pt3

Question 1

In which tissues does coagulative necrosis typically occur?

Answer 1

All tissues except the brain following hypoxic injury.

Question 2

What are the key microscopic features of coagulative necrosis?

Answer 2

Preservation of cell architecture with loss of nuclei and coagulated eosinophilic cytoplasm.

Question 3

What type of necrosis is characteristic of bacterial infections and CNS hypoxic injury?

Answer 3

Liquefactive necrosis.

Question 4

What causes liquefactive necrosis?

Answer 4

The accumulation of inflammatory cells, leading to enzymatic digestion of dead cells into a liquid mass.

Question 5

What is the gross appearance of caseous necrosis?

Answer 5

A cheesy, yellow-white appearance due to tissue destruction, commonly seen in tuberculosis.

Question 6

What disease is most commonly associated with caseous necrosis?

Answer 6

Tuberculosis.

Question 7

What is fat necrosis?

Answer 7

A focal area of fat destruction due to pancreatic lipase release, commonly seen in acute pancreatitis.

Question 8

What is a characteristic feature of fat necrosis?

Answer 8

White chalky calcium soap deposits at lipid breakdown sites.

Question 9

What is apoptosis?

Answer 9

A regulated process of programmed cell death that removes unwanted or damaged cells without causing inflammation.

Question 10

How does apoptosis differ from necrosis?

Answer 10

Apoptosis is controlled and does not cause inflammation, whereas necrosis is uncontrolled and triggers inflammation.

Question 11

What happens when apoptosis is reduced?

Answer 11

Cells accumulate, leading to conditions like cancer (neoplasia).

Question 12

What happens when apoptosis is excessive?

Answer 12

Excessive cell loss, leading to conditions like atrophy.

Question 13

What are the main cellular events in apoptosis?

Answer 13

• DNA fragmentation
• Cytoskeletal breakdown
• Mitochondrial dysfunction
• Cell shrinkage
• Formation of apoptotic bodies

Question 14

What nuclear changes occur in apoptosis?

Answer 14

Pyknosis (nuclear shrinkage) followed by karyorrhexis (nuclear fragmentation).

Question 15

How are apoptotic bodies cleared from the body?

Answer 15

They are rapidly phagocytosed by neighbouring cells or immune cells.

Question 16

How is apoptosis regulated?

Answer 16

By an intracellular program involving pro-apoptotic and anti-apoptotic factors.

Question 17

What are two examples of pathological apoptosis?

Answer 17

1. Radiation-induced apoptosis
2. Viral infection-induced apoptosis

Question 18

What are the key differences between necrosis and apoptosis?

Answer 18

• Necrosis: Uncontrolled, inflammatory, involves large groups of cells.
• Apoptosis: Controlled, non-inflammatory, affects individual cells.

Question 19

What happens to cellular contents in necrosis vs. apoptosis?

Answer 19

• Necrosis: Leakage of cell contents.
• Apoptosis: Cellular components are neatly packaged into apoptotic bodies.

Question 20

What is the most likely type of necrosis seen in the brain?

Answer 20

Liquefactive necrosis.

Question 21

Why does liquefactive necrosis occur in the brain after ischemic injury?

Answer 21

The brain lacks structural proteins that can maintain architecture after cell death, leading to complete tissue digestion.

Question 22

What is haemostasis?

Answer 22

A tightly regulated process that keeps blood fluid in normal vessels while allowing clot formation at injury sites.

Question 23

What are the three main components of haemostasis?

Answer 23

1. Vascular wall (endothelium)
2. Platelets
3. Coagulation cascade

Question 24

How is thrombosis different from haemostasis?

Answer 24

Thrombosis is a pathological process where a solid mass of blood components forms inappropriately within the vascular system.

Question 25

What is the main risk of thrombosis in the vascular system?

Answer 25

Thrombi are poorly attached and prone to fragmentation, which can cause embolism.

Question 26

What are the three major factors that contribute to thrombosis?

Answer 26

Virchow’s Triad: 1. Endothelial injury (e.g., trauma, atherosclerosis) 2. Abnormal blood flow (stasis or turbulence) 3. Hypercoagulability (thrombophilia)

Question 27

How does endothelial injury promote thrombosis?

Answer 27

* Exposes the extracellular matrix (ECM) * Allows platelet adhesion * Triggers the release of tissue factor, activating the clotting cascade

Question 28

What type of abnormal blood flow is associated with arterial and venous thrombosis?

Answer 28

* Turbulence → Contributes to arterial and cardiac thrombosis * Stasis → Contributes to venous thrombosis

Question 29

What is hypercoagulability, and what are common causes?

Answer 29

* Increased tendency of blood to clot * Can be due to genetic factors (e.g., Factor V Leiden mutation) or acquired factors (e.g., prolonged immobility, pregnancy, cancer).

Question 30

Where do arterial thrombi typically form?

Answer 30

At sites of turbulence or endothelial injury, often superimposed on atherosclerosis.

Question 31

What are common sites of arterial thrombosis?

Answer 31

* Coronary arteries (heart attack) * Cerebral arteries (stroke) * Femoral arteries (limb ischemia)

Question 32

How do arterial thrombi appear microscopically?

Answer 32

They consist of alternating layers of platelets, fibrin, and red blood cells, known as lines of Zahn.

Question 33

Where does venous thrombosis usually occur?

Answer 33

In superficial or deep veins of the leg (deep vein thrombosis, DVT).

Question 34

Why does venous thrombosis often remain asymptomatic?

Answer 34

Collateral bypass channels can compensate, making about 50% of cases asymptomatic.

Question 35

What are the two main complications of venous thrombosis?

Answer 35

1. Local pain and oedema (due to impaired drainage) 2. Pulmonary embolism (if thrombus dislodges)

Question 36

What is the most common cause of thrombotic lesions in deep veins?

Answer 36

Blood stasis at venous valves, which creates turbulence and promotes clot formation.

Question 37

How can deep vein thrombosis (DVT) be prevented during long flights?

Answer 37

* Leg exercises * Hydration * Compression stockings * Avoiding prolonged immobility

Question 38

What are the four possible outcomes of a thrombus?

Answer 38

1. Propagation – Thrombus enlarges. 2. Embolization – Thrombus dislodges and travels to another site. 3. Dissolution – Thrombus breaks down via fibrinolysis (e.g., t-PA therapy). 4. Organization & recanalization – The thrombus is incorporated into the vessel wall, restoring blood flow.

Question 39

Why are fibrinolytic agents like tissue plasminogen activator (t-PA) most effective when given early?

Answer 39

Because fibrinolysis is most effective within 5 hours of thrombus formation.

Question 40

What are the main complications of arterial thrombosis?

Answer 40

Distal tissue infarction due to obstruction of blood flow.

Question 41

What are the main complications of venous thrombosis?

Answer 41

Congestion, oedema, and embolism due to impaired venous drainage.

Question 42

What is an embolism?

Answer 42

A detached thrombus or fragment that travels through the bloodstream and causes obstruction elsewhere.

Question 43

What happens if a venous thrombus embolizes?

Answer 43

It enters the pulmonary circulation, causing a pulmonary embolism (PE), which can be fatal.

Question 44

What happens if an arterial thrombus embolizes?

Answer 44

It can block downstream organs, leading to stroke, myocardial infarction, or limb ischemia.

Question 45

Why does arterial blood clot formation often occur at sites of atherosclerosis?

Answer 45

Because atherosclerotic plaques cause endothelial injury and turbulent blood flow, promoting clot formation.