Lecture 2 Flashcards
Define homeostasis
The balance achieved when the physiological needs of the body are met.
Disease will occur when the body can no longer adapt to its internal or external environment.
Define atrophy
Decrease in cell size. If enough cells in an organ atrophy the entire organ will decrease in size.
Where might atrophy occur?
Tissues and organs especially susceptible to atrophy include skeletal muscle, cardiac muscle, secondary sex organs, and the brain.
Define hypertrophy
Increase in cell size
Where might hypertrophy occur?
The heart and kidney have increased susceptibility to hypertrophy
Define hyperplasia
Increase in the number of cells. Result of increased cell mitosis or division. (Two types - compensatory and hormonal)
Where might hyperplasia occur?
Common in epithelial cells of epidermis and intestine, liver hepatocytes, bone marrow cells, and fibroblasts.
(A common pathologic hyperplasia in women occurs in the endometrium - endometriosis)
Define Dysplasia
Abnormal changes in cellular shape, size and/or organisation. Sometimes called ‘atypical hyperplasia’
Where might dysplasia occur?
Tissues prone to dysplasia include cervical and respiratory epithelium - strongly associated with development of cancer.
Define metaplasia
When a differentiated cell or a certain type is replaced by another cell type, which may be less differentiated.
Where might metaplasia occur?
The respiratory tract in response to inhalation of irritants - most common example is Barrett’s eosphagus.
Define neoplasia
New growth
Abnormal growth of tissue, that may result in a tumour.
Define anaplasia
Structural differentiation loss within a cell or group of cells
Where might anaplasia occur?
In malignant neoplasms
Describe the clinical features of inflammation
- Injury
- Chemical mediator release
- Vasodilation of arterioles (red and heat)
- Capillary permeability (leaky capillaries - swelling and pain)
- Leukocyte migration
- Phagocytosis
(Immobility may be a feature if joints are involved)
