Describe the process of urine formation in kidneys.
Answers
ANSWER
Q-1). Describe the process of urine formation in kidneys.
Ans. Urine is formed in the nephron present inside the kidneys. There are three main steps through which urine is formed. They are:
1). Glomerular filtration:- Due to very high pressure of blood in glomerulus (concentrated blood capillaries), the plasma only passes through it and the other substances including blood cells remains back into the filter and pass to the blood flow. The plasma is the filtrate here.
2). Tubular re-absorption:- The filtrate then enters the tubule where the necessary nutrients are absorbed again and returned back to the blood flow. The remaining filtrate then passes to the collecting tubule.
3). Water conservation:- It collecting tubule additional water is absorbed and a concentrated urine is formed.
ANSWER
The three main steps in urine formation are:-
⏺️Glomerular filteration.
⏺️Reabsorption.
⏺️Secretion.
Glomerular filteration occurs in malphigian corpuscles formed together by glomerulars and its surrounding bowman's capsule.
Reabsorption & secretion occurs in highly coiled renal tubule.
URINE FORMATION
1.Glomerular filteration
The total volume of blood is filtered the kidney. The filteration forms an ultra filtrate in the lumen's of the bowman's capsule are removed from the plasma that flows through the glomerulus.
2.Reabsorption
Reabsorption occurs through the epithelial cells of the various segments of the nephrons. The small molecules which are essential for the body must be returned to the interstitial fluid and blood plasma. This selective transport of the substances across the epithelial of the excretory tubule from the ultrafiltration to the interstitial fluid is called reabsorption. The proximal & distal convoluted tubules, henle's loop and collecting duct contribute to reabsorption. Nearly all sugar, vitamins, organic nutrients and most of water is reabsorbed.
3.Secretion
Secretion is a selective process involving both active & passive transport. As the filtrate travels through the nephrons tubule, tubular cells secrete substances such as H+, k+ and ammonia into the filterate. The proximal & distal convoluted tubules are the main sites of tubular secretion and helps in maintenance of ionic & acid-base balance of body fluids.