The Nephron PDF

1 Nephrons Nephrons are the filters inside the kidney. There are over 1 million nephrons inside each kidney. They are located inside the cortex and medulla of the kidneys. Each nephron consists of six parts: -glomerulus -loop of Henle -Bowmanʼ...

1 Nephrons Nephrons are the filters inside the kidney. There are over 1 million nephrons inside each kidney. They are located inside the cortex and medulla of the kidneys. Each nephron consists of six parts: -glomerulus -loop of Henle -Bowmanʼs capsule -distal tubule -Proximal tubule -collecting duct 2 3 Parts of the Nephron Glomerulus Mass of thin-walled capillaries (filtration of blood, water, electrolytes, glucose, urea). Bowmanʼs capsule Double-walled, cup-shaped structure. Proximal tubule Leads from the Bowmanʼs capsule to the Loop of Henle. Loop of Henle Long loop which extends into the medulla (middle part of kidney). Distal tubule Connects the loop of Henle to the collecting duct. Collecting duct Leads from the medulla into the pelvis. The function of tubules is for the reabsorption of glucose, water, salts, and urea. 4  Step 1 Glomerulus receives branches that come from renal artery (blood enters kidney through renal arteries, which branch 5 into arterioles). Step 2 Some of the water and dissolved substances in the blood The Nephron plasma (not proteins or blood cells) are forced from the (steps) glomerulus and into the Bowmanʼs capsule (now known as filtrate). Step 3 Some blood plasma and small particles (water, ions, urea) exit the Bowmanʼs capsule and enter the proximal tubule. Step 4 While in the proximal tubule, materials that the body needs (glucose, amino acids, or ions) are absorbed back into the blood via diffusion, osmosis, or active transport. Step 5 The liquid enters into the loop of Henle where water is reabsorbed (osmosis) into the blood (only if it needs it); NaCl is also pulled from the liquid here.  Step 6 The liquid enters into the distal tubule where drugs such as penicillin are typically filtered out. 6 Step 7 The liquid enters the collecting duct where it can now be called urine. The Nephron (steps) Step 8 The urine enters into the pelvis of the kidney where it can enter into a ureter. 7 8 9 Urine Formation of the Nephron Glomerular Filtration ▹ Creates a plasma-like filtrate of the blood. This process results in the movement of water and solutes, except proteins, from the blood plasma into a nephron down a pressure gradient. Tubular Reabsorption ▹ Removes useful substances such as sodium from the filtrate and returns them to the blood for reuse. Tubular Secretion ▹ Adds wastes from the blood to the filtrate in the nephron; uses mainly active transport. Water Reabsorption ▹ Removes water from the filtrate and returns is to the blood for reuse by body systems. 10