Altered cell function Flashcards
(18 cards)
Altered cellular and tissue biology happens because of (5)
(1) Adaptation
(2) Injury
(3) Neoplasia (malignant growth)
(4) Aging
(5) Death
Name and define the two types of cell injury
Reversible - Prolonged stress and repeated injury
Irreversible - Point of no return, after which the cell dies.
Characteristics about irreversible damage
(1) Lack of ATP because of mitochondrial damage
(2) Major damage in membrane function
List some injurious stimuli of cells (8)
(1) chemical agents
(2) lack of sufficient oxygen (hypoxia)
(3) free radicals
(4) infectious agents
(5) physical and mechanical factors
(6) immunologic reactions
(7) genetic factors
(8) nutritional imbalances
3 common forms of cell injury
(1) hypoxic
(2) free radicals and reactive oxygen species
(3) chemical
What is the most common cause of hypoxia?
Ischemia
What causesischemic injury?
Gradual narrowing of arteries (arteriosclerosis), and complete blockage by blood clots (thrombosis)
Name the 4 adaptive changes in cells
(1) atrophy (decrease in cell size)
(2) hypertrophy (increase in cell size)
(3) hyperplasia (increase in cell number)
(4) metaplasia (reversible replacement of one mature cell type by another less mature cell type)
Ischemia in Heart muscle - Response to cellular hypoxic injury
- 1 min: heart pale (no blood supply)
- 3 to 5 min: rapid decrease in mitochondrial phosphorylation - no ATP - no contraction
- Increased anaerobic metabolism (glycogen)
What is atrophy?
What are its mechanisms?
Cellular size shrinkage due to:
(1) decreased protein synthesis
(2) increased protein catabolism
What is Necrosis?
Irreversible injury and cellular dissolution due to hydrolytic enzyme activation
What is Fat (enzymatic) Necrosis?
Cellular dissolution by lipases, which saponify fats
What is Gangrenous Necrosis?
Death of tissue from severe hypoxic injury and bacteria.
Swollen and black, odorous coagulation
What is Liquefactive Necrosis?
Ischaemic injury to brain nerve cells due to bacteria
Hydrolytic enzymes liquefy tissue (proteinaceous soup)
What is Caseous Necrosis?
Combination of coagulative and liquefactive necrosis
Lung tissue becomes soft and liquefies due to infection
What is Coagulation Necrosis?
When severe ischaemia leads to hypoxia in kidneys, heart, and adrenal glands
Loss of nuclei and cell but architecture remains as there are no enzymes for digestion
What is dysplasia?
Abnormal change in cell size or shape and organisation of mature cells.
What is hyperplasia?
Increase in the rate of cellular division
