Intro To Pathology Flashcards
What does pathology include?
Aetiology, Epidemiology (incidence), Presentation (signs and symptoms), Morphology of the disease (gross and macroscopic features), Molecular features, Complications, Prognosis/outcome, Management
What factors might influence the response of cells the mimic a disease state?
Trauma, Radiation damage, Environmental factors, Infectious agents, Carcinogenic substances, Others; congenital, degenerative, vascular.
How may cells respond to damaging stimuli?
1) . Adaptation - usually physiological, reversible. Includes hyperplasia, hypertrophy, atrophy, metaplasia.
2) . Cell death - severe injury (apoptosis and necrosis).
3) . Genetic derangement - usually irreversible. Benign or malignant.
Describe hyperplasia.
Hyperplasia is when proliferation of cells exceeds a normal level.
Hyperplasia may result in the gross enlargement of an organ or tissue.
And example is epidermal hyperplasia secondary to friction and endometrial hyperplasia.
Describe hypertrophy.
Hypertrophy is the increase in the volume of an organ or tissue due to the enlargement of its component cells but not the number of component cells.
It may be pure hypertrophy (i.e. heart muscle in hypertension) or more frequently associated with hyperplasia (increase in both number and size of the cells, e.g. Uterus in pregnancy).
Describe atrophy.
Atrophy is the partial or complete wasting of an organ or part of the body.
Atrophy may be caused by genetic mutations, poor nourishment, poor circulation, loss of hormonal support, loss of nerve supply to the target organ, disuse or lack or exercise.
Examples include atrophy of the thymus after puberty and limb/muscle atrophy in paralysis.
What is an example of hyperplasia?
Epidermal hyperplasia secondary to friction.
Give an example of pure hypertrophy.
Hypertrophy of the heart muscle in hypertension.
Give an example of a situation where hypertrophy and hyperplasia occur simultaneously.
In the uterus during pregnancy.
Give an example of a situation where atrophy occurs.
Muscle atrophy due to lack of exercise.
What is metaplasia?
Metaplasia is a reversible change in which one adult cell type is replaced by another adult cell type.
Give an example of squamous metaplasia.
Suqamous metaplasia occurs in the upper respiratory tract in smokers. The columnar or transitional epithelium is replaced by squamous epithelium.
Give an example of a situation where columnar metaplasia occurs.
In Barrett’s oesophagus the squamous epithelium changes to columnar epithelium.
What is dysplasia?
It is an alteration to adult cells that is characterised by variation in their size, shape and organisation.
Dysplasia can be used to refer to developmental abnormalities such as renal dysplasia, or more commonly neoplastic abnormalities such as epidermal dysplasia.
In neoplastic dysplasia the changes are reversible in the early stages but at later stages (carcinoma in situ) there may be further deviation from the norm leading to invasive cancer.
What is neoplasia?
Neoplasia is excessive, unregulated, autonomous growth, usually irreversible proliferation resulting from genetic alteration.
Neoplastic lesions are either benign or malignant (in situ or invasive).
What are the two components that all tumour consist of?
1) . Parenchyma - proliferating neoplastic cells.
2) . Supportive Stroma - blood vessels and connective tissue.
What is tumour nomenclature based on?
Tumour nomenclature is based on parenchymal cells.
What effect does the stromal support have on the consistency of a tumour?
If stromal support is scanty then the neoplam will be soft and fleshy.
If stromal support is abundant and forms collagen and scar-like tissue then the tumour will be hard (e.g. Schirrous carcinoma of the breast).
What influences whether a tumour is benign or malignant?
The neoplastic changes in the target cells. It depends how these changes influence the cells ability to grow and or invade.
What distinguishes a malignant tumour from a benign tumour?
Neoplastic transformation is a malignant and aggressive process rather than the benign and limited process that takes place in benign tumours.
Malignant tumours will display local invasion of the basement membrane, stroma and blood vessels and distant metastasis may form.
What suffix is added on to the cell of origin when describing benign tumours?
The suffix -oma.
e.g. Fibroma, lipoma, chondroma, haemagioma, adenoma, papilloma.
What is a carcinoma?
A malignant tumour arising from epithelial tissue. May be in situ with an in tact basement membrane or invasive (primary or metastatic).
What is a sarcoma?
A sarcoma is a malignant tumour arising from mesenchymal tissue. All sarcomas will be invasive as there is no basement membrane.
How are carcinomas sub-classified?
Carcinomas are sub-classified based on origin or pattern.
E.g. Squamous carcinoma, adenocarcinoma.
Pattern may be signet cell, mucinous, angiomatous, lympho-epithelioma.
Often the organ of origin is also added (e.g. Renal cell adenocarcinoma, bronchogenic carcinoma).
