Question

Glomerular filtrate contains
A. Blood without blood cells and proteins
B. Plasma without sugar
C. Blood with proteins but without cells
D. Blood without urea

Answer 1

Hint: Our body excretes only those substances which are either in excess in our body or are not required anymore. Some toxic materials are flushed out of our system. Ultrafiltration method filters out the products very finally. Dialysis is done when our body is unable to carry out the excretion process.

Complete answer:
The excretion system of our body produces urine which will wash away all the unwanted liquids and excess water from our body. Filteration of blood is the first step of urine formation. This is carried out by the glomerulus and the process is called glomerular filtration.

The kidney is the body part of conducting all this process. Why do we need to make urine? Our body absorbs almost all the nutrients from the food and stores it. But the unwanted and undigested which can harm our body are to be eliminated. The excess of everything is bad and so is with the nutrients.

The water-soluble products are flushed via urine including sodium, urea, potassium whereas the water-insoluble products are releases in the faecal matter such as bacteria, undigested fibres.

The first step in glomerular filtration is the separation of the liquid part of the blood which will have all the dissolved solutes. Each nephron has a glomerulus in it which will act as a microscopic filter. This glomerulus is placed in a cup-like sac at the end of the nephron called the glomerular capsule. Glomerulus + glomerular capsule = renal corpuscle.

This figure describes the flow of the blood from the glomerulus to the collecting duct (from where the urine is passed to the bladder for excretion.

The three kinds of membranes in the glomerular capillary tube include endothelium of glomerular vessel, epithelium of bowman’s capsule and the casement membrane between them both. They make this process of filtration so fine that all the blood constituents pass except the blood cells and the proteins. This ultrafiltration process will make the blood cells + proteins equal to glomerular filtrate to pass through the bowman’s capsule lumen, then the loop of Henle and ultimately the collecting tube. During this whole process, the needed constituents will be passively transported to the blood tube which is a part of our circulatory system.

This is done to make sure that only the unwanted material is secreted out of the body. So, with this, we get to know that the glomerular filtrate is just made of proteins and blood cells with no blood.
> In option B – plasma without sugar – its wrong as the plasma without proteins is filtered out.
> In option C- blood with proteins but without cells- it's also wrong as we know cells are also a part of the filtrate.
> Option D – blood without urea – urea is excreted out of the body as it is harmful to us.

So, our answer is option A – Blood without blood cells and proteins.

Note: Except for secretion by the kidney, other body parts also excrete the waste materials. Our skin excretes the waste by sweating. Lungs will expel carbon dioxide. The bladder can hold up to 400 ml of urine. 1 gallon of blood is filtered by an average kidney throughout a lifetime.