Your cells are always producing wastes, and these wastes must be carried away and removed from the body. Some of them, like CO2, can be exhaled. The wastes produced by metabolizing proteins, however, are a bigger problem because they contain ammonia, a highly toxic chemical. The liver can transform this into urea, but that is still toxic, so it must be removed from the blood by the kidneys.
The challenge of producing urine is this; how do you filter the blood fast enough to get the nitrogenous wastes out, without losing lots of the other solutes and fluid in the blood? Kidneys must not only filter the blood, but they must reabsorb the needed solutes and water back into the blood and secrete toxins from the blood into the urine.

Can explain diffusion and osmosis

Can list the steps of the RAA system and explain their effects

Can write the equation for blood pressure and explain how blood volume, vasoconstriction, and vasodilation affect it

Review the kidneys at:
kidney tutorial

Chapter 20: pp 770, 775-778 and fig 20.12 (nephron structure and function), fig 20.14 and 20.15 and pp 783-788 (filtration and urine formation), fig 20.23 and table 20.3 (ADH and urine volume/ osmolarity regulation)
Ch 13, p. 513-514 (aldosterone and RAAS)

--STATE the functions of the urinary system

--DESCRIBE and DIAGRAM the events involved in the production of urine

--EXPLAIN the function of the different parts of the nephron in urine production

--EXPLAIN the control of urine production by the SNS and RAAS

--EXPLAIN how Antidiuretic Hormone controls urine volume and osmolarity

A man has developed severe atherosclerosis, which has partially blocked both of his renal arteries. However, his glomerular filtration rate has not gone down. His blood pressure has gone up, and so has his hematocrit. How did the kidneys maintain the GFR? Are they involved with his high BP and hematocrit? If so, how?

Practice question with example answer