Glomerular Filtration Rate

GFR is dependent on blood pressure and is regulated by constricting the afferent vessel to Bowman's capsule. The auto-regulation is set off by either a myogenic response (by stretch sensitive receptors in the juxtaglomerular apparatus), or a Tubuloglomerular feedback loop. The latter is regulated by the sodium content in the filtrate which is sensed by cells in the macula densa.

Bowman's capsule has three barriers:

1. The vascular endothelium is fenestrated allowing smaller molecules through
2. The basal membrane repels negatively charges proteins
3. The podocytes are inside the capsule and lets only small molecules past their slits.

Electrolytes, glucose and urea are among the substances that are filtrated.

Plasma proteins and blood cells are not filtrated and is stopped by the barriers above.

Diuretics are used to control body fluid volume. There are two main types. Loop and Thiazide. Loop is mainly used when there is a lowered kidney function. They work roughly the same way, by keeping the electrolytes in the tubulus they keep the osmolarity higher in the filtrate which draws out fluids.