Renal Systems Kahn Academy Questions HELP

[Radioactive1112]

Which of the following is least likely to be present in the glomerular filtrate (the filtrate produced by the nephron before it enters the loop of Henle) of a healthy adult nephron?

• Glucose
• Amino acids
• Large molecular weight protein
• Electrolytes

Electrolytes, glucose, and amino acids are all filtered from the blood into the tubular filtrate, and subsequently reabsorbed.

Ok I got the answer correct but then I confused myself about the process. The filtrate that gets to the bowmans capsule is fluid this is the glomerular filtrate correct? So blood enters the kidney through the afferent arteriole, goes into the glomerulus where large proteins are filtered out and go where? and everything else (glucose, aa, electrolytes) go with the filtrate (fluid) down the proximal tubule,loop of henle, and to the distal tubule. At the distal tubule these small molecules (glucose, aa, electrolytes) get reabsorbed?

I thought at some point the vesa recta (may have spelled that incorrectly) picked up some of these molecules...but where?

Thanks in advance for the help.

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[Czarcasm]

The filtrate that gets to the bowmans capsule is fluid this is the glomerular filtrate correct?

Yes. This is essentially the contents of blood plasma that are small enough to pass through the different barriers and be filtered out, forming "filtrate" - a plasma like fluid that consists of both nutrients and waste products which are eventually selectively reabsorbed as it passes through the nephron (the functional unit of the kidney).

So blood enters the kidney through the afferent arteriole, goes into the glomerulus where large proteins are filtered out and go where? and everything else (glucose, aa, electrolytes) go with the filtrate (fluid) down the proximal tubule,loop of henle, and to the distal tubule. At the distal tubule these small molecules (glucose, aa, electrolytes) get reabsorbed?

What is it that we are filtering? Blood. Blood consists of plasma and formed elements. Plasma includes various proteins (both large and small), various nutrients, and waste products. Collectively, only substances small enough to pass through the barriers form the filtrate. These substances are basically vacuumed into the bowman's capsule due to a pressure gradient. Some of these substances (formed elements and large proteins) are too large to pass through this barrier and stay behind. As an analogy, it's basically like the coffee grinds left behind in the filter while making coffee. This is actually an essential and unique aspect of the nephron, because various large proteins (ie. albumin produced by the Liver) are necessary in order for that "vacuum-like-suction" (pressure gradient) to be established and continually function to filter out substances. The substances small enough to be passed on are then selectively reabsorbed. Most glucose and other essential nutrients such as amino acids, are brought back in. Some nutrients are left behind if they are in excess (ie. Sodium or Potassium). Waste products are continually pumped out, to avoid toxic build up in our body. The way all this occurs, and where it occurs is very intricate and detailed but as long as you understand the purpose and big picture of what's happening, it'll make understanding everything much easier.

 

[Radioactive1112]

Thanks.