The Effect of Arteriole Radius on Glomerular Filtration Lab Report

Exercise 9: Renal System Physiology: Activity 1: The Effect of Arteriole Radius on Glomerular Filtration Lab Report Pre-lab Quiz Results You scored 100% by answering 5 out of 5 questions correctly. 1. There are approximately __________ nephrons in a healthy human kidney. You correctly answered: c. 1 × 106 2. Which of the following lists the anatomical structures in the correct order as they are encountered by the blood and filtered fluid during the process of filtration? You correctly answered: d. afferent arteriole, glomerular capillary, Bowman's capsule 3. Bowman's capsule is connected to the beginning of the You correctly answered: b. proximal convoluted tubule. 4. The functional unit of the kidney is the You correctly answered: c. nephron. 5. During the process of renal reabsorption, fluid and solutes move from the You correctly answered: b. renal tubule into the peritubular capillaries. Experiment Results Predict Question: Predict Question 1: What will happen to the glomerular capillary pressure and filtration rate if you decrease the radius of the afferent arteriole? Your answer : b. Both pressure and filtration rate will decrease. Predict Question 2: What will happen to the glomerular capillary pressure and filtration rate if you increase the radius of the afferent arteriole? Your answer : a. Both pressure and filtration rate will increase. Predict Question 3: What will happen to the glomerular capillary pressure and filtration rate if you decrease the radius of the efferent arteriole? Your answer : a. Both pressure and filtration rate will increase. Stop & Think Questions: Caffeine consumption leads to increased urine formation. From the results in this experiment thus far, you might propose that You correctly answered: d. caffeine dilates the afferent arteriole. When you are in the desert and dehydrating, which of the following arteriole combinations would benefit you the most? You correctly answered: c. afferent constriction and efferent dilation Experiment Data: Afferent Radius (mm) 0.50 0.45 0.40 0.35 0.55 0.60 0.50 0.50 0.50 0.50 Efferent Radius (mm) 0.45 0.45 0.45 0.45 0.45 0.45 0.45 0.40 0.35 0.30 Beaker Press. (mm Hg) 90 90 90 90 90 90 90 90 90 90 Glomerular Press. (mm Hg) 55.08 51.54 48.52 46.16 58.94 62.88 55.08 56.10 56.84 57.34 Glom. Filt. Rate (ml/min) 124.99 81.06 43.66 14.35 172.86 221.69 124.99 137.69 146.82 152.96 Urine Volume (ml) 200.44 179.88 143.91 76.33 212.87 220.74 200.44 227.49 247.96 262.23 Post-lab Quiz Results You scored 100% by answering 4 out of 4 questions correctly. 1. If you increase the afferent arteriole radius and keep all other variables constant, the glomerular filtration rate would You correctly answered: a. increase. 2. If you decrease the efferent arteriole radius and keep all other variables constant, the volume of urine flowing into the urinary bladder would You correctly answered: a. increase. 3. If you increase the efferent arteriole radius and keep all other variables constant, the glomerular filtration rate would You correctly answered: b. decrease. 4. If you decrease the afferent arteriole radius and keep all other variables constant, the volume of urine flowing into the urinary bladder would __________. You correctly answered: b. decrease. Review Sheet Results 1. What are two primary functions of the kidney? Your answer: The two primary functions of the kidney are to excrete wastes, excess water, including unknown substances that are in the blood and to also maintain homeostasis in the body which include regulating the following: plasma osmolarity, plasma volume, electrolyte, and the acid to base balance. 2. What are the components of the renal corpuscle? Your answer: The components of the renal corpsule include the glomerules, which are a cluster of capillaries that are enclosed by a capsule called Bowman's capsule (also known as the glomerular capsule). Bowman's capsule receives it's blood supply through the afferent arteriole that assists in filtration. 3. Starting with the renal corpuscle, list the components of the renal tubule as they are encountered by filtrate. Your answer: The componenets of the renal tubule, by order of filtration commences with proximal convoluted tubule, loop of henle, and the distal convoluted tubule. 4. Describe the effect of decreasing the afferent arteriole radius on glomerular capillary pressure and filtration rate. How well did the results compare with your prediction? Your answer: When the radius of the afferent arteriole was decreased, the glomerular capillary pressure and filtration rate decreased which matched my prediction. 5. Describe the effect of increasing the afferent arteriole radius on glomerular capillary pressure and filtration rate. How well did the results compare with your prediction? Your answer: When the radius of the afferent arteriole was increased, the glomerular capillary pressure and filtration rate increased This matched my prediction. 6. Describe the effect of decreasing the efferent arteriole radius on glomerular capillary pressure and filtration rate. How well did the results compare with your prediction? Your answer: When the radius of the efferent arteriole was decreased, the glomerular capillary pressure and filtration rate both increased. This matched my prediction. 7. Describe the effect of increasing the efferent radius on glomerular capillary pressure and filtration rate. Your answer: Increasing the efferent radius should decrease both the capillary pressure and the filtration rate.