Hormones that Affect Blood Sugar Pancreatic Hormones Produced

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.

QUESTION 1 What happens when the body does not produce insulin or the receptors no longer responds to insulin?

Diabetes • Type I Diabetes (Insulin Dependent): – Early degradation of beta cells. – Unable to produce insulin. • Type II Diabetes (Non-Insulin Dependent): – Decreased insulin production or ineffective use of insulin. – Controlled with diet, exercise and oral drugs. Suffer from hyperglycemia (high blood sugar).

QUESTION 2 If glucose is not taken into body cells, how does the body produce energy?

Diabetes • Absence of insulin means little or no glucose in body cells. – Cells metabolize fats and proteins for energy.

QUESTION 3 If a person has very high blood sugar, how does this impact filtration?

QUESTION 4 With respect to kidney function and water balance, what happens when glucose reabsorption does not occur?

Diabetes • Kidneys are unable to reabsorb all of the blood glucose, so excess glucose appears in urine. • People with untreated diabetes are thirsty. Why?

Try This! Describe why a person with untreated diabetes would urinate frequently. Refer to the two osmotic gradients in urine formation in your answer.

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): – ↑ blood amino acids. • Converted to glucose. • Repairs damaged tissues. – Fats broken down into fatty acids to ↑ available energy. – ↓ insulin to ↓ blood glucose uptake (except brain).

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 (T 4) • Triiodothyronine (T 3) – Both need iodine to be made. – Used to oxidize sugar and other nutrients. – More T 4 in the blood will “boost metabolism”

Hypothyroid or Hyperthyroid If the thyroid gland produces T 4 and T 3, hormones that regulate metabolism, what would happen if: a) The thyroid stopped producing T 4 and T 3? (hypothyroidism) b) The thyroid could not stop producing T 4 and T 3? (hyperthyroidism)

Calcitonin is also released by the thyroid, and it counter-acts parathyroid hormone (PTH) by: • Inhibiting Ca 2+ absorption by the intestines • Increases Ca 2+ reabsorption in the nephrons of the kidney

Thyroid Negative Feedback Loop

Acronyms: • TRH – Thyroid Releasing Hormone • TSH – Thyroid Stimulating Hormone

What happens if the body lacks iodine?

Goiter

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

Human Growth Hormone (HGH) • Too much? - Giantism • Too little? - Dwarfism • Produced in and released from the anterior pituitary gland. Famous Example: How did Andre the Giant die?

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

Growth Hormone Doping? • Some athletes believe that taking human growth hormone supplements will increase their athletic performance. – In small groups, look up the practice of “doping” with human growth hormone. Come to a consensus about whether or not this practice is safe. Be prepared to back up your stance with evidence.