write in detail about four organs of the excretary organs of human beings ?
Answers
Answer:
The four organs of the excretory system are:
1. Skin
2. Liver
3. Large Intestine
4. Kidneys
Skin
The skin is part of the integumentary system, but it also plays a role in excretion through the production of sweat by sweat glands in the dermis. Although the main role of sweat production is to cool the body and maintain temperature homeostasis, sweating also eliminates excess water and salts, as well as a small amount of urea. When sweating is copious, as in the figure below, ingestion of salts and water may be helpful to maintain homeostasis in the body.
Liver
The liver has numerous major functions, including secreting bile for digestion of lipids, synthesizing many proteins and other compounds, storing glycogen and other substances, and secreting endocrine hormones. In addition to all of these functions, the liver is a very important organ of excretion. The liver breaks down many substances in the blood, including toxins. For example, the liver transforms ammonia — a poisonous by-product of protein catabolism — into urea, which is filtered from the blood by the kidneys and excreted in urine. The liver also excretes in its bile the protein bilirubin, a byproduct of hemoglobin catabolism that forms when red blood cells die. Bile travels to the small intestine and is then excreted in feces by the large intestine.
Large Intestine
The large intestine is an important part of the digestive system and the final organ in the gastrointestinal tract (see figure above). As an organ of excretion, its main function is to eliminate solid wastes that remain after the digestion of food and the extraction of water from indigestible matter in food waste. The large intestine also collects wastes from throughout the body. Bile secreted into the gastrointestinal tract, for example, contains the waste product bilirubin from the liver. Bilirubin is a brown pigment that gives human feces their characteristic brown color.
Kidneys
The paired kidneys are often considered the main organs of excretion. The primary function of the kidneys is the elimination of excess water and wastes from the bloodstream by the production of the liquid waste known as urine. The main structural and functional units of the kidneys are tiny structures called nephrons. Nephrons filter materials out of the blood, return to the blood what is needed, and excrete the rest as urine. As shown in the diagram below, the kidneys are organs of the urinary system, which also includes the ureters, bladder, and urethra — organs that transport, store, and eliminate urine, respectively.
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