{"content_id":"cvg00topdu","slug":"kidney-electrolyte-reabsorption-and-excretion","locale":"en","schema_type":"Article","category":"knowledge_base","category_name":"Knowledge Base","title":"Kidney Electrolyte Regulation and Reabsorption","summary":"The kidneys maintain electrolyte balance by controlling the reabsorption and secretion of substances filtered from the blood. Hormonal signals from the brain, adrenal glands, heart, bones, and other organs are involved in this process.","sponsorship_disclosure":null,"affiliate_disclosure":null,"commerce_disclosure":null,"author":{"name":"Injoys Editorial Team","url":"https://injoys.com/ko/about"},"key_points":["The kidneys adjust the amounts of water and electrolytes excreted in urine based on the body's condition.","Reabsorption is the process of returning substances in the renal tubules to the blood.","The amount excreted in urine is the result of filtration, reabsorption, and secretion.","Hormones change how the kidneys process water and electrolytes.","Blood electrolyte levels are not fixed numbers but are regulated within normal ranges."],"content_markdown":"The kidneys regulate reabsorption and excretion to keep electrolytes in the blood within the normal range. The tubules return substances the body needs to the blood. This regulation involves hormonal signals from other organs.\n\nThis basic explanation of kidney function is based on an NIDDK guide reviewed in June 2018.\n\n## What Is Electrolyte Regulation by the Kidneys?\n\nElectrolyte regulation by the kidneys balances the amount retained in the body with the amount released in urine. Electrolytes are electrically charged substances in body fluids. They include sodium, potassium, and calcium.\n\nThe balance of these substances is necessary for nerves and muscles to function normally. The body's ability to keep its internal conditions within a certain range is called homeostasis. The kidneys are the main organs responsible for the homeostasis of water and electrolytes. A basic explanation is available in the [NIDDK guide to kidney function](https://www.niddk.nih.gov/health-information/kidney-disease/kidneys-how-they-work).\n\n## Comparison of Reabsorption, Secretion, and Excretion\n\nReabsorption and secretion are processes in which substances move in opposite directions. The nephron is the basic functional unit of the kidney. A nephron consists of a glomerulus that filters the blood and a tubule that processes the filtrate.\n\n| Process | Direction of substance movement | Meaning |\n|---|---|---|\n| Filtration | From the blood in the glomerulus to the space leading into the tubule | Filters water and small substances from the blood |\n| Reabsorption | From inside the tubule toward the blood | Returns filtered substances to the body |\n| Secretion | From the blood into the tubule | Adds substances to the fluid that will become urine |\n| Excretion | Out of the body through urine produced by the kidneys | Ultimately removes substances from the body |\n\nNot every filtered substance leaves the body. The tubules recover much of the filtered water and needed substances. The remaining fluid becomes urine. This process is described in the [NIDDK explanation of nephrons](https://www.niddk.nih.gov/health-information/kidney-disease/kidneys-how-they-work).\n\nTherefore, the amount of a substance excreted is not determined solely by the amount filtered. Reducing reabsorption can increase the amount remaining in the urine. For some substances, such as potassium, the amount secreted into the tubules is also regulated. The role of secretion is explained in [OpenStax's overview of fluid regulation](https://openstax.org/books/anatomy-and-physiology-2e/pages/25-9-regulation-of-fluid-volume-and-composition).\n\n## How Do the Kidneys Detect the Body's Condition?\n\nThe kidneys respond to hormones, nerve signals, and local sensing mechanisms. Hormones are chemical signals that travel through the blood. Changes in blood flow to the kidneys also provide cues that initiate regulation.