The excretory system is responsible for removing any dangerous, unnecessary or excess material form the body. Through this process it allows the body to maintain homeostasis, thereby preventing any damage from occurring. Most organs in the body that are functioning normally will produce metabolic wastes and because of this, the entire body depends on the excretory system. Organs of the excretory system include the four organs of the urinary system, lungs, the skin, the liver and large intestines. Read on to learn more about the organ functions.
1. Urinary System
The kidneys are located in the back of the abdominal cavity that is found in the retroperitoneum and they get blood from paired renal arteries. The kidneys excrete urine into one of the ureters. The kidneys serve a variety of functions including regulating blood pressure, maintaining the body’s acid-base balance and regulating electrolytes. They also naturally filter the blood, diverting the waste towards the urinary bladder. When the kidneys produce urine, they excrete wastes including ammonium and urea. Other functions include producing hormones and reabsorbing amino acids, glucose and water.
Each ureter is a muscular tube that brings the urine between the kidneys and the urinary bladder. They usually have a diameter of between 3 and 4 mm and a length of between 25 and 30 cm. They cross over the pelvic brim close to the bifurcation of iliac arteries, which is where kidney stones are commonly found. They then run along the pelvis’s lateral walls before curving towards the bladder in the back.
The urinary bladder is responsible for collecting any urine that the kidneys excrete. The urine is stored here before urination occurs. In order to fulfill this function, the bladder is an elastic, hollow, and muscular organ that rests on a person’s pelvic floor. Urine enters the urinary bladder using the ureters and the urethra carry it out.
The urethra is a tube which connects a person’s urinary bladder to their genitals so that urine can be removed from the body. In females, the urethra exits on top of the vaginal opening. The urethra in males is longer and it carries urine (as well as sperm) through the penis. There is also an external urethral sphincter which allows us to voluntarily control urination.
Take a look at this video to learn more about how the urinary system functions:
Cellular respiration is necessary to provide our bodies with energy as without it, the body’s cells will die. However, cellular respiration produces the waste product of carbon dioxide which then needs to be eliminated from the system. This carbon dioxide diffuses out from the cells in the body, entering the bloodstream and eventually going to the lungs. The lungs contain alveoli which diffuse the carbon dioxide from the blood so it can enter the lung tissue and eventually leave the body during exhalation.
3. The Skin
Sweat is a crucial part of the excretory system as it is responsible for eliminating sweat from the body. Sweat contains several metabolic wastes including urea, salts and water. In addition to excreting metabolic wastes, sweat also cools down the body. The sweat glands are able to receive the various wastes because they are mixed in with capillaries, which are tiny blood vessels. This means that the wastes can diffuse out of the blood and enter the sweat glands before passing out of the skin in the form of sweat.
The large intestine is around 5 feet in length and is responsible for transporting waste so it can be excreted. In general, it collects waste from all over the body and then extracts usable water, allowing for the removal of solid waste. It does so because any waste products or food that the small intestine doesn’t absorb will enter the large intestine. Once it is there, bacteria, water and undigested food are combined to create feces. Sometimes it will take food 24 hours to complete its journey through a person’s large intestine.
5. The Liver
The liver is responsible for detoxifying and breaking down any toxins such as chemicals and poisons that enter our bodies. One of the ways in which the liver fulfills this function is by taking ammonia in its poisonous form and converting it into urea which the kidney will eventually filter, creating urine. In addition, the liver produces bile which the body then uses to help break fats down into unusable waste and usable fats. Bile is stored in a person’s gall bladder after the liver produces it. The small intestine uses it to break down acidic wastes such as ammonia as well as fats and ethanol, converting them into harmless substances.
The liver also serves several functions within the circulatory system. It is also responsible for maintaining the body’s proper levels of glucose based on cues from insulin (which increases the amount of glucose stored) and glucagon (which decreases the amount of glucose stored). The liver also helps detoxify the blood by removing any chemicals that are potentially hazardous.
Video- Excretory System Structure and Function: