Proportion

Question 1

what are pituitary tumours associated with?

Answer 1

gigantism - it secretes growth hormones

Question 2

what does the pituitary gland secrete?

Answer 2

growth hormones which act on local tissue, these tissues secrete IGF1 and IGF2 and control growth of tissues

Question 3

what can a lack of growth hormone cause?

Answer 3

laron syndrome

Question 4

how does growth hormone affect different tissue types?

Answer 4

affects post natal muscle growth directly
affects other tissues only indirectly

Question 5

how does the growth plate maintain itself?

Answer 5

using internal and external signals
mature cells die and become bone cells, new cells replace this

Question 6

what is a possible explanation for the rate of growth?

Answer 6

the larger the bone gets the further the signals have to travel and eventually the feedback system fails

Question 7

what is the vulnerability of limb growth?

Answer 7

takes place very rapidly and requires a high demand of oxygen, this means that to keep up with limb growth the vascular system need to grow very quickly into the elongating limbs
limb growth is vulnerable to anything that impairs vascular growth

Question 8

what does thalidomide do?

Answer 8

inhibits blood vessel growth, this meant many babies were born with limb deformitites

Question 9

what does fibroblast growth factor do?

Answer 9

inhibits both proliferation and differentiation of chondrocytes via FGFR3
activating mutations in FGFR3 causes premature growth plate closure

Question 10

how is soft tissue affected by limb growth?

Answer 10

soft tissue of the limb always match the bone growth, tissues are not independent to each other