| Alveoli | Nephron |
| 1. Alveoli are tiny balloon-like structures present inside the lungs. | 1. Nephrons are tubular structures present inside the kidneys. |
| 2.The walls of the alveoli are one cell thick and it contains an extensive network of blood capillaries. | 2. Nephrons are made of glomerulus, bowman’ capsule, and a long renal tube. It also contains a cluster of thin walled capillaries. |
| 3. The exchange of O2 and CO2 takes place between the blood of the capillaries that surround the alveoli and the gases present in the alveoli. Alveoli are the site of gaseous exchange. | 3. The blood enters the kidneys through the renal artery which branches into many capillaries in the glomerulus. The water and solute are transferred to the nephron at Bowman’ capsule. Then the filtrate moves through the proximal tubule, distal tubule and collecting duct. The collecting duct collects the ***** from many nephrons and passes it to the ureter. During the flow of filtrate, some substances such as glucose, amino acids, and water are selectively reabsorbed. Nephrons are the basic filtration unit. |
