Osmoregulation refers to the balancing of osmotic pressure within a living organism. Its basis is osmosis: a biological process in which water diffuses through a semipermeable membrane. Osmoregulation leads to the development of edema in the event of biochemical imbalance.
What is osmoregulation?
Osmotic regulation refers to a biochemical process that aims to balance the concentration of solutes within an organism. Osmotic regulation refers to a biochemical process that aims to balance the concentration of solutes within an organism. The membranes of living cells represent a so-called semi-permeable surface. This means that they allow a partial exchange of fluid between the interior of the cell and its environment. Osmoregulation has the task of establishing a balanced and constant state. This balanced state is called homeostasis and refers both to equilibrium at the cellular level and to equilibrium between whole organs and their respective environments. Imbalance, on the other hand, creates osmotic pressure that forces a balance based on physical laws of nature.
Function and task
Osmoregulation follows two fundamental principles. In equilibration based on the concentration gradient, water diffuses to the side of the membrane that has a higher concentration of a solute. For example, if a cell is in an environment that has a high concentration of salt, the water in the cell moves out of it due to osmotic pressure and the cell loses fluid inside. This condition continues until the concentration gradient shifts, forcing rebalancing: osmoregulation is a continuous process that the human body cannot inhibit or promote. The second active principle of osmosis is balancing due to electrical charge. Electrically charged particles, called ions and anions, play an important role in the functioning of cells at the biochemical level. Ions have a positive electrical charge, while anions are negatively charged. Voltage changes in the cell, for example, influence the nature of the membrane and thus alter its permeability for certain substances. Osmoregulation strives for an identical electrical charge on both sides of the membrane. For example, if negative polarization prevails within a cell, this creates osmotic pressure, as in concentration imbalance, and water diffuses into the cell. In extreme cases, excessive diffusion of water into the cell can lead to irreversible damage or even its rupture. However, such an extreme condition is more than unlikely in the human body. With the help of osmoregulation, the organism not only balances the ratio of solutes inside and outside individual cells, but also controls diffusion for entire tissue structures on a macroscopic level. The organ that is most important for the osmoregulation of the organism as a whole is the kidneys – because they determine the excretion of water in the form of urine. They are regulated by various hormones, including aldosterone and angiotensin II; for their part, the kidneys also produce hormones that influence numerous metabolic processes. They are also responsible for regulating blood pH, filtration, and energy storage through glucose.
Diseases and ailments
Osmoregulation plays a role in the context of various underlying diseases, such as the development of edema. Edema is a swelling of the tissues caused by increased storage of water. Excessive storage of fluid in the intercellular spaces (stroma), especially the connective or supporting tissue, cause the characteristic swollen appearance of edema. However, the swellings can also manifest themselves in a hidden manner, for example in the brain, where they sometimes cause severe damage. As a rule, edema does not occur in isolation, but represents the consequence of another disease. Examples include kidney, liver or heart failure.The restricted function of one of the above organs results in unwanted osmotic pressure in the tissue, which is not biologically intended in this form. Because of automatic osmoregulation, water flows into the intercellular spaces; the lymphatic system cannot remove the excess fluid and the tissue swells. Depending on the extent and localization, the swelling can cause pain and restrict mobility. An underlying disease because of which osmoregulation causes such complaints is hypalbuminemia. This is a deficiency of the protein albumin, which is the most abundant of all proteins in the human organism. Potential causes of albumin deficiency include poor nutrition, liver or kidney damage, and burns or acute inflammation. Physiologically, hypalbuminemia may also appear during pregnancy. The deficiency of the protein albumin leads to a change in the osmoregulation of the body: along the concentration gradient, water diffuses out of the blood plasma and accumulates in a known manner in the intercellular spaces. In developing countries, crisis areas and regions with insufficient food supply, famine edema (kwashiorkor) often appears as a special variant of hypalbuminemia. Its therapy essentially consists of providing protein-rich food to compensate for the lack of protein. However, water retention is not necessarily the result of severe disease. Excessive dietary salt intake also partly triggers the unwanted storage of fluid in the stroma. The use of diuretic medications may shift osmoregulation in favor of increased fluid excretion.
