Tag: excretion to maintain homeostasis

The statement "skin is the main excretory organ" is incorrect because in all chordates kidneys act as main excretory organ.

The submaxillary duct is also known as the Wharton's duct opens into the floor of the mouth. They are the major ducts of the submaxillary (submandibular gland) and help in the transfer of saliva from the submaxillary gland to the opening under the tongue.

Sweat glands are coiled and tubular in structure. Coiled part of this gland is called as secretory unit. Around secretory unit, myoepithelial cells are present. When they contract sweat comes out from sweat gland. This secretion is called as sweat. 

The skin has sweat glands that excrete perspiration (salt, water, and nitrogenous wastes) through its pores. 

Skin serves in excretion of waste material through the process of sweating. Large intestine serves to reabsorb water and essential minerals from the undigested food and to store it till it is excreted at the anus. Lungs serve in excretion via expiration. The liver serves in the formation of urea which is then excreted by kidneys. Kidneys are the organs of urine formation. This makes option B correct answer as large intestine only stores the undigested material; it does not excrete it directly. 

Evaporation or the loss of water from the body due to heat is called as perspiration. The heat present in the surrounding causes water to be lost from the body in the form of sweat through the sweat glands on the skin. The water is deposited on the surface of the organism's body leading to a cooling effect. Thus the correct answer is option A.

Sweat glands secrete a fluid called sweat that contains water and dissolved salts of Calcium, Sodium, Magnesium etc Thus, it helps in excreting water and salts to some extent by a process called sweating or perspiration.