Nephrons

Question 1

What happens in the nephrons?

Answer 1

• blood is filtered
• then the majority of the material is returned to blood, removing nitrogenous waste and balancin the mineral ions and water

Question 2

Describe the basic structure of the nephorns?

Answer 2

each is 3cm and there are around 1.5 million

provides the body with several kilometres of tubules for the reabsorbtion of:

• water
• glucose
• salts
• and other substances

back in the blood

Question 3

What are the main structures in the nephron?

Answer 3

1. Bownman’s capsule
2. Proximal convoluted tube
3. Loop of Henle
4. Distal convoluted tube
5. Collecting duct

Question 4

What is the Bowman’s capsule?

Answer 4

• cup-shaped
• contains the glomerulus, a tangle of capillaries
• more blood goies into the glomerulus then leaves it due to the ultrafiltration processes that take place

Question 5

What is the proximal convoluted tube?

Answer 5

• the first, coiled region of the tubule after the Bowman’s capsule
• found in the cortex of the kidney
• this is where many of the substances needed by the body are reabsorbed in the blood

Question 6

What is the Loop of henle

Answer 6

• a long loop of tubule that creates a region with a very high solute concentration in the tissue fluid deep in the kidney medulla
• the decending loops runs down the cortex thorugh the medulla to a hairpin bend at the bottom of the loop
• the ascending limb travels back up throuigh the medulla to the cortex

Question 7

WHat is the dital convoluted tubule?

Answer 7

• a second twisted tubule where the fine-tining of the water balance of the body takes place
• the permability of the walls to water varies in response to the levels of the antidiuretic hormone
• further regulation of the ion balance and the pH of the blood also takes place in this tubule

Question 8

What is the collecting duct?

Answer 8

• urine passes down the collecting duct through the medulla to the pelvis
• more fine-tuning of the water balance takes place
• the walls of this part of the tubule are sensittive to ADH

Question 9

How do concentration of the blood entering and leaving the kiney vary?

Answer 9

• urea - vastly reduced
• aminop acids and other substances needed by the body - almost the sasme
• slightly less glucose
• mineral ion conc in the blood is restored to ideal levels

Question 10

Why does the gluocse conc slightly decrease?

Answer 10

• glucose is reabsorbed
• but some may have been used for selective reabsorbtion