Nephron Excretory Function

Question 1

Where does the first reabsorption step occur and what happens?

Answer 1

proximal tube, where ions, water, and nutrients are removed
some toxic materials and ions are secreted into the filtrate which decreases volume as water is reabsorbed through nephron

Question 2

After first reabsorption, what happens to filtrate?

Answer 2

it descends not the loop of hence, an area of higher osmolarity
allows further reabsorption of H2O since the interstitial fluid becomes increasingly hyperosmotic
filtrate becomes further concentrated

Question 3

What happens to filtrate at the bottom of the Loop of Henle?

Answer 3

reaches region of highest osmolarity
allows for the most reabsorption of water, given the hyperosmotic area
the filtrate then starts to turn and react the loop of Henle

Question 4

What happens during the first ascent of the Loop of Henle?

Answer 4

goes through a thin region with high osmolarity and is very concentrated.
Salt concentration is higher in filtrate than kidney and passively diffuse into the interstitial fluid
First area where salt is reabsorbed from the filtrate

Question 5

Describe the middle region of the Loop of Henle ascent.

Answer 5

still has high osmolarity
does not have enough osmolarity for passive transport of salt
reabsorption of salt must be active at this point

Question 6

What happens at the end of the loop of Henle?

Answer 6

filtrate ascends further up into the distal tubule, into a relatively lower osmolarity zone
distal tubule is an important region for regulation of salts in the body and for blood pH

Question 7

What occurs in the distal tubule?

Answer 7

regulated reabsorption and secretion, which depends on homeostasis conditions

Question 8

What is the last step?

Answer 8

filtrate moves into the collecting duct, higher osmolarity zone
salt is actively transported out once more and reabsorbed
moves into highest osmolarity zone where more water and even some urea can be reabsorbed, due to hyperosmotic area
hormonal control can occur here

Question 9

What is the final function?

Answer 9

excretion of the filtrate where it moves to the real pelvis via the ureter, and then into the bladder and urethra

Question 10

What type of control is the kidney under?

Answer 10

hormonal control

endocrine system can affect the rate of urine production and concentration of urine