BIOD 102 Biology II Module 4 Exam (GRADED A) Questions and Answers - Portage Learning

Module 4 Exam- Requires Respondus LockDown Browser Due No due date Points 100 Questions 38 Time Limit 120 Minutes Requires Respondus LockDown Browser Attempt History Attempt Time Score LATEST Attempt 1 84 minutes 94.5 out of 100 Score for this quiz: 94.5 out of 100 Submitted Jul 21 at 5:55pm This attempt took 84 minutes. Question 3 3 / 3 pts (short answer) Describe the mechanisms of calcitonin and how blood calcium is increased: Your Answer: Calcitonin is a pepetide hormone that is released by parafollicular cells of the thyroid when the blood calcium levels are detected to be too high. After it is released it binds to receptors of the bone to inhibit osteoclasst acticvity and binds to kidney tubule receptor to increase calcium excretion. Calcitonin limits the absorption of calcium from the tubules of the kidney. Calcitonin is released, and it binds to osteoclasts to prevent breakdown. Second, it binds to renal tubes to increase the excretion of calcium. Question 30 3 / 3 pts (short answer) Explain how heat stroke occurs. Your Answer: One factor is the relative humidity of the air. usually humidity of 60% or higher in conjuction with high temperatures. the evaporating cooling mechanism becomes less effective by the humidity because sweat does not evaporate because the air is saturated with water vapor (humid). evaporative cooling is the most effective mechanism that humans have to reduce body temperature and with heat stroke these mechanisms do not work properly as explained above. When humidity is above 60% water (sweat) does not evaporate. Evaporative cooling is the body’s most effective means of cooling, so one can rapidly overheat when it is impaired. Question 37 3 / 3 pts (short answer) Describe the step (s) in which positive feedback is observed within the blood clotting cascade. Your Answer: 1. clotting starts when connective tissue of vessel is exposed 2. platelets then "stick" to the exposed tissue 3. platelts release clotting factors -- activate thrombin 4. thrombin isan enztme that converts fibrinogen to fibrin 5. fibrin then forms into threads that formteh structure of the clot Thrombin is repsonsible for the positive feedback loop in the clotting cascade because it amplifies the converstion of prothrombin to thrombin until teh clot is formed. There is a positive feedback amplification loop once prothrombin is converted to thrombin. Thrombin increased the amount of activated clotting factors which in turn activates more thrombin. This amplification continues until a fibrin clot is formed. Quiz Score: 94.5 out of 100 Show Less