4. Macroscopic Structure of the Kidney
• Cortex: Outer region
• Medulla: Inner region
• Renal pelvis: large cavity that collects the
urine as it is produced. Continuous with ureter
9. Nephron Structure
Nephrons have two parts:
1. Renal corpuscle
a. Glomerulus: cluster of capillaries
b. Glomerular (Bowman’s) Capsule: cup that
surrounds the glomerulus and receives
blood filtrate from it
10. 2. Renal tubule
a. Proximal convoluted tubule: Highly coiled.
Located in cortex
11. 2. Renal tubule
a. Proximal convoluted tubule: Highly coiled.
Located in cortex
b. Loop of Henle: A hairpin loop that dips into
the medulla, makes a U-turn, and ascends
back to the cortex
12. 2. Renal tubule
a. Proximal convoluted tubule: Highly coiled.
Located in cortex
b. Loop of Henle: A hairpin loop that dips into
the medulla, makes a U-turn, and ascends
back to the cortex
c. Distal convoluted tubule: Coiled, in cortex
13. Urine Formation
• Nephrons form urine in 3 steps
1. Filtration: Water and small solutes enter the
nephron (blood cells and proteins do not
enter). Filtrate is similar to blood plasma.
14. Urine Formation
• Nephrons form urine in 3 steps
1. Filtration: Water and small solutes enter the
nephron (blood cells and proteins do not
enter). Filtrate is similar to blood plasma.
2. Reabsorption: Useful substances
(water, glucose, amino acids, needed ions) are
transported out of the filtrate and back into
the blood
15. Urine Formation
• Nephrons form urine in 3 steps
1. Filtration: Water and small solutes enter the
nephron (blood cells and proteins do not enter).
Filtrate is similar to blood plasma.
2. Reabsorption: Useful substances
(water, glucose, amino acids, needed ions) are
transported out of the filtrate and back into the
blood
3. Secretion: Harmful substances (H+, excess
K+, some drugs and poisons) are removed from
the blood and put into the filtrate
