Cell Injury

Question 1

What is lethal and sublethal?

Answer 1

Lethal: produces cell death
Sublethal: produces injury not amounting to cell death may be reversible or progress to cell death

Question 2

What are the causes of injury

Answer 2

Oxygen deprivation
chemical agents
infectious agents
immunological reactions
genetic defects
nutritional imbalances
physical agents
aging
ICOGINPA

Question 3

1. What does the cellular response to injurious stimuli depend on?
2. what does the consequence of an injurious stimulus depend on?

Answer 3

1, the type of injury, duration, and severity

2. on the type of cell ( brain and heart need lots of oxygen), its status, adaptability and gentic makeup

Question 4

What four intracellular mechanisms are particularly vulnerable to cell injury?

Answer 4

• Cell membrane integrity –Protein synthesis: affect cell membrane
• ATP Generation: imp to maintain cell integrity
• Integrity of the genetic apparatus: if damaged there could be a malfunction in protein synthesis

Question 5

Define Atrophy and give an example

Answer 5

Shrinking in the size of a cell or organ by the loss of cell substance.
e.g. dementia

Question 6

Why can you not see anything at post mortem but it kills the person

Answer 6

cellular function is lost before cell death occurs, so no cell injury happens yet but there is a loss of function which kills them

Question 7

Define Hypertrophy and what is it caused by give an example

Answer 7

Increase in the size of cells and, consequently, an increase in the size of the organ.
Can be physiological or pathological
Caused by:
-increased functional demand 
-specific hormonal stimulation

e.g. cardiomyocytes adapatation to increased stress is hypertrophy

Question 8

Define Hyperplasia and what is caused by give an example

Answer 8

Increase in the number of cells in an organ.
Can be physiological and pathological.
Physiological hyperplasia: hormonal or compensatory.
-Hormonal: oestrogenic wave of proliferation of the endometrium
-Compensatory: if some tissue is lost

Pathological hyperplasia is usually due to excessive hormonal or growth factor stimulation

e.g. carcinoma — pathological hyperplasia

Question 9

Define Metaplasia give an example

Answer 9

A REVERSIBLE change in which one adult cell type is replaced with another

e.g. barett’s oesophagus: instead of squamous lined epithelium you get columnar epithelium

Question 10

Define Dysplasia.give an example

Answer 10

Pre-cancerous cells which show the genetic and cytological features or malignancy but not invading the underlying tissue
Hasn’t invaded the basal lamina
once you get metaplasia, likely to then get dysplasia which is where cells become more changed

e.g. dysplasia in baretts oesophagus

Question 11

Define Ulcer.

Answer 11

A local defect, or excavation of the surface, of an organ or tissue, produced by sloughing of necrotic inflammatory tissue

Question 12

What are the two physiological causes of hyperplasia?

Answer 12

Hormonal (e.g. oestrogenic wave of proliferation) Compensatory; if some tissue is lost

Question 13

What are two light microscopic changes associated with reversible injury?
The Light Microscopic Changes Associated with Irreversible Injury

Answer 13

The Light Microscopic Changes Associated with Reversible Injury

Fatty change
Cellular swelling
The Light Microscopic Changes Associated with Irreversible Injury

Coagulative necrosis
Liquefactive necrosis
Caseous necrosis
Fat Necrosis

Question 14

Define Necrosis

Answer 14

Confluent cell death associated with inflammation.

-not just single cells,whole areas of cells die.

Question 15

What are the four types of necrosis and explain them?

Answer 15

Coagulative: substance changes but the shape of the molecule DOES NOT change.
Liquefactive: cells liquify, brain has totally liquefied
Caseous : cheesy, necrotic area is granular which makes it caseous
Fat: . Could also be due to fat trauma.

Question 16

What disease is fat necrosis associated with and why?

Answer 16

Acute pancreatitis - release of lipases that break down triglycerides into free fatty acids and glycerol. Free fatty acids associate with calcium deposits in the extracellular fluid and deposits

Question 17

Describe some causes of apoptosis

Answer 17

Embryogenesis - lumen of intestine created because of apoptosis
Removal of auto-reactive T in the thymus
Cell deletion in proliferating populations

Question 18

Describe differences between apoptosis and necrosis.

Answer 18

Apoptosis is an active process (required energy) Apoptosis can be physiological or pathological but necrosis is pathological
Apoptosis is not associated with inflammation as inside cells are not exposed to the outside.
-apoptosis is usually offered as a response to mild injury,necrosis is a response to severe injury
-apoptosis is a neater process, nucleus shrinks and little bits of the cell break off. it is then phagocytosed by macrophages.

Question 19

What is necroptosis

Answer 19

Programmed cell death associated with inflammation e.g. viral infections

Question 20

Barrett’s oesophagus is a classic example of:

Answer 20

Barrett’s oesophagus is an abnormal change in the cells of the lower oesophagus, thought to be caused from chronic exposure to stomach acid. Metaplasia is a reversible change from one type of cell to another.