The Urinary and Excretory Systems
Our body needs food and oxygen to produce energy. In this process, waste products are also produced by the body. These waste products need to be collected and properly disposed of by our body. Removing wastes from our body is the work of one of the body systems, the excretory system. The urinary system is an important part of the excretory system.
The Excretory System
The kidney, Skin, Large Intestine and lungs help remove the different wastes, the by-products of the different activities of our body. These wastes include excess water, carbon dioxide, excess salts, nitrogenous compounds, and undigested food.
The process of removing these wastes from our body is called excretion.
The Urinary System
The urinary system consists of the kidneys, ureters, urinary bladder and urethra.
The kidneys are the major organs of the urinary system. There are two bean-shaped kidneys found on each side of the spinal column in line with our elbows.
The main function of the kidney is to filter impurities from the blood and regulate the water level and chemicals in the body. Each kidney is composed of about a million nephrons. A nephron is the filtering unit of the kidney.
All the blood in the body passes through the kidneys about 20 times every hour. The blood, which carries waste materials and other substances, enters the kidneys through an artery. The kidneys filter some body wastes form the blood. The substances that are useful to the body are brought back into circulation. Together with the clean blood, they leave the kidneys through the veins.
The waste material left in the kidneys after filtration is in the urine. It is made up of metabolic wastes such as excess water, excess salts, and the nitrogenous compounds urea and uric acid. The urine leaves the kidneys through the ureters. The ureters are tubes attached to each kidney that lead to the urinary bladder. Urine is temporarily stored in the urinary bladder. When the urinary bladder is full, it contracts and urine moves from the bladder through the urethra and passes out of the body.
The Large Intestine
Not all foods are digested and absorbed by our body.
The undigested food is passed into the large intestine for temporary storage. The undigested food contains a large amount of water and dissolved minerals like iron, calcium, and magnesium. Some of the water and the dissolved minerals are absorbed by the walls of the large intestine and returned to our body through blood circulation. The remaining solid waste after absorption is called feces. Feces contains bacteria, undigested food, bile, and the remaining water and minerals. It is discharged by the large intestine through the rectum. It then leaves our body through the anus.
The Skin 
The skin also removes metabolic wastes. From the body cells, water, urea, heat, and salts move through the blood vessels into the skin. These metabolic wastes move out of the blood vessels through the capillaries into the sweat glands. The skin excretes water, urea, and salt through the sweat glands. Each sweat gland has a sweat tube that leads to a small opening in the skin’s surface called pore.This is where water and salt pass out of the skin. These wastes are collectively called sweat or perspiration. The waste water in the sweat evaporates and the salts stay on the skin surface.
The blood vessels help the skin remove the excess heat from our body. When we feel hot, the blood vessels in the skin dilate. More blood is then brought near the surface of the skin to release the heat into the surroundings.
When we feel cold, the opposite happens. The blood vessels in the skin contract to move the blood away from the skin’s surface. Heat is then conserved in the body.
The Lungs
The lungs are not only organs of respiration but also organs of excretion. The lungs give off carbon dioxide and water vapor as waste products. These are picked up by the blood from the cells and brought to the lungs. Then, the lungs give them off as we exhale or breathe out.
Category: Science, Urinary & Excretory System
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i want to know the different ailments in the urinary system with its cause,sympton and treatment thats all.