Exercise Describe the processes involved in urine formation. List all excretory organs and their respective products in tabular format.

1. Urine formation involves three main processes that occur in the nephrons of the kidneys: Glomerular Filtration: Blood is filtered in the glomerulus, where water, salts, glucose, amino acids, and waste products (like urea) pass from the blood into the Bowman's capsule, forming the glomerular filtrate*. Large proteins and blood cells are retained. Tubular Reabsorption*: As the filtrate moves through the renal tubules, essential substances like most water, glucose, amino acids, and some salts are reabsorbed back into the blood capillaries surrounding the tubules. This ensures the body retains vital nutrients and maintains fluid balance. Tubular Secretion*: Waste products and excess ions (e.g., hydrogen ions, potassium ions, certain drugs) are actively secreted from the blood into the renal tubules. This process helps to eliminate additional wastes and regulate blood pH. 2. Here are the main excretory organs and their respective products: | Excretory Organ | Excretory Products | | :-------------- | :----------------------------------------------- | | Kidneys | Urea, uric acid, creatinine, excess salts, water | | Lungs | Carbon dioxide, water vapor | | Skin | Sweat (water, salts, urea, lactic acid) | | Liver | Bile pigments, cholesterol, drug metabolites | What's next? 📸