222 EXPERIMENTAL PHYSIOLOGY. 



(a) What is the effect on blood pressure; on diuresis? 



(b) How can these effects be correlated? 



3. Stimulate the vagus. 



(a) What is the effect on blood pressure; on diuresis? 

 (E) The Effect of the Chemical Composition of the Blood upon 

 the Secretion of Urine. 



4. Inject 15 c.c. of a 1% solution of urea into the femoral vein. 



(a) What is the effect on diuresis? 



(b) Can this effect be attributed to changes in blood pressure? 



5. After the diuresis returns to normal inject 50 c.c. of a warm 

 isotonic salt solution slowly into the femoral vein. 



(a) What is the effect on diuresis? 



(b) Can this effect be attributed to changes in blood pressure? 



(C) The Time Interval of Urine Secretion. 



Introduce 5 c.c. of a saturated solution of indigo-carmine into 

 the vein. Note the time which elapses until the blue colour first 

 appears in the urine. 



(D) Asphyxiation of Kidney. 



6. Close the tracheal cannula with the finger for 60 seconds. 



(a) Note and explain effect upon diuresis. 



(b) Can this be explained by the changes in blood pressure? 

 The operator may now open the body cavity and place ligatures 



around the renal arteries and veins of both kidneys and around 

 the aorta caudad to renal arteries. Look for rhythmic movements 

 of the ureters. 



7. Close aorta below renal arteries. 



(a) State and explain effect on diuresis. 



8. Close the renal veins by pulling up on the ligatures about 

 them. Do not check the renal circulation for more than a minute 

 in this way. 



(a) State and explain effect on diuresis. 



9. Close the renal artery by pulling up on the ligatures for three 

 minutes. 



(a) What is the effect upon diuresis? 



(b) Explain. 



(c) Does the kidney recover from the asphyxiation? 