\n\nDescribing this as an information network among organs is a metaphor for these physiological processes. It is not a system in which every organ directly reports a deficiency in each substance. Different signals work together to affect how the kidneys process substances.\n\n### Hormones from the Brain and Adrenal Glands\n\nHormones from the brain and adrenal glands change how the kidneys process water and electrolytes. Antidiuretic hormone signals the kidneys to increase water reabsorption. This hormone is produced in the hypothalamus of the brain. It is released into the blood from the back of the pituitary gland. [Society for Endocrinology's explanation of antidiuretic hormone](https://www.yourhormones.info/hormones/anti-diuretic-hormone/)\n\nAldosterone from the adrenal glands increases sodium reabsorption. This hormone also promotes the excretion of potassium in urine. Even the same signal can direct different substances to be processed differently. [Society for Endocrinology's explanation of aldosterone](https://www.yourhormones.info/hormones/aldosterone)\n\n### Connections with the Heart and Liver\n\nThe heart and liver are also connected to the kidneys' regulation of body fluids. Natriuretic peptides released by the heart promote sodium excretion. This signal acts to reduce the amount of sodium and water retained in the body.\n\nThe liver produces a protein called angiotensinogen. Renin released by the kidneys is an enzyme that cleaves this protein. The pathway initiated by this reaction promotes sodium retention. This connection is described in the [Society for Endocrinology's explanation of angiotensin](https://www.yourhormones.info/hormones/angiotensin/).\n\n### Connections Among the Bones, Parathyroid Glands, and Intestines\n\nThe kidneys, bones, parathyroid glands, and intestines all contribute to the balance of calcium and phosphorus. The parathyroid glands are small endocrine glands in the neck. When blood calcium levels fall, secretion of parathyroid hormone increases.\n\nParathyroid hormone increases calcium reabsorption by the kidneys. It acts to reduce phosphate reabsorption. Phosphorus exists in the body mainly in the form of phosphate.\n\nThe kidneys also convert vitamin D into its active form. Active vitamin D helps the intestines absorb calcium. This connection is summarized in [OpenStax's explanation of calcium and phosphate regulation](https://openstax.org/books/anatomy-and-physiology-2e/pages/25-9-regulation-of-fluid-volume-and-composition).\n\nBones are also organs that produce hormones. FGF23, which is produced in the bones, is involved in regulating phosphorus metabolism. Related information is available in the [NIDDK guide to mineral and bone disorder in kidney disease](https://www.niddk.nih.gov/health-information/kidney-disease/mineral-bone-disorder).\n\n## Comparison of Regulation According to the Body's Condition\n\nThe kidneys respond differently depending on which substances are deficient or increased. Responses that conserve water are distinct from those that conserve sodium. The table below shows the main effect produced by each signal.\n\n| Change or signal in the body | Typical response | Key distinction |\n|---|---|---|\n| Water deficiency raises the concentration of solutes in the blood | Increased water reabsorption through antidiuretic hormone | Water is the main target of regulation |\n| Blood flow to the kidneys decreases | Promotion of sodium retention through the renin pathway | The state of the blood supply is also a cue for regulation |\n| Stretching of the heart's atria increases | Increased secretion of natriuretic peptides | Acts to increase sodium excretion |\n| Blood calcium levels fall | Increased calcium reabsorption through parathyroid hormone | Phosphate reabsorption decreases |\n\nThis comparison assumes that the kidneys and hormonal systems can respond. In practice, several signals affect the amount excreted at the same time. The main regulatory pathways are based on [OpenStax's explanation of fluid volume and composition regulation](https://openstax.org/books/anatomy-and-physiology-2e/pages/25-9-regulation-of-fluid-volume-and-composition).