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Endocrine System. SBI4U Nov 9. The Pituitary Gland: Master Gland Posterior Anterior. Anterior vs posterior pituitary lobe. Posterior (back lobe) : stores & releases hormones. Anterior (front lobe) : produces hormones . Thyroid Gland. Controlled by TSH T3+ T4 Calcitonin
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Endocrine System SBI4U Nov 9
Anterior vs posterior pituitary lobe • Posterior (back lobe) : stores & releases hormones. • Anterior (front lobe) : produces hormones.
Thyroid Gland • Controlled by TSH • T3+ T4 • Calcitonin • In liver T4 T3+I to become active.
Thyroid disorders • Goiter • Graves’ disease
Parathyroid Gland • 4 small glands • Secrete PTH • Need vitamin D for Calcium reabsorption. N.B: 2 anatagonistic hormones control Ca 2+ levels in blood
Regulation of calcium levels through negative feedback control
Ricket Disease -Vitamin D deficiency -Most frequent childhood disease.
Answer: The lower the thyroxine is released the slower blood sugar is used therefore the faster fat stores build up. These individuals secrete high levels of thyroxine which oxidize sugars and other nutrients at a faster rate. Food 60 % heat (these individuals feel very warm) 40% ATP production
Q3- As a person ages growth hormone production decreases. Explain the link between growth hormone production and aging?
As a person ages growth hormone (GH) production begins to decline therefore cellular and protein replacement is compromised.GH increases cell size in muscle cells & connective tissues by promoting protein synthesis and inhibiting protein degradation. As you age protein is often replaced by fat causing changes in body’s shape.
Q4. A nuclear accident in Chernobyl caused the release of radioactive wastes in air. The effect of the problem is still unknown but the effect on children has been the most extreme. One of the most radioactive materials released was Iodine-131 which causes inflammation and can lead to cancer. Draw a feedback loop that shows how thyroxine levels might be affected.
Increase in Iodine-131 levels-thyroid damagedthyroid cannot detect TSH levels T3+T4 production reduced low T4 levels do not turn off hypothalamus therefore increased production of TRHhypothalamus increases production of TRH anterior pituitary produces TSH thyroid cannot detect levels of TSH.