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30 Cards in this Set
- Front
- Back
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what is cytology?
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the study of cell structure and activity
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what is histology?
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study of the microscopic structure of tissues and organs
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what is the cell theory?
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all animals and plants are composed of cells and cell products
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why are histology and cell ultrastructure important?
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once you know the structure, the function can be derived and vice versa. helps with pathology - the study of abnormal structure and function.
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what are the 3 different functions that proteins on the plasma membrane may have?
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act as receptor molecules
as ion channels as membrane pumps etc |
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what is the apical surface?
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portion of the cell exposed to the lumen
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what is the basolateral surface?
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the rest of the cell
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what are the 3 possible junctions between cells?
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tight junctions, adhering junctions and gap junctions
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what do tight junctions do?
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seal adjacent epithelial cells in a narrow band beneath their apical surface
prevent the movement of integral membrane proteins so the special functions of each surface can be preserved |
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how do materials get through tight junctions?
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diffusion or active transport
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what do adhering junctions do?
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provide strong mechanical attachments between cells
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what are adhering junctions built from?
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cadherins (transmembrane proteins) and catenins (proteins)
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what do gap junctions do?
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allow free passage of ions and small molecules between cells and so allow changes in membrane potential to pass from cell to cell
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what are gap junctions built of?
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they are cylinders made from 6 copies of connexins
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what are desmosomes?
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localised patches that hold 2 cells closely together. They are attached to intermediate filaments of keratin in the cytoplasm
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what is the space between the 2 membranes surrounding the nucleus called? what does it communicate with?
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perinuclear cisterna. communciates with lumen of RER.
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after staining a cell, a nucleus has dark speckles, is it active or not?
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not very active.
if nucleus is light, it is active (transcription) |
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what are the 3 things the nuclear membrane encloses?
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1. nucleoplasm
2. chromatin - clumps = heterochromatin or dispersed = euchromatin 3. nucleolus - region of RNA and ribosome formation |
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how does the nuclear contents communicae with the cytoplasm?
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through nuclear pores
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where does protein synthesis occur?
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ribosomes
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what are the main functions of smooth ER?
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steroid hormone synthesis, lipid metabolism and detoxification of drugs (especially in liver)
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what does the golgi apparatus do?
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modifies, sorts and packages macromolecules for secretion or delivery to other organelles
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what are the folds of the inner membrane of the mitochondria called? why are they important?
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cristae - provide sites for many of the biochemical enzyme systems like citric acid cycle and electron transfer system that produces ATP
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what happens within the inner membrane of mitochondria?
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nutrients oxidised to produce ATP and heat. The ATP then passes to the cytoplasmic matrix providing energy for other processes
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what are primary lysosomes?
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membrane-bound vesicles containing hydrolytic enzymes that are concerned with intracellular digestion
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how are secondary lysosomes formed?
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primary lysosome+phagosome
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what are peroxisomes?
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membrane-bounds vesicles containing oxidases and catalases
they may participate in fatty acid and amino acid oxidation |
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where are peroxisomes mostly abundant?
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in the liver - may be concerned with cholesterol metabolism
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what do peroxisomes have an important role in?
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synthesis of specialised phospholipids required for nerve cell myelination
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what are the 6 steps needed to do to examine a tissue under the microscope?
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1.sampling
2. fixation - stabilizes and preserves cell contents and protects against subsequent treatment 3. dehydration+embedding 4. section cutting 5. staining 6. examination |