\n\n## Common Misconceptions About Kidney Function\n\nIt is inaccurate to understand electrolyte regulation in terms of fixed concentrations or immediate responses. Normal regulation also allows a range of variation. The following statements need to be distinguished carefully.\n\n| Common misconception | More accurate explanation |\n|---|---|\n| Concentrations must always remain exactly the same | They are regulated within a physiologically acceptable range |\n| Even a slightly high or low level is life-threatening | Risk depends on the substance and the extent and speed of the change, among other factors |\n| The kidneys make more of a deficient substance to replace it | Reabsorption is the process of recovering substances that have already been filtered |\n| Blood sodium concentration reflects only salt intake | The amount of water in the body also affects the concentration |\n| All organs send signals to the kidneys in the same way | Each organ is connected through different hormones and physiological pathways |\n\nBlood sodium concentration, in particular, must be interpreted together with the amount of water in the body. Excessive antidiuretic hormone can cause water to remain in the body. As a result, sodium concentration may decrease. This principle is explained in the [Society for Endocrinology's guide to antidiuretic hormone](https://www.yourhormones.info/hormones/anti-diuretic-hormone/).\n\n## What Changes When Kidney Function Declines?\n\nWhen kidney function declines, the ability to maintain mineral balance may weaken. One example is an inability to excrete enough phosphorus. The activation of vitamin D may also be affected.\n\nThese changes place strain on the system that regulates calcium and phosphorus. They may also lead to excessive secretion of parathyroid hormone. Mineral and bone disorder in chronic kidney disease demonstrates these connections. The explanation of this condition is based on the [NIDDK guide](https://www.niddk.nih.gov/health-information/kidney-disease/mineral-bone-disorder).","content_html":"\u003cp\u003eThe kidneys regulate reabsorption and excretion to keep electrolytes in the blood within the normal range. The tubules return substances the body needs to the blood. This regulation involves hormonal signals from other organs.\u003c/p\u003e\n\u003cp\u003eThis basic explanation of kidney function is based on an NIDDK guide reviewed in June 2018.\u003c/p\u003e\n\u003ch2\u003e\n\u003ca href=\"#what-is-electrolyte-regulation-by-the-kidneys\" class=\"anchor\" id=\"what-is-electrolyte-regulation-by-the-kidneys\"\u003e\u003c/a\u003eWhat Is Electrolyte Regulation by the Kidneys?\u003c/h2\u003e\n\u003cp\u003eElectrolyte regulation by the kidneys balances the amount retained in the body with the amount released in urine. Electrolytes are electrically charged substances in body fluids. They include sodium, potassium, and calcium.\u003c/p\u003e\n\u003cp\u003eThe balance of these substances is necessary for nerves and muscles to function normally. The body's ability to keep its internal conditions within a certain range is called homeostasis. The kidneys are the main organs responsible for the homeostasis of water and electrolytes. A basic explanation is available in the \u003ca href=\"https://www.niddk.nih.gov/health-information/kidney-disease/kidneys-how-they-work\"\u003eNIDDK guide to kidney function\u003c/a\u003e.\u003c/p\u003e\n\u003ch2\u003e\n\u003ca href=\"#comparison-of-reabsorption-secretion-and-excretion\" class=\"anchor\" id=\"comparison-of-reabsorption-secretion-and-excretion\"\u003e\u003c/a\u003eComparison of Reabsorption, Secretion, and Excretion\u003c/h2\u003e\n\u003cp\u003eReabsorption and secretion are processes in which substances move in opposite directions. The nephron is the basic functional unit of the kidney. A nephron consists of a glomerulus that filters the blood and a tubule that processes the filtrate.