Disorders of Growth and Differentiation

Question 1

define auxetic growth of a cell

Answer 1

growth of a pre-existing cell (in size)

Question 2

Define: accretionary growth of cells

Answer 2

ECM grows and cells do not

Question 3

Physiological Hypertrophy in Muscle

Answer 3

Increase in cell size but not number

Question 4

What pathologies cause pathological cell hypertrophy?

Answer 4

The right ventricle in cardiac dysfunction

Question 5

What are some examples of physiological cell hyperplasia?

Answer 5

Adaptation to Altitude: Raised RBC count

Lactation: alveolar buds increase during pregnancy and lactation

Tissue Repair: Angiogenesis, Wound Healing, Liver Regeneration, Scarring

Question 6

What are some examples of pathological hyperplasia?

Answer 6

Psoriasis: autoimmune skin disease

Keloid Scarring

Liver regeneration leading to cirrhosis, fatty change, or alcoholic hepatitis

Question 7

Physiological Atrophy

Answer 7

Reduced Cell Size or Number or Both

Question 8

What are some examples of Physiological Atrophy?

Answer 8

The thymus gland atrophies with age

Atrophy is a common part of ageing

Question 9

What are some examples of pathological atrophy?

Answer 9

Muscles after trauma
Nerves in Paraplegics
Pressure from Bedsores
Diet in Anorexia Nervosa

Question 10

What is Turner Syndrome?

Answer 10

Lack one chromosome containing the SHOX gene, resulting in 45XO
Results in Short Stature

Question 11

What is the function of the SHOX gene?

Answer 11

Allows Chromosomes to realign and recombinate

Question 12

Where is the SHOX gene located?

Answer 12

In the pseudoautosomal region of the X chromosome (tip), so it escapes X-inactivation

Expressed in chondrocytes of the human growth plate

Question 13

Why does Turner Syndrome cause short stature?

Answer 13

Mutated/Missing SHOX gene

Question 14

Beckwith-Wiedemann Syndrome

Answer 14

Inheritance of two copies of a chromosome from 1 parent and none from the other

Increased expression of IGF-II; Decreased expression of H19

Causes overgrowth in early childhood

Question 15

Pituitary Gigantism

Answer 15

Increased IG1 and Growth Hormone, often from pituitary tumours

Question 16

What mutation is present in the majority of cases of achondroplasia?

Answer 16

G80 Mutation

Question 17

What is the function of the FGFR3 gene?

Answer 17

Inhibits growth in the proliferative zone and has most effect in chondrocytes, particularly in long bones

Question 18

Metaplasia

Answer 18

Change of differentiated cell type as a response to altered cellular environment; this most often happens in epithelial or mesenchymal cells

Question 19

Dysplasia

Answer 19

Increased cell proliferation, decreased differentiation, and expansion of malignant cells

Often a sign of premalignancy

Question 20

Agenesis (Disorder of Differentiation)

Answer 20

Complete failure to develop an organ or structure

Question 21

Atresia (Disorder of Differentiation)

Answer 21

Failure to develop a lumen

Question 22

Hypoplasia (Disorder of Differentiation)

Answer 22

Failure of an organ to develop to a normal size

Question 23

Ectopia/Heterotopia

Answer 23

small areas of mature tissue from one organ are present in another (eg endometriosis)

Question 24

Maldifferentiation

Answer 24

Failure of Normal Differentiation with persistence of primitive embryological features

Question 25

Wilms Tumour

Answer 25

Childhood malignancy of the kidney