Isolation is the removal of toxins from the body from metabolism. This process is a necessary condition for maintaining the constancy of its internal environment - homeostasis. The names of the organs of animal excretion are diverse - specialized tubes, methanephridia. A person has a whole mechanism for implementing this process.
Excretory system
Metabolic processes are quite complex and occur at all levels - from molecular to organismic. Therefore, their implementation requires a whole system. Human excretory organs excrete various substances.
Excess water is removed from the body using the lungs, skin, intestines and kidneys. Heavy metal salts secrete the liver and intestines.
Lungs - the respiratory system, the essence of which is the ingress of oxygen into the body and the removal of carbon dioxide from it. This process is of global importance. After all, plants emit carbon dioxide from plants for photosynthesis. In the presence of carbon dioxide, water and light in the green parts of the plant, which contain the chlorophyll pigment, they form glucose and oxygen carbohydrate. This is the vital cycle of substances in nature. Excess water is also continuously removed through the lungs.
The intestines remove undigested food remnants, and with them harmful metabolic products, which can cause poisoning of the body.
Digestive gland liver - a real filter for the human body. In it, poisonous substances are taken from the blood. The liver secretes a special enzyme - bile, which deoxidizes toxins and removes them from the body, including alcohol poisons, drugs and drugs.
The role of skin in excretion processes
All organs of excretion are indispensable. After all, if their functioning is disturbed, toxic substances, toxins, will accumulate in the body. Of particular importance in the implementation of this process is the largest human organ - the skin. One of its most important functions is the implementation of thermoregulation. During intense work, the body releases a lot of heat. Accumulating, it can cause overheating.
The skin regulates the intensity of heat transfer, retaining only its necessary amount. Together with sweat, in addition to water, mineral salts, urea and ammonia are removed from the body.
How does heat transfer occur?
Man is a warm-blooded creature. This means that his body temperature does not depend on climatic conditions in which he resides or is temporarily located. Organic substances that come with food: proteins, fats, carbohydrates - in the digestive tract are broken down to their components. They are called monomers. During this process, a large amount of thermal energy is released. Since the ambient temperature is most often lower than body temperature (36.6 degrees), according to the laws of physics, the body gives off excess heat to the environment, i.e. in the direction where it is less. This maintains temperature equilibrium. The process of return and heat generation by the body is called thermoregulation.
When does a person sweat most intensely? When it's hot outside. And in the cold season, sweat is practically not released. This is because the body is not profitable to lose heat when it is already not very much.
The nervous system also affects the process of thermoregulation. For example, when palms sweat on the exam, this means that in a state of excitement, the vessels expand and the heat transfer increases.
The structure of the urinary system
An important role in the processes of isolation of metabolic products is played by the urinary system. It consists of paired kidneys, ureters, a bladder that opens out through the urethra. The figure below (diagram of the "Organs of excretion") illustrates the location of these organs.
Kidneys - the main organ of excretion
Human excretory organs begin with the kidneys. These are paired bean-shaped organs. They are located in the abdominal cavity on both sides of the spine, to which they are turned with the concave side.
Outside, each of them is coated. Through a special depression called the renal gates, blood vessels, nerve fibers and ureters enter the organ.
The inner layer is formed by two types of substances: cortical (dark) and brain (light). Urine is formed in the kidney, which collects in a special container - the pelvis, coming from it into the ureter.
Nephron - the elementary unit of the kidney
The excretory organs, in particular the kidney, consist of elementary units of the structure. It is in them that metabolic processes occur at the cellular level. Each kidney consists of a million nephrons - structural and functional units.
Each of them is formed by the renal corpuscle, which, in turn, surrounds a goblet capsule with a ball of blood vessels. Urine is initially collected here. From each capsule, the convoluted tubules of the first and second tubules open, opening with collecting ducts.
Urine formation mechanism
Urine is formed from the blood as a result of two processes: filtration and reabsorption. The first of these processes occurs in the bodies of the nephron. As a result of filtration, all components except proteins are released from blood plasma. Thus, in the urine of a healthy person there should not be this substance. And its presence indicates a violation of metabolic processes. As a result of filtration, a liquid is formed, which is called primary urine. Its amount is 150 liters per day.
Then comes the next stage - reabsorption. Its essence lies in the fact that all the substances useful for the body are absorbed from the primary urine into the blood: mineral salts, amino acids, glucose, a large amount of water. As a result, secondary urine is formed - 1.5 liters per day. In this substance, a healthy person should not have glucose monosaccharide.
Secondary urine is 96% water. It also includes sodium, potassium and chlorine ions, urea and uric acid.
The reflex nature of urination
From each nephron, secondary urine enters the renal pelvis, from which it flows down the ureter into the bladder. It is a muscular unpaired organ. The volume of the bladder increases with age and in an adult reaches 0.75 liters. Outwardly, the bladder opens through the urethra. At the exit, it is limited by two sphincters - circular muscles.
In order to urge to urinate, about 0.3 liters of fluid should accumulate in the bladder. When this happens, the wall receptors become irritated. The muscles contract and the sphincters relax. Urination occurs arbitrarily, i.e. an adult is able to control this process. Urination is regulated by the nervous system, its center is located in the sacral region of the spinal cord.
Functions of the excretory organs
The kidneys play an important role in the process of removing the final metabolic products from the body, regulate water-salt metabolism and maintain the constancy of the osmotic pressure of the body’s fluid medium.
Excretion organs cleanse the body of toxins, maintaining a stable level of substances necessary for the normal full functioning of the human body.