Lesson 8Assignment: Urine Formation in the Nephron
Biology 20: Module 8: Lesson 81AssignmentModule 8: Lesson 8 ASSIGNMENT
This Module 8: Lesson 8 Assignment is worth 29 marks. The value of each assignment and each question is stated in the left margin.
(29 marks) /
Lesson 8Assignment: Urine Formation in the Nephron(12 marks) / TR 1. Glomerular Filtration
Urine formation occurs as blood pressure forces filtrate from the glomerulus into Bowman’s capsule. This bulk flow of fluids into the Bowman’s capsules of the nephrons in both kidneys creates about 180 L of filtrate per day. All but about 1 L will be actively reabsorbed back into the blood, with a great expenditure of ATP.
Inquiry into Biology (Whitby, ON: McGraw-Hill Ryerson, 2007), 311, fig. 9.4. Reproduced by permission.
(2 marks) / 1. / How does the bulk flow of filtrate into the capsule differ from diffusion?
Answer:(2 marks) / 2. / In what ways is nephric filtration similar to the formation of interstitial fluid (lymph) in other tissues in the body?
Answer:(3 marks) / 3. / One of the effects of a drug overdose is a serious decrease in blood pressure. How might this affect kidney function?
Answer:(1 mark) / 4. / Explain why blood cells and proteins are not usually found in the filtrate.
Answer:(2 marks) / 5. / Why are useful molecules like glucose and other nutrients found in the filtrate along with urea and other wastes?
Answer:(2 marks) / 6. / Sometimes bacterial infection causes nephritis—an inflammation of membranes in the glomerulus and capsule. Large pores are created where blood cells enter the nephron. What symptom would indicate this problem?
Answer:(17 marks) / TR 2. Tubular Reabsorption
Inquiry into Biology (Whitby, ON: McGraw-Hill Ryerson, 2007), 312, fig. 9.5. Reproduced by permission.
(4 marks) / 1. / In terms of energy costs to the cells in the proximal tubule, the reabsorption of salt (Na+and Cl–) and water has been called a deal where we get “3 for the price of 1.” Explain.
Answer:(2 marks) / 2. / What other useful substances, in addition to Na+, Cl–, and water, are reabsorbed in the proximal tubule?
Adapted from Inquiry into Biology (Whitby, ON: McGraw-Hill Ryerson, 2007), BLM 9.2.2. Reproduced by permission.
(1 mark) / 3. / Why are the two parts of the nephron loop called descending and ascending?
Answer:(2 marks) / 4. / Explain the process of reabsorption from the descending loop.
Answer:(1 mark) / 5. / Where is the highest concentration of Na+ found?
Answer:(2 marks) / 6. / Explain the process of reabsorption from the ascending loop.
Answer:(2 marks) / 7. / Explain how the reabsorption of ions and water occurs from the distal tubule.
Answer:Use this additional information to answer the next question.
Excess ions and other substances are added to the filtrate from the surrounding capillaries in a process called tubular secretion. This has been called reabsorption in reverse.
(3 marks) / 8. / List three examples of substances that are actively secreted into the filtrate.
Answer:Once you have completed all of the questions, submit your work to your teacher.