Cell Injury Flashcards
What is cyanosis ?
Bluish discolouration of skin & nails
Sign of hypoxia/increase in deoxygenated haemoglobin
What is is the difference between hypoxia & ischaemia ?
Which is worse ?
Hypoxia - reduced oxygen to tissue
Ischaemia - reduced blood supply to tissue
Ischaemia is worse
What is hypoxaemic hypoxia?
Low oxygen in arteries
What is anaemic hypoxia ?
Hypoxia causes by reduced functional haemoglobin
What is ischaemic hypoxia?
Hypoxia caused by disrupted blood supply to tissue
What is histiocytic hypoxia?
- Enough oxygen available to tissue but cells unable to use it
- due to inhibited oxidative phosphorylation enzymes (eg cytochrome oxidase)
What are 2 causes of hypoxaemic hypoxia?
- high altitude = reduced inspiration of o2
- lung disease = reduced o2 absorption
What are 2 causes of anaemic hypoxia?
- Anaemia
- CO poisoning
What are 2 causes of ischaemic hypoxia?
- local blockage of blood supply eg thrombus/embolus
- heart failure = low perfusion pressure = global ischaemia
What is a cause of histiocytic hypoxia ?
Cyanide poisoning - inhibits oxidative phosphorylation enzyme
Which cells would be disabled first without o2?
Neurones within few mins
How long can fibroblasts last without o2?
Few hours
What are urticaria? And what causes them ?
Hives
Hypersensitivity reaction
What is a hypersensitivity reaction?
Over active immune system injuring host tissue
What is an auto immune condition?
Failure of immune system to distinguish self from non self.
Which components of the cell are most susceptible to injury?
- membrane
- nucleus
- structural proteins - enzymes
- mitochondria (oxidative phosphorylation)
At a molecular level, how can Low ATP be detrimental to a cell?
1) inactive na+/k+ ATPase pump = na+, ca2+, h2o influx = swelling
2) increase in glycolysis = increase pyruvic acid = lower PH
3) detachment of ribosomes = reduced protein synthesis = reduced lipid transportation = lipid deposition.
How does increased ca2+ in the cytoplasm of a cell damage the cell?
Activates enzymes which will break up molecules/structures in the cell
What enzymes does increased cytosolic ca2+ active?
- Proteases
- Phospholipases
- ATPases
- Endonucleases
What do endonucleases do ?
Break down DNA
What are free radicals?
Molecules that have one or more unpaired electrons in their outer orbit
What is the most common type of free radicals in the body?
Reactive oxygen species
What are the 3 main reactive oxygen species in the cells?
Hydroxyl radical
Superoxide 02^-
Hydrogen peroxide h2o2
What is the most dangerous reactive oxygen species ?
Hydroxyl radical