PhysioEx The Effect of Pressure on Glomerular Filtration

11/6/2019 PhysioEx Exercise 9 Activity 2 PhysioEx Lab Report Exercise 9: Renal System Physiology Activity 2: The Effect of Pressure on Glomerular Filtration Name: Date: 6 November 2019 Pre-lab Quiz Results You scored 100% by answering 4 out of 4 questions correctly. 1 Which of the following forces promotes filtration? You correctly answered: blood pressure in the glomerular capillaries. 2 The glomerular filtration rate can be altered by You correctly answered: changing the afferent arteriole resistance. 3 In 24 hours human glomerular capillaries can filter as much as __________ liters of filtrate. You correctly answered: 180. 4 Which of the following statements about the filtrate in the renal corpuscle is false ? You correctly answered: Normally, more than 40% of the blood that enters the glomerular capillaries becomes filtrate. Experiment Results Predict Questions 1 Predict Question 1: What will happen to the glomerular capillary pressure and filtration rate if you increase the blood pressure in the left source beaker? Your answer: Both pressure and filtration rate will increase. 2 Predict Question 2: What will happen to the filtrate pressure in Bowman's capsule (not directly measured in this experiment) and filtration rate if you close the one-way valve between the collecting duct and the urinary bladder? Your answer: Pressure will increase and filtration rate will decrease. Stop & Think Questions 1/4 11/6/2019 PhysioEx Exercise 9 Activity 2 1 What is the important relation that underlies the observed increase in glomerular filtration rate when the blood pressure is increased? You correctly answered: pressure and flow are directly proportional. 2 What medical condition is analogous to the closed valve? You correctly answered: a tumor obstructing the renal tubule. Experiment Data Afferent Radius (mm) Efferent Radius (mm) Beaker Press. (mm Hg) Glomerular Press. (mm Hg) Glom. Filt. Rate (ml/min) 0.50 0.45 70 49.72 0.50 0.45 80 52.40 91.78 186.23 open 0.50 0.45 90 55.08 124.99 200.44 open 0.50 0.45 100 57.76 158.20 209.72 open 0.50 0.45 70 49.72 58.57 161.76 open 0.50 0.45 70 49.72 26.94 0.00 closed 0.50 0.45 100 57.76 115.80 0.00 closed 0.50 0.45 100 57.76 158.20 209.72 open 58.57 Urine Volume (ml) 161.76 Valve Status open Post-lab Quiz Results You scored 100% by answering 4 out of 4 questions correctly. 1 In humans, the glomerular filtration rate normally ranges from You correctly answered: 80 to 140 ml/min. 2 Which of the following does not have a significant impact on the glomerular filtration rate? You correctly answered: renal tubule length. 3 In the absence of any regulatory mechanisms, what do you think would happen to the glomerular filtration rate of a person who experiences an increase in blood pressure? You correctly answered: The glomerular filtration rate could increase. 4 What would happen to the glomerular filtration rate of a person who experiences a large hemorrhage? You correctly answered: The glomerular filtration rate would decrease. Review Sheet Results 2/4 11/6/2019 PhysioEx Exercise 9 Activity 2 1 As blood pressure increased, what happened to the glomerular capillary pressure and the glomerular filtration rate? How well did the results compare with your prediction? Your answer: I predicted that as blood pressure increased so will the glomerular capillary pressure and filtration rate. The results proved my prediction because the more that blood enters the capillaries in the Bowman's capsule, the higher the pressure goes up, as well as the filtration rate increasing due to the high pressure. This always for more filtration of blood. 2 Compare the urine volume in your baseline data with the urine volume as you increased the blood pressure. How did the urine volume change? Your answer: It can be seen that when blood pressure increases so does urine production increased. Thus showing that glomerular pressure, filtration rate, and urine volume will all increase because every time the glomerular pressure increased the filtration rate had to increase from the high pressure and lastly the high filtration rate causes an increase in urine volume. 3 How could the change in urine volume with the increase in blood pressure be viewed as being beneficial to the body? Your answer: An increase in urine volume can be beneficial for the body because that means waste is getting filtered out of the body faster than it would normally. The more frequent urination causes a loss in water, resulting in a higher consumption of fluids to replace the fluid lost from urination. Which is also increases the urine volume, creating a beneficial cycle in filtering out waste at a fast rate from consuming fluids at an increasing rate to replace what was lost. 4 When the one-way valve between the collecting duct and the urinary bladder was closed, what happened to the filtrate pressure in Bowman's capsule (this is not directly measured in this experiment) and the glomerular filtration rate? How well did the results compare with your prediction? Your answer: Whenever the valve was closed the filtration pressure remained the same, but the glomerular filtration rate decreased. I previously predicted that the pressure would increase and the filtration rate would decrease. The data shows that the glomerular pressure was the same compared to the rates with the valve open, showing that the pressure was not effected. However, the data did prove that the filtration rate decreased whenever the valve 3/4 11/6/2019 PhysioEx Exercise 9 Activity 2 was closed, compared to open. This is because there is already filtrate in the bladder because there was no urinary output, therefore the system is not able to filtrate more. 5 How did increasing the blood pressure alter the results when the valve was closed? Your answer: Whenever the blood pressure was increased while the valve was closed, it mainly effected the glomerular filtration rate. The glomerular filtration rate decreased because there was no urinary output. This filtration rate is decreased because the glomerular pressure stays the same and is overloading the filtration system causing to move at a slower rate. 4/4