Introduction: In this lab we will learn how the kidney processes blood and produces urine.
Activity 1: Investigating the Effect of Flow Tube Radius on Glomerular filtration.
Data/Results:
Afferent Radius Efferent Radius Beaker Pressure Glomerular Pressure Glom. Filt. Rate Urine Volume
0.35 40 90 47.16 26.74 145.57
0.40 40 90 49.54 56.28 190.18
0.45 40 90 52.57 93.82 213.92
0.50 40 90 56.10 137.69 227.49
0.55 40 90 59.94 185.24 235.69
0.60 40 90 63.83 233.45 240.89
Questions: Please answer the questions in complete sentences and explain your answers.
1. What effect does increasing the afferent radius have on glomerular filtration rate and pressure? Increasing the afferent radius increased the glomerular pressure, glomerular rate and the volume of urine.
2. What effect will decreasing the efferent radius have on glomerular filtration rate? When the efferent radius was decreased, the blood flow was faster and the glomerular pressure, glomerular rate, and the volume of urine increased as well.
Summary:
In this Activity, I learned/observed that: the effects of flow tube radius on glomerular filtration rate and pressure. With a bigger flow tube, urine is filtered at a higher filtration rate than when it’s a smaller flow tube.
Activity 2: Studying the Effect of Pressure on Glomerular Filtration
Data/Results:
Afferent Radius Efferent Radius Beaker Pressure Glomerular Pressure Glom. Filt. Rate Urine Volume
0.55 0.45 70 51.96 86.37 183.17
0.55 0.45 80 55.45 129.61 201.96
0.55 0.45 90 58.94 172.86 212.87
0.55 0.45 100 62.43 216.10 220.00
Questions: Please answer the questions in complete sentences and explain your answers.
1. What effect does increasing the beak pressure have on glomerular filtration rate and pressure? As the pressure was increased, the pressure in the glomerulus also increased and the glomerular filtration rate also kept increasing with gradual increase of the pressure.
2. In the absence of any regulatory mechanisms, what effect do you think an increase in blood pressure would have on glomerular filtration rate? I think that an increase in blood pressure without any regulatory mechanism would cause it to be a decrease in filtration rate.
Summary:
In this Activity, I learned/observed that: the effects an increase in blood pressure would have on glomerular filtration rate and pressure. With a gradual increase in blood pressure, there will also be a gradual increase in glomerular filtration rate, which I believe would lead to urine and sodium retention.
Activity 3: Exploring Intrinsic Controls: Renal Autoregulation
Data/Results:
Afferent Radius Efferent Radius Beaker Pressure Glomerular Pressure Glom. Filt. Rate Urine Volume
0.55 0.45 100 62.43 216.10 220.00
0.55 0.45 80 55.45 129.61 201.96
0.55 0.45 85 57.20 151.24 208.05
Questions: Please answer the questions in complete sentences and explain your answers.
1. In the body, what mechanisms play a role in maintaining glomerular filtration rate with fluctuating blood pressure? The size of blood vessels plays a role in maintaining glomerular filtration rate and pressure.
2. What was the glomerular filtration rate at 80mmHg beaker pressure, 0.55 mm afferent radius, and 0.45 mm efferent radius? 129.61
Summary:
In this Activity, I learned/observed that: the effects that both, tube radius and blood pressure would have on glomerular filtration rate and pressure. The afferent and efferent arterioles play an important role in blood flow control and blood pressure into the glomerulus.
Activity 4: Exploring the role of the Solute Gradient on Maximum Urine Concentration Achievable
Data/Results:
Glucose Conc. Potassium Conc. Urine Volume Urine Conc. Conc. Grad. Aldosterone ADH
6.00 15.59 60.57 300 300 Absent present
6.00 31.19 40.28 600 600 Absent present
6.00 46.78 26.86 900 900 Absent present
6.00 62.37 20.14 1200 1200 Absent present
Questions: Please answer the questions in complete sentences and explain your answers.
1. When you increase the concentration gradient of the interstitial fluid, what happened to the concentration of the urine? When I increased the concentration gradient of the interstitial fluid, the urine solute concentration also increased, with the same values as the concentration gradients.
