Karteikarten
Skin
Karten in diesem Stapel (15)
- 116% of body weight Composed of epithelial layer (epidermis) sitting on connective tissue (dermis)Thick skin - cornified, lacks hair
Thin - normally has hair
e.g. body skin: sparse, fine hairs (vellus)
scalp: numerous, packed, coarse (terminal) - 2EpidermisStratified squamous keratinising epithelium
Resistant
Keratinocytes
Organised into visible layers - 3Layers of EpidermisBasal layer - cuboidal/columnar, site of cell division
Prickle - numerous spot desmosomes, mechanical junctions, cells enlarged accumulate keratin
Granular - cells flatten, keratohyaline granules, keratin becomes embedded
Cornified - squamous, keratins have S-S bridges, resistant, cells die, loose nuclei, dehydrated, programmed cell death - 4As cells ascend through prickle cell layer...Membrane coating granules appear (lamellar bodies)
Stacks of concentric phospholipid lamellae
Released from cells into intracellular space
Fuse together to form multiple lipid bilayers arranged in sheets between cells
Seals gaps, water tight barrier - 5MelaninUV protection
Produced by melanocytes (pale cytoplasm)
Melanin made from tyrosine in melanosomes, bud off and are endocytose by keratinocytes
Hyper pigmented skin - epidermal cells arrange melanin in cap over nucleus
Vitiligo - autoimmune destruction of melanocytes - 6Langerhans cellsIn upper prickle cell layer, pale, macrophage-like, make skin grafting difficult
- 7Merkel cellsExpress different keratins to keratinocytes, associated with nerve endings
- 8DermisDense, irregular, consists of papillary and reticular layers, conveys blood vessels/lymphatics/nerves.
Consists of parallel bundles of collagen fibres, lines of cleavage
Pacinian corpuscle - deep, coarse touch
Meissner's corpuscle - superficial, light touch - 9HypodermisLoose connective tissue
Abundant fat cells
Allow skin motility
Fibrous collagen bands, anchor dermis to deep fascia - 10Sweat GlandsFor thermoregualtion
Down growth from epidermis
Innervated by sympathetic
Secretory portion - highly coiled, dermis/hypodermis juntion, single layer cuboidal cells, secrete isotonic solution
Excretory duct - double layer of cuboidal cells, absorbs NaCl to produce hypotonic sweat - 11Sebaceous GlandsDischarge into middle portion of hair follicles
Secrete sebum (lipid rich, maintains skin suppleness) by holocrine secretion - 12Apocrine sweat glandsIn axial and genital regions, discharge into hair follicles
- 13Arector pili musclesBundle of smooth tissue, inserts into connective tissue sheath around hair follicle and into papillary layer of dermis
- 14HairsKeratinocytes
Concentric circles - 15Hair papillaSpecialised aggregation of CT cels, inductive role in directing hair formation, forms only in development
Informationen
- Beschreibung
- Karteikarten am Skin, erstellt von maryamnc am 04/01/2015.
- Erstellt von
- maryamnc
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