7.19: structure of the nephron

What are the areas of the nephron?

Glomerulus, bowman’s capsule, proximal convoluted tubule, loop of Henle, distal convoluted tubule, collecting duct

What’re the events in the nephron?

Ultrafiltration, selective reabsorption of glucose and water

What happens at the glomerulus?

The blood is at very high pressure here, helping ultrafiltration as small molecules are squeezed out into the nephron tubule while larger molecules are too big to fit so remain in the blood

What are the large molecules that remain in the blood?

Red and white blood cells, platelets, proteins

What are the small molecules that are filtered into the nephron?

Amino acids, water, mineral salts, mineral ions, urea and glucose

What happens at selective reabsorption?

Some molecules are reabsorbed depending on what the body needs. This happens in the convoluted tubules (proximal and distal)

What molecules are selectively reabsorbed?

All glucose (no glucose should be found in urine), water (depending on the body’s need to maintain a constant water level in the blood plasma), and mineral ions (depending on the body’s need to maintain a constant balance of mineral ions in the blood plasma)

What is the role of the liver?

Since the body cannot store excess protein or amino acids (which is protein broken down as part of digestion), ammonia is formed by the liver as it deaminates it. However, ammonia is highly toxic so is converted to urea which is less toxic and carried from the liver to the kidneys via the bloodstream to be excreted

What does the collecting duct do?

Collects the substances found in the nephrons to be taken to the bladder via the ureter