Karteikarten
MICROSCOPY-LAB
Karten in diesem Stapel (25)
- 1SMALL INTESTINEThe small intestine is part of the digestive system. At first glance it looks like a tube of a couple of centimeters in diameter that is connected to the stomach. It is surrounded by two layers of smooth muscles that contract in a wavelike pattern.
- 2CELL JUNCTIONSThe intestinal lining consists of a single columnar epithelium. The palisade-like cells are tightly connected with cell junctions.
- 3DESMOSOMESThey are protein complexes that connect the keratin fibers of two epithelial cells like a hook-and-loop fastener.
- 4TIGHT JUNCTIONSThe lateral (outer) side of the epithelium is sealed by a network of tight junctions. These sealing strands connect the plasma membrane of two neighboring cells forming a virtually impermeable barrier to fluid.
- 5ADHERENS JUNCTIONSThe tight junctions are supported by the adherens junctions, which are located a bit more basally (inside). Adherens junctions are anchor-like protein complexes similar to desmosomes, but they are connected with the actin cytoskeleton
- 6MICROVILLImicroscopic cell extensions on the lateral side of epithelial cells.
- 7GLYCOCALIXIn addition, the surface of the microvilli is covered with the glycocalix. These tree-like glycoprotein structures increase the active surface even more by anchoring digestive enzymes and binding substances for uptake.
- 8CELLS ENTEROCYTESThe most abundant cells are enterocytes, which are also called intestinal absorptive cells, because their apical membrane and glycocalix is packed with digestive enzymes and transporters.
- 9BRUSH CELLSThe brush cells are another type of epithelial cells with microvilli on the apical side. Although brush cells have longer microvilli, they have a thinner glycocalix than enterocytes.
- 10GLOBET CELLSGoblet cells are easily distinguished from the other two types. Goblet cells produce and secrete mucus into the lumen of the small intestine.
- 11VILLIThe villi are kept in shape by the lamina propria; a loose web of connective tissue. It mainly consists of extracellular macromolecules, such as proteoglycan, polysaccharides, and collagen.
- 12MICROSCOPYScientists use microscopes (micro- = “small”; -scope = “to look at”) to study structures that are too small to see with the naked eye, like most cells. A microscope is an instrument that magnifies an object.
- 13LIGHT MICROSCOPYLight microscopy is the most commonly used microscopy technique. It often requires staining of the specimen to be able to visualize the structures of interest.
- 14MINIMAL RESOLUTIONThe minimal resolution is defined as the distance between two points that are still distinguishable as two separate entities.
- 15FLORENSCENCE MICROSCOPYtake advantage of the difference in emission and transmission wavelengths of fluorophores to produce high contrast images. There are several fluorescent dyes that can freely diffuse into a living cell.
- 16IMMERSION OILWithout the immersion oil, the light is refracted when it moves from glass to air and back into the glass of the objective lens. If you use immersion oil with the same optical density as glass, this effect can be diminished and the minimal resolution can be achieved.
- 17ELECTRON MICROSCOPYElectrons have wavelike properties. Due to their high energy, electrons have a very short wavelength. This translates into much higher resolutions than what would be possible with light microscopes.
- 18TYPES OF ELECTRON MICRSCOPESTransmission Electron Microscopes (TEM) use a high voltage electron beam to produce an image, and the electrons that pass through the sample are detected.
Scanning Electron Microscopes (SEM) produce an image by probing the surface of a specimen.
Reflection electron microscopes (REM) use an electron beam that is pointed at a thin specimen to detect the scattered electrons that are reflected by the specimen. - 19STAINING TECHNIQUESMost cells are almost transparent and it is very hard to distinguish any structures. To better visualize cells and their specific components you can use chemicals that stain certain structures.
- 20DEHYDRATIONReplacing the water within the sample with some other chemical
- 21PERMIABILIZATIONdissolving cell membranes to allow lager dyes to penetrate the inside of the cell
- 22FIXATIONinvloves several techniques, such as creating chemical bonds between proteins to increase their rigidity.
- 23MOUNTINGattaching samples to the microscopy slide.
- 24MORDANT APPLICATIONa substance that forms a strong complex with the dye and the tissue
- 25FLORESCENT DYESFluorescent dyes are fluorophores that bind to specific cellular structures.
The following fluorophores are frequently used as fluorescent dyes:
DAPI
CY3 and CY5
Rhodamine
Fluorescein isothiocyanate (FITC)
Informationen
- Beschreibung
- Tercero Inglés Karteikarten am MICROSCOPY-LAB, erstellt von Samantha Olvera am 29/09/2023.
- Erstellt von
- Samantha Olvera
- Aufrufe
- 52
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