Question

Explain the full process of excretion
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Answer 1

Answer:

u should refer to ncert class 11 biology book chap. excretion and transportation

Answer 2

Explanation:

Excretion is a process by which metabolic waste is eliminated from an organism. In vertebrates this is primarily carried out by the lungs, kidneys and skin.

Excretory System Organs

The human excretory system organs include:

A pair of kidneys

A pair of ureters

A urinary bladder

A urethra

Kidneys

Kidneys are bean-shaped structures located on either side of the backbone and are protected by the ribs and muscles of the back. Each human adult kidney has a length of 10-12 cm, a width of 5-7 cm and weighs around 120-170g.

The kidneys have an inner concave structure. At the centre, there is a notch called hilum through which the blood vessels and nerves enter the organ. Towards the inner surface of the hilum, there is a large funnel-shaped space called renal pelvis with projections called calyces.

Structure of Kidney

The structure of the kidney is explained below:

Capsule

The outer layer is called the capsule. Inside the kidney, there are two zones- the outer zone is cortex and the inner zone is medulla. The cortex extends in between the medullary pyramids as renal columns called columns of Bertin.

Nephrons

Nephrons are the functional units of the kidney. Each nephron has two parts- glomerulus and renal tubule.

Glomerulus consists of a bunch of capillaries formed by afferent arterioles. Blood from glomerulus is carried away by efferent arterioles.

The renal tubule starts with a cup-like structure called Bowman’s capsule and this encloses the glomerulus. The malpighian body consists of glomerulus and Bowman’s capsule. The highly coiled structure in the tubule next to the Bowman’s capsule is the proximal convoluted tubule.

Henle’s loop

The next part of the tubule is Henle’s loop which has an ascending and a descending limb. The ascending loop continues as a distal convoluted tubule. The distal convoluted tubules of many nephrons open into the collecting duct.

The cortical region of the kidney comprises of malpighian corpuscle, proximal convoluted tubule and distal convoluted tubule and the medullary region contains a loop of Henle.

There are two types of nephrons – cortical and juxtamedullary. In the case of cortical, the loop of Henle is very short and extends only a little into the medulla. In juxtamedullary, the loop of Henle is very long and runs deep into the medulla.

Ureter

A thin muscular tube called the ureter comes out of each kidney extending from the renal pelvis. It carries urine from the kidney to the urinary bladder.

Urinary Bladder

It is a sac-like structure that stores urine until micturition. Micturition is the expulsion of urine from the body. The urine is carried to the bladder through the ureters.

Urethra

This tube arises from the urinary bladder and helps to expel urine out of the body. In males, it acts as the common route for sperms and urine. Its opening is guarded by a sphincter.

Human Excretory System Diagram

The diagram below represents the different parts of the human excretory system.