+380.000 andere samenvattingen
Een unieke studietool
Een oefentool voor deze samenvatting
Studiecoaching met filmpjes
Onthoud sneller, leer beter. Wetenschappelijk bewezen.
Samenvatting - Junqueira's basic histology : text and atlas.
1 Epithelial Tissue
membrane associated sturcture.
Form a seal that prevents the flow of materials between epithelial cells in either directions. Helps to form two functional compartiments: apical&basal. Prevent the integral membrane proteins to travel from abpical to basolateral and vice versa.
Uit welke 4 weefsels bestaat het menselijk lichaam?
epitheel, bind, spier, zenuw
desmosome /macula adherensMembrane associated structure, specialized in adhesion. A single- spot weld, does not form a belt around the cell.Form very strong attachment points which supplement the role of the zonulea adherens ans play a major role to maintain the integrity of an epithelium.
gap junctionscommunication.Serve as inter cellular channels for flow of molecules. Allow cells in many tissues to act in a coordinated manner rather then as independent unit. In the heart muscle abundant gap junctions greatly responsible for the heart's coordinated beat.
- most epithelia rest on connective tissue. In case of epithelia lining the cavity of internal organs, this layer of connective tissue is often called lamina propria. It supports epithelium, but also provides nutrition and binds it to underlying structures.
All epithelial cells in contact with subjacent connective tissue have at their basal surfaces a felt-like sheet of extracellular material called basal lamina.
Basal laminae are attached to reticular fibers made of type III Collagen in the underling connective tissues by anchoring fibrils of type IV Collagen. These proteins are produced by cells of connective tissue and form a layer below basal lamina, called reticular lamina.
Functions of basal laminae
- able to influence cell polarity
- regulate cell proliferation and differentiation by binding and concentration growth factors.
- influence cell survival and metabolism
- organize the proteins the the adjacent plasma membrane ( affecting signal transduction)
- and serve as pathways for cell migration
basement membraneformed by combination of basal lamina and a reticular lamina.
Nucleair form corresponds roughly to the shape of the cell.
Epithelia kuneen ingedeeld worden in : covering(lining) & glandular.
one layer of cells;
squamous(thin), cuboidal(as thick as wide),columnar( taller then wide)
more than one layer;
squamous ker.( epidermis) squamous non-ker. (mouth, laynx, vagina, anal canal), cuboidal ( sweat glands, transitional( bladder, renal calyces), columnar ( conjuctiva)
types of secretion: merocrine, holocrine, apocrine
produce proteins by means of exocytosis at the apical end of secetory cells. Most exocrine glands are merocrine
holocrine secretionby e desintergation of the secretory cells themselves after they complete differentiation which involves becoming filled with product
apocrine secretionloss of large membrane enclosed portion of apical cytoplasm, containing one or more lipid droplets. Im mamary glands together with merocrin secretion.
serous or mucous glandular cellsCategories of exocrine merocrine glands. Based on the nature of the protein secreted &staining properties of the secetory cells
serousstain intensivley with basophilic&acidophilic stain. The acinair cells of the pancreas, parotid salivary glands = examples of serous type that secrete digestive enzymes. Cells are filled with secretory granules in different stages of maturation.
mucousgoblet cells. Secretory granules contain strongly hydrophilic glycoproteins mucins. When they are released from the cell, they hydrate and become mucus, vicious elastic protective material. Stain not intensly acidophilic.
exocrine glandsretain connection with the surface epithelium; in the form of tubular ducts through which the secretion pass to the surface.Saliva glands, sweat glands, mamary gland,pancreas, blie(liver)
endocrine glandsdont have a connection with surface epitheluim.Ductless. Their secretions are picked up and transported by bloodstream.hypofise, hypothalamus, thymus, thyroid gland,bijnieren/kidney
Laatst toegevoegde flashcards
buitenste laag en beschermt het lichaam tegen hitte en mechanische invallen
allen te vinden in dicke huid
cellen hebben geen kern of organellen meer
dunne laag van keratinocyten
Bind de huid aan de basal lamina en vormt nieuw epitheelcellen