Histology of Integument System II: Skin Appendages PDF

Histology of integument system II Skin appendages Netter’s Essential Histology, 3nd Edition pp 274-281 1 1  Objectives Compare and...

Histology of integument system II Skin appendages Netter’s Essential Histology, 3nd Edition pp 274-281 1 1  Objectives Compare and contrast the morphology and function of various skin appendages Ø Sweat glands Ø Sebaceous glands Ø Hair follicles Describe the histology of nails 2 2  Sweat glands Two types of sweat glands distinguished by their secretory mechanism Ø Eccrine: Do NOT lose cytoplasm in their secretions Ø Apocrine: Release some of their cytoplasm in their secretions Types of secretion http://medsci.indiana.edu/a464/docs/struct8.htm 3 3 Sweat glands Eccrine sweat glands Found in majority of the body except parts of external genitalia Most numerous in palms and soles Tubular with secretory and excretory portions Secretory coil is in deep dermis or subcutis, has secretory (clear and dark cells) and myoepithelial cells Excretory portion has dermal (straight) and intraepidermal (spiral, also called acrosyringium) portions Regulating body temperature http://www.lab.anhb.uwa.edu.au/mb140/corepages/integumentary/integum.htm#sweat 4 4 Sweat glands Eccrine sweat glands 5 5 Sweat glands Eccrine sweat glands https://www.ouhsc.edu/histology/Text%20Sections/Integument.html 6 6 Sweat glands Eccrine sweat glands Usually smaller lumen with smooth surface http://faculty.une.edu/com/abell/histo/histolab3g.htm 7 https://www.ouhsc.edu/histology/Text%20Sections/Integument.html 7 Sweat glands Apocrine sweat glands Concentrated in axilla, groin and perineum; also in face, external auditory meatus, eyelid and areola. Have secretory and excretory components The secretory portion has an outer discontinous layer of myoepithelial cells and an inner layer of cuboidal to columnar eosinophilic secretory cells Decapitation secretion is conspicuous Secretory cells have abundant eosinophilic cytoplasm with lipid, iron or lipofuscin 8 8 Sweat glands Apocrine sweat glands Secretory cells with bleb Myoepithelial cells at basal layer http://medcell.med.yale.edu/histology/skin_lab/apocrine_sweat_glands.php 9 9 Sweat glands Myoepithelial cells Smooth muscle like cells with epithelial origin Contract to aid in ejection of secretions Participating in organization of gland development 10 Breast Cancer Res. 2005; 7(5): 190–197 10 Sweat glands Eccrine vs apocrine sweat glands Apocrine Eccrine Distribution Axilla, groin, perineum Majority of the skin Lumen Large Small Secretory cells Eosinophilic cytoplasm Dark and clear cells, no blebs Myoepithelium Discontineous Contineous Drainage Into hair follicle Skin surface Function Unclear Temperature regulation 11 http://health.howstuffworks.com/wellness/hygiene-tips/body-odor1.htm 11 Sweat glands Cystic fibrosis Autosomal recessive disorder of exocrine gland function Most common lethal inherited disease in Caucasians Defects in the cystic fibrosis gene that encoding cystic fibrosis transmembrane conductance regulator (CFTR) Characterized by abnormal transport of chloride and sodium across an epithelium, leading to thick, viscous secretions CF patients with higher level of sweat chloride (Sweat chloride test) Involves multiple organ systems but chiefly results in chronic respiratory infections, pancreatic enzyme insufficiency, and associated complications 12 http://emedicine.medscape.com/article/1001602-overview 12  Pilosebaceous unit Hair and hair follicle Sebaceous gland Arrector pili muscle http://www.dartmouth.edu/~anatomy/Histo/lab_4/skin/DMS193/popup.html 13 13  Pilosebaceous unit Hair Columns of dead keratinized cells Derived from epidermis Shaft and root Three layers Ø Medulla: Shrunken, soft keratinized cuboidal cells Ø Cortex: Parallel twisted fiber, keratinized squamous cells containing pigment Ø Curticle: Overlapping scales of hard keratin https://www.researchgate.net/publication/235646318_Feather_keratin_hydrolysates_obtained_from_microbial_keratinases_Effect_on_hair_fiber 14 14  Pilosebaceous unit Hair follicle Contains protected epithelial stem cells Matrix: Mitotically active pleuripotential keratinocytes, give rise to hair shaft and inner root sheath Hair forming process Ø Anagen or growing phase Ø Catagen/involuting phase Ø Telogen/resting phase http://www.lab.anhb.uwa.edu.au/mb140/corepages/integumentary/integum.htm 15 15 Pilosebaceous unit Hair follicle http://www.dermweb.com/hairnailsmucousmembranes/diagram3page.htm 16 16  Pilosebaceous unit Hair follicle http://intranet.tdmu.edu.ua/data/kafedra/theacher/infections/shkilna_mi/English/Recommendations%20for%20preparing%20practical%20classes/ Lesson1.%20Anatomy,%20histology%20of%20the%20skin.%20Skin%20lesions.