Roles of the medulla

• The medulla is a region in the lower/mid-section of the kidney which has an increasing/high salt concentration ✔
• Generally, the loop of Henle descends through into the medulla ✔

Roles of the loop of Henle

• The high salt concentration/osmolarity in the medulla causes water to passively be drawn out of the descending loop of Henle ✔
• The ascending loop of Henle actively pumps out salt ✔

• This creates a concentration gradient between the medulla ✔
• It regulates a high concentration of urea near the medulla ✔

4

• The percentage of water distribution depends on body composition ✔
• Muscle contains 65–75% water, whereas fat mass is 5–20% water ✔
• A trained athlete is likely to have more muscle mass compared to an untrained individual ✔