Hyperplasia, Hypertrophy

Question 1

Hypertrophy

Answer 1

Increase in the size of a cell, or increase in the size of a tissue

Question 2

Hyperplasia

Answer 2

Increase in the number of cells in a tissue

- often both hypertrophy and hyperplasia are present

Question 3

What are the 3 causes for hypertrophy/hyperplasia?

Answer 3

• increased demand
• endocrine stimulation
• nutrition

Question 4

Increased cell activity leads to _______

Answer 4

Proliferation of organelles and/or cell division until a new balance is reached

Question 5

Hypertrophy and hyperplasia are _____ in many cases

Answer 5

Beneficial

• lymphoid hyperplasia
• persistent change in the environment leads to overcompensation = harmful effects

Question 6

Physiologic

Answer 6

• hormonal: maturity/development

- compensatory: liver resection

Question 7

Pathologic

Answer 7

• chronic irritation
• endocrine
• virus induced
• increased bloodflow
• nodular hyperplasia

Question 8

Hypertrophy can occur in _____

Answer 8

Any tissue

• size/number of organelles increase
• physiologic or pathologic (cardiac hypertrophy)

Question 9

5 causes/effects of hypertrophy

Answer 9

• increased workload
• endocrine stimulation
• thyroid (anabolic effect)
• adrenal (cortisol excess)
• estrogens - uterine/mammary development

Question 10

Increased workload

Answer 10

Enlarged hearts and muscle mass in athletic animals

• myofilaments increase in length and number (resistance), mitochondria increase (endurance)
• kidney hypertrophy when the other is removed

Question 11

What is an example of thyroid hypertrophy?

Answer 11

Hyperthyroidism in cats

- cardiac hypertrophy

Question 12

What is an example of adrenal hypertrophy?

Answer 12

Hepatocyte hyperplasia = steroid hepatopathy

Question 13

Nodular gingival hyperplasia

Answer 13

Reaction to chronic inflammation

- inherited in Boxers, Swedish silver foxes

Question 14

Canine prostate can develop ______

Answer 14

Benign hyperplasia

- testosterone dependent

Question 15

Cystic endometrial hyperplasia

Answer 15

Occurs in horse uterus

- hypertrophy of gland cells

Question 16

Lmyphocystis disease is an example of _____

Answer 16

Hypertrophy

- iridovirus infection of dermal fibroblasts

Question 17

Canine papillomavirus is an example of _____

Answer 17

Hyperplasia

- grows on any mucosal surface

Question 18

Characteristics of hyperplasia

Answer 18

• definite structures
• increased cells
• well differentiated

Question 19

Hyperplasia in the bone marrow

Answer 19

• enteritis, blood loss
• erythroid
• myeloid

Question 20

Thyroid

Answer 20

• expansile nodules
• well differentiated cells
• colloid filled follicles
• hypertrophy and hyperplasia

Question 21

Iodine deficiency

Answer 21

Occurs in goats, presented as large thyroids bilaterally

• goiter
• hypertrophy and hyperplasia

Question 22

Hyperthyroidism in the cat

Answer 22

Chronic renal disease –> retained phosphorus –> increased FGF23 –> reduced calcitriol –> increase PTH synthesis –> parathyroid hypertrophy and hyperplasia

Question 23

Fibrous osteodystrophy

Answer 23

• diet high in phosphorous (wheat bran)
• loss of maxillary/mandibular bone
• reactive fibroblast hyperplasia and connective tissue production

Question 24

Hypertrophic osteopathy

Answer 24

Increased bloodflow due to hyperplasia

- will often see chronic process in the chest cavity

Question 25

Nodular hyperplasia

Answer 25

Bulging pale tan/yellow nodules in the liver - friable, glycogen and lipid - not associated with hepatocellular dysfunction! Also occurs in the pancreas

Question 26

Nodules in the spleen

Answer 26

- hyperplastic white pulp and dilated red pulp sinuses - can lead to hematomas - marginal sidero-calcific plaques

Question 27

Hyperplastic nodules in the spleen

Answer 27

- excessive white pulp - expansile margin - unencapsulated

Question 28

Splenic hematomas

Answer 28

Bleeding from - hyperplastic nodule - hemangiosarcoma

Question 29

Nodular cortical hyperplasia in the adrenal gland of horses is often _____

Answer 29

Incidental

Question 30

Eimeria stiedae causes _____

Answer 30

Hyperplasia of biliary epithelium in the rabbit - finger like projections of biliary epithelium - many coccidian stages within epithelial cells - cholestasis - atrophy of surrounding tissues

Question 31

Recurrent choke in horses due to ______

Answer 31

Muscular hypertrophy | - diverticula

Question 32

Which condition in cats causes myofiber disarray?

Answer 32

Hypertrophic cardiomyopathy | - also causes fibrosis

Question 33

Polyploidy is found in

Answer 33

Horse livers due to chronic toxicosis (pyrrolizidine alkaloids) - hypertrophy - megalocytes, necrosis, fibrosis (hepatic atrophy)