Lecture 3 - Cell death

Question 1

Describe irreversible cell death

Answer 1

loss of cell nuclei, fragmentation of cells, leakage of cell contents

Question 2

Describe necrosis

Answer 2

Enzymatic digestion of cell (autolysis and heterolysis, denaturation of cellular protein

Question 3

What are the morphological types of irreversible cell death

Answer 3

Coagulative - architecture retained (hypoxia)
liquefactive - bacterial/fungal following brain ischaemia (cellular destruction and pus formation)
Caseous - coagulative and liquefactive (cheesy appearance)
Fatty - lipases (pancreas/breast)
Gangrenous - severe hypoxia -> bacterial infection

Question 4

Describe inflammatory response

Answer 4

clearing of necrotic material and healing -> disruption of plasma membrane

Question 5

Describe apoptosis

Answer 5

quick and precise
Cell shrinkage, chromatin condensation, cytoplasmic blebs and apoptotic bodies, phagocytosis of apoptotic bodies by adjacent cells
membrane and organelles preserved
No inflammatory response

Question 6

Physiology of apoptosis

Answer 6

Cell removal during embryogenesis (implantation, organogenesis, development), hormone dependent involution, cell death via immune system, removal of damage cells during normal cell division

Question 7

Describe extrinsic apoptosis

Answer 7

Death receptor mediated - ligands - caspase 8 mediated

Question 8

Describe intrinsic response cell injury

Answer 8

Mitochondria - caspase 9 mediated - specialised proteases that mediate apoptosis
BH3 sensors - bcl-2 family members (permeability of mitochondria - chromatin C leaks - activating caspases)

Question 9

What does malfunction of apoptosis lead to

Answer 9

Disease - cancer (TNF - microphages produce and activates extrinsic pathway, inactivation of p53 by HPV causes cervical cancer), neurodegenerative disease, AIDS, ischaemic stroke, autoimmune disease