what do you mean by tabular reabsorption in kidney filteration and name the part involved in it
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Answers
Answer:
Tubular reabsorption is the process that moves solutes and water out of the filtrate and back into your bloodstream.
DCT-distal convoluted tubule
EXPLANATION:
The fluid that filters through the glomerulus and Bowman’s capsule (glomerular filtrate) is very similar to blood plasma without the proteins, and at this point not at all like urine. If this filtrate flowed straight to your bladder and then out your body, you would lose more than 10-times the entire volume of your extracellular body fluids (plasma and interstitial fluid) every day. Fortunately, tubular reabsorption mechanisms in the nephrons of your kidneys return the water and solutes that you need back into your extracellular fluid and circulatory system. In addition to reabsorbing the substances that you need, your nephrons are able to secrete unwanted substances from your bloodstream into the filtrate. Together these processes complete the transformation of the glomerular filtrate into urine.
Tubular reabsorption is the process that moves solutes and water out of the filtrate and back into your bloodstream. This process is known as reabsorption, because this is the second time they have been absorbed; the first time being when they were absorbed into the bloodstream from the digestive tract after a meal.
How does reabsorption in the nephrons work?
The nephrons in your kidneys are specifically designed to maintain body fluid homeostasis. This means keeping extracellular body fluid volumes stable, as well as maintaining the right levels of the salts and minerals that are essential for the normal function of your tissues and organs; regardless of how much you eat, or how active you are. Nephrons are divided into five segments, with different segments responsible for reabsorbing different substances.
Overview of the nephron showing which substances get reabsorbed along the various structures of the nephron (like the proximal convoluted tubule).
Overview of the nephron showing which substances get reabsorbed along the various structures of the nephron (like the proximal convoluted tubule).
Reabsorption is a two-step process:
The first step is the passive or active movement of water and dissolved substances from the fluid inside the tubule through the tubule wall into the space outside.
The second step is for water and these substances to move through the capillary walls back into your bloodstream, again, either by passive or active transport.
Nephrons are comprised of different segments that perform specific functions. The walls of the nephron are made of a single layer of cube-like cells, called cuboidal epithelial cells, and their ultrastructure changes depending on the function of the segment they are in. For example, the surface of the cells facing the lumen of the proximal convoluted tubule are covered in microvilli (tiny finger-like structures). This type of surface is called a brush border. The brush border and the extensive length of the proximal tubule dramatically increase the surface area available for reabsorption of substances into the blood enabling around 80% of the glomerular filtrate to be reabsorbed in this segment. Another notable feature of these cells is that they are densely packed with mitochondria (the cell’s energy generators). The mitochondria ensure a good supply of energy is available to fuel the active transport systems needed for efficient reabsorption.
