The excretory system is a passive biological system that removes excess, unnecessary materials from the body fluids of an organism, so as to help maintain internal chemical homeostasis and prevent damage to the body. The dual function of excretory systems is the elimination of the waste products of metabolism and to drain the body of used up and broken down components in a liquid and gaseous state.
Liver is a very important organ in the human body. The liver is the largest gland contained in the human body. In addition to the liver, in the human body there are also several kinds of glands that have their respective functions each of which there are mammary glands, lymph nodes, and thyroid gland, but this is the most vital heart.
Characteristics and Location of the Liver
Some of the following characteristics may make us understand more about liver organ such as:
- The location of the liver inside the human body under the diaphragm in the abdominal cavity on the right or rather on the right side of the abdomen.
- The liver is brown red,
- The liver weighs approximately 1.47 kg,
- The liver has many soft blood vessels.
The structure of the Heart and its Functions
The liver has several parts or more often known as the lobes. This liver has four lobe parts, there are two main lobes consisting of right lobe and left lobe. The right lobe typically has a larger size. Then there are two more lobes that are small and located behind the main lobe to the right. Within each lobe alone there is a multi-sided unit called lobules.
For more details, the following will be explained more about the structure of the liver and its function.
- The right lobe and left lobe, as described in the introduction, one of the liver structures of the right lobe and left lobe. In the right lobe and left lobe is the main liver processing. Here is produced bile that serves as an antidote to the poison.
- Lobules, as has been explained also in the introduction that the liver also has a multi-sided unit called lobulus, which is precisely located in the lobes. In the liver itself there are about 50,000 to 100,000 lobes and in each lobe consists of a central vein surrounded by small liver cells.
- Central vein, this vein is located in the central part of the lobule.
- Vepatica vein, this blood vessel functions in the circulatory mechanism that is to transport blood that has been filtered by the liver to the inferior vena cava.
- Lacuna, lacuna is a separator between the one lobule with the other lobules.
- Gallbladder, this section serves as a storage reservoir for bile. For more details read the following articles: function of the gallbladder and bile function.
The Function of the Liver in the Human Excretion System
Many vital functions have been identified with the liver. Some of the more well-known functions include the following:
- Production of bile, which helps carry away waste and break down fats in the small intestine during digestion
- Production of certain proteins for blood plasma
- Production of cholesterol and special proteins to help carry fats through the body
- Store and release glucose as needed
- Processing of hemoglobin for use of its iron content (the liver stores iron)
- Conversion of harmful ammonia to urea (urea is one of the end products of protein metabolism that is excreted in the urine)
- Clearing the blood of drugs and other harmful substances
- Regulating blood clotting
- Resisting infections by producing immune factors and removing bacteria from the bloodstream
- Clearance of bilirubin (if there is a buildup of bilirubin, the skin and eyes turn yellow).
Although considered a secondary, or accessary excretory system organ, the liver plays a vital part in keeping the body clean. Harmful poisons and chemicals that are either produced in the body or consumed are broken down and detoxified by the liver. For example, a bi-product of the metabolic process within the body is ammonia and the liver processes this into urea, a less harmful substance which continues to be filtered and excreted by the kidneys as urine.
The liver detoxifies and breaks down chemicals, poisons and other toxins that enter the body. For example, the liver transforms ammonia (which is poisonous) into urea in fish, amphibians and mammals, and into uric acid in birds and reptiles.
Urea is filtered by the kidney into urine or through the gills in fish and tadpoles. Uric acid is paste-like and expelled as a semi-solid waste (the "white" in bird excrements). The liver also produces bile, and the body uses bile to break down fats into usable fats and unusable waste.
Invertebrates lack a liver, but most terrestrial groups, like insects, possesses a number of blind guts that serve the similar functions. Marine invertebrates do not need the ammonia conversion of the liver, as they can usually expel ammonia directly by diffusion through the skin.
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