\u003c/p\u003e\n\u003cdiv class=\"overflow-x-auto\"\u003e\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eProcess\u003c/th\u003e\n\u003cth\u003eDirection of substance movement\u003c/th\u003e\n\u003cth\u003eMeaning\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd data-label=\"Process\"\u003eFiltration\u003c/td\u003e\n\u003ctd data-label=\"Direction of substance movement\"\u003eFrom the blood in the glomerulus to the space leading into the tubule\u003c/td\u003e\n\u003ctd data-label=\"Meaning\"\u003eFilters water and small substances from the blood\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd data-label=\"Process\"\u003eReabsorption\u003c/td\u003e\n\u003ctd data-label=\"Direction of substance movement\"\u003eFrom inside the tubule toward the blood\u003c/td\u003e\n\u003ctd data-label=\"Meaning\"\u003eReturns filtered substances to the body\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd data-label=\"Process\"\u003eSecretion\u003c/td\u003e\n\u003ctd data-label=\"Direction of substance movement\"\u003eFrom the blood into the tubule\u003c/td\u003e\n\u003ctd data-label=\"Meaning\"\u003eAdds substances to the fluid that will become urine\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd data-label=\"Process\"\u003eExcretion\u003c/td\u003e\n\u003ctd data-label=\"Direction of substance movement\"\u003eOut of the body through urine produced by the kidneys\u003c/td\u003e\n\u003ctd data-label=\"Meaning\"\u003eUltimately removes substances from the body\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\u003c/div\u003e\n\u003cp\u003eNot every filtered substance leaves the body. The tubules recover much of the filtered water and needed substances. The remaining fluid becomes urine. This process is described in the \u003ca href=\"https://www.niddk.nih.gov/health-information/kidney-disease/kidneys-how-they-work\"\u003eNIDDK explanation of nephrons\u003c/a\u003e.\u003c/p\u003e\n\u003cp\u003eTherefore, the amount of a substance excreted is not determined solely by the amount filtered. Reducing reabsorption can increase the amount remaining in the urine. For some substances, such as potassium, the amount secreted into the tubules is also regulated. The role of secretion is explained in \u003ca href=\"https://openstax.org/books/anatomy-and-physiology-2e/pages/25-9-regulation-of-fluid-volume-and-composition\"\u003eOpenStax's overview of fluid regulation\u003c/a\u003e.\u003c/p\u003e\n\u003ch2\u003e\n\u003ca href=\"#how-do-the-kidneys-detect-the-bodys-condition\" class=\"anchor\" id=\"how-do-the-kidneys-detect-the-bodys-condition\"\u003e\u003c/a\u003eHow Do the Kidneys Detect the Body's Condition?\u003c/h2\u003e\n\u003cp\u003eThe kidneys respond to hormones, nerve signals, and local sensing mechanisms. Hormones are chemical signals that travel through the blood. Changes in blood flow to the kidneys also provide cues that initiate regulation.\u003c/p\u003e\n\u003cp\u003eDescribing this as an information network among organs is a metaphor for these physiological processes. It is not a system in which every organ directly reports a deficiency in each substance. Different signals work together to affect how the kidneys process substances.\u003c/p\u003e\n\u003ch3\u003e\n\u003ca href=\"#hormones-from-the-brain-and-adrenal-glands\" class=\"anchor\" id=\"hormones-from-the-brain-and-adrenal-glands\"\u003e\u003c/a\u003eHormones from the Brain and Adrenal Glands\u003c/h3\u003e\n\u003cp\u003eHormones from the brain and adrenal glands change how the kidneys process water and electrolytes. Antidiuretic hormone signals the kidneys to increase water reabsorption. This hormone is produced in the hypothalamus of the brain. It is released into the blood from the back of the pituitary gland. \u003ca href=\"https://www.yourhormones.info/hormones/anti-diuretic-hormone/\"\u003eSociety for Endocrinology's explanation of antidiuretic hormone\u003c/a\u003e\u003c/p\u003e\n\u003cp\u003eAldosterone from the adrenal