9. Describe the feedback loop observed in insulin secretion. 10. During starvati
ID: 260922 • Letter: 9
Question
9. Describe the feedback loop observed in insulin secretion.
10. During starvation what happens to the acetyl co-A made available from stored fats?
11. How are the cellular effects of insulin mediated? How does insulin regulate the activity of glycogen phosphorylase?
12. Adrenalin is stored in and released from membrane bound vesicles. Why are testosterone and estrogen not stored in this manner?
13. Describe the differences between Type 1 and Type 2 diabetes and the kinds of therapy used to control each.
14. Why are peptide hormones are initially synthesized as inactive precursors (prepro- or pro-hormones) and processed to the active hormone?
15. Compare and contrast the mechanisms and locations of the effects of peptide and amine hormones and steroid hormones. (Answer in table form if you wish.)
16. Why are the effects of steroid and thyroid hormones slower in action and lengthier in duration than other types of hormones?
17. What factors are released from the hypothalamus, and what cells do they target?
18. Why are the hormones of the anterior pituitary gland often described as tropic?
19. Cells of the islets of Langerhans are found in the _____________. Glucagon is produced by the ____ cells and insulin by the ____ cells.
20. Which hormones are catecholamines? When acting as hormones, from where are they secreted? Where else might these molecules be found?
21. Briefly describe the major actions of the catecholamines on carbohydrate and lipid metabolism.
22. Describe the general pathways and end products of carbohydrate and lipid metabolism in each of the following mammalian tissues: a) Liver b) Adipose c) Muscle (skeletal and heart) d) Brain tissues e) Blood
Explanation / Answer
9. Insulin secretion is under negative feedback control. It's secretion depends upon the amount of glucose present in blood. When blood glucose level rises in blood, glucose enters into beta cells of islets which in turn causes release of insulin from these cells. Insulin when released promotes synthesis of glycogen from glucose and its storage in liver and muscle cells. As the amount of glucose starts declining in blood ,secretion of insulin from beta cells starts also starts declining. Insulin secretion causes decresse in the concentration of glucose in blood. This is example of negative feedback mechanism.
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