4C: hormonal control of growth

Question 1

what is the proper name of the growth hormone?

Answer 1

somatotropin

Question 2

what is the function of the growth hormone?

Answer 2

• stimulation of liver, muscle, cartilage, bone and other tissues to synthesize n secrete IGFs

Question 3

what are IGFs?

Answer 3

insulin-like growth factors
- promote growth of body cells, protein anabolism. tissue repair, lipolysis n elevation of blood glucose concentration

Question 4

what are hypothalamic hormones associated w somatotropin?

Answer 4

release: GHRH and TRH
inhibition: GHIH

Question 5

what is GHRH?

Answer 5

growth hormone releasing hormone

Question 6

what is TRH?

Answer 6

thyrotropin

Question 7

what is GHIH?

Answer 7

growth hormone inhibiting hormone aka somatostatin

Question 8

how is low blood glucose regulated with help of GHRH?

Answer 8

• hypoglycaemia stimulates release of GHRH
• GHRH stimulates release of GH by somatotrophs
  -> GH and IGFs increase lipolysis n promote gluconeogenesis
• blood glucose level rises to normal

Question 9

how is high blood glucose regulated w help of GHIH?

Answer 9

• hyperglycaemia stimulates release of GHIH
• GHIH inhibits GH secretion by somatotrophs
• a low level of GH and IGFs decreases lipolysis and reduces gluconeogenesis
  -> blood glucose falls back to normal

Question 10

how is low blood sugar regulated w help of glucagon?

Answer 10

• glucagon released by alpha cells, acts on hepatocytes (liver cells)
  ->converts glycogen into glucose -> glycogenolysis
  -> forms glucose from lactic acid n amino acids -> gluconeogenesis

Question 11

how is high blood sugar regulated w help of insulin

Answer 11

• insulin released by beta cells, acts on various body cells
  -> accelerate facilitated diffusion of glucose into cells
  -> speeds up glycogenesis
  -> increase uptake of amino acids and increase protein synthesis
  -> speed lipogenesis
  -> slow glycogenolysis
  -> slow gluconeogenesis

Question 12

which 6 endocrine glands are involved in control of growth and development?

Answer 12

• hypothalamus
• pituitary
• thyroid
• gonads
• pancreas
• adrenal glan

Question 13

what are the four major tropic of the hypothalamus?

Answer 13

GHRH - growth hormone releasing hormone
TRH - thyrotropin RH
GnRH - gonadotropin RH
CTRH - corticotropin RH

Question 14

what are 5 major hormones of the pituitary gland?

Answer 14

GH/STH - growth hormone/somatotropin
TSH - thyroid stimulating H
FSH - follicle stimulating H
LH - luteinising H
ACTH - adrenocorticotropic H

Question 15

what does the thyroid gland secrete and what does this affect?

Answer 15

• stimulated by TSH to secrete thyroxine
• affects metabolism n physical development
• provides nutrients to generate energy for protein synthesis

Question 16

what do the gonad glands secrete?

Answer 16

secrete oestrogens and androgens, important in fat n protein metabolism

Question 17

what do the adrenal glands secrete?

Answer 17

steroid hormones like cortisol, affect metabolism n decrease protein synthesis

Question 18

how is the liver relevant to g n d?

Answer 18

• stimulated by GH to produce IGFs
• glucose transport, incorporation of amino acids into muscle

Question 19

how is the pancreas relevant to g n d?

Answer 19

not directly controlled by hypothalamus, but produces
- insulin
- glucagon
- somatostatin