Path processes

Question 1

what are the four causes if hypoxia?

Answer 1

• hyperaemic hypoxia: arterial content of oxygen low
• anaemic hypoxia: decreased ability of haemoglobin to carry oxygen (CO poisoning)
• ischaemic hypoxia: interruption to blood supply
• histiocytic hypoxia: inability to utilise oxygen in cells due to disabled oxidative phosphorylation enzymes (eg cyanide poisoning)

Question 2

what are the cell components most susceptible to injury?

Answer 2

cell membranes - plasma and organellar membrane
nucleus- DNA
protein- structural
mitochondria- oxidative phosphorylation

Question 3

describe the process of reversible ischaemic injury

Answer 3

• mitochondria decrease oxidative phosphorylation
• decreased amount of ATP production
• NA pump decreases- causes increase in calcium, water and sodium and decrease in potation => cell swells
• by anaerobic respiration glycolysis increases which decreases pH => clumping of nuclear chromatin
• detachment of ribosomes decreases protein synthesis => lipid deposition

Question 4

describe the process of irreversible prolonged hypoxia

Answer 4

increased cytosolic calcium- from mitochondria andER

• activates ATPase which decreases ATP
• activates phospholipase- decreases phospholipids
• activates protease- disruption of membrane and cytoskeletal proteins
• activates endonuclease- nuclear chromatin damage

Question 5

how are free radicals produced?

Answer 5

• normal metabolic reactions eg oxidative phosphorylation
• inflammation eg oxidative burst of neutrophils
• radiation
• contact with unbound metals within the body eg iron and copper
• drugs and chemicals

Question 6

how does the body control free radicals?

Answer 6

• antioxidant scavengers ( vit ACE)
• metal carrier and storage proteins ( transferrin, ceruloplasmin)- sequester iron and copper
• enzymes that neutralise free radicals ( superoxide dismutase, catalase, glutathione peroxidase)

Question 7

how do free radicals injure cells?

Answer 7

• cause lipid peroxidation- leads to generation of free radicals
• oxidise proteins, carbohydrates and DNA

Question 8

what are the clinical features of acute inflammation?

Answer 8

rubor (redness)
tumor (swelling)
calor (redness)
dolor (pain)
loss of function

Question 9

what are the key changes in blood flow during acute inflammation?

Answer 9

vasoconstriction
vasodilation - arterioles then capillaries
increased permeability of blood vessels
increased conc of RBCs in small vessels

Question 10

what is the primary WBC in inflammation?

Answer 10

neutrophil