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How Do The Kidneys Help Regulate Blood Pressure

How Do Kidneys Help Regulate Blood Pressure

High Blood Pressure and Your Kidneys – A to Z Guide

The kidneys ensure that the make-up and volume of the fluids in the body is correct. They help control the chemical balance of the blood and regulate the bodys level of sodium, potassium and calcium. The kidneys remove waste products and excess water from the body and so help to regulate blood pressure.

How Can I Prevent Or Slow The Progression Of Kidney Disease From High Blood Pressure

The best way to slow or prevent kidney disease from high blood pressure is to take steps to lower your blood pressure. These steps include a combination of medicines and lifestyle changes, such as

  • being physically active
  • managing stress
  • following a healthy diet, including less sodium intake

No matter what the cause of your kidney disease, high blood pressure can make your kidneys worse. If you have kidney disease, you should talk with your health care professional about your individual blood pressure goals and how often you should have your blood pressure checked.

How Does Renal Acid Base Control Take Place

Renal Acid-Base Control. Importantly, excretion of hydrogen ions by the kidneys is molecularly coupled to novel generation of bicarbonate which is subsequently added to the extracellular fluid, thus replenising the ECF bicarbonate buffer. The specific molecular mechanisms and regulation of these processes are covered in Renal Acid Excretion.

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Functional Structure Of The Kidneys

nephrons

1. The tubule begins with a hollow enlargement called Bowman’s capsule, which is where water and solutes initially enter the tubule from the bloodstream. This process is known as filtration. The structure comprised of Bowman’s capsule and associated capillaries is called the renal corpuscle.

2. From Bowman’s capsule the tubular fluid flows towards the proximal tubule, which remains in the outer layer of the kidney. The proximal tubule is the major site of reabsorption of water and solutes in equal proportions from the filtered tubular fluid.

3. Then the tubule dips into the hairpin loop of Henle, which descends toward the center of the kidney and then rises back to the cortex. The loop of Henle is also a major site of reabsorption, but unlike the proximal tubule, proportionately more solute than water is reabsorbed, so the tubular fluid is dilute relative to plasma by the end of this segment.

4. The next segment is the distal tubule, which like the proximal tubule remains in the cortex. Both reabsorption and secretion take place in this segment, which is where sodium and potassium concentrations and the pH of the tubular fluid are adjusted to ensure homeostasis.

1. An afferent arteriole takes blood to the renal corpuscle, where the blood passes through the first capillary bed, a ball-shape tuft known as the glomerulus.

2. An efferent arteriole takes blood away from the glomerulus.

Role Of The Kidneys In The Regulation Of Intra

How Do The Kidneys Help Regulate Blood Pressure?  Turn To ...

Seriki A Samue1*, Adebayo O Francis1 and Odetola O Anthony2

1Department of Human Physiology, College of Medicine, Bingham University, Karu, Nigeria2Department of Human Physiology, Faculty of Medicine, Nnamdi Azikiwe University, Awka, Nigeria

*Address for Correspondence: Seriki A. Samuel, Department of Human Physiology, College of Medicine, Bingham University, Karu, Nigeria, Tel: +2348036041121 Email: [email protected]

Dates:Submitted: 05 July 2018 Approved: 16 July 2018 17 July 2018

How to cite this article: Samuel SA, Francis AO, Anthony OO. Role of the Kidneys in the Regulation of Intra- and Extra-Renal Blood Pressure. Ann Clin Hypertens. 2018 2: 048-058. DOI: 10.29328/journal.ach.1001011

Copyright License:© 2018 Samuel SA, et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Keywords: Hypertension Renin Angiotensin System Natriuresis Sodium balance homeostasis

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Treatments For Renal Hypertension

Medications are used first to try to control high blood pressure in renal hypertension. The most important blood pressure medications to treat renal hypertension include:

For most people with renal hypertension due to renal artery narrowing, medications can effectively control blood pressure. More than one blood pressure drug is often needed, however.

