Methods in Light Microscopy Flashcards
Explain the value of histology in diagnosis.
Proof of diagnosis by histology and biopsy. It’s the gold standard of diagnosis. It also types the disease, e.g. malignant or benign.
Define tissue.
A collection of cells specialised to perform a particular function.
What scale is a micrometer compared to a metre?
10-6 m
What scale is a nanometer compared to a metre?
10-9 m
What is the average diameter of a human cell?
10-20 um
What is the diameter of a red blood cell?
7.2 um
Define biopsy.
The removal of a small piece of tissue taken from an organ, or part of the body, for microscopic examination.
List 6 types of biopsies.
Smear, curettage, needle, direct incision, endoscope and trans vascular.
Explain what a smear is and give an example of when it would be used.
A specimen of tissue taken from. Part of the body, and smeared on a microscopes slide for examination.
E.g. Cervix or buccal cavity.
Define curettage, state an advantage of its use and give an example of its use.
The scraping of a body surface by a spoon-shaped instrument (curette), to obtain a specimen or to remove diseased tissue.
Advantage- Causes little scaring.
Example- endometrial lining of the uterus.
What is a needle biopsy, and give examples of its use?
A hollow needle is used to withdraw a sample of tissue or fluid for examination.
Used in brain, breast and liver.
Define direct incision biopsy and give examples of its use.
Cutting of soft tissue.
Used for skin, mouth, larynx and muscle.
Define endoscopic biopsy and give examples of its use.
A tube with a light and a video camera at the end.
Used in the lung, intestine and bladder.
What is a transvascular biopsy and when is it used?
A wire with grabbers at the end. X-Ray images are used instead of a camera due to fast/strong blood flow.
Used in heart and liver.
Explain why tissue processing is needed for microscopy, and why you can’t use a fresh biopsy?
A fresh biopsy is too wet and bloody. Tissue processing enables you to section it into thin slithers.
