-
*Note the aberrant growth in the stratum spinosum.
+
-
 
+
-
http://www.medicalook.com/diseases_images/squamous_cell_carcinoma.jpg
+
-
 
+
-
http://missinglink.ucsf.edu/lm/DermatologyGlossary/img/Dermatology%20Glossary/Glossary%20Histo%20Images/squamous_cell_carcinoma_in_situ_high_power.jpg
+
-
 
+
-
=====Malignant melanoma=====
+
-
*Note the excessive number of melanocytes.
+
-
*'''Mohs surgery''' first removes the visible melanoma and then uses microscopic examination of the tumor site and a precise map and excision technique to remove the '''roots of the cancer'''.
+
-
 
+
-
http://www.prlog.org/10263280-malignant-melanoma.jpg
+
-
 
+
-
http://sunsafekids.tripod.com/sitebuildercontent/sitebuilderpictures/melanomas.jpg
+
-
 
+
-
http://www.nature.com/modpathol/journal/v18/n8/images/3800395f1.jpg
+
-
 
+
-
http://rad.usuhs.mil/derm/lecture_notes/Images/melanoma_histo.jpg
+
-
 
+
-
====Griscelli syndrome====
+
-
*Griscelli syndrome is also called "silver baby syndrome".
+
-
*Griscelli syndrome can result from a defective Rab27a protein which is part of the transport complex that moves '''melanosomes''' along '''microtubules''' for cyotocrine passage to other cells.
+
-
*Patients with silver baby syndrome have '''hypopigmentation''' and also '''immunodeficiency'''.
+
-
 
+
-
 
+
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*stopped here on 04/06/11.
+

Revision as of 10:55, 26 October 2013

  • started here on 04/06/11.


PFgvi4 Enjoyed every bit of your post. Great.

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