Download 8.2 Hormones that Affect Blood Sugar - Ms. Pasic

Hormones that Affect
Blood Sugar
Pancreatic Hormones
• Produced in the islets of Langerhans.
– Beta (β) cells produce insulin.
– Alpha (α) cells produce glucagon.
Hormonal Response to High
Blood Sugar
• ↑ blood sugar = release of insulin.
• Causes muscle, liver and other body cells
to become permeable to glucose.
• Glucose stored as glycogen.
• Result = ↓ blood sugar.
Hormonal Response to Low
Blood Sugar
• ↓ blood sugar = release of glucagon.
• Promotes breakdown of glycogen into
glucose, which is released into the blood.
• Result = ↑ blood sugar.
Adrenal Glands
• Each composed of two glands.
1. Adrenal medulla  short-term stress.
2. Adrenal cortex  long-term stress.
Adrenal Medulla
• Produces epinephrine (adrenaline) and
norepinephrine (noradrenaline).
• “Fight-or Flight Response”.
– ↑ blood sugar (glycogen  glucose).
– ↑ HR, breathing rate & cell metabolism.
– Dilation of blood vessels.
– Pupil dilation.
Adrenal Cortex
• Produces 3 types of hormones:
– Glucocorticoids.
– Mineralcorticoids.
– Sex hormones.
Adrenal Cortex
• Glucocorticoids (e.g., cortisol):
– Promotes conversion of amino acids to
glucose
– Promotes breakdown of fats to fatty acids
– Decreased glucose uptake by muscles
– Increased blood sugar in response to stress
Fight or Flight and Blood Sugar
Why block insulin during fight-or-flight
response?
Hormones that Affect
Metabolism
Two Major Glands
• Thyroid Gland
• Parathyroid Gland
Thyroid Gland
• Thyroxine (T4)
• Triiodothyronine (T3)
– Both need iodine to be produced.
– Used to oxidize sugar and other nutrients.
– More T4 in the blood will “boost metabolism”
Hypothyroid or Hyperthyroid
If the thyroid gland produces T4 and T3,
hormones that regulate metabolism, what
would happen if:
a) The thyroid stopped producing T4 and
T3? (hypothyroidism)
b) The thyroid could not stop producing T4
and T3? (hyperthyroidism)
Acronyms:
• TRH – Thyroid Releasing Hormone
• TSH – Thyroid Stimulating Hormone
Parathyroid Glands
• Four groups of cells on the thyroid gland.
• Release a hormone called parathyroid
hormone, or “PTH”.
– PTH raises the calcium levels in the blood.
Negative Feedback
Calcitonin
Calcitonin is also released by the thyroid,
and it counter-acts parathyroid hormone
(PTH) by:
• Inhibiting Ca2+ absorption by the intestines
• Inhibits Ca2+ reabsorption in the nephrons
of the kidney
Human Growth Hormone
(HGH)
• Too much? - Giantism
• Too little? - Dwarfism
• Produced in and released
from the anterior
pituitary gland.
Andre the giant
7 ft 4 inches 520 lb.
Human Growth Hormone
• Cause cells to grow in size and in number.
• Promotes protein synthesis.
• Promotes the breakdown of fats.
– ↑ GH, muscles use fatty acids as energy
– Loss of fat during growth spurts