Renal Physiology

  1. What are the functions of the renal system?
  1. Describe the anatomy of the urinary system, including the microanatomy of the nephronic tubule.
  1. Describe the three basic processes and how they interact to form urine. Define the difference between secretion and excretion.
  1. Discuss the forces involved in glomerular filtration. What is the average GFR and how is it regulated?
  1. Distinguish between active and passive reabsorption and describe all the tubular transport processes that are linked to the Na+/K+ ATPase.
  1. Describe sodium regulation in the body.
  1. Describe water regulation in the body.
  1. How is the medullary osmotic gradient produced and what is its major function?
  1. Describe K+ regulation in the body
  1. Describe Ca2+ regulation in the body
  1. What is the filtered load of sodium if inulin clearance is 125 ml/min and the sodium concentration in plasma is 145 mM?
  1. Calculate the rate of urine production, given that the inulin clearance is 125 ml/min and the urine and plasma concentrations of inulin are 300 mg/liter and 3 mg/liter, respectively.
  1. If the urine concentration of a substance is 7.5 mg/ml of urine, its plasma concentration is 0.2 mg/ml of plasma, and the urine flow rate is 2 ml/min, what is the clearance rate of the substance? Is the substance being reabsorbed or secreted by the kidneys?
  1. Predict the changes (increase/decrease/no change) that will be present in the following parameters as a consequence of a pathological condition that results only in a leaky glomerulus (permeable to plasma proteins), explain your answer.
  1. plasma protein concentration
  2. plasma colloid osmotic pressure
  3. total body sodium
  4. plasma volume
  5. interstitial fluid volume
  1. Predict the changes (increase/decrease/no change) that will occur in the following parameters when plasma volume decreases, explain your answer.
  2. mean arterial pressure
  3. glomerular filtration rate
  4. renal blood flow
  5. plasma rennin concentration
  6. plasma aldosterone concentration
  7. Na excretion
  8. Vasopressin secretion

16. Use the following data to answer the questions below:
Plasma inulin concentration = 0.01 mg/ml
Urine inulin concentration = 1.00 mg/ml
Urine flow rate = 1.20 ml/min
Plasma concentration of solute x = 0.05 mg/ml
Urine concentration of solute x = 2.00 mg/ml
Plasma PAH concentration = 0.001 mg/ml
Urine PAH concentration = 0.390 mg/ml
Hematocrit = 0.50
Calculate:
a) GFR
b) Whether there is net reabsorption or net secretion (or neither) of solute x.
c) Filtered Load of X
d) Renal blood flow
17. The human kidney can produce a maximal urine osmotic concentration of about 1400 mOsm, an impressive feat but poor in comparison to some desert mammals. Knowing what you do about the concentrating mechanism (or what you can learn by studying the text), how might our kidneys be altered, either functionally or anatomically, to improve our concentrating performance?

  1. List and indicate the functions of each of the body’s chemical buffer systems
  1. Describe the three lines of defense against changes in [H+] in terms of mechanisms
  1. What are the causes of the four categories of acid-base imbalances and what compensation does the body affect for each.
  1. Describe the actions of the kidney that lead to H+ secretion and HCO3- reabsorption.
  1. Of what importance is PO43- and NH3?
  1. How do the kidney’s produce ‘new’ HCO3-?
  1. Death occurs if the plasma pH falls outside the range of 6.8 to 8.0 for an extended time. What is the concentration range of H+ represented by this pH range?
  1. Given an αCO2 = 0.03 mM/mmHg, a normal pH of 7.4, a normal [HCO3-] of 25 mM, and a normal PCO2 of 40 mmHg; How much would the PCO2 have to change to produce a pH of 6.8 (assume only a respiratory change)? How much would the [HCO3-] have to change to produce the same pH change (assume only non-respiratory change)?