The body maintains fluid and electrolyte balance through a complex mechanism involving multiple systems in the body. Your question refers to the role the cardiovascular system plays in this mechanism.
There are two main fluid compartments in the body. The intracellular compartment, which means fluid contained within cells. This compartment holds two thirds of body fluids by volume under normal conditions.
The extracellular compartment, which means fluid outside the cells, has two major subdivisions: first...
The body maintains fluid and electrolyte balance through a complex mechanism involving multiple systems in the body. Your question refers to the role the cardiovascular system plays in this mechanism.
There are two main fluid compartments in the body. The intracellular compartment, which means fluid contained within cells. This compartment holds two thirds of body fluids by volume under normal conditions.
The extracellular compartment, which means fluid outside the cells, has two major subdivisions: first is the plasma, which refers to the fluid portion of the blood, and the second is the interstitial fluid, which refers to fluid in spaces between the cells. A less significant contribution to the body’s extracellular compartment in terms of volume includes gastrointestinal secretions, lymph, cerebrospinal fluid, synovial fluid and serous fluid.
The cardiovascular system exerts its role in this regulatory mechanism mainly through its plasma volume control. An increase in plasma volume gives rise to a concomitant increase in plasma pressure. The pressure increase is picked up by baroreceptors in the heart and the large vessels such as the aorta and the carotid arteries and the signal is transmitted to the hypothalamus.
The signal inhibits the secretion of anti-diuretic hormone (ADH), a peptide hormone produced by the hypothalamus. A diminished production of ADH enables the kidneys to get rid of excess fluid by making urine that is dilute compared to plasma.
When the pressure falls as a result of diminished plasma volume, the stretch receptors in the heart and the large vessels stimulate the hypothalamus, this time to increase production of anti-diuretic hormone (ADH). This hormone acts on the kidneys to reabsorb more water to maintain enough plasma volume for the body and make more concentrated urine compared to plasma.
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