L1- Introduction

Question 1

What is atrophy?

Answer 1

A reduction in the size or function of an organ (by reduced cell size/number) under pathophysiological stress
• Reversible when abnormal stimulus is removed

Question 2

What are stresses causing atrophy?

Answer 2

• Reduced functional demand
• Inadequate supply of oxygen or nutrients
• Altered balance between protein synthesis and degradation
• Aging (normal)

Question 3

What is autophagy?

Answer 3

• Structural proteins and organelles are destroyed reducing cell size and the functional capacity of the cell
• Allows cell to survive by reducing its metabolic requirements

Question 4

How does autophagy occur?

Answer 4

1. ER derived membrane surrounds organelle
2. Early autophagic body forms
3. Fuses with lysosomal hydrolase to form tubulovesicular body
4. Organelle is degraded and residual body is yellow/orange

Question 5

What is hypertrophy?

Answer 5

An adaptive change resulting in an increase in cellular size to either satisfy increased functional demand or in response to trophic signals

Question 6

What is physiological hypertrophy?

Answer 6

• Skeletal muscle due to exercise

* Compensatory of a kidney after removal of the other kidney

Question 7

What is pathological hypertrophy?

Answer 7

• Asthma- smooth muscle

* Cardiac- due to hypertension

Question 8

What is hyperplasia?

Answer 8

An adaptive increase in the number of cells in an organ/tissue.
Often occurs concurrently with hypertrophy

Question 9

Why does hyperplasia occur?

Answer 9

• Due to hormonal stimulation, increased functional demand or chronic injury/inflammation
• Physiological- breast enlargement in pregnancy
• Pathologic- ductal hyperplasia of the breast

Question 10

What is metaplasia?

Answer 10

An adaptive response to chronic injury in which the tissue adopts the most protective phenotype
Almost always pathologic but reversible when the stress is removed

Question 11

What are examples of metaplasia?

Answer 11

Squamous metaplasia of the lungs

Glandular metaplasia of the oesophagus

Question 12

What is dysplasia?

Answer 12

The disordered growth and maturation of cells within a tissue/organ. Often viewed as a precursor to malignancy and most irreversible

Question 13

What are signs of dysplasia?

Answer 13

• Variation in cell size and shape
• Nuclear enlargement
• Disorganised arrangement of cells within the epithelium

Question 14

What are the causes of cell injury?

Answer 14

• Hypoxia
• Ischaemia
• Trauma
• Infections

Question 15

What happens in necrosis?

Answer 15

Enzymatic digestion and leakage of cellular contents occurs after swelling of contents (always pathologic)

Question 16

What happens in apoptosis?

Answer 16

Formation of apoptotic bodies and the phagocytosis of apoptotic cells and fragments (pathologic and physiologic)

Question 17

What are the consequences of necrosis?

Answer 17

1. Acute or chronic inflammation
2. Immunological reactions to sub-cellular components released by dead tissue or self antigens
3. Lysis and absorption
4. Isolation and discharge
5. Encapsulation, calcification