glands increases sodium reabsorption. This hormone also promotes the excretion of potassium in urine. Even the same signal can direct different substances to be processed differently. \u003ca href=\"https://www.yourhormones.info/hormones/aldosterone\"\u003eSociety for Endocrinology's explanation of aldosterone\u003c/a\u003e\u003c/p\u003e\n\u003ch3\u003e\n\u003ca href=\"#connections-with-the-heart-and-liver\" class=\"anchor\" id=\"connections-with-the-heart-and-liver\"\u003e\u003c/a\u003eConnections with the Heart and Liver\u003c/h3\u003e\n\u003cp\u003eThe heart and liver are also connected to the kidneys' regulation of body fluids. Natriuretic peptides released by the heart promote sodium excretion. This signal acts to reduce the amount of sodium and water retained in the body.\u003c/p\u003e\n\u003cp\u003eThe liver produces a protein called angiotensinogen. Renin released by the kidneys is an enzyme that cleaves this protein. The pathway initiated by this reaction promotes sodium retention. This connection is described in the \u003ca href=\"https://www.yourhormones.info/hormones/angiotensin/\"\u003eSociety for Endocrinology's explanation of angiotensin\u003c/a\u003e.\u003c/p\u003e\n\u003ch3\u003e\n\u003ca href=\"#connections-among-the-bones-parathyroid-glands-and-intestines\" class=\"anchor\" id=\"connections-among-the-bones-parathyroid-glands-and-intestines\"\u003e\u003c/a\u003eConnections Among the Bones, Parathyroid Glands, and Intestines\u003c/h3\u003e\n\u003cp\u003eThe kidneys, bones, parathyroid glands, and intestines all contribute to the balance of calcium and phosphorus. The parathyroid glands are small endocrine glands in the neck. When blood calcium levels fall, secretion of parathyroid hormone increases.\u003c/p\u003e\n\u003cp\u003eParathyroid hormone increases calcium reabsorption by the kidneys. It acts to reduce phosphate reabsorption. Phosphorus exists in the body mainly in the form of phosphate.\u003c/p\u003e\n\u003cp\u003eThe kidneys also convert vitamin D into its active form. Active vitamin D helps the intestines absorb calcium. This connection is summarized in \u003ca href=\"https://openstax.org/books/anatomy-and-physiology-2e/pages/25-9-regulation-of-fluid-volume-and-composition\"\u003eOpenStax's explanation of calcium and phosphate regulation\u003c/a\u003e.\u003c/p\u003e\n\u003cp\u003eBones are also organs that produce hormones. FGF23, which is produced in the bones, is involved in regulating phosphorus metabolism. Related information is available in the \u003ca href=\"https://www.niddk.nih.gov/health-information/kidney-disease/mineral-bone-disorder\"\u003eNIDDK guide to mineral and bone disorder in kidney disease\u003c/a\u003e.\u003c/p\u003e\n\u003ch2\u003e\n\u003ca href=\"#comparison-of-regulation-according-to-the-bodys-condition\" class=\"anchor\" id=\"comparison-of-regulation-according-to-the-bodys-condition\"\u003e\u003c/a\u003eComparison of Regulation According to the Body's Condition\u003c/h2\u003e\n\u003cp\u003eThe kidneys respond differently depending on which substances are deficient or increased. Responses that conserve water are distinct from those that conserve sodium. The table below shows the main effect produced by each signal.\u003c/p\u003e\n\u003cdiv class=\"overflow-x-auto\"\u003e\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eChange or signal in the body\u003c/th\u003e\n\u003cth\u003eTypical response\u003c/th\u003e\n\u003cth\u003eKey distinction\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd data-label=\"Change or signal in the body\"\u003eWater deficiency raises the concentration of solutes in the blood\u003c/td\u003e\n\u003ctd data-label=\"Typical response\"\u003eIncreased water reabsorption through antidiuretic hormone\u003c/td\u003e\n\u003ctd data-label=\"Key distinction\"\u003eWater is the main target of regulation\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd data-label=\"Change or signal in the body\"\u003eBlood flow to the kidneys decreases\u003c/td\u003e\n\u003ctd data-label=\"Typical