In some people with renal hypertension due to narrowing of the renal artery, even taking three or more medications every day may not adequately control blood pressure. In these situations, a procedure to improve blood flow to the kidneys may help.

Possible procedures include:

Angioplasty. A doctor threads a catheter through a large artery in the groin and advances it into the renal artery. A balloon is then inflated for a few moments. This widens the artery and improves blood flow.

Stenting. During angioplasty, a wire-mesh stent can be expanded inside the renal artery. The stent stays in place. This keeps the artery open after the balloon is removed. Research, however, has not shown that stenting is more effective than medication for renal hypertension.Ã

Surgery. A surgeon can bypass the narrowed renal artery by sewing a healthy blood vessel next to it. Surgery is generally considered only when angioplasty and stenting are not possible.

These procedures are similar to those used to improve blood flow in the heart in people with coronary artery disease.

Water And Electrolyte Balance

People consume water regularly in order to maintain life. More water is produced by the processing of food. If the amount of water added to the body is not matched by an equal amount going out, water accumulates rapidly and the person becomes ill and may even die. Excess water dilutes the body’s electrolytes, whereas water restriction concentrates them. The body’s electrolytes must be maintained at very precise concentrations. The kidneys regulate and help maintain the proper balance of water and electrolytes.

Blood enters a glomerulus at high pressure. Much of the fluid part of blood is filtered through small pores in the glomerulus, leaving behind blood cells and most large molecules, such as proteins. The clear, filtered fluid enters Bowman space and passes into the tubule leading from Bowman capsule. In healthy adults, about 47 gallons of fluid is filtered into the kidney tubules each day. Nearly all this fluid is reabsorbed by the kidney. Only about 1.5 to 2% of the fluid is excreted as urine. For this reabsorption to occur, different parts of the nephron actively secrete and reabsorb different electrolytes, which pull the water along, and other parts of the nephron vary their permeability to water, allowing more or less water to return to the circulation. The details of these processes are a bit complicated.

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Does Potassium Affect The Heart

Your Heart and Other Muscles If you have a low potassium level, you can get muscle weakness and cramps. Because its a muscle, your heart needs potassium. It helps cells send the right electrical signals so that the heart pumps correctly. Having too much potassium in the body can alter the hearts rhythm.

Everyday Connections: Stem Cells And Repair Of Kidney Damage

Kidney Regulates Blood Pressure

Stem cells are unspecialized cells that can reproduce themselves via cell division, sometimes after years of inactivity. Under certain conditions, they may differentiate into tissue-specific or organ-specific cells with special functions. In some cases, stem cells may continually divide to produce a mature cell and to replace themselves. Stem cell therapy has an enormous potential to improve the quality of life or save the lives of people suffering from debilitating or life-threatening diseases. There have been several studies in animals, but since stem cell therapy is still in its infancy, there have been limited experiments in humans.

Acute kidney injury can be caused by a number of factors, including transplants and other surgeries. It affects 710 percent of all hospitalized patients, resulting in the deaths of 3540 percent of inpatients. In limited studies using mesenchymal stem cells, there have been fewer instances of kidney damage after surgery, the length of hospital stays has been reduced, and there have been fewer readmissions after release.

How do these stem cells work to protect or repair the kidney? Scientists are unsure at this point, but some evidence has shown that these stem cells release several growth factors in endocrine and paracrine ways. As further studies are conducted to assess the safety and effectiveness of stem cell therapy, we will move closer to a day when kidney injury is rare, and curative treatments are routine.

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P2 Receptor Activation In Renal Tubular Segments

Sodium balance and regulation of ECFV is controlled by regulating sodium transport along the nephron. An increase in systemic blood pressure increases renal perfusion pressure to the kidney. While autoregulation is efficient, it is not perfect, leading to a subtle increase in glomerular capillary pressure and a small increase in glomerular filtration rate which can increase tubular fluid flow rate, stimulate ATP release from tubular epithelium where it can activate P2 receptors and reduce epithelial sodium transport. Therefore, regulation of ECFV occurs in part by P2-receptor-mediated regulation of salt and water reabsorption by the nephron .

