Foundation and Tools in Cytology Flashcards
What is the origin of the word “Cytology”?
Comes from the Greek “Kytos” meaning hollow vessel, and “logos” meaning study
Who is considered the father of cytology?
Robert Hooke, who first described cells in 1665 using a microscope
What major discovery did Theordor Schwann and Matthias Schleiden contribute?
The Cell Theory, stating that all living organisms are made of cells, and cells are the basic unit of life
What are the types of microscopes used in cytology?
- Light microscope (LM): Uses visible light for magnification
- Electron Microscope (EM): Includes Transmission (TEM) and Scanning (SEM)
- Fluorescence Microscope: Uses fluorescence dyes to visualise cell structures
What is the difference between TEM and SEM?
TEM: Provides 2D images of cell ultrastructure by passing electrons through a thin section of the sample
SEM: Provides 3D images of surface structures by detecting scattered electrons
What is the magnification and resolution of a light microscope?
Magnification: Up to 1000x
Resolution: Around 0.2 micrometers
What staining technique is commonly used for light microscopy?
Haematoxylin and Eosin (H&E). Haematoxylin stains nuclei blue, and eosin stains cytoplasm and extracellular matrix pink
What are the key steps in tissue preparation for microscopic study?
- Fixation - preserves tissue structure (e.g. with formaldehyde)
- Dehydration - Removes water using alcohol
- Embedding - Encases tissue in paraffin or resin
- Sectioning - Enhances contrast for visualisation
- Staining - Enhances contrast for visualisation
What is differential centrifugation?
A technique to separate cell components based on size and density using high-speed spinning
What is histochemistry?
A branch of cytology that uses chemical reactions to visualise cellular components in tissues
Name a method to demonstrate carbohydrates in histochemistry
Periodic Acid-Schiff (PAS) staining, which reacts with polysaccharides and glycoproteins to produce a magenta colour
How are nucleic acids visualised in a cell
Using a Feuglen staining (DNA-specific) or Acridine Orange for fluorescence imaging of DNA and RNA
What is confocal microscopy?
A technique that uses laser light and optical sectioning to produce sharp, 3D images of cells and tissues
What is the principle behind fluorescence microscopy?
Fluorescent dyes absorb light of a specific wavelength and emit light of a longer wavelength, allowing visualisation of specific cell components
What is phase-contrast microscopy used for?
Observing live cells without staining by enhancing the contrast of transparent specimens
What is autoradiography
A technique that uses radioactive isotopes to trace biochemical processes in cells, such as DNA replication or protein synthesis
What is X-ray crystallography used for in cytology?
Determining the atomic structure of biomolecules like proteins and DNA by analysing X-ray diffraction patterns
What is immunohistochemistry
A method using antibodies tagged with fluorescent dyes or enzymes to detect specific proteins within cells
What is the purpose of a cell culture?
Growing cells in a controlled environment to study cell function, behaviour, and drug testing
What are the basic requirements for cell culture?
- Sterile conditions
- Culture medium (nutrients, salts, pH buffer)
- Controlled temperature (37°C) and CO2 levels
What are the two types of cell cultures?
Primary culture - derived directly from tissues
Cell lines - immortalised cells that can be cultured indefinitely
Which stains are used to visualise lipid droplets?
Sudan Black and Oil Red O
How is protein localisation studied in cells?
Using immunohistochemistry or western blot techniques with specific antibodies
What is flow cytometry?
A technique to analyse the physical and chemical properties of cells in suspension using laser light
What is spectrometry used for in cell studies?
Measuring the concentration of molecules like DNA, RNA, or proteins by analysing light absorption
