Download hormones 3

Hormonal Coordination 3
• Hormones produced by,
 parathyroid
 pancreas and
 adrenals
• Their physiological effects
Parathyroid glands
• Small round 4 tissue masses attached to
posterior surface of lateral lobes of thyroid
gland
• Contain
– Principal cells (chief cells) - source of
parathyroid hormone
– Oxyphil cells
Parathyroid hormone action
• Bone
Increase number & activity of osteoclasts,
bone resorption increased, release Ca2+ &
HPO42- to blood
Parathyroid hormone action cont.
• Kidney
1. increase the rate at which kidneys
remove Ca2+ & mg2+ from urine &
returns to blood (Increase blood Ca2+ &
Mg2+ levels)
2. Inhibits reabsorption of HPO42filtered by kidneys, more HPO42- is
excreted through urine (decrease blood
HPO42- level (overall)
Parathyroid hormone action cont..
• Kidney
3. promote formation of calcitriol
hormone rom vitamin D
(Calcitriol increase the rate of absorption of Ca2+ ,
Mg2+ & HPO42- from GastroIntestinal tract to the
blood)
Pancreas –Islets of Langerhans
4 types of hormone secreting cells
•
•
•
•
Alpha cells (A cells) – secrete glucagon
Beta cells (B cells) – secrete insulin
Delta cells(D cells)–secrete somatostatin
F cells – secrete pancreatic polypeptide
Main effects of pancreatic hormones
•
•
•
•
Glucagon - increase blood glucose level
Insulin-decrease blood glucose level
Somatostatin- inhibit insulin release
Pancreatic polypeptide– Inhibit secretion of somatostatin
– Inhibit contraction of gall bladder
– Inhibit secretion of pancreatic digestive
enzymes.
How glucagon increase blood glucose..
Act on hepatocytes
•
Convert glycogen to glucose
•
Form glucose from lactic acid & amino acids
Glucose release by hepatocytes to blood
How insulin decrease blood glucose
Acts on various body cells to
• Increase facilitated diffusion of glucose into cells
• Speed conversion of glucose to glycogen
• Slow synthesis of glucose from other sources
• Increase uptake of amino acids & increase
protein synthesis
• Speed synthesis of fatty acids
Diabetes mellitus
• As blood glucose level increases glucose
appear in urine
• Unable to reabsorb water-excessive urine
production, excessive thirst
• Two major types
– Type I diabetes (insulin dependent)
– Type II diabetes (maturity onset diabetes)
Adrenal glands
• Located above
each kidney
• Divided in to
cortex and
medulla
Adrenal cortex
• Outer zone- mineral corticoids
• Middle zone- glucocorticoids
• Inner zone – gonadocorticoids
(low levels of sex hormones- androgens)
Mineral corticoids
• Help to control water and electrolyte
homeostasis
• Aldosteron act on kidney and stimulate
increase absorption of water and Na+
glucocorticoids
• Promote normal metabolism and
resistance to stress
• Cortisol, cortocosterone, cortisone
Hormones produced by adrenal medulla
• Adrenalin and Noradrenalin
• Both produce effects that mimic the effects
of autonomic nervous system during
stress.
• Responsible for “fight or fright response”