Biology [2 Mark Question Answer]

1 - Collecting duct
2 - Distal convoluted tubule (DCT)
3 - Descending limb of loop of Henle
4 - Bowman's capsule

1 - Afferent arteriole
2 - Glomerulus
3 - Bowman's capsule
4 - Efferent arteriole

The blood vessel 'B' is renal artery and the blood vessel 'A' is renal vein.
So the blood vessel 'B' contains oxygenated blood with high concentration of urea and glucose whereas the blood vessel 'A' contains deoxygenated blood with low concentration of urea and glucose as compared to renal artery.

(i) 4/cortex

(ii) medulla

(iii)5/pelvis

1-renal artery,
2-renal vein,
3-ureter,
4-cortex,
5-pelvis

Excretion is the process of removal of chemical wastes especially nitrogenous wastes from the body. Catabolism on the other hand is the set of metabolic pathways which break down molecules into smaller units and release energy.

Urea is the chief excretory product which is excreted in the form of urine whereas urine is the filtrate left after reabsorption and tubular secretion which contains 95% water and 5% solid wastes.

During summer, a considerable part of water is lost through perspiration so the kidneys have to reabsorb more water from the urine. This makes the urine thicker in summer than in winters.

Maintaining a normal osmotic concentration in the body means regulating the percentage of water and salts. If this regulation mechanism fails we either end up losing vital salts and water or may accumulate unwanted salts and excess water in our body.

A uriniferous tubule also known as the kidney tubule is the structural and functional unit of the kidney. It takes in impure blood from the renal artery and removes wastes in the form of urine. It also provides a larger surface area for reabsorption of salts and water.

Excretion helps in removing toxic wastes from our body and it also plays an important role osmoregulation i.e. the maintenance of the homeostasis of the body.
Carbon dioxide, water, nitrogenous compounds such as urea, uric acid and excess salts are some common excretory products.

Glomerulus is involved in the process of ultrafiltration. The liquid part of the blood which is plasma including urea, salts, glucose filters out from the glomerulus into the renal tubule.

Micturition: The process of expelling urine out of the body through urethra by opening the sphincter muscles passing of urine involving relaxation of sphincter muscles between the urinary bladder and urethra.

Ultrafiltration - The process of the filtration of blood in the glomerulus under great pressure during which the liquid part of the blood i.e. plasma along with urea, glucose, amino acids and other substances enter the renal tubule.

Tubular Reabsorption : Tubular reabsorption is a process in the nephrons of the kidney.It involves the transfer of essential substances and water from the renal tubule back into the blood.This process ensures that useful substances like glucose, salts, and amino acids are not lost in urine.

Urinary Bladder : The urinary bladder is a muscular sac in the pelvis, just above and behind the pubic bone.It stores urine, allowing urination to be infrequent and voluntary.The bladder expands as it fills with urine and contracts during urination to expel it.

Ureter : The ureter is a tube that carries urine from the kidney to the urinary bladder. Humans have two ureters, one attached to each kidney. The ureters use peristaltic waves to propel urine towards the bladder.

Loop of Henle : The Loop of Henle is a U-shaped tube in the nephron of the kidney. It plays a crucial role in concentrating urine and in the reabsorption of water and solutes from the filtrate, helping to maintain water and electrolyte balance in the body.

Glomerulus: The glomerulus is a network of capillaries located at the beginning of a nephron in the kidney. It is responsible for filtering blood to remove waste products and excess substances, initiating the process of urine formation.

Bowman's Capsule : it is a cup-like sac at the beginning of the tubular component of a nephron in the mammalian kidney. It performs the first step in the filtration of blood to form urine. The capsule encloses a cluster of capillaries called the glomerulus.

Malpighian body : The Malpighian body, also known as the renal corpuscle, is a structure in the kidney that consists of the Bowman's capsule and the glomerulus. It is involved in the initial stage of filtering blood to form urine.

Ureotelism : This term refers to the excretion of nitrogenous waste in the form of urea. Organisms like humans, which excrete urea are called ureotelic. It is a metabolic process, where urea is synthesised in the liver and excreted by the kidneys.