Define hypertrophy.
The enlargement of an organ due to enlargement of its constituent cells.
Number of cells remains the same, size of each cell increases.
Define hyperplasia.
An increase in the number of cells within a tissue or organ.
What type of organ normally exhibits hypertrophy?
An organ with an inability or decreased capacity to increase its number of cells.
Give an example of an organ with a limited ability to increase its number of cells.
The heart: myocytes have a limited ability to divide and icnrease in number.
Exercise leads to “stretch” of individual cells and release of adrenergic hormones and growth factors.
E.g. athletes may develop hypertrophy of the heart to accomodate for exercise levels.
What are the 3 main causes of hypertrophy?
- Increased demand for work or increased stimulus for the function which that organ provides (e.g. exercise)
- Pathophysiology e.g. hypertension leading to left ventricular hypertrophy
- Drugs: phenytoin is an anti-convulsive drug which can cause gingival hypertrophy
Give an example of hyperplasia in the liver.
Partial resection of the liver causes all remaining hepatocytes to proliferate and increase in number
Give an example of hyperplasia in the female reproductive system.
Pituitary hormones and oestrogen can cause endometrial hyperplasia.
Give an example of hyperplasia in the skin.
Proliferation of fibroblasts and endothelial cells in response to injury.
Give an example of hyperplasia involved in HPV infection.
Virus infects eipdermal cell and replicates, producing a cold sore.
Give an example of hyperplasia in the prostate.
The prostate gland enlarges with age.
Which cellular responses are involved in pregnancy?
Cells in the uterus undergo hyperplasia and hypertrophy to accomodate the foetus.
Define aplasia.
Failure for a body part/limb/organ to develop at all.
Define hypoplasia.
Underdevelopment of a body part/limb/organ.
Define atrophy.
Shrinkage in size of a cell, tissue or organ.
What are the 4 forms of atrophy?
- Disuse
- Nutritional
- Pressure
- Denervation
Describe disuse atrophy.
- Decreased demand for usage creates an imbalance between protein synthesis and protein degradation
- Regulated by signalling pathways induced by mechanical stress, physical activity, nutrient supply and GFs
- E.g. tooth loss, reduced mastication, reduced mechanical stress = alveolar bone atrophy
Describe nutritional atrophy.
- Inadequate supply of nutrients
- Induces catabolic state (breakdown of tissues) to use cell protein for energy
- E.g. cachexia associated with cancer: TNF suppresses appetite thus inducing nutritional atrophy
Describe pressure atrophy.
- Decreased size due to pressure
- Pressure created by expanding mass e.g. benign tumour, cyst
- Compresses BVs supplying tissue leads to lack of nutrients and oxygen
Describe denervation atrophy.
- Absence of connection of functioning neural supply
- Induces breakdown of contractile proteins, causes atrophy
- E.g. motor neurone disease
Define metaplasia.
A change from a mature (normal) epithelium to a different (normal) epithelium type.
Benign change.
E.g. Barrett’s oesophagus (change from non-keratinised squamousmucosa to columnar mucosa due to reflux).
Define dysplasia.
When applied to organs = disordered growth of mature cells, often congenital abnormalities.
When applied to cells = abnormalities which are known to progress to cancer.
Define necrosis.
Appearance of pathological cell death.
- Associated with characteristic cellular appearances including loss of membrane integrity.
- Release of cell constituents from necrosing cell triggers inflammation.Usually affects large numbers of adjacent cells
- E.g. tuberculosis: caseous necrosis (dead tissue resembles cheese)
Define apoptosis.
Programmed cell death.
Physiological process of cell death (as opposed to necrosis which is pathological).
- Often part of a physiological process such as renewal of epithelia
- May be induced by noxious stimuli
- Integrity of cell membrane retained – a “cleaner” form of cell death which doesn’t release cell products that induce inflammation
What is ischemia?
Insufficient vasulcar supply.
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1 Pathological processes I34
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2 Pathological processes II40
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3 Injury and the vulnerable patient10
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4.1 Principles of pharmacology43
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4.2 Adrenal steroids44
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5.1 Erythropoiesis39
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5.2 White blood cells32
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6.1 Basis of germline inheritance and investigation of inherited disease37
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6.2 Inherited disorders in dentistry26
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7.1 Viral and orofacial infection44
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7.2 Antibiotics and their use in dentistry27
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8.1 Adaptive immunity31
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8.2 Innate immunity29
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9.1 Special care dentistry23
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9.2 Benign, premalignant and malignant tumours of relavence to dentistry29
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9.3 Clinical cases15
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10.1 Surgical treatment of cancer20
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10.2 Pharmacological treatment of cancer25
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12.1 Clinical immunology35
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12.2 Allergy and anaphylaxis33
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12.3 Principles of vaccination20
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13 Haemostasis and bleeding disorders46
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15.2 Clinical examination of the clothed patient18
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16.1 Cardiovascular disease and drugs40
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16.2 Heart failure therapeutics33
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16.3 Dysrhythmia for dentists30
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17.1 Valvular heart disease and infective endocarditis41
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17.2 Venous thromboembolism and anticoagulants41
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17.3 Management of dental patients taking anticoagulant and antiplatelet drugs49
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18.1 Asthma and COPD42
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18.2 Pneumonia24
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19.1 Coeliac disease and inflammatory bowel disease29
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19.2 Gastrointestinal drugs39
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19.3 Causes and consequences of liver disease9
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20.1 Acute kidney injury3
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21.1 Diabetes mellitus15
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21.2 Thyroid disease35
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22.3 Skin cancer19
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23.1 STIs in the UK7
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23.2 HIV and the oropharynx15
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23.3 STIs and the oropharynx16
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24.1 Neurology for dentistry36
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24.2 Epilepsy29
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24.3 Movement disorders24
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25.1 Mental health for dentistry20
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25.2 Drugs in the management of mental health disorders40
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26.3 Medical emergencies in dentistry39
