Nephrons

Question 1

What is a nephron?

Answer 1

-structures within kidney where blood is filtered and useful substances are reabsorbed

Question 2

Where are nephrons found?

Answer 2

-begin in cortex and loop of henle
-then moved down into medulla

Question 3

Where does filtration occur?

Answer 3

-Bowman’s capsule

Question 4

What is the role of proximal convoluted tubule?

Answer 4

-where glucose is reabsorbed

Question 5

What is the role of the loop of henle?

Answer 5

-Na ions are actively transported out of ascending limb into the medulla where WP is low

Question 6

What are the 3 steps to filtration?

Answer 6

1. water moves out of descending and out of distal convoluted tube
2. collecting duct by osmosis is due to WP gradient
3. remaining liquid forms urine
   -contains water, salts, urea and hormones

Question 7

What is ultrafiltration?

Answer 7

-small molecules filtered out of blood and pass into nephron lumen

Question 8

What are the 7 steps to ultrafiltration?

Answer 8

1. blood enters through afferent arterioles - then splits into smaller capillaries
2. causing high hydrostatic pressure
3. water, glucose and mineral ions are forced out to form glomerulus filtrate
4. forced out fluid goes through basement membrane = acts like a sieve
5. bowman’s has podocytes - act as additional filters
6. large proteins are left in capillary

Question 9

What is selective re -absorption?

Answer 9

-occurs in PCT
-most glomerulus filtrate is reabsorbed leaving urea

Question 10

What are the 3 steps to selective reabsorption?

Answer 10

1. conc of Na in PCT is decreased as Na are actively transported out
2. due to conc gradient - Na diffuse down gradient into cells lining the PCT
3. glucose can then diffuse from PCT cells into blood

Question 11

What is an example of co-transport?

Answer 11

-Na diffusing down gradient into cells lining the PCT