8/19 Epithelial Cells Flashcards
(154 cards)
Explain the mechanisms underlying epithelial functions of protection, absorption, and secretion. I.E. how is it like an international border?
Protection: Mechanical barrier due to junctions, mucus and cilia in some cases to expel foriegn particles, and defensins (small cationic atibiotic peptides) and antibody transport. in some case as well Absorption/Secretion: Through pumps such as the N,K-ATPase, or through carrier or channels (co-transport, passive etc.) through gap junctions to adjoining cells,
Describe the fundamentals of tissue maintenance by stem cells.
cells turnover, in days to months and progenitor cells (stem cells) divide to replace them, Mitosis occurs on basal layer (touching the basal lamina) so stem cells are there. They recieve signals from cytokines (influence rate of development) etc. Transient amplifying cells or the proliferating progenitors of the stem cells divide rapidlyto move in and fill the epithelial as it is lost.
identify the 9 types of epithelia
- Simple Low – single layer of squished cells 2. Simple Cuboidal – single layer of round cells 3. Simple Columnar – single layer of tall cells 4. Statified Squamous – multi-layer with squished on top 5.Stratified Cuboidal – multi-layer round cells 6. Stratified Columnar – multi-layer tall cells 7. Urothelium – domed at the top with multi-nucleated 8. Pseudostratified Columnar – look multilayer, but tall and not multi-layer 9.Ciliated/non; Karatinized/non; Stereociliated/non; microvilli/non (brush border)
Describe the classification, of connective tissue proper
Loose conective tissue (lots of cells and ground substances and less connective tissue, just below basil lamina); Dense connective tissue (less cell bodies many collagen fibers, and below the loose connective tissue); Adipose tissue (recognizable from the large clear circles of lipids
list and describe the sources and properties of the resident and transient connective tissue cells
Resident: Fibroblasts (make ECM), Macrophages (immune responce and stimulate ECM createion), Mast Cells (immune and allergic response), Adipocytes (energy and hormones/cytokines) Transient: Plasma cells (Activated B Lymphocytes; they have a clockface or wheel and spoke nucleus lots of gogi and ER); Lymphocyte(
describe the components, properties of the extracellular matrix: ground substance and extracellular fibers
Components: Fibers and Ground Substance
Properties:
Fibers: 3 main types: Collagen (collagen I), Reticular (collagen III), Elastic
Collagen: Very abundent, 20 types and 4 catagories: figril forming (I,II,III), gibril associated, and two found in the basal lamina: anchoring fibrils (VII) and network forming (IV).
reticular Small, non-bundling, not as supportive, loose connective tissue!
Elastic Fiber: Straight fibers composed of randomly coiled molecules; elastin surrounded by fibrillin
Ground Substance: Viscous transparent filled with glycoprotiens, proteoglycans, tissue fluid; store electrolytes and water, resist compression, and form viscous barrier, and attachment amd movement of cells in ECM.
made of GAGs and connected togeterh to form a proteoglycan: looks like pipe cleaner, highly necative charge, and very hydrated/viscous
describe the basics of wound healing
Epidermal stem cells at the periphery provide source of new epithelium, and the epitheilial cells express integrins and laminins to coat the fibers in the wound bed and cause migration of cells (Create own road to travel across the wound bed)
Thin wound:
- Inflammation (24 hours): neutrophils in the space, clot forms due to platelets
- Proliferation (3-7 days): myogibroblasts appear (new epithelial cells start to form, granulatied tissue, macrophages, fibroblasts, new blood capillaries)
- Maturation: Fibrous union and normal tissue
Larger wound with scar: also have contraction take place
Describe the nature of granulation tissue
Wound granulation is an important stage in healing, where an injury fills with a matrix of fibrous connective tissue and blood vessels. This creates a framework for other cell types to grow, filling in the wound and restoring function
Describe the consequences of fibrosis rather than normal healing
this is due to persistant tissue damage, like cirrrhosis, chronic inflamatory diseases etc.) This will result in diminished function and permanent change in the composition of the tissue. Can impede blood flow and cell function!
Define Adenocarcinoma
malignant tumor formed from the glanular structures in the epithelial
define apical and basal
The top and bottom layer of the epithelial cell layer
Define barrier epithelia
epithelia that are facing the outside world: skin, trachia, esophagus, intestines etc. characterized by a need to provide a tight physical barrier.
Define basal lamina
the electron microscophy term for the basement membrane
Define basement membrane
the layer just under the epithelium: containing mixture of proteins including laminin and type IV collagen and glycosominoglycans.
Define brush border
the thin cilia lining the simple colomnar cells of the interstinal tract.
Define carcinoma
a cancer arising from the epithelial tissue
Define CFTR
CFTR is an ABC transporter-class ion channel that codes for a protein that conducts chloride[3] and thiocyanate[4] ions across epithelial cell membranes. Mutations of the CFTR gene affecting chloride ion channel function lead to dysregulation of epithelial fluid transport in the lung, pancreas and other organs, resulting in cystic fibrosis.
Define cilia
Long, motile, apical membrane projections (move mucus)(move the ovum)
Define connexons
one of six proteins that form a gap junction
define defensins
Small cationic protiens that have antibiotic properties
Define desmosome/macula adherens
a linkage between epithelial cells: made of keratin filaments into the cell and cadherins linking the cell like velcro.
Define dysplasia
the disease (often cancer realted) related change in the tissue of an adult
define endo / exo / and transcytosis
transport into out of and through out a cell.
define endothelium
Cells lining blood vessels etc. a lining to the inside of the body not the outside.