Lecture 1 Flashcards
What is the average size of a cell, and the size of a red blood cell?
Cells are ~15um
Red blood cells are 7um
State the relationship between milli, micro and nanometres
Milli 10^-3
Micro 10^-6
Nano 10^-9
State the meaning of the term tissue
An aggregation of specialised cells which perform a particular function
State the meaning of the term organ
Aggregations of tissues constitute an organ
Name the four types of tissue
Epithelial tissue
Connective tissue
Muscle tissue
Nervous tissue
Explain the value of histology in diagnosis
Histology is the gold standard in diagnosis. Some diseases cannot be treated on without histological diagnosis; the diagnosis can inform the treatment
Name 6 biopsy techniques
Smear Curretage Needle Direct incision Endoscopic Transvascular
What is smear biopsy used for?
Buccal cavity, cervix
What is needle used for?
Brain, breast, live, kidney, muscle
What is direct incision used for?
Skin, mouth, larynx
What is endoscopic biopsy used for?
GI and respiratory tracts
What is transvascular biopsy used for?
Heart, liver
What is curretage used for
Endometrial lining of the uterus
What does biopsy mean
Removal of a small piece of tissue from an organ or part of the body for microscopic examination
Why do tissues need to be fixed? (Give examples of fixatives)
To prevent autolysis and putrefaction (glutaraldehyde, formaldehyde)
What are shrinkage artefacts?
Shrinkage artefacts appear due to processing of tissue samples. They appear as gaps between tissues.
What components of a cell are stained by periodic acid schiff and what colour is the stain?
Stains glycoproteins and carbohydrates and goblet cells magenta
What components of the cell are stained by Haemotoxylin and what colour is the stain?
Acidic components stain purple/blue
E.g. Nucleus (DNA)
What components of the cell are stained by Eosin
Stains basic components pink
E.g. Cytoplasmic proteins
How does phase contrast microscopy work?
Cell components interfere with the phase of light, so this can be detected by differences in contrast on the image, allowing components to be identified.
How does dark field microscopy work?
Creates an image from scattered light (reflected or diffracted)
How does fluorescence microscopy work?
Fluorescent dyes/markers bind to specific cell components to make them identifiable on an image.
How does confocal microscopy work?
Using fluorescent images, sections of a sample can be made non invasively to produce a 3D image.
