Topic 2 - Cellular injury and inflammation

Question 1

What are the four types of cell adaptation?

Answer 1

hypertrophy, hyperplasia, atrophy, metaplasia

Question 2

What is hypertrophy and what causes it? Give one example.

Answer 2

Hypertrophy is the increase in the size of cells that results in an increase in the size of the affected organ.
The increased size of the cells is due to the synthesis and assembly of additional intracellular structural components.

E.g. Cells that cannot multiply
◦ muscles in body builders
◦ cardiac muscle in hypertension

Question 3

What is hyperplasia? Give one example.

Answer 3

Hyperplasia is defined as an increase in the number of cells in an organ or tissue in response to a stimulus
Eg. Physiologic: Female breast during pregnancy (epithelium)
Eg. Pathologic: Hyperplasia of prostate in old age

Question 4

What is atrophy? Give one example.

Answer 4

Atrophy is defined as a reduction in the size of an organ or tissue due to decrease in cell size and number.
Eg. Pathologic
- Disuse atrophy
- Loss of nutrition

Question 5

Define metaplasia. Give examples.

Answer 5

Metaplasia is a reversible change in which one differentiated cell type (epithelial or mesenchymal) is replaced by another differentiated cell type.

Eg. Pathologic:
- the bronchial columnar epithelium becomes squamous epithelium due
to chronic inflammation.
- In chronic cervicitis, the cervical columnar epithelium metastasizes into squamous epithelium.

Question 6

What would happen if metaplasia persists?

Answer 6

The influences that predispose to metaplasia, if persistent, can initiate malignant transformation in metaplastic epithelium.

Question 7

What are the causes of cellular injury?

Answer 7

1. Hypoxia – lack of blood supply or lack of oxygen
2. Physical agents – Heat, mechanical trauma, radiation, electric shock, sudden change in atmospheric pressure
3. Chemical agents - glucose or salt in high concentration, poisons, drugs, insecticides
4. Biological agents - viruses, bacteria, fungi and parasites
5. Autoimmunity
6. Nutritional defects - anorexia nervosa, Atherosclerosis

Question 8

4 mechanisms of cellular injury?

Answer 8

1) Mechanical disruption of whole cell
2) Failure of cellular membrane integrity
3) Blockage of metabolic pathways in cells
4) Damage or loss of nuclear DNA

Question 9

Two most common degeneration? (reversible cell injury)

Answer 9

Best examples are cellular swelling and fatty change.
Cellular swelling:
- Cellular swelling is the first manifestation of almost all forms of injury to cells
- Gross: It causes some pallor, increase in weight of the organ
- Light microscopy: small clear vacuoles may be seen within the cytoplasm

Fatty change:
The terms steatosis and fatty change describe abnormal accumulations of triglycerides within parenchymal cells
Fatty change is often seen in the liver, because it is the major organ involved in
fat metabolism, but is also occurs in heart, muscle, and kidney

Question 10

What is apoptosis?

Answer 10

programmed cell death. It is induced by a tightly regulated suicide program

Question 11

What is necrosis?

Answer 11

the death of cells or tissues in a living organism – occurs in pathological conditions (e.g. blood flow problems, diseases, or injury, etc.)

Question 12

Differentiate apoptosis and necrosis in terms of induction, extent, cell membrane integrity, morphology, inflammatory response?

Answer 12

Apoptosis:
- induced by physiological or pathological stimuli
- limited to single cells
- Cells maintain their cell
membrane
- Shrink and fragment to form apoptotic bodies with dense chromatin
- No inflammation

Necrosis:

• due to pathological injury
• affects cell groups
• cells lose their cell membrane
• swell and lyse
• usually have inflammation

Question 13

6 types of necrosis?

Answer 13

1. Coagulative necrosis
2. Liquefactive necrosis
3. Fat necrosis (a) enzymatic (b) non-enzymatic/traumatic
4. Caseous necrosis
5. Fibrinoid necrosis (FYI)
6. Gangrene (a) dry (b) wet (c) gas

Question 14

What is coagulative necrosis? (what it is, where it occurs, why it occurs, and microscopic morphology)

Answer 14

Coagulative necrosis is a form of necrosis in which the architecture of dead
the tissue is preserved.

Occurs in:
◦ Solid organs like kidney, heart, spleen and adrenal gland
◦ Liver cells (result of viruses or toxic chemicals)
◦ Skin (burns)
Cause: is mainly ischemia caused by obstruction in a vessel (resulting deficient
blood supply (ischemia) and anoxia)

Microscopic Morphology:
o The necrotic cell retains cellular outline for several days.
o The cell, devoid of its nucleus, appears as a coagulated, pink-staining,
homogeneous cytoplasm