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Learn about the endocrine system control, hormone regulation, functions of the thyroid and parathyroid glands, and the role of prostaglandins. Explore the effects of hormone binding on target cells.
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Bell Ringer • Which of the following does the endocrine system NOT control: • Body coordination • Mobilizing body defenses against stressors • Maintain electrolyte balance • Regulate cellular metabolism • Growth and development
Bell Ringer • Hormone concentrations in the blood are usually regulated by: • Positive feedback mechanisms • Negative feedback mechanisms • Neurological control • Hypothalmic control • Tropic hormone control
Bell Ringer • Being lipid soluble, steroids can do all of the following EXCEPT: • Diffuse through plasma membranes of target cells • Catalyze cyclic AMP • Enter the nucleus • Bind to receptor proteins in the nucleus • Activate genes to transcribe mRNA for protein synthesis
Bell Ringer • The pituitary gland is located: • At the brain stem • Within the “Turk’s saddle” of the sphenoid bone • Below the Adam’s apple • Within the mediastinum • Within the temporal lobe
Bell Ringer • The type of endocrine stimulus that involves changing levels of certain blood-borne ions and nutrients is called: • Hormonal stimulus • Humoral stimulus • Cell-mediated stimulus • Neural stimulus • Steroid stimulus
Thyroid Gland • Two lobes joined by isthmus • Follicles produce thyroid hormone (TH) • Thyroxine (T4) • Triiodothyronine (T3) • C-cells produce calcitonin
Thyroid Hormones • Thyroxine (T4) Triiodothyronine (T3) • Are produced in the follicular cells • Increase rate at which cells produce ATP from carbs, synthesize proteins and breakdown lipids • These hormones set your BMR – base metabolic rate (number of calories required to maintain life) • TSH from anterior pituitary controls their levels • Follicular cells require iodine to make T4 and T3
Not enough iodine? • Goiter • Follicles make the protein portion of the hormones, but don’t have iodine to complete the project. • Protein accumulates and forms a goiter.
Calcitonin • Synthesized by c-cells in the thyroid • Lowers blood calcium levels and phosphate ion concentrations • Inhibits osteoclasts • Stimulates osteoblasts
Parathyroid Glands • Hidden behind the thyroid gland • Secretes parathyroid hormone (PTH) • Increases blood calcium levels.
Something you should look up: • How is the nervous system affected by abnormally low calcium levels in the blood? • How is the nervous system affected by abnormally high calcium levels in the blood? • *HINT* this isn’t about bone density.
Thyroid problems Underactive thyroid = cretinism Hyperthyroidism = Graves Disease
Be sure to look up • Prostaglandins • Which classification of hormone are they? • What are they made of? (lipid, carb, proteins…) • What do some prostaglandins regulate?
And this… • Which one of the following is NOT typical of the changes that follow the binding of a hormone to its target cells? • Plasma membrane permeability changes • Cellular mutations occur • Enzymes are activated or inactivated • Mitosis is stimulated • Proteins are synthesized in the cell