Mention the two factors that decide the reabsorption of water in the kidney during urine formation
Answers
Introduction
Formation of urine is a process important for the whole organism. Not only acid-base balance is modulated by it, but also blood osmolarity, plasma composition and fluid volume, and thus it influences all cells in our body.
A healthy adult person produces 1.5-2 liters of urine per day and this process involves three basic mechanisms:
1) Glomerular filtration
2) Tubular reabsorption
3) Tubular secretion
Functional anatomy
The basic functional unit for the urine formation is called nephron. Very important is the arrangement of nephron: it begins with renal corpuscle (Malpighi) that consists of a glomerulus, which is supplied by afferent glomerular arteriole and drained by efferent glomerular arteriole, and Bowman’s capsule (capsula glomeruli, glomerular capsule). Renal tubules have three segments. The proximal tubule, in which we distinguish pars convoluta (initial section) and pars recta, loop of Henle (intermediate tubule), where can be recognized the descending limb and ascending limb (its proximal part is formed by a thick segment of the ascending limb), and distal convoluted tubule (which has conversely first pars recta and then the pars convoluta) that subsequently joins the collecting ducts.
Answer:
Re-absorption is the process by which the water and solutes via the nephron are removed from the tubular fluid and then return them back to blood.
Substances are reabsorbed from the renal tubule, it occurs as a result of sodium transport into the blood by Na+/K+ in the membrane of epithelial cells. It makes the glomerular filtrate concentrated, which is essential for the urine formation.
It allows useful solutes such as glucose, salts, an amino acid that passed through the Bowman's capsule to return to the circulation.