PMI03-2009 Cell response to injury

Question 1

What is hyperplasia?

Answer 1

Hyperplasia is an increase in the number of cells in the tissue or organ without an associated increase in sizer

Question 2

Where does hyperplasia occur?

Answer 2

Occurs in tissues capable of cell division eg: female breasts during puberty

Question 3

What is hypertrophy?

Answer 3

An increase in the size of cells without an increase in the number of cells

Question 4

Where does hypertrophy occur?

Answer 4

In cells incapable of division such as cardiac and skeletal muscle
Eg: Left ventricle hypertrophy after heart failure

Question 5

What is atrophy?

Answer 5

A reduction in the size of an organ due to a reduction in the size and number of cells

Question 6

When does atrophy occur?

Answer 6

Vaginal epithelium during menopause

Question 7

What is metaplasia?

Answer 7

The change from one to another differentiated cell type

Question 8

What is dysplasia?

Answer 8

The disordered stratification and maturation

Question 9

What processes are reversible once the stimulus is removed?

Answer 9

Hyperplasia
Hypertrophy
Atrophy
Metaplasia

Question 10

What can metaplasia progress to?

Answer 10

Dysplasia

Question 11

What are two mechanisms of injury?

Answer 11

Disruption of metabolism

Nutrient/ growth factor deprivation

Question 12

How will metabolism be disrupted?

Answer 12

ATP depletion, which arises from hypoxia

Mitochondria is highly sensitive during hypoxic states and can be damaged by calcium influx or generation of ROS

Question 13

How will nutrient and growth factor deprivation occur?

Answer 13

Ischaemia/ hypoxia could lead to downstream destruction of metabolism
Lack of autocrine/ endocrine/ exocrine growth factor can cause further disruption to metabolism

Question 14

What are some causes of cell damage/ death?

Answer 14

DNA damage
Inflammation
Free radical/ ROS formation
Membrane disruption

Question 15

What are the 2 types of cell death?

Answer 15

Apoptosis

necrosis

Question 16

Where does the point of irreversibility in necrosis?

Answer 16

Where the membrane damage is no longer repairable, which leads to swelling of the ER and mitochondria

Question 17

What are the early stages of necrosis characterised by?

Answer 17

Increased eosinophils and increased pinkiness of the cell, which results from degraded cytoplasmic RNA
There is cariolysis

Question 18

What is cariolysis?

Answer 18

Loss of nuclear definition due to a loss of basophilia

Question 19

What is pyknosis?

Answer 19

Condensation of the nucleus, which gives increased basophilia

Question 20

What occurs after pyknosis?

Answer 20

karyorrhexis

Question 21

What is karyorrhexis?

Answer 21

Degradation and fragmentation of nuclei

Question 22

What occurs after karyorrhexis?

Answer 22

Karyolysis

Question 23

What is karyolysis?

Answer 23

the nucleus dissolves into the cytoplasm due to endonucleases

Question 24

What is coagulative necrosis?

Answer 24

A gel-like substance in dead tissues due to protein degradation

Question 25

What are common causes of coagulative necrosis?

Answer 25

Ischaemic and infarction

Question 26

What is liquefactive necrosis?

Answer 26

A collection of liquid viscous material due to protein degradation

Question 27

Where is liquefactive necrosis common?

Answer 27

In the CNS or there is a bacterial or fungal infection in the presence of pus

Question 28

What is caseous necrosis?

Answer 28

A type of tissue death where all cellular outline is lost and tissue appears crumbled and cheese like

Question 29

what causes caseous necrosis?

Answer 29

TB

Question 30

What is apoptosis?

Answer 30

Regulated and targeted programmed cell death

Question 31

What is the extrinsic pathway of apoptosis?

Answer 31

A death ligand binds to a death receptor
On activation, it causes the activation of downstream apoptosis intermediates called caspases
Activation of caspase 8 activates caspase 3, which causes the execution of apoptosis through the degradation of DNA and cytoskeletal proteins

Question 32

What is the intrinsic pathway of apoptosis?

Answer 32

The release of cytochrome C in mitochondria causes the downstream activation of caspase 9, which causes the activation of caspase 3, which causes apoptosis

Question 33

When is the extrinsic pathway of apoptosis initiatied?

Answer 33

During cytotoxic T cell mediated death

Question 34

When is the intrinsic pathway of apoptosis initiated?

Answer 34

During DNA damage

Question 35

What are the early stages of apoptosis characterised by?

Answer 35

The shrinkage of nucleus and cytoplasm, which progresses to the formation of membrane bound bodies, which contain organelles called apoptotic bodies that undergo phagocytosis

Question 36

Where does apoptosis occur?

Answer 36

In the germinal centres of lymph nodes

Question 37

What is the main differences between characterisation of necrosis and apoptosis?

Answer 37

Necrosis is characterised by cell swelling and apoptosis is characterised by shrinkage
Necrosis affects groups of cells, whereas apoptosis only individual cells
Necrosis is energy dependant, apoptosis is non energy dependent
There is inflammation in necrosis but not apoptosis

Question 38

When may induced apoptosis be useful?

Answer 38

Cancer treatment

Question 39

What is autophagy?

Answer 39

A response to cell stress- the ability of the cell to recycle its own cell contents

Question 40

What is the process of autophagy?

Answer 40

Starts by the formation of an isolated membrane
The membrane elongates to isolate off the organelles to form the autophagosome
This merges with lysosomes, which degrade the components of the organelles