Kidney Filtration
Kidney Filtration - Related Videos
01:32
Filtration and Urine Formation
0 Views •
2019
The function of the kidneys is to filter, reabsorb, secrete, and excrete. Every day the kidneys filter nearly 180 liters of blood, initially removing water and solutes but ultimately returning nearly all filtrates into circulation with the help of osmoregulatory hormones. This process removes wastes and toxins but is also crucial to maintain water and electrolyte levels. Most of these functions are performed by the tiny but numerous nephrons contained within the kidneys. Blood enters the renal...
01:45
Kidney Structure
0 Views •
2019
The kidneys are two large bean-shaped organs located in the upper abdomen. They filter the blood several times a day to remove toxins and rebalance water and electrolytes of the circulatory system via the renal veins. The kidneys receive blood directly from the heart via the renal arteries. These arteries enter the kidney at the hilum, the concave surface of the bean, where they branch and divide into smaller vessels and capillaries. The renal cortex is the thick outer layer of the kidney. It...
08:19
The Mouse Isolated Perfused Kidney Technique
0 Views •
Cited by 24 •
2016
The mouse isolated perfused kidney (MIPK) is a technique for keeping a mouse kidney under ex vivo conditions perfused and functional for 1 hr. The buffers and surgical technique are described in detail.
01:26
Glomerular Filtration: Net Filtration Pressure
0 Views •
2025
Glomerular filtration, a key process in the kidneys, is regulated by three main pressures: Glomerular blood hydrostatic pressure (GBHP), Capsular hydrostatic pressure (CHP), and Blood colloid osmotic pressure (BCOP). GBHP, with an average value of 55 mmHg, promotes filtration by pushing water and solutes through the filtration membrane. This is balanced by two opposing forces: CHP, a "back pressure" exerted against the filtration membrane by fluid already in the capsular space and renal tubule,...
10:42
Normothermic Machine Perfusion of Rat Kidneys for Transplantation
0 Views •
2026
This protocol describes the ex vivo normothermic machine perfusion of a rat kidney for subsequent transplantation into a recipient rat.
FAQs
Pressure is the immediate driving force: blood pressure within the glomerular capillaries pushes water and small dissolved substances across the filtration barrier into Bowman’s capsule. That barrier is selective rather than simply porous, because it allows the filtrate to form while retaining blood cells and most plasma proteins. This preserves the composition of the circulating blood.
Retention prevents these blood components from entering the tubular fluid during ultrafiltration. Their exclusion helps distinguish the initial filtrate from whole blood, while water and small dissolved substances can proceed into Bowman’s capsule. In biological terms, the barrier provides selectivity that supports both waste removal and preservation of important circulating material.
Renal tubules modify the filtered fluid through two complementary processes. Reabsorption returns needed water and solutes, whereas secretion adds additional wastes to the tubular fluid. This means the material leaving the filtration stage is not yet the final urine. Tubular processing helps determine the eventual water and solute content and contributes to electrolyte, volume, and acid-base regulation.
Blood is first filtered as it passes through glomerular capillaries, and the resulting fluid enters Bowman’s capsule. The fluid then travels through renal tubules, where needed water and solutes are reabsorbed and additional wastes are secreted. The final product is urine, so studying the sequence distinguishes filtration from the later modification that completes urine formation.
Because filtration is an organized nephron process that produces urine while influencing fluid balance, electrolytes, blood volume, and acid-base balance, it provides a physiological basis for evaluating kidney function. Investigators can use knowledge of this process to interpret how effectively the kidney performs its regulatory roles in health and disease.
Filtration occurs within each nephron, allowing the process to be examined as a sequence from glomerular capillaries and Bowman’s capsule to renal tubules. This organization connects specific renal structures with whole-body outcomes, including urine production and regulation of fluid, electrolytes, blood volume, and acid-base balance. It therefore links renal anatomy with broader biological physiology.