response\"\u003ePromotion of sodium retention through the renin pathway\u003c/td\u003e\n\u003ctd data-label=\"Key distinction\"\u003eThe state of the blood supply is also a cue for regulation\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd data-label=\"Change or signal in the body\"\u003eStretching of the heart's atria increases\u003c/td\u003e\n\u003ctd data-label=\"Typical response\"\u003eIncreased secretion of natriuretic peptides\u003c/td\u003e\n\u003ctd data-label=\"Key distinction\"\u003eActs to increase sodium excretion\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd data-label=\"Change or signal in the body\"\u003eBlood calcium levels fall\u003c/td\u003e\n\u003ctd data-label=\"Typical response\"\u003eIncreased calcium reabsorption through parathyroid hormone\u003c/td\u003e\n\u003ctd data-label=\"Key distinction\"\u003ePhosphate reabsorption decreases\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\u003c/div\u003e\n\u003cp\u003eThis comparison assumes that the kidneys and hormonal systems can respond. In practice, several signals affect the amount excreted at the same time. The main regulatory pathways are based on \u003ca href=\"https://openstax.org/books/anatomy-and-physiology-2e/pages/25-9-regulation-of-fluid-volume-and-composition\"\u003eOpenStax's explanation of fluid volume and composition regulation\u003c/a\u003e.\u003c/p\u003e\n\u003ch2\u003e\n\u003ca href=\"#common-misconceptions-about-kidney-function\" class=\"anchor\" id=\"common-misconceptions-about-kidney-function\"\u003e\u003c/a\u003eCommon Misconceptions About Kidney Function\u003c/h2\u003e\n\u003cp\u003eIt is inaccurate to understand electrolyte regulation in terms of fixed concentrations or immediate responses. Normal regulation also allows a range of variation. The following statements need to be distinguished carefully.\u003c/p\u003e\n\u003cdiv class=\"overflow-x-auto\"\u003e\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eCommon misconception\u003c/th\u003e\n\u003cth\u003eMore accurate explanation\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd data-label=\"Common misconception\"\u003eConcentrations must always remain exactly the same\u003c/td\u003e\n\u003ctd data-label=\"More accurate explanation\"\u003eThey are regulated within a physiologically acceptable range\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd data-label=\"Common misconception\"\u003eEven a slightly high or low level is life-threatening\u003c/td\u003e\n\u003ctd data-label=\"More accurate explanation\"\u003eRisk depends on the substance and the extent and speed of the change, among other factors\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd data-label=\"Common misconception\"\u003eThe kidneys make more of a deficient substance to replace it\u003c/td\u003e\n\u003ctd data-label=\"More accurate explanation\"\u003eReabsorption is the process of recovering substances that have already been filtered\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd data-label=\"Common misconception\"\u003eBlood sodium concentration reflects only salt intake\u003c/td\u003e\n\u003ctd data-label=\"More accurate explanation\"\u003eThe amount of water in the body also affects the concentration\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd data-label=\"Common misconception\"\u003eAll organs send signals to the kidneys in the same way\u003c/td\u003e\n\u003ctd data-label=\"More accurate explanation\"\u003eEach organ is connected through different hormones and physiological pathways\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\u003c/div\u003e\n\u003cp\u003eBlood sodium concentration, in particular, must be interpreted together with the amount of water in the body. Excessive antidiuretic hormone can cause water to remain in the body. As a result, sodium concentration may decrease. This principle is explained in the \u003ca href=\"https://www.yourhormones.info/hormones/anti-diuretic-hormone/\"\u003eSociety for Endocrinology's guide to antidiuretic hormone\u003c/a\u003e.