Pathology 1: role of pathologist and functional histology Flashcards
What is pathology?
- Pathology = the study of disease
What is the difference between a histopathologist and a cytopathologist?
- Histology = the study of tissue and histopathologists study diseases in tissue biopsies, usually using a light microscope
- Cytology = the study of cells and cytopathologists study cells from fluids scrapings/brushings or from fine needle aspirates
How do you distinguish a benign cell from a malignant cell?
- Malignant cells have high nuclear to cytoplasmic ratios, irregular nuclear membranes and an irregular distribution of chromatin within the nucleus
- Benign cells have low nuclear to cytoplasmic ratios, smooth nuclear membranes and evenly distributed chromatin
Into what medium do you place a biopsy for histopathological assessment?
- Tissue biopsies are placed in formalin (a mixture of formaldehyde and saline)
What happens to tissue if you do not do place it in formalin?
- The tissue will rot and will not be able to be examined
- Formalin crosslinks proteins within the tissue stopping its breakdown
What is the stain used most commonly in histopathology?
- H+E (Haematoxylin and Eosin)
- Haematoxylin stains nuclei blue and eosin stains cytoplasm pink
Which cell produces collagen which makes some tumours feel hard on palpation?
- Fibroblasts produce collagen around tumours
- Collagen is a protein which makes tumours and scar tissue hard to palpation
What is the difference between a transudate and an exudate?
- Transudate = a fluid which is low in protein (eg. a pleural effusion caused by heart failure)
- Exudate = a fluid which is high in protein (eg. an effusion caused by infection or malignancy)
What is an adenocarcinoma?
- Adenocarcinoma = a malignant epithelial tumour showing gland formation (glandular differentiation)
What is immunohistochemistry?
- Immunohistochemistry is the application of labelled antibodies to tissue slides in order to detect the presence of certain antigens of interest within the nucleus, cytoplasm or membranes of cells.
- This technique is used to tell pathologists where a tumour has come from or the cell type which is present or what receptors a tumour is expressing.
Role of pathologist quiz Q1…
Answer: cytopathologist
Role of pathologist quiz Q2…
Answer: radiologist, surgeon, clinical nurse specialist, pathologist
Role of pathologist quiz Q3…
Answer: False
Role of pathologist quiz Q4…
Answer: Haemotoxylin and Eosin (H+E)
Role of pathologist quiz Q5…
Answer: image shows correct matches
Role of pathologist quiz Q6…
Answer: third option
What is gastrulation?
- The formation of the 3 germ cell layers in the embryo (ectoderm, mesoderm and endoderm)
List some examples of mature tissues which derive from ectoderm.
- Skin, nerves, eyes and ears, adrenal, medulla and pituitary gland
List some examples of mature tissues which derive from mesoderm.
- Muscle, bone + cartilage, heart + blood vessels, the urogenital system, bone marrow, the lymphatic system and the adrenal cortex
List some examples of mature tissues which derive from endoderm.
- Lining of the gastrointestinal (GI) and respiratory tracts, GI organs (liver + pancreas), larynx, trachea, lungs, thyroid gland, parathyroid glands and thymus
What epithelium covers the skin?
- Stratified squamous keratinising epithelium forms the epidermis of the skin.
Structure of keratin (keratin makes up hair, nails, outer layer of skin)…
What happens to the surface keratin layer of the skin in psoriasis?
- In psoriasis there is an increased rate of epidermal turnover and this causes the keratin layer to get thickened
- Normal keratin has a basket-weave pattern with no nuclei visible but in psoriasis this basket weave is lost, the keratin layer is thickened and nuclei are retained in this layer because the keratinocytes do not have time to fully mature
Which structures provide strong adhesion between keratinocytes in the epidermis?
- Desmosomes
- (image shows desmosomes structure and seen as ladders between the keratinocytes in bottom image)
What disease is caused by antibodies attacking desmosomes?
- Pemphigus vulgaris
What do you call a malignant tumour which derives from the epidermis of the skin (a malignant tumour of squamous epithelium) and how can you identify this?
- Squamous cell carcinoma
- you can recognise a squamous cell carcinoma because it produces keratin and because you can identify desmosomes between the malignant cells
Which cell produces myelin and speeds up peripheral nerve conduction?
- Schwann cell
- The schwann cell wraps its cytoplasm around the axon of a nerve insulating it and speeding up nerve conduction
- A schwann cell has a wavy spindle shaped nucleus
List 6 functions of epithelial cells.
- Protection.
- Absorption
- Surface transport
- Secretion
- Excretion
- Gas exchange
List the 4 simple epithelial types and give 1 example of where you might find each type.
- Simple squamous epithelium eg. mesothelium covering the lungs
- Simple cuboidal epithelium eg. lining the renal (kidney) tubules
- Simple columnar epithelium eg. epithelial lining of the stomach
- Pseudostratified columnar epithelium eg. lining of the bronchi
The most important stratified epithelial types are stratified squamous epithelium which may be keratinised or non-keratinised and transitional epithelium. Give one example of where you might find each of these in the body.
- Keratinised stratified squamous epithelium eg. epidermis of the skin.
- Stratified squamous non-keratinising epithelium eg. cervix and oral mucosa.
- Transitional epithelium eg. bladder, ureters and renal pelvis.
What is the main function of transitional epithelium?
- Transitional epithelium allows the ureters and bladder to stretch
List the important connective tissues and muscle types.
- The connective tissues include adipose tissue, fibrous tissue (such as dermis, tendons, ligaments), cartilage, bone and haemopoietic tissue (blood, bone marrow)
- The muscles include cardiac, skeletal and smooth muscle
If you have a bacterial infection which white blood cell would be raised on a full blood count?
- Neutrophils
- a raised neutrophil count is usually seen with bacterial infections.
If you have asthma which white blood cells would be found in the bronchial lining?
- Eosinophils.
What is the term used to describe a rounded aggregate of activated macrophages/giant cells?
- A granuloma
Which cell is the bodies main producer of antibodies?
- The plasma cell
List the 4 mucosal types lining the gastrointestinal tract and give an example of each.
The 4 basic mucosal types which are found lining the GIT can be classified as being:
- Protective (eg. stratified squamous epithelium of the mouth and oesophagus).
- Secretory (eg. acid secreting glands lining the stomach).
- Absorptive (columnar cells with surface microvilli lining the small intestine).
- Mixed absorptive/protective (columnar cells lining the glands of the large bowel).
Pathology diagram of neutrophil, erythroid precursors, eosinophil, and megakaryocyte…
- (neutrophil looks like mickey mouse)
Functional histology quiz Q1…
Functional histology quiz Q2…
