Cell Injury 2 Flashcards
Cell response to injury is a…
Dynamic response
Causes of cell injury
Oxygen deprivation
-hypoxia
-ishaemia
Physical agents
-mechanical trauma
● extreme temperatures (burns, cold)
● sudden changes in atmospheric pressure
● radiation
● electric shock
Chemicals/toxins/drugs
-arsenic, copper, mercury, lead… & more
-environmental and air pollutants
-rodenticides / insecticides / herbicides, benzene… & more
-industrial & occupational hazards carbon monoxide, asbestos… & more
-therapeutic drugs overdosage
Infectious agents
-Viruses
-Bacteria
-Fungi
-Parasites (protozoa, nematodes, trematodes, cestodes, arthropods)
Immunologic dysfunction
-inflammatory reactions to endogenous self-antigens are responsible for several autoimmune diseases
● immune reactions to external agents (microbes and environmental substances)
Genetic defects
-Gene defects resulting in
● malformations
● enzyme defects causing functional impairments
Nutritional deficiencies & imbalances
-malnutrition (protein-calories deficiencies)
● vitamins / minerals deficiencies
● overnutrition
- excess dietary cholesterol / lipids / glucose
- excess dietary vitamins ( vit A, D toxity)
What 3 things does reversible cell injury cause
Hydropic change/degeneration
Fatty change/degeneration/lipidosis
Neuronal chromatolysis
What is Hydropic degeneration
Swelling/Enlargement of organs with extensive fluid
Turn pale, turgid
What is lipidosis/fatty degeneration
Hypoxia damage or toxic/metabolic injury
Accumulation of lipid vacuoles in cells
Cells commonly involved in fat metabolism
Hepatocytes
Myocardial cells
Renal tubule cells
Causes of fatty liver/ hepatic lipidosis
Increased mobilisation of fat stores
-late pregnancy (pregnancy toxaemia)
-early lactation (ketosis)
Nutritional disorders
-obesity
-increased transport of dietary lipids mobilisation from adipose tissue
Endocrine diseases
-diabetes mellitus
-increased mobilisation of triglycerides
(reduced insulin-dependent glucose uptake by cells leads to accelerated lipolysis from adipose tissue)
What is vacuolation
The formation of vacuoles
Describe the 2 types of microscopic patterns of hepatocellular lipid vacuolation
1.Macrovesicular lipidosis
-Single large round vacuoles filling the cytoplasm
-Peripheral displacement of the nucleus
-Accumulation of triglycerides with higher hydrophobicity
2.Microvesicular lipidosis
-Multiple small round vacuoles
-No peripheral displacement of the nucleus
-Indicator of more severe hepatocellular dysfunction
-Toxic hepatopathies causing mitochondrial damage
Causes of excessive hepatic glycogen accumulation
-Diabetes Mellitus (type II)
-Glycogen Storage Disease Ia (GSD Ia)- an inherited disorder caused by the buildup of a complex sugar called glycogen in the body’s cells.
-prolonged corticosteroid/ corticosteroids treatment (important in dogs especially)
-hyperadrenocorticism
What is hepatic glycogen accumulation
The build up of glycogen in the liver
What is neuronal chromatolysis
The dissolution/breaking down of the Nissl bodies of a neuron cell body
Which disease contains a mixture of reversible and irreversible cell injury?
Equine grass sickness- destruction of autonomic ganglia (nerves)
(Chromatolysis and necrosis of ganglionic neurones)
Usually fatal
Describe the differences between reversible and irreversible cell injury
-swelling?
-changes to plasma membrane/nuclear chromatin/mitochondria/lysosome?
Reversible
-general cell swelling
-blebbing of plasma membrane
-clumping of nuclear chromatin
Irreversible
-severe ER swelling
-severe mitochondrial swelling
-lysosome rupture
-cell membrane bless progress to membrane fragmentation degradation of cellular proteins)
-nuclear shrinkage & condensation with nuclear membrane rupture & chromatin fragmentation
Morphological changes associated with reversible cell injury
- decreased generation of ATP
- loss of cell membrane integrity - defects in protein synthesis
- cytoskeletal damage
- DNA damage