\u003c/p\u003e\n\u003ch2\u003e\n\u003ca href=\"#what-changes-when-kidney-function-declines\" class=\"anchor\" id=\"what-changes-when-kidney-function-declines\"\u003e\u003c/a\u003eWhat Changes When Kidney Function Declines?\u003c/h2\u003e\n\u003cp\u003eWhen kidney function declines, the ability to maintain mineral balance may weaken. One example is an inability to excrete enough phosphorus. The activation of vitamin D may also be affected.\u003c/p\u003e\n\u003cp\u003eThese changes place strain on the system that regulates calcium and phosphorus. They may also lead to excessive secretion of parathyroid hormone. Mineral and bone disorder in chronic kidney disease demonstrates these connections. The explanation of this condition is based on the \u003ca href=\"https://www.niddk.nih.gov/health-information/kidney-disease/mineral-bone-disorder\"\u003eNIDDK guide\u003c/a\u003e.\u003c/p\u003e\n","tags":["Kidney health","Kidney function"],"faqs":[{"question":"What is reabsorption in the kidneys?","answer":"Reabsorption is the process of returning substances in the renal tubules to the blood. It recovers water and other substances that have already been filtered from the blood."},{"question":"Are all filtered substances excreted in the urine?","answer":"Not all filtered substances are excreted. A significant portion of the water and other substances the body needs is reabsorbed in the renal tubules."},{"question":"What is the difference between tubular secretion and excretion?","answer":"Tubular secretion is the process of moving substances from the blood into the renal tubules. Excretion means that substances ultimately leave the body."},{"question":"How do the kidneys receive information from other organs?","answer":"Hormones and other substances carried through the blood help regulate the kidneys. Changes in blood flow that the kidneys themselves detect also serve as signals that trigger a response."},{"question":"Do electrolyte concentrations always have to remain at the same exact levels?","answer":"Electrolyte concentrations are regulated within normal ranges. Not every small fluctuation is life-threatening."},{"question":"Does aldosterone act on sodium and potassium in the same way?","answer":"It acts on them in different ways. Aldosterone increases sodium reabsorption. It also promotes the excretion of potassium in the urine."},{"question":"Does the sodium concentration in the blood reflect only how much salt has been consumed?","answer":"The amount of water in the body also affects the sodium concentration in the blood. If the body retains too much water, the sodium concentration may decrease."},{"question":"What is the relationship between the kidneys and bones?","answer":"The kidneys regulate the balance of calcium and phosphorus. They also convert vitamin D into its active form. These functions are linked to bone health."},{"question":"Do the kidneys create electrolytes when the body does not have enough?","answer":"Reabsorption is not a process that creates new electrolytes. It returns substances that have already been filtered to the blood, reducing the amount lost in the urine."}],"sources":[{"url":"https://www.niddk.nih.gov/health-information/kidney-disease/kidneys-how-they-work","title":"NIDDK, Your Kidneys \u0026 How They Work","type":"source"},{"url":"https://www.niddk.nih.gov/health-information/kidney-disease/mineral-bone-disorder","title":"NIDDK, Mineral \u0026 Bone Disorder in Chronic Kidney Disease","type":"source"},{"url":"https://www.yourhormones.info/hormones/anti-diuretic-hormone/","title":"Society for Endocrinology, Anti-diuretic hormone","type":"source"},{"url":"https://www.yourhormones.info/hormones/aldosterone","title":"Society for Endocrinology, Aldosterone","type":"source"},{"url":"https://www.yourhormones.info/hormones/angiotensin/","title":"Society for Endocrinology, Angiotensin","type":"source"},{"url":"https://openstax.org/books/anatomy-and-physiology-2e/pages/25-9-regulation-of-fluid-volume-and-composition","title":"OpenStax, Anatomy