Lecture 2

Question 1

Three basic processes are involved in forming urine:

Answer 1

1. Glomerular filtration
2. Tubular reabsorption
3. Tubular secretion

Question 2

Question 3

During glomerular filtration

Answer 3

Protein-free plasma filters through the glomerular capillaries into Bowman’s capsule.

Question 4

Approx. _____ of the plasma that enters the glomerulus is filtered

Answer 4

20%

Question 5

the first step in urine formation

Answer 5

Glomerular filtration

Question 6

125 mL of glomerular filtrate (filtered fluid) are formed collectively through all the glomeruli each minute.

Answer 6

This amounts to 180 liters each day - the kidneys filter the entire plasma volume about 65 times per day.

Question 7

Substances of value to the body are returned to the

Answer 7

peritubular capillary plasma

Question 8

Substances of value to the body are returned to the peritubular capillary plasma this selective movement of substances from inside the tubule into the blood is called

Answer 8

tubular reabsorption

Question 9

Reabsorbed substances are not lost from the body in the urine, they are

Answer 9

carried back to the heart to be recirculated.

Question 10

Of the 180 liters of plasma filtered per day, 178.5 liters, on average, are reabsorbed.

Answer 10

The remaining 1.5 liters of filtered fluid left in the tubules pass into the renal pelvis to be eliminated as urine.

Question 11

Tubular Secretion

Answer 11

The selective transfer of substances from the peritubular capillary blood into the tubular lumen
- It provides a second route for substances to enter the renal tubules from the blood

Question 12

Only about 20% of the plasma is filtered into _________; the remaining 80% flows on into the ______________.

Answer 12

Bowman’s capsule
peritubular capillaries

Question 13

How does tubular secretion provide a mechanism for more rapidly eliminating selected substances from the plasma

Answer 13

by adding it to the quantity of the substance already present in the tubule.

Question 14

elimination of substances from the body in the urine.

Answer 14

Urine Excretion

Question 15

Is urine excretion a separate process?

Answer 15

It is not a separate process but the result of the first three processes

Question 16

Process of urine excretion

Answer 16

All plasma constituents filtered or secreted but not reabsorbed remain in the tubules and pass into the renal pelvis to be excreted as urine and eliminated from the body