NEET Excretory Systems Important Questions - Free PDF Download
FAQs on NEET Important Questions for Excretory Systems
1. Give the general idea about Kidneys
There are two kidneys each shaped like a bean. These kidneys are placed on either side of the human’s backbone. Kidneys are protected by the back muscles and ribs. The kidney of an adult human is 10 to 12 cm with a width of 5 to 7 cm and a weight of about 120 - 170 g. Kidneys have a structure that is concave in nature. Blood vessels, ureters and nerves enter these kidneys via the hilum. The hilum is a notch present at the inner concave structure of the kidney. The renal Pelvis is present inner to the hilum and the renal pelvis is shaped like a large funnel. There are also many projections in the kidneys that are called calyces. Kidneys are one of the most important parts of our body and should be taken care of.
2. What are Nephrons?
The functional units of the kidney are termed Nephrons. Nephron has two parts known as renal tubule and glomerulus. Renal tubules begin with a structure that is cup-like and is known as Bowman’s capsule. It is enclosed with glomerulus as well. The part known as the Malpighian has a glomerulus and bowman’s capsule. Both of them are coiled in a high manner and form a highly coiled structure in the tube that is next to the Bowman’s Capsule called a proximal convoluted tubule. The Glomerulus have a bunch of capillaries that are formed by afferent arterioles. The blood from the glomerulus is carried away with the help of different arterioles.
3. What is Ureter and Urinary Bladder? Are they different?
Yes, Ureter and Urinary Bladder are different. Ureter is a pair of two muscular tubes that are thin in nature. These come out of each Kidney present on either side of the human backbone. They extend from the renal pelvis. These tubes carry urine from the kidney to the bladder ( urinary bladder ). The Urinary Bladder is nothing but a sac-like structure that stores human urine. This bladder is emptied when the process of micturition known as urination happens. We can conclude that Ureter brings the urine down to the urinary bladder and then it is excreted out of the body.
4. How is urine formed?
The following process will make us aware of how urine is formed and excreted.
The formation of urine takes place in the nephrons and involves three steps:
Glomerular Filtration
This is the first step of urine formation. This process includes the filtration of excess fluid and waste products from the kidneys of the blood into the tubules of kidney that proceed to urine collection. The filtrate produced by the Kidneys every minute is termed GFR ( Glomerular Filtration Rate ).
Tubular Reabsorption
In this process the absorption of ions and molecules like glucose, sodium ions, amino acids, water etc. passive absorption is involved in the water and glucose and sodium ions go through the active absorption.
Secretion
Hydrogen ions, Potassium and ammonia are secreted out to maintain equilibrium between the fluids of the body.
5. What are the various tubules that are involved in the excretion process?
There are many tubules involved in the process of excretion. They are as follows:
Glomerulus helps to filter the blood.
PCT (Proximal Convoluted Tubules) helps in the reabsorption of water, nutrients, and ions. This helps in removing the toxins and also helps in maintaining the balance of ions and the pH level of the body fluids. They also secrete potassium, ammonia, and hydrogen to filtrate and reabsorb bicarbonate ions.
Descending Loop of Henle helps in a way that they are permeable to the water and the filtrate that is present gets concentrated because they are impermeable to electrolytes.
Ascending Loop of Henle helps in such a manner that is impermeable to the water and permeable to the electrolytes. Here, the filtered urine is diluted because of the movement of electrolytes.
