The glomerulus filters blood into Bowmans capsule, and the proximal convoluted tubule selectively reabsorbs useful solutes and water in human physiology.
Coverage 2013–2023 · Updated 16 Jul 2026
The glomerulus and Bowman's capsule form filtrate by ultrafiltration; the proximal convoluted tubule (PCT) then returns useful substances to blood.
| Site | Mechanism and outcome |
|---|---|
| Glomerulus → Bowman's capsule | High hydrostatic pressure forces water and small solutes through fenestrations, basement membrane and podocyte slits; cells and most plasma proteins remain in blood |
| PCT | Membrane transport selectively reabsorbs all normal glucose and amino acids, much Na⁺ and other ions; water follows by osmosis into surrounding capillaries |
Ultrafiltration is mainly size/pressure based, so it cannot distinguish useful small solutes from wastes. Selective transport in the PCT performs that recovery.
Glucose enters Bowman's filtrate because it is small, then is normally reabsorbed in the PCT rather than excreted in urine.
Large proteins or blood cells in urine are not normal products of ultrafiltration and may indicate damage to the filtration barrier.
This objective is assessed through structured response, commonly using Identify.
Identify
Build the answer around this relationship: Ultrafiltration occurs from the glomerulus into Bowmans capsule.
Representative question
Explain the presence of glucose in the urine of a diabetic person and its absence in the urine of a person with type I diabetes that is being successfully treated.
HL D3.3 adds kidney and circulation mechanisms. The route is still feedback logic: nephrons filter and reabsorb, the loop of Henle builds a gradient, ADH changes collecting duct permeability, and blood vessels redistribute flow according to activity.
HL homeostasis transfer is about structure-function precision. In kidney answers, say where filtration, reabsorption, salt pumping, water movement, ADH, and aquaporins happen. In blood-flow answers, say which vessels dilate or constrict and how activity changes tissue demand.
