Control of Blood Sugar Levels

joeyma.club Answers Answer Key Answers Key Key Control of Blood Sugar Levels What hormones are involved in the homeostasis of blood sugar? Why? All living things use glucose as a source of energy. In vertebrates it is critical that the levels of glucose in the blood are consistent. Small fluctuations are fine, but if the glucose concentration in the blood gets too high, a coma could result. If the glucose concentration in the blood gets too low, the person could experience seizures, go into a coma or die. In humans, hormone levels help regulate the glucose concentration in the blood and keep us in homeostasis. Model 1 – Hormonal Control of Glucose Relative Concentration in the Blood Insulin Glucagon Glucose Glucose baseline Insulin baseline Glucagon baseline Meal Eaten Time 1. The relative blood concentrations of which three molecules are recorded in the graph of Model 1? Insulin, glucagon, glucose 2. Which molecule from Model 1 is found in the blood at the highest concentrations? Glucose 3. Why do cells need glucose? Cells need glucose for energy for cellular respiration to make ATP 4. According to the graph in Model 1, what happens to blood glucose levels after a meal has been eaten? Blood glucose levels increases Control of Blood Sugar Levels 1 5. Refer to Model 1. a. As blood glucose levels increase above baseline, the level of which hormone also increases? Insulin b. As blood glucose levels begin to drop below baseline, the concentration of which hormone increases? Glucagon c. As blood glucose returns to its baseline level, what happens to the levels of insulin and glucagon in the blood? The levels of insulin and glucagon returns to their baseline levels Model 2 – Feedback Control of Blood Glucose Liver Pancreas ge Stora U se d Blood glucose is too high. Cycle A Other cells Blood glucose drops. Glucose Insulin Glycogen Glucagon Baseline blood glucose level. Blood glucose rises. Cycle B Liver 2 Release Blood glucose is too low. Pancreas 6. According to Model 2, what are three of the organs/tissues of the body that interact to regulate blood glucose levels? Liver, pancreas, and other cells such as red blood cells 7. According to Model 2, where in the body do the insulin and glucagon originate? Pancreas 8. Refer to Model 2. a. What shape in the model represents glucose? Hexagon b. Describe how glycogen is related to glucose. Glycogen is a polymer of glucose monomers c. Which form of sugar, glucose or glycogen is stored in the liver for future use? Glycogen Read This! Most cells in the body have insulin receptors. When insulin is present, the transfer of glucose into cells increases. This takes the glucose out of the bloodstream and puts it where it can be used, or in some cases stores it as glycogen. The glycogen can be converted back into glucose when it is needed. But glycogen cannot be used by cells directly as an energy source. Excess glucose that remains in the blood gets excreted out in urine. 9. Refer to Model 2. a. In which cycle is glucose removed from the blood by storing it or moving it into cells to use for fuel? Cycle A b. Which hormone, insulin or glucagon, helps glucose move into cells of the body? Insulin c. In which cycle is glucose added to the blood from storage areas? Cycle B d. Which hormone, insulin or glucagon, helps turn glycogen into glucose? Glucagon Control of Blood Sugar Levels 3 10. In grammatically correct sentences, explain the role of insulin in maintaining glucose levels after a large meal. After a large meal, blood glucose levels rise causing the pancreas to then release insulin. This presence of insulin increases the transfer of glucose into the cell where glucose can be used or stored for energy. As glucose moves inside the cells, blood glucose levels decreases. 11. In grammatically correct sentences, explain the role of glucagon in maintaining glucose levels when the organism is hungry. When the organism is hungry, blood glucose levels decreases below the baseline which causes the pancreas to release glucagon which then releases glycogen from the liver and muscles. As glycogen converts into glucose, blood glucose levels increase. 12. For each of the cycles in Model 2 identify the stimulus and response for the feedback loops and indicate whether the feedback loop is positive or negative feedback. Stimulus Response Positive or Negative? Cycle A High glucose levels Release of insulin Negative Cycle B Low glucose levels Release of glycogen Negative 13. Predict the levels of glucose, glucagon, and insulin in a person who has: a. Skipped a meal. Low glucose, high glucagon, low insulin b. Just run 5 miles. Low glucose, high glucagon, low insulin c. Just ate a large dinner. High glucose, low glucagon, high insulin 4 Extension Questions 14. In the past, diabetes mellitis was diagnosed by tasting the urine of the patient. What evidence for diabetes were the doctors looking for? If the urine tasted sweet, it would indicate diabetes because glucose was not absorbed by the cells. 15. In Type I diabetes, the Beta cells of the pancreas produce little to no insulin. What effect does this have on an organism’s ability to regulate blood glucose levels? The movement of glucose into cells remain at their constant levels and increase at low levels. Blood glucose levels remain high after a meal. The blood glucose levels decrease when cells use glucose for energy. 16. Type I diabetics must eat frequent small meals. Explain why this is necessary using what you have learned about blood glucose regulation. Eating frequent small meals is necessary because in type I diabetes, the pancreas produce little to no insulin. The movement of glucose into the cell will remain at their constant level or will not increase. Eating large meals will cause their blood sugar levels to drastically increase due to insulin resistance, and excess glucose does not enter the cell and remains the in the bloodstream where it is then it is excreted in urine. 17. Other symptoms of Type I diabetes are increased thirst and frequent urination. Explain these symptoms using what you have learned in this activity as well as your knowledge of osmosis and diffusion. In diabetes, there is a high concentration of glucose in the blood because the body can not produce insulin and therefore not absorb glucose, so the blood will have more solute than the cells. This causes the fluids to move from the cells to the blood. The increased amount of water in the fluids will need to be filtered and disposed by the kidneys by urine, so the kidneys will excrete the excess glucose in the urine taking more fluid in the excretion increasing urination. As the body is urinating frequently, it is continuously losing fluid causing dehydration. To compensate for this lack of water, if the water volume of the body falls below a certain threshold or the osmolyte concentration becomes too high, the brain signals thirst causing an increase in thirst. 18. Type II diabetes shares many of the same symptoms as Type I diabetes. Using your textbook and/ or a computer, research the cause of this type of diabetes. Type II diabetes is caused when the pancreas does not produce sufficient insulin to maintain a normal blood glucose level, or when the receptors are unable to the insulin that is produced. When the body is insulin resistant, the glucose remains in the bloodstream until it is excreted by urination and the movement of glucose into cell can not increase. Control of Blood Sugar Levels 5