and Physiology 2e, Regulation of Fluid Volume and Composition","type":"source"}],"images":[{"id":1421,"url":"https://injoys.com/rails/active_storage/blobs/proxy/eyJfcmFpbHMiOnsiZGF0YSI6MjA1MDAsInB1ciI6ImJsb2JfaWQifX0=--deac216463f80982b22be3c1e86e19ceeeecb8dc/ai-8edb651b.webp","is_representative":true,"generation_method":"ai_photo","license":"ai_generated","mime_type":"image/webp","width":1536,"height":1024,"translations":{"ko":{"alt":"연구원이 색 액체가 흐르는 투명한 콩팥과 네프론 모형을 조절하는 모습","caption":"투명 모형은 콩팥의 혈류와 세뇨관을 통한 여과·재흡수 경로를 보여준다.","description":null},"en":{"alt":"Researcher adjusting a transparent kidney and nephron model filled with colored fluids","caption":"The transparent model illustrates renal blood flow and filtration and reabsorption along the tubules.","description":null},"ja":{"alt":"色付きの液体が流れる透明な腎臓とネフロンの模型を調整する研究者","caption":"透明な模型が腎血流と尿細管での濾過・再吸収経路を示している。","description":null},"es":{"alt":"Investigadora ajustando un modelo transparente de riñón y nefrona con líquidos de colores","caption":"El modelo muestra el flujo sanguíneo renal y las vías de filtración y reabsorción tubular.","description":null},"id":{"alt":"Peneliti mengatur model ginjal dan nefron transparan berisi cairan berwarna","caption":"Model transparan ini menunjukkan aliran darah ginjal serta jalur filtrasi dan reabsorpsi di tubulus.","description":null},"pt":{"alt":"Pesquisadora ajustando um modelo transparente de rim e néfron com líquidos coloridos","caption":"O modelo mostra o fluxo sanguíneo renal e as vias de filtração e reabsorção nos túbulos.","description":null},"zh-hant":{"alt":"研究人員調整裝有彩色液體的透明腎臟與腎元模型","caption":"透明模型呈現腎臟血流及腎小管中的過濾與再吸收路徑。","description":null},"de":{"alt":"Forscherin justiert ein transparentes Nieren- und Nephronmodell mit farbigen Flüssigkeiten","caption":"Das Modell zeigt den renalen Blutfluss sowie Filtration und Rückresorption in den Tubuli.","description":null}}},{"id":1422,"url":"https://injoys.com/rails/active_storage/blobs/proxy/eyJfcmFpbHMiOnsiZGF0YSI6MjA1MDYsInB1ciI6ImJsb2JfaWQifX0=--a09ec1fcd87d1dfb9474e1b5486ae570168fe3d9/ai-13cfbd82.webp","is_representative":false,"generation_method":"ai_semi","license":"ai_generated","mime_type":"image/webp","width":1536,"height":1024,"translations":{"ko":{"alt":"실험실에서 콩팥과 네프론 모형의 전해질 이동 경로를 살펴보는 두 연구자","caption":"연구자가 콩팥 모형을 가리키며 네프론의 전해질 재흡수와 이동 과정을 설명한다.","description":null},"en":{"alt":"Two researchers examining electrolyte pathways in a kidney and nephron model","caption":"A researcher points to a kidney model illustrating electrolyte movement and reabsorption in the nephron.","description":null},"ja":{"alt":"腎臓とネフロン模型で電解質の移動経路を確認する2人の研究者","caption":"研究者が腎臓模型を指し、ネフロンでの電解質の移動と再吸収を説明している。","description":null},"es":{"alt":"Dos investigadoras observan las rutas de electrolitos en un modelo de riñón y nefrona","caption":"Una investigadora señala un modelo renal que muestra el movimiento y la reabsorción de electrolitos.","description":null},"id":{"alt":"Dua peneliti mengamati jalur elektrolit pada model ginjal dan nefron","caption":"Seorang peneliti menunjuk model ginjal yang memperlihatkan pergerakan dan reabsorpsi elektrolit.","description":null},"pt":{"alt":"Duas pesquisadoras analisam as rotas de eletrólitos em um modelo de rim e néfron","caption":"Uma pesquisadora aponta para um modelo renal que mostra o movimento e a reabsorção de eletrólitos.","description":null},"zh-hant":{"alt":"兩名研究人員觀察腎臟與腎元模型中的電解質移動路徑","caption":"研究人員指著腎臟模型，說明電解質在腎元中的移動與再吸收。","description":null},"de":{"alt":"Zwei Forscherinnen untersuchen Elektrolytwege an einem Nieren- und Nephronmodell","caption":"Eine Forscherin zeigt an einem Nierenmodell die Bewegung und Rückresorption von Elektrolyten.","description":null}}}],"published_at":"2026-09-20T21:19:18+09:00","updated_at":"2026-09-20T21:19:18+09:00","license":"cc_by","translation_status":"reviewed","available_locales":["ko","en","ja","es"],"data_locales":["ko","en","ja","es","id","pt","zh-hant","de"],"url":"https://injoys.com/en/articles/kidney-electrolyte-reabsorption-and-excretion"}