Name: Overview of Human Digestive and Excretory Systems
Uploaded: 2019-07-19
Duration: 3 min 31 s
Description: The digestive system and excretory system both work together to process the nutrition present in food. Let us conduct a thorough examination of both systems.

Question

What is excretory substance? Where is urea in urine formed? Write the role of lungs and skin in human excretion.

Accepted Answer

The nitrogenous and non-nitrogenous wastes that are formed by the cellular metabolism are called the excretory substance. These substances are toxic and harmful to the body. Urea is a nitrogenous waste that is formed in the liver due to the breakdown of proteins in the human body.

Skin: The skin of human possesses glands for the secreting fluids on its surface, such as sweat from sweat glands, and sebum from sebaceous glands. Sweat is an aqueous fluid containing 99.5 % water containing sodium chloride, lactic acid, urea, amino acids, and glucose. The sebum is a waxy protective secretion to keep the skin oily and eliminates some lipids and fatty acids.

Lungs: The human lungs remove around 18 litres of carbon dioxide per hour and about 400 ml of water per day in normal resting condition. Several volatile materials are also eliminated through the lungs. The blood vessels collect the carbon dioxide from the body cells and transport to the alveoli of the lungs. During exhalation, the diaphragm become dome-shaped and the carbon dioxide in exhaled out from the body.

What is excretory substance? Where is urea in urine formed? Write the role of lungs and skin in human excretion.

Important Questions on Excretion

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