Your kidneys are the master chemists in your body and maintain the purity and constancy of your internal fluids. Much like a city’s water filtration plant that keeps the water supply drinkable and disposes of its waste, the kidneys are usually unappreciated until there is a malfunction and our internal fluids become tainted.
For your body to work properly, it must contain just the right amount of water. One of the important jobs of the kidneys is to remove excess water from the body or to retain water when the body needs more. This balance is directly related to your blood pressure.
Many of the substances in the blood and body fluids must be kept at the correct level for the body to function properly. For example, sodium and potassium are minerals that come from our diet and a balance of these two minerals must be maintained at very specific levels. Every day, your kidneys filter gallons of fluid from the bloodstream. They then process this filtrate, allowing wastes and excess elements to leave the body in urine while returning needed substances to the blood in just the right proportions. Your kidneys shoulder the major responsibility for eliminating wastes, toxins and drugs from the body and maintaining a constant balance. In this article we’ll examine the anatomy of a kidney, how your kidneys work, what causes them to malfunction, and what you have to do to maintain a fluid balance.
ANATOMY OF THE KIDNEY
These small dark organs, each about the size of a clenched fist, sit on either side of the spine between your 11th and 12th ribs. Each kidney is enclosed in a renal capsule which gives it a fresh, glistening appearance. A fatty mass, the adipose capsule, surrounds each kidney and helps hold it in place against the muscles of the trunk wall.
Inside each kidney there are more than one million tiny units called nephrons, the workhorse of the kidney. Nephrons are the structural and functional units of the kidneys and, as such, are responsible for forming the urine product. Each nephron is made up of a very small filter, called a glomerulus (glo-mer u-lus), which is attached to a renal tubule.
PHYSIOLOGY OF THE KIDNEY
The nephron is a tangled combination of blood vessels and tubules. Through an intricate dance, toxins brought to the nephron by the blood are filtered out by the glomerulus. Leaving the glomerulus, the journey through the twisted tubules sees the filtrate percolate through a series of filtration, reabsorption and secretion processes. The focus of these three processes is to rid the body of toxins and reabsorb vital elements such as sodium, potassium, chloride, etc. The final product leaving the collecting duct is urine and the body’s fluids and elements are balanced one more.
Water, Water Everywhere
Water accounts for nearly the entire volume of body fluids and occupies locations within the body referred to as fluid compartments. There is the intracellular fluid (contained within living cells) and extracellular fluid (all body fluids located outside the cells, including blood plasma, cerebrospinal fluid, and humors of the eye, lymph and others.
However, there is more to fluid balance than just water.
Electrolytes are a chemical in the body that, when dissolved, produce ions, conducts an electric current, and is itself changed in the process. Examples of electrolytes are calcium, sodium, and potassium.1
Electrolytes and water balance are tightly linked as the kidneys continuously process the blood. Very small changes in electrolyte balance cause water to move from one compartment to another. This alters blood volume and blood pressure.
Hormones, Kidneys and Blood Pressure
When blood volume drops, blood pressure drops, which decreases the amount of filtrate formed by the kidneys. This causes highly sensitive cells in the hypothalamus to react to the change. Nerve impulses are sent to the pituitary, which then releases an antidiuretic hormone (ADH). The function of this hormone is to prevent excessive water loss in the urine. ADH travels in the blood to the kidneys where it causes the reabsorption of more water, returning water to the bloodstream, allowing blood volume and blood pressure to return to normal ranges.
DISEASES OF THE KIDNEY
Kidney diseases basically stop the functioning of the kidneys. Unlike other parts of the body, there are only a few significant diseases to be concerned with when discussing the kidney. However, other diseases can have serious effects on kidney function.
Nephrotic syndrome results from damage to the kidneys’ glomeruli. When working properly, the glomeruli keep protein in the blood from leaking into the urine. As a result of this protein loss, the blood is deficient. Normal amounts of blood protein are needed to help regulate fluid throughout the body. Protein acts like a sponge to soak up fluid into the bloodstream. When blood is low in protein, fluid accumulates in the body’s tissues rather than circulating. The fluid causes swelling and puffiness.
Nephrotic syndrome can occur with many diseases. In adults, the most common causes are diabetic nephropathy and membranous nephropathy. In older adults, the most common cause is amyloidosis. Prevention of nephrotic syndrome relies on controlling these diseases. Frequently, however, the cause of nephrotic syndrome is unknown.2
Diabetes Insipidus – When ADH is not released, huge amounts of very dilute urine flush from the body day after day. This condition is called diabetes insipidus and can lead to severe hydration and electrolyte imbalance.
Acute Renal Failure (ARF)
ARF can be brought on due to heart failure or low blood pressure, or conditions associated with reduced blood volume, such as severe hemorrhage. ARF can occur due to abnormalities of the kidney itself, including the blood vessels, glomeruli or tubules.
Chronic Kidney Disease (CKD)
Damage to nephrons may leave kidneys unable to remove wastes. Usually the damage occurs slowly over years. There are no obvious symptoms, so you don’t know it is happening. The most unfortunate part is that clinical symptoms only show up when there is 70% destruction of functional nephrons. The most common causes of chronic kidney disease are high blood pressure, diabetes, heredity and heart disease. CKD can also be caused by serious infections elsewhere in the body or urinary blockages. Your doctor will ask you about risk factors for kidney disease such as diabetes and high blood pressure and will test your blood and urine for signs of CKD. 3
Symptoms of CKD:
- Feeling tired
- Feeling weak
- Loss of appetite
- Not sleeping
- Not thinking clearly
- Swelling of the feet and ankles
A kidney stone is a solid piece of material that forms in the kidney from substances in the urine. It may be as small as a grain of sand or as large as a pearl. Most kidney stones pass out of the body without help from a doctor. But sometimes a stone will not go away. It may get stuck in the urinary tract, block the flow of urine and cause great pain.