2. Does the volume of urine increase or decrease as the concentration gradient of the interstitial fluid is increased? The urine volume decreased as the concentration gradient of the interstitial fluid increased.
3. What is the maximum osmolality of the interstitial fluid? The maximum osmolality of interstitial fluid is 1200 mOsm.
4. What factors result in dilute urine? In the absence of ADH, dilute filtrate produced by the countercurrent mechanism remains dilute as it pass through the collecting duct. Also, Na+ and selected other ions can be removed from the filtrate by DCT and collecting duct cells so that urine becomes even more dilute before entering the renal pelvis.
Summary:
In this Activity, I learned/observed that: the aspects of urine formation by manipulating the interstitial solute concentration. I also learned the effects of aldosterone and ADH and the role that glucose carrier proteins play in renal function.
Activity 5: Studying the Effects of Glucose Carrier Proteins on Glucose Reabsorption
Data/Results:
Glucose Conc. Potassium Conc. Urine Volume Urine Conc. Conc. Grad. Aldosterone ADH
4.29 6.25 201.00 100 1200 Absent Absent
2.57 6.25 201.00 100 1200 Absent Absent
2.57 6.25 201.00 100 1200 Absent Absent
2.57 6.25 201.00 100 1200 Absent Absent
2.57 6.25 201.00 100 1200 Absent Absent
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Questions: Please answer the questions in complete sentences and explain your answers.
1. Why would we expect to find glucose in the urine of a diabetic person? I would expect to find glucose in the urine of a diabetic due to the lack of glucose carriers relatively less than the amount of glucose to be transported. High amounts of glucose can’t be carried across, leaving high concentration discarded with the urine formed.
2. What happens to the concentration of glucose in the urine as the number of glucose carriers increased? The glucose concentration decreases, because the added carriers were able to carry the glucose across the walls of the glomerulus for reabsorption.
3. What is the renal threshold of glucose? Please explain why this is important. The renal threshold of glucose is between 160 and 180mg. This is important to control diabetes and to control the amount of glucose in the blood and urine, because excessive glucose excretion can damage the functioning of the kidneys.
Summary:
In this Activity, I learned/observed that: the effects of varying the number of glucose transport proteins in the proximal convolute tubule.
Activity 6: Testing the Effect of Hormones on Urine Formation
Data/Results:
Glucose Conc. Potassium Conc. Urine Volume Urine Conc. Conc. Grad. Aldosterone ADH
2.57 6.25 201.00 100 1200 Absent Absent
2.57 10.42 180.90 100 1200 Present absent
2.57 62.37 20.14 100 1200 Absent present
Questions: Please answer the questions in complete sentences and explain your answers.
1. How does Aldosterone and ADH affect urine volume? Both hormones reduced urine volume.
2. If you are dehydrated, what hormones are stimulated? Explain the physiology behind the hormones being stimulated (blood volume or blood pressure) and refer to your text if necessary. When dehydrated, ADH and aldosterone are stimulated to conserve water and maintain blood volume levels in the body. These hormones increase the permeability of the distal and collecting tubules, allowing water to re-enter the interstitial fluid and increasing the solute concentration in urine.
3. Why did the concentration of potassium change in the presence of ADH without a change in the excretion of potassium? The concentration of potassium changed in the presence ADH because, when the water from the urine was allowed to be reabsorbed, the activity of potassium is increased allowing more of it to enter the urine.
4. There are two forms of diabetes insipidus. Please discuss both (one that affects the posterior pituitary and the other effects the kidney). What type of urine is produced? How are the forms of Diabetes insipidus treated? The 2 forms of diabetes insipidus are (1).Central diabetes insipidus, which gives rise to polyuria and polydipsia by diminishing the patient’s ability to concentrate urine. (2). Nephrogenic diabetes insipidus, known as which is due to the resistance of the kidneys to respond normally to ADH. Severely diluted urine is what is produced by the 2 forms of DI. Pharmacologic treatment of DI generally involves the use of desmopressin, non-hormonal drugs, or both.
Summary:
In this Activity, I learned/observed that: the effects of ADH and aldosterone on renal function. I also observed how both hormones effects urine volume. I also learned about two forms of DI, and how the hormones affect the concentration of urine.
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