Excretion and Osmoregulation

Introduction

     The steam engine uses the power generated from steam pressure to move. Coal is used in furnaces to heat water in the boiler to generate steam. Steam pressure makes the wheels of the engine move. As coal is burnt, smoke is emitted and ash is left behind in the furnace. Smoke is let off through the chimney and the ash is removed periodically.

Significance of Excretion and Osmoregulation

     The different chemical activities in the body produce many by-products several of which are wastes. These waste products if allowed to accumulate will turn out to be toxic and affect the physiological activities of the body. These wastes have to be expelled out or it may eventually result in the death of the organism.

Substances Excreted in Animals

     Carbon dioxide and water are the by-products of catabolism of all varieties of foodstuffs. In lower animals carbon dioxide is eliminated directly into the environment through the body surface. In higher animals it is excreted out along with the exhaled air through the lungs. Excess water is excreted in the form of urine and sweat.

Excretion and Osmoregulation in Amoeba

     Amoeba is a protozoan which forms the simplest of all groups in the animal kingdom. Inspite of being unicellular it is physiologically balanced and performs all the essential processes of an animal.

Excretion and Osmoregulation in Earthworm

     The earth worm belongs to the phylum Annelida. This group of higher invertebrates possess a number of highly developed organs and organ-systems for performing various vital functions.

Excretion and Osmoregulation in Man

     Carbon dioxide is a catabolic waste product formed due to oxidation of food releasing energy. It is carried by the blood to the lungs. During expiration this carbon dioxide along with a small quantity of water vapour is expelled out of the lungs.

Excretion and Osmoregulation in Man - contd.

     This process regulates the water content in the blood by producing hypotonic or hypertonic urine. It regulates pH (acid - base balance) of the blood. The rate of secretion of acid or alkaline phosphates is regulated when the blood becomes too acidic or alkaline.

Disorders of the Urinary System

     Stones are formed from accumulation of mineral substances filtered by the kidneys during the formation of urine. The compounds of kidney stones are calcium oxalate, calcium phosphate, magnesium ammonium phosphate, uric acid and cystine stones

Summary

     The removal of harmful and unwanted toxic waste products of metabolism is known as excretion.