Measuring How Your Kidneys Work

It is difficult to calculate the exact rate at which your kidneys work. The best measure of kidney function is called the glomerular filtration rate . The GFR can be estimated using a mathematical formula. This formula uses the level of creatinine in your blood to estimate how well your kidneys are filtering waste from your blood. It can indicate if there is any kidney damage.

The higher the filtration rate, the better the kidneys are working. A GFR of 100 mL/min/1.73 m2 is in the normal range. This is about equal to 100 per cent kidney function. Based on this measurement system, a GFR of 50 mL/min/1.73 m2 could be called 50 per cent kidney function and a GFR of 30 mL/min/1.73 m2 could be called 30 per cent kidney function.

If your doctor orders a blood test to learn more about your kidney function, an eGFR result is provided automatically, along with your creatinine results.

Your doctor may also test for other signs and conditions that may indicate you have chronic kidney disease. These may include tests for:

  • protein in your urine
  • blood in your urine
  • high blood pressure
  • diabetes.

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How High Blood Pressure Can Damage Your Kidneys

Your heart, the key organ of the circulatory system, constantly pumps blood through your blood vessels. Good blood flow is essential for normal kidney function, and even minor blood flow problems can affect kidney function and increase your risk of serious health problems.

Although a certain amount of force is needed to push blood through the blood vessels, the pressure inside the vessels sometimes becomes too high. High blood pressure can damage the blood vessels that lead to the kidneys, causing them to stiffen or narrow.

As a result, less blood reaches your kidneys, making it difficult for the organs to function properly. Tiny blood vessels inside the kidneys that filter blood may also be damaged.

How Does Kidney Disease Affect Your Body

How Do The Kidneys Help Regulate Blood Pressure?  Turn To ...

Kidney disease can affect you in a number of different ways. These include:

Proteinuria or protein in the urine is frequently the earliest symptom of kidney disease. You will have read, in the previous section, how the kidney works and that the kidney has about a million filters. When the kidney is healthy it allows very little protein into the urine. If these filters become leaky, small amounts of protein will leak into the urine. This is frequently an early sign of kidney trouble long before the kidney function itself begins to deteriorate.

Doctors frequently test patients urine for the presence of blood or protein, to try to detect kidney disease early. There are many causes of protein in the urine, including diabetes and glomerulonephritis. Whilst your doctor will conduct a number of special blood tests, to try to determine the underlying cause, it may be necessary to undergo a kidney biopsy, to establish the exact cause of the protein.

Patients who have very large amounts of protein in the urine, , are described as having nephrotic syndrome. Patients with nephrotic syndrome frequently have swollen legs.

Haematuria or blood in the urine can either be present in amounts that you can see or in amounts that you cannot see in which it is only detected with urine testing. Blood in the urine may not appear red but more like strong tea coloured.

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Why Are The Kidneys So Important

Most people know that a major function of the kidneys is to remove waste products and excess fluid from the body. These waste products and excess fluid are removed through the urine. The production of urine involves highly complex steps of excretion and re-absorption. This process is necessary to maintain a stable balance of body chemicals.

The critical regulation of the body’s salt, potassium and acid content is performed by the kidneys. The kidneys also produce hormones that affect the function of other organs. For example, a hormone produced by the kidneys stimulates red blood cell production. Other hormones produced by the kidneys help regulate blood pressure and control calcium metabolism.

The kidneys are powerful chemical factories that perform the following functions:

  • remove waste products from the body
  • remove drugs from the body
  • balance the body’s fluids
  • release hormones that regulate blood pressure
  • produce an active form of vitamin D that promotes strong, healthy bones
  • control the production of red blood cells

Below you will find more information about the kidneys and the vital role they play in keeping your body functioning.

