Session 1- Cell injury Flashcards
What’s the difference between hypoxia and ischaemia?
Hypoxia: Not enough oxygen is reached a tissue
Ischaemia: Decrease in blood supply to the tissue
What are the four causes of Hypoxia
HHypoxaemic Hypoxia: Arterial content of O2 is low
Anaemic hypoxia: Decreased ability for haemoglobin to carry O2
Ischaemic Hypoxia: Reduced O2 supply due to interruption in blood supply
Histiocytic Hypoxia: Inability to utilise the O2 in tissue due to some disabled oxidative phosphorylation enzyme
How does our own immune system damage our own body cells?
Autoimmune response (Fails to distinguish self form non self) Hypersensitivity (Host tissue damaged due to an overvigorous immune system
What are the three processes of cell death with regards to what happens to the nucleus?
Pykosis: The irreversible clumping of nuclear chromatin
Karyorrhesis: Nucleus breaks into fragments
Karyolysis: Nucleus dissolves in the cytoplasm and so cannot be seen
What reversible damage and then irreversible damage can you see under a electron microscope when a cell dies?
Reversible: Blebs form ER swells Chromatin clumps Mitochondria swell Intramembranous particles aggregate on the surface of the cell
Irreversible: Lysosomes rupture
Nucleus–>Pykosism, Karyolysis or Karyorrhexis
Defects in the cell membrane appear
What test is used to determine the time of death?
Dye exclusion test
Dye enters the dead cells where the cell membrane has been ruptured. Doesn’t enter the alive ones
Whats the difference between oncosis and necrosis?
Oncosis: Cell death with swelling
Necrosis: The morphological change s that occur after a cell has been dead for some time
What are the two types of necrosis?
Coagulative- Where Denaturation of proteins dominate over the release of proteases. Ghost outline of the cells
Liquefactive: Enzyme activity greater than protein denaturation
Enzymes digest cells leaving liquefaction of tissue
What type of necrosis is commonly found in TB
Caseous necrosis
Containss structureless debris
What is gangrene?
Necrosis visible to the naked eye
What are the three types of gangrene
Dry Gangrene= Where necrosis is exposed to air
Wet gangrene= Gangrene modified by infection
Gas gangrene= Where the infection is caused by an anaerobic bacteria that produces gas
What is white and red infarcts?
White: Occurs in solid organs. Coagulative necrosis Due to occlusion of an end artery (So no blood supply reaching the area of infarct, so white) Red Infarct: Occurs in loose tissue Number of anastomoses Blood leaks out of blood vessels
What can happen if you return blood to an area of necrotic tissue
It can result in inflammation that can cause increased tissue injury, and oxidative damge
What can increasing potassium levels cause?
The heart to stop
What enzyme is the main indicator of a myocardial infarction?
Troponin
What does the presence of myoglobin in the blood indicate? What can this cause
Muscle tissue injury
BTW the increase of myoglobin is called Rhabdomyolysis
Can cause renal failure
Give the process of the intrinsic pathway of apoptosis
P53 triggered (Eg by irreparable damage to DNA)
Mitochondrial membrane becomes leaky
Releases cytochrome C
Activates caspases
These cleave DNA and protein in the cytoskeleton
Name 7 key differences between apoptosis and necrosis (Pattern, cell size, nucleus, plasma membrane, cellular contents, adjacent inflammation?, Buds or blebs)
Pattern: N: Continuous groups of cells
A: Single cells
Cell size: N:Enlarged
A:Shrink
Nucleus: N: Pyknosis, Karyorrhexis or Karyolysis
A: Karyorrhexis is seen
Plasma membrane: N: Disrupted, early lysis
A: Remains intact
Cellular contents: N:Enzymatic digestion, leak out of the cell
A: Remain intact, released into apoptotic bodies
Adjacent inflammation: N: Frequent
A: No
Budding or Blebbing: N: Blebbing
A: Budding
Name 5 things that can accumulate in cells
Lipids- Steatosis Iron- Haemochromatosis Pigments Proteins Bilirubin- Jaundice
What are the four mechanisms that result in intracellular accumulations?
Abnormal metabolism
Alterations in protein folding/transport
Deficiency of critical enzymes
Inability to degrade phagocytosed particles
What is dystrophic calcification? What causes it?
Localised calcification
A local change that favours the nucleation of hydroxyapatite
What causes metastatic calcification?
Hypercalcaemia either caused by:
Increased secretion of the parathyroid hormone–>Bone resorption
Destruction of bone tissue