The following may be signs of kidney stones that need a doctor’s help:
- Extreme pain in your back or side that will not go away
- Blood in your urine
- Fever and chills
- Urine that smells bad or looks cloudy
- A burning feeling when you urinate4
Renal Tubular Acidosis (RTA)
Renal tubular acidosis (RTA) is a disease that occurs when the kidneys fail to excrete acids into the urine, which causes a person’s blood to remain too acidic. Without proper treatment, chronic acidity of the blood leads to growth retardation, kidney stones, bone disease, chronic kidney disease, and possibly total kidney failure.
The body’s cells use chemical reactions to carry out tasks such as turning food into energy and repairing tissue. These chemical reactions generate acids. Some acid in the blood is normal, but too much acid—acidosis—can disturb many bodily functions. Healthy kidneys help maintain acid-base balance by excreting acids into the urine and returning bicarbonate—an alkaline, or base, substance—to the blood. This “reclaimed” bicarbonate neutralizes much of the acid that is created when food is broken down in the body. The movement of substances like bicarbonate between the blood and structures in the kidneys is called transport.
One researcher has theorized that Charles Dickens may have been describing a child with RTA in the character of Tiny Tim from A Christmas Carol. Tiny Tim’s small stature, malformed limbs, and periods of weakness are all possible consequences of the chemical imbalance caused by RTA.1 In the story, Tiny Tim recovers when he receives medical treatment, which would likely have included sodium bicarbonate and sodium citrate, alkaline agents to neutralize acidic blood. The good news is that medical treatment can indeed reverse the effects of RTA. 5
NATURAL SUPPLEMENTS USED FOR THE KIDNEY
The natural benefit of many herbal supplements is their ability to help cleanse the blood. The normal function of the kidneys is also to filter the blood. Because air, water and food pollution is so rampant, your kidneys can use all the help they can get. Some herbs serve as diuretics and this may cause kidney irritation. Use diuretic herbs sparingly and with supervision.
As with any type of supplementation, always advise your health care professional of any supplements you may, or may want to, consume. Some supplements have been known to conflict with prescription medications.
The National Center for Complementary and Alternative Medicine, National Institutes of Health, in the United States outlines the use of dandelion, commonly used to treat kidney diseases. Today, dandelion is used by some as a kidney tonic. The leaves and roots of the dandelion, or the whole plant, are used fresh or dried in teas, capsules, or extracts. Dandelion leaves are used in salads or as a cooked green, and the flowers are used to make wine.
Cautions: Dandelion use is generally considered safe, however there have been rare reports of upset stomach and diarrhea, and some people are allergic to the plant. People with an inflamed or infected gallbladder, or blocked bile ducts, should avoid using dandelion.
Ginseng is long-known for it’s blood-cleansing abilities. Ginseng’s action as a free radical scavenger is important since free radical production is implicated in progressive kidney disorders.
Cautions: Ginseng may be harmful where chronic kidney disease is already established. It has been noted that women should use white ginseng and avoid red ginseng.
Many other herbs relate to kidney health, including:
- Juniper (berry) – acts as a diuretic and helps regulate blood sugar levels
- Parsley (leaf) – helps with normal kidney function
- Ginger (root) – strong antioxidant
- Uva Ursi (leaf) – promotes excretion of fluids, useful for kidney infections
- Marshmallow (root) – aids in expelling excess fluid
- Cramp Bark – relieves muscle spasms and pain
- Goldenseal (root) – fights infection, cleanses the body
Carol Roy is a Natural Health Practitioner, registered with Natural Health Practitioners Canada, who received her diploma from the Alternative Medicine College of Canada in Montreal, Quebec. With 9 years experience in her area of expertise, naturopathic medicine, Carol has also trained to become a fully qualified Reiki Master, Quantum Touch ® Practitioner and Reflexologist.
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replacement for any prescriptions. Seek medical advice for any health concerns.
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1 . Barron’s Dictionary of Medical Terms.
2 . National Kidney and Urologic Diseases Information Clearinghouse, National Institutes of Health, http://kidney.niddk.nih.gov/kudiseases/pubs/nephrotic/
3. U.S. National Library of Medicine and National Institutes of Health,http://www.nlm.nih.gov/medlineplus/kidneydiseases.html
4. U.S. National Library of Medicine and National Institutes of Health,http://www.nlm.nih.gov/medlineplus/kidneystones.html
5. National Kidney and Urologic Diseases Information Clearinghouse, National Institutes of Health, http://kidney.niddk.nih.gov/kudiseases/pubs/tubularacidosis/index.htm
The Kidney Foundation of Canada, www.kidney.ca
Essentials of Human Anatomy & Physiology, Seventh Edition, Elaine N. Marieb
Further Reading Suggestions:
Medical Herbalism, Journal for the Clinical Practitioner
Urinary-Kidney Support, by Sharol Tilgner, N.D.
Medline Plus, National Institutes of Health, Kidney Diseases
The Use Of Salvia For Patients With Renal Failure, by Subhuti Dharmananda, Ph.D., Director, Institute for Traditional Medicine, Portland, Oregon, http://www.itmonline.org/arts/salviarenal.htm