Session 1- Cell injury

Question 1

What’s the difference between hypoxia and ischaemia?

Answer 1

Hypoxia: Not enough oxygen is reached a tissue
Ischaemia: Decrease in blood supply to the tissue

Question 2

What are the four causes of Hypoxia

Answer 2

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

Question 3

How does our own immune system damage our own body cells?

Answer 3

Autoimmune response (Fails to distinguish self form non self)
Hypersensitivity (Host tissue damaged due to an overvigorous immune system

Question 4

What are the three processes of cell death with regards to what happens to the nucleus?

Answer 4

Pykosis: The irreversible clumping of nuclear chromatin
Karyorrhesis: Nucleus breaks into fragments
Karyolysis: Nucleus dissolves in the cytoplasm and so cannot be seen

Question 5

What reversible damage and then irreversible damage can you see under a electron microscope when a cell dies?

Answer 5

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

Question 6

What test is used to determine the time of death?

Answer 6

Dye exclusion test

Dye enters the dead cells where the cell membrane has been ruptured. Doesn’t enter the alive ones

Question 7

Whats the difference between oncosis and necrosis?

Answer 7

Oncosis: Cell death with swelling
Necrosis: The morphological change s that occur after a cell has been dead for some time

Question 8

What are the two types of necrosis?

Answer 8

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

Question 9

What type of necrosis is commonly found in TB

Answer 9

Caseous necrosis

Containss structureless debris

Question 10

What is gangrene?

Answer 10

Necrosis visible to the naked eye

Question 11

What are the three types of gangrene

Answer 11

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

Question 12

What is white and red infarcts?

Answer 12

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

Question 13

What can happen if you return blood to an area of necrotic tissue

Answer 13

It can result in inflammation that can cause increased tissue injury, and oxidative damge

Question 14

What can increasing potassium levels cause?

Answer 14

The heart to stop

Question 15

What enzyme is the main indicator of a myocardial infarction?

Answer 15

Troponin

Question 16

What does the presence of myoglobin in the blood indicate? What can this cause

Answer 16

Muscle tissue injury
BTW the increase of myoglobin is called Rhabdomyolysis
Can cause renal failure

Question 17

Give the process of the intrinsic pathway of apoptosis

Answer 17

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

Question 18

Name 7 key differences between apoptosis and necrosis (Pattern, cell size, nucleus, plasma membrane, cellular contents, adjacent inflammation?, Buds or blebs)

Answer 18

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

Question 19

Name 5 things that can accumulate in cells

Answer 19

Lipids- Steatosis
Iron- Haemochromatosis
Pigments
Proteins
Bilirubin- Jaundice

Question 20

What are the four mechanisms that result in intracellular accumulations?

Answer 20

Abnormal metabolism
Alterations in protein folding/transport
Deficiency of critical enzymes
Inability to degrade phagocytosed particles

Question 21

What is dystrophic calcification? What causes it?

Answer 21

Localised calcification

A local change that favours the nucleation of hydroxyapatite

Question 22

What causes metastatic calcification?

Answer 22

Hypercalcaemia either caused by:
Increased secretion of the parathyroid hormone–>Bone resorption
Destruction of bone tissue