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Thyroid Gland. An introduction to regulation of metabolism and the use of isotopes in medical diagnosis AP Big Idea #2 Homeostasis. Can you diagnose this patient?. Overview . Structure of the thyroid gland Structure of the thyroid hormones
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Thyroid Gland An introduction to regulation of metabolism and the use of isotopes in medical diagnosis AP Big Idea #2 Homeostasis
Overview • Structure of the thyroid gland • Structure of the thyroid hormones • Regulation of thyroid hormones (Examples of feedback to maintain homeostasis) • Pathology: What happens when control is off? how are isotopes used to determine thyroid function?
What is a gland? • “A group of special cells that make substances so that other parts of the body can work. • Example: • The pancreas produces insulin that is released into the blood to signal muscles cells to uptake sugar.
Other Glands of the Endocrine System Endocrine System: System of all the hormone secreting cells in an animal Figure 45.5
What is a hormone? • Chemical signal secreted into the body fluids (blood) that regulate the activity of specific target cells
A hormone cascade pathway Fig 45.17 What is the interactions between each of the thyroid related hormones?
What elemental substance is needed to catabolize (build) functional T4?
What are the targets of T3? • T3 signals the following responses: • Increase the rate of oxygen consumption and cellular metabolism • Maintain heart rate • Normal blood pressure • Muscle tone • Digestion • Reproduction
Mechanism of T3 & T4 • Enter cell membrane through transport proteins • Bind receptor in nucleus • Alter gene expression • What if this keeps on going and going and going????
Mechanisms of Cell Signaling: Which mechanism would T3 use (Fig 45.3)?
Review Case Study • Hyperthyroidism? • Hypothyroidism? • Homeostasis: Why is elevated TSH levels a signal for thyroid malfunction?
What is an isotope? • Can you remember this from chemistry? • Tracers: radioactive isotopes can be ingested and detected using a variety of methods • How can isotopes work as tracers and help us make medical diagnoses/study living things?
How are isotopes used to diagnose Graves or Goiter? • RAUI (Radioactive iodine uptake) • > baseline = Hyperthyroidism (Graves) • < baseline =Hypothyroidism (Goiter) Normal
On your own… • Using Campbell’s Figure 45.9, determine how feedback of calcitonin and PTH maintain blood calcium level.
Formative Assessment • Can you define negative feedback and explain the advantage of using a feedback system? • Can you identify negative feedback in each of the three systems we discussed? • Thermoregulation • Thyroid Regulation of Metabolism • Calcium Regulation • If given information about a person, can you identify how the appropriate regulatory mechanism is working in his/her body.