How Does Eating Diet And Nutrition Affect High Blood Pressure And Kidney Disease

Following a healthy eating plan can help lower your blood pressure. Reducing the amount of sodium in your diet is an important part of any healthy eating plan. Your health care professional may recommend the Dietary Approaches to Stop Hypertension eating plan. DASH focuses on fruits, vegetables, whole grains, and other foods that are healthy for your heart and lower in sodium, which often comes from salt. The DASH eating plan

  • is low in fat and cholesterol
  • features fat-free or low-fat milk and dairy products, fish, poultry, and nuts
  • suggests less red meat, sweets, added sugars, and sugar-containing beverages
  • is rich in nutrients, protein, and fiber

A registered dietitian can help tailor your diet to your kidney disease. If you have congestive heart failure or edema, a diet low in sodium intake can help reduce edema and lower blood pressure. Reducing saturated fat and cholesterol can help control high levels of lipids, or fats, in the blood.

People with advanced kidney disease should speak with their health care professional about their diet.

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When To See A Specialist

If you’re at risk of kidney disease due to high blood pressure, your primary care doctor may recommend annual testing. You may also be referred to a nephrologist, a doctor who specializes in kidney disorders.

At Temple, our nephrologists will work with you to find the best way to maintain kidney function. And if necessary, guide you through a range of treatment options.

Blood Pressure Control In Times Of Stress

Renin angiotensin system regulates blood pressure

In other cases, your blood pressure may fall suddenly, such as when you are injured and lose a lot of blood . In addition to triggering changes in your heart beat and blood vessel walls, the sudden drop in blood pressure will also trigger the release of hormones that affect your kidney function . If you lose a lot of blood, your body senses the drop in blood volume and triggers the productions of hormones that signal the kidneys to retain salt and water . This increases your blood volume, thereby increasing blood pressure .

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How Does The Urinary System Work

Your kidneys work non-stop, with all of your blood passing through them every 5 minutes.

The urine that collects is a mix of waste and excess fluid. It is carried to your bladder to be stored. Muscles in the bladder wall stay relaxed, so it can expand as it fills. Other muscles work like a dam to keep urine in your bladder until you are ready to go to the toilet. Your brain controls your bladder, signalling it when to hold urine and when to empty. Urinary incontinence is when there is accidental or involuntary loss of urine from the bladder.

To urinate normally, all parts of your urinary tract must work together in proper order. When you are ready to go to the toilet, your bladder outlet muscles relax and your bladder wall muscles contract. Urine empties from your bladder through your urethra and exits your body.

The Inextricable Role Of The Kidney In Hypertension

1Division of Nephrology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, North Carolina, USA. 2Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-NUS Graduate Medical School, Singapore.

Address correspondence to: Thomas M. Coffman, Department of Medicine/Division of Nephrology, Duke University Medical Center, Room 2028 MSRB2, 2 Genome Court, Durham, North Carolina 27710, USA. Phone: 919.684.9788 Fax: 919.684.3011 E-mail: .

Find articles byCrowley, S.in: |PubMed |

1Division of Nephrology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, North Carolina, USA. 2Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-NUS Graduate Medical School, Singapore.

Address correspondence to: Thomas M. Coffman, Department of Medicine/Division of Nephrology, Duke University Medical Center, Room 2028 MSRB2, 2 Genome Court, Durham, North Carolina 27710, USA. Phone: 919.684.9788 Fax: 919.684.3011 E-mail: .

J Clin Invest.

Acknowledgments

The authors work in this area has been supported by funding from the Medical Research Service of the Veterans Administration, the NIH , the Mandel Center for Hypertension and Atherosclerosis at Duke, and the American Heart Association.

Conflict of interest: The authors have declared that no conflict of interest exists.

Reference information: J Clin Invest. 2014 124:23412347. doi:10.1172/JCI72274.

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