Cellular and tissue responses and adaptations

Question 1

What are the different types of adaptations?

Answer 1

• Hypertrophy: swelling (cell size increases)
• Hyperplasia: need cells to divide, get some swelling (cell number increases)
• Atrophy: cells switch off/ undergo apoptosis (number of cells reduce)
• -Metaplasia: change- from simple columnar to squamous

Question 2

What is the basic cause of hypertrophy/ hyperplasia/ atrophy/ metaplasia?

Answer 2

Hypertrophy: increase demand/ stimulation
Hyperplasia: increase demand/ stimulation
Atrophy: decrease nutrients/ stimulation
Metaplasia: chronic irritation

Question 3

What are the 2 types of physiological hyperplasia?

Answer 3

• Hormonal

- Compensatory

Question 4

What is the usual cause of pathologic hyperplasia?

Answer 4

Excesses of hormones or growth factors in certain viral infections (e.g. poxviruses and papillomaviruses

Question 5

Give examples of physiologic and pathologic hyperplasia

Answer 5

Physiologic= dairy cow with enlarged mammary gland
Pathologic= benign enlarged prostate/ congenital goitre/ Orf

Question 6

Give some examples of pathologic atrophy?

Answer 6

• atrophy of disuse
• denervation atrophy (spinal muscular atrophy)
• inadequate nutrition
• diminished blood supply

Question 7

What are the causes of metaplasia?

Answer 7

• Chronic irritation
• Deficiencies (e.g. vit A)
• Result of cell/ tissue injury
• oestrogen toxicity

Question 8

In what cell type does hypertrophy normally occur?

Answer 8

-Stable or permanent

Question 9

In what cell type does hyperplasia normally occur?

Answer 9

In labile cells

often only in epithelial

Question 10

What are the definitions for labile/ stable/ permanent cells?

Answer 10

Labile: routinely proliferate (epidermis, intestinal epithelium/ bone marrow cells)

Stable cells: intermediate in ability to regenerate/ divide (bone/ cartilage/ smooth muscle)

Permanent: Very little capacity to regenerate (neurons/ cardiac/ skeletal muscle cells)

Question 11

What is the name for a disorderly arrangement of cells?

Answer 11

Dysplasia (e.g. cancer cells)

Question 12

What are the different types of disorders of growth?

Answer 12

• Agenesis
• Aplasia
• Atresia
• Hypoplasia
• Dysplasia
• Neoplasia

Question 13

What is the definition of agenesis?

Answer 13

-complete failure of an organ to develop during embryonic stage due to absence of primordial tissue

Question 14

What is the definition of aplasia?

Answer 14

lack of development of an organ (different is that in this case the precursor did exist at some point)… i.e. it started to develop but never fully formed

Question 15

What is the definition of atresia?

Answer 15

absence or closure of a normal body orifice or tubular passage such as anus/ intestine.

Question 16

What is the definition of hypoplasia in terms of growth?

Answer 16

Incomplete development of an organ

Question 17

What is the definition of dysplasia in terms of growth?

Answer 17

Disordered growth

Question 18

What is the definition of neoplasia in terms of growth?

Answer 18

Abnormal growth of cells- new formation (lump/ swelling)

Question 19

What are the different types of intracellular accumulations?

Answer 19

Accumulations of normal cellular constituents

• Abnormal substance
• Pigment

typically lipids/ glycogen/ proteins

Question 20

What is lipidosis?

Answer 20

Accumulation of triglycerides within parenchymal cells. Most commonly occurs in the liver.

Question 21

Which animals are prone to glycogen intracellular accumulation?

Answer 21

• Animals with abnormal glucose levels or glycogen metabolism
• Diabetes mellitus, glycogen storage diseases, corticosteroid therapy

Question 22

What are the causes of protein accumulation in cells?

Answer 22

• Proteinuria
• Excessive production of normal protein (Mott cells)
• Defects in protein folding (TSEs/ prion diseases)

Question 23

What are the types of extracellular accumulations?

Answer 23

• Amyloid (generic term for a load of proteinaceous substances with a hyaline appearance)
• Gout (deposition of sodium urate crystals or urates in tissue-common in dehydrated birds/ reptiles)
• Cholesterol (by products of haemorrhage and necrosis)

Question 24

What are the types of calcification?

Answer 24

• Dystrophic calcification (locally in necrotic tissue)

- Metastatic calcification ( normal tissue secondary to hypercalcaemia

Question 25

What are the causes of metastatic calcification?

Answer 25

• Renal failure
• Vitamin D toxicosis
• PTH and PTH related protein (relleassed by types of neoplasia)
• Destruction of bone from primary/ metastatic neoplasms

Question 26

Give an example of dystrophic pathologic calcification

Answer 26

-Myodegeneration (Vitamin E/ selecium deficiency)

Question 27

What is an example of metastatic pathologic calcification?

Answer 27

• Pleural calfication secondary to renal failure

Question 28

What are the different types of pigmentation?

Answer 28

• Exogenous (carbon/ carotenoid/ tetracyline)
• Endogenous (melanin/ lipofuscin-ceroid)
• Haematogenous (haemoglobin/ hemosiderin/ bilirubin)