%20Features%20of%20clinical%20motion%20of%20scabies,%20pedi 17 culosis,%20demodecosis..htm 17 Pilosebaceous unit Hair follicle http://slideplayer.com/slide/3439128/ 18 18  Dermal papilla: Connective tissue with vessels to support growing epithelium 19 http://medcell.med.yale.edu/histology/skin_lab/hair_follicle.php 19 Pilosebaceous unit Root sheath External: Continuous with the epithelium Internal: Three layers, Henle's, Huxley's, and a cuticle https://www.ouhsc.edu/histology/Glass%20slides/44_10.jpg 20 https://www.ouhsc.edu/histology/Glass%20slides/44_11.jpg 20 Pilosebaceous unit http://slideplayer.com/slide/6339088/ 21 21 Pilosebaceous unit Alopecia areata Recurrent non-scarring type of hair loss May affect any hair-bearing area and can manifest in many different patterns Unclear pathogenesis but probably T-cell-mediated autoimmune disorder Impaired hair growth at anagen phase http://emedicine.medscape.com/article/1069931-overview 22 22 Pilosebaceous unit Sebaceous glands Lobulated holocrine glands with lateral protrusion from the outer root sheath of hair follicles Number correlates with the number of follicles Outer germinative cells differentiate, move inward and accumulate intracytoplasmic lipid droplets Secreted sebum drained into infundibulum of hair follicle http://www.dartmouth.edu/~anatomy/Histo/lab_4/skin/DMS193/popup.html 23 23 Pilosebaceous unit Sebaceous glands http://www.lab.anhb.uwa.edu.au/mb140/corepages/integumentary/integum.htm 24 24 Pilosebaceous unit Sebaceous glands Sebocyte filled with lipid and lysosomes Lysosomal enzymes induce autolysis and holocrine secretion Secretion contains a mixture of lipids containing triglycerides, wax esters, squalene, cholesterol esters, and cholesterol Substantial amount of sebum may lead to development of acne https://www.derm101.com/inflammatory/embryologic-histologic-and-anatomic-aspects/sebaceous-units/ 25 25 Pilosebaceous unit Arrector pili muscle A band smooth muscle of mesoderm origin Connect fibrils of the dermis and hair follicle Elevate hair in response of stimuli, such as fear or anger due to adrenaline surge, or cold http://histologylab.ccnmtl.columbia.edu/lab10/skin_slides.html 26 26  Nail Plate of hard keratin at distal ends Grow out from nail bed, modified stratum corneum Composed of a free edge, nail body, and the nail root Made up of tightly packed, hard, keratinized squamous cells http://classroom.sdmesa.edu/anatomy/Histologyphotos/Integument/Nail%201.jpg 27 27  Nail Nail root: Embedded in nail grooves, proliferating cells forming nail matrix Nail bed: Tissue under nail plate, consists of stratum germinativum and underlying dense dermis firmly attached to periosteum of terminal phalanges Eponychium: Projecting crescentic fold of stratum corneum at the proximal end, overlying nail plate Hyponychium: Thickened region of stratum corneum that secures the nail to the finger tip, and lies below the nail plate Lunula: White crescent at the proximal end, thicker underlying epithelium 28 28  Nail http://www.easynailart.co.uk/the-anatomy-of-the-natural-nail/ 29 29  Nail Layers of tightly packed keratinized squames of nail body http://www.iupui.edu/~anatd502/Labs.f04/integument%20lab/m7.10x.i4.jpg 30 30  Onychomycosis Spread of fungi to nail apparatus Often multiple fungal species Common in patients with diabetes; associated with NOT washing feet daily Present with pain, discomfort, and disfigurement 31 http://www.meddean.luc.edu/lumen/meded/medicine/pulmonar/pd/Images/onychomycosis.JPG 31  Onychomycosis Special stain reveal fungal hyphae in nail 32 http://www.dermpedia.org/node/23058 32  What are these structures Sebaceous glands: Pale cells forming an almost solid nest Hair follicle: Epidermal cells surrounding hair shaft 33 33  What are these cells Melanocyte: Cell at basal layer, condensed nuclear chromatin, pericellular halo Keratinocytes: Eosinophilic cytoplasm, intercellular bridges 34 34  What are these structures Sebaceous glands: Pale cells forming an almost solid nest Hair follicle: Epidermal cells surrounding hair shaft Hair shaft: Keratin column at the center of hair follicle, usually not stained 35 35  What are these structures Sebaceous glands: Pale cells forming an almost solid nest Hair follicle: Epidermal cells surrounding hair shaft Eccrine sweat gland: Relatively small lumen with smooth surface 36 36  What are these structures Dermal papilla: Bud of connective tissue at follicular bulb Matrix: Epidermal cells surrounding dermal papillae 37 37  What are these structures Sebaceous glands: Pale cells forming an almost solid nest Hair follicle: Epidermal cells surrounding hair shaft Hair shaft: Keratin column at the center of hair follicle, usually not stained 38 38  This skin is most likely from which part of the body Scalp/face: Quantity of pilosebaceous unit, relatively thin dermis 39 39