Cell Injury Flashcards
What causes cell injury?
Infectious agents Chemical agents Physical agents Immunological reactions Nutritional imbalances Genetic defects Hypoxia Ageing
What are the types of cell injury?
Lethal and sub-lethal
cell death vs reversible
What does cellular response to injurious stimuli rely on?
Type
Duration
Severity
‘ of injury
Consequences of an injurious stimulus depend on
Type of cell and its status
Which intracellular systems are at risk?
Cell membrane integrity
ATP generation
Protein synthesis
Integrity of genetic apparatus
What are the types of cellular adaptation to injury?
Atrophy Hypertrophy Hyperplasia Metaplasia Dysplasia
What is atrophy and give an example
Shrinkage of cell due to loss of cell substance.
Dementia, pernicious anaemia
What is hypertrophy and give an example
Increase in cell size.
Physiological (uterus for birth) or pathological (bulking)
Muscle building
What is hyperplasia and give an example
Increase in number of CELLS in an organ
Again, pathological or physiological.
Menstrual cycle, carcinoma
What is metaplasia and give an example
Where cells are replaced by those of another type. Is reversible.
Barrett’s oesophagus - reflux in pubertal teens
What is dysplasia and give an example
Precancerous showing genetic and cytological hallmarks of malignancy but don’t invade.
What are the morphological changes associated with reversible injury?
Fatty changes
Cellular swelling
What are the morphological changes associated with irreversible injuries?
Necrosis - confluent cell death associated with inflammation
Coagulative - cells die, recognisable
Liquefactive - die, become liquid
Caseous - become granulous, not recognisable - TB
Fat - fat deposition
What is apoptosis
Programmed cell death, independent of inflammation
Is physiological
Requires ATP
Why does apoptosis occur?
Embryogenesis - digits
Deletion of autoreactive T cells
Irreparable DNA
