1 / 13

Metabolism Regulation

Metabolism Regulation. Intro to Metabolism Regulation. The Thyroid gland produces the hormones thyroxine (T4), calcitonin , triiodothyronine (T3) . The parathyroid glands produce parathyroid hormone (PTH). The pituitary gland produces growth hormone ( hGH ). Important Hormones in Metabolism.

darius-padilla
Download Presentation

Metabolism Regulation

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Metabolism Regulation

  2. Intro to Metabolism Regulation • The Thyroid gland produces the hormones thyroxine (T4), calcitonin, triiodothyronine (T3). • The parathyroid glands produce parathyroid hormone (PTH). • The pituitary gland produces growth hormone (hGH).

  3. Important Hormones in Metabolism • The two important thyroid hormones are T4 and T3. • They both regulate body metabolism and the growth and differentiation of tissues.

  4. Metabolism Feedback Loop • If the metabolic rate decreases then: • Hypothalamus sends thyroid releasing hormone (TRH) to the pituitary. • Pituitary sends thyroid stimulating hormone (TSH) to the thyroid • Thyroid secretes the iodine packed hormone thyroxine. • Thyroxine raises metabolism by increasing sugar usage by the body tissues which increases metabolic rate. • Thyroxine inhibits the release of TRH by the hypothalamus. TRH TSH T4 Body Tissues use more sugar

  5. Metabolism Feedback Loop Triiodothyronine(T3) is also produced. It is similar to thyroxine (T4) but with fewer iodine molecules associated with it. It is the more powerful thyroid hormone and is only released in a small quantity. It has many roles. It increases the production of RNA polymerase and therefore acts to increase the rate of protein synthesis.

  6. Fast Metabolism Individuals who secrete high levels of thyroxine can oxidize sugars and other nutrients at a faster rate. Approximately 60% of the glucose oxidized is released as heat. The other 40% is transferred to ATP which is consumed during activity and therefore there is no weight gain. Could be caused by hyperthyroidism.

  7. Slow Metabolism • Individuals who do not secrete high levels of thyroxine cannot oxidize sugars as quickly and the glucose is converted to glycogen and stored. Once the glycogen stores are filled, excess sugar is stored as fat. These individuals gain weight! • This could be a case of hypothyroidism (low thyroid secretions).

  8. Calcium Level Regulation

  9. Calcium Level Feedback Cycle If Calcium Levels Drop • If blood calcium levels drop, the parathyroid gland acts as the sensor, co-ordinating center and effector. • It senses the level of calcium dropping and releases parathyroid hormone (PTH). • PTH activates vitamin D which increases the amount of calcium absorbed in the intestines. • PTH causes the nephron (distal tubule primarily) to reabsorb more calcium. • PTH also causes bones to release calcium into the bloodstream.

  10. Calcium Level Feedback Cycle If Calcium Levels Rise • If blood calcium levels rise the thyroid gland acts as the sensor, co-ordinating center and effector. • It senses the level of calcium rising and releases calcitonin. • Calcitonin inhibits the nephron from reabsorbing calcium. • Calcitonin also inhibits bones from releasing calcium into the bloodstream.

  11. Homework • p. 387 #3, 6, 7

More Related