Kidney: Definition & Functions
In the human body, there are two kidneys located in the abdominal cavity, on each side of the spine just below the ribs. Each kidney is about the size of your fist (weighing 120-150g). A nephron is the basic structural and functional unit of the kidney, there are approximately 1.000.000 nephrons in each kidney
Kidneys act as intelligent filters: their main functions are to clean toxins and wastes out of your blood. Because of this, kidneys play a central role in regulating blood pressure and balancing important electrolytes which maintain your heart’s rhythm. Therefore, it comes as a natural consequence that kidney dysfunction affects the body in general, and the heart in particular. The opposite is also true; i.e., such cardiovascular diseases as arterial hypertension greatly affect the entire body, especially kidneys.
Kidney Functions:
- Urine excretion: as it includes dissolved salts and chemicals necessary to be regularly got rid of.
- Elimination of metabolic wastes: including paulina, creatinine, uric acid, and many other toxins.
- Maintaining fluid balance: kidneys reabsorb useful nutrients (e.g., glucose, sodium, potassium, and water). They, also, excrete basic materials if superfluous, and keep them if required (as is the case during fasting). In case of large fluid intake, there will be larger quantities of urine than usual.
- Acid-base homeostasis: which means the maintenance of pH around a relatively stable value. Kidneys have two very important roles in maintaining the acid-base balance: to reabsorb bicarbonate from urine, and to excrete hydrogen ions into urine
- Arterial blood pressure regulation: by secreting some hormones that either increases or maintains blood pressure.
- Red blood cells regulation: by secreting erythropoietin, which stimulates bone marrow to produce red blood cells.
Activation of Vitamin D: which is responsible for the absorption of intestinal calcium and regularly depositing it in bones, as well as eliminating it, if superfluous, through kidneys.
Renal Diseases & Causes:
There are numerous renal diseases, varying according to the cause, severity and impact on the kidney functions. Causes of renal diseases could be summed up as follows:
Infection-caused diseases.
Diseases caused by bilharzias (schistosomiasis).
Environmentally-related diseases.
Genetically-inherited diseases.
Misuse of drugs.
Diabetes.
Low/High arterial blood pressure.
Cardiac diseases.
Immunological diseases (e.g., systemic lupus erythematosus).
Viral diseases (e.g., AIDS).
Kidney-Heart Connection
Given the heart is the body's sole blood pump; any deficiency of the heart performance is reflected in the performance of all organs, including the kidneys. The deterioration of cardiac performance leads up to an analogous renal deterioration (or even renal failure). The unbalanced blood pressure could cause renal failure.
Long-term regulation of blood pressure predominantly depends upon the kidney. Although the kidney cannot directly sense blood pressure, changes in the delivery of sodium and chloride to the distal part of the nephron alter the kidney's secretion of the enzyme renin. Consequently, any renal dysfunction or deficiency affects the blood pressure. Following are some of the renal diseases causing high blood pressure:
Given kidneys are responsible for eliminating superfluous fluid and toxins, maintaining the acid-base homeostasis, controlling blood pressure, production of red blood cells and absorption of calcium, when kidneys don’t work properly, waste products build up in the blood, and the body’s hormones are disturbed. Those changes can affect how the heart and blood vessels work. The kidneys help to maintain the body’s chemical balance which in turn plays an important role in maintaining healthy blood pressure. If kidneys aren’t working properly, the blood pressure can rise. If high blood pressure is left unchecked, it tends to thicken the blood vessel walls causing blood vessels to narrow. Severe, uncontrolled blood pressure weakens the heart and eventually causes kidney failure.
Treatment:
Treatment of chronic renal diseases is intended to:
A) Dialysis:
Hemodialysis is useful for balancing the body's fluid, by removing wastes and toxins from the blood.
Types of dialysis:
Hemodialysis: an outer device used for cleaning blood, by eliminating wastes and toxins from outside the body. This method, however, is not suitable for diabetics and cardiac patients.
Peritoneal dialysis: In peritoneal dialysis, a sterile solution containing glucose is run through a tube into the peritoneal cavity, the abdominal body cavity around the intestine, where the peritoneal membrane acts as a partially permeable membrane. The peritoneal membrane or peritoneum is a layer of tissue containing blood vessels that lines and surrounds the peritoneal, or abdominal, cavity and the internal abdominal organs (stomach, spleen, liver, and intestines). Nevertheless, this method is not suitable for patients who have undergone critical surgeries, as well as tall, well-built or obese people.
B) Kidney transplantation:
Kidney transplantation (also known as: renal transplantation) is the organ transplant of a kidney into a patient with end-stage renal disease, when it becomes difficult for the patient to undergo dialysis. The kidney is taken from a donor; either dead or alive.
To identify their level of immunity, and ensure compatibility with donors' immunity, patients have to undergo several examinations, seeking to have a successful renal transplantation surgery. The patient is supposed to take medicines for preserving his immunity for the rest of his life, with the aim to prevent his body from attacking the new kidney. It is necessary for the patient, as well, to regularly see a doctor, and undergo blood and urine tests to assess his health condition, as well as the kidney performance.
Treatment of the Diseases Causing Renal Diseases:
- Control of blood sugar, especially for diabetics; to avoid the complications affecting the kidneys.
- Control of blood pressure, and maintaining it within the normal range, by measuring it regularly, and keeping to the medications prescribed by the doctor.
- Recent studies have shown that the impaired production of "renin" stimulates the production of angiotensin, which, in turn, heightens blood pressure, and, accordingly, affects the kidneys.
Kidney Patients' Nutrition:
It has proven that sound nutrition protects kidney patients from the complications of chronic kidney disease (CKD). Patients, therefore, should cooperate with the nutrition specialist to arrange a proper diet.
Early Examination:
Early examination is of crucial importance for detecting any renal problems and taking the right preemptive action; especially for people who are more prone to renal diseases, such as older persons and diabetics.
Prevention of Renal Diseases:
1. Regular exercise:
Regular exercise is effecting in lowering blood pressure, and, accordingly, reducing the risk of CKD.
2. Control of blood pressure and maintaining it within the normal range:
It is of pivotal importance for diabetics to undergo regular examination of kidney functions. Kidney complications in diabetics could be averted by the early detection and preemptive treatment of any kidney problems.
3. Control of blood pressure and maintaining it within the normal range:
In case the kidney patient suffers from high blood pressure, he'd better consult his doctor, and measure his blood pressure regularly, so as to control it. Complications could be evaded by abiding by the doctor's tips and instructions, as well as taking the prescribed medications regularly.
4. Eating healthy food and maintaining ideal body weight:
Health food is necessary for preventing or limiting such kidney-related diseases, such as diabetes and cardiovascular diseases.
5. Drinking adequate fluid (6-8 cups daily). The quantity of necessary to be drunk varies from one person to another, depending on their gender, weather and the type of physical activity.
6. Avoiding smoking:
Smoking may slow down the blood flow towards the kidneys, and this may impair their ability to work properly. Besides, smoking increases the risk of kidney cancer by 50 per cent.
7. Avoiding from using any medicines unless prescribed by the doctor:
It is well known that commonly used medicines, such as non-steroidal and non-inflammatory drugs (e.g. Ibuprofen) may cause kidney damage if taken excessively. Such drugs, however, are not dangerous in case the kidneys are healthy. Still, if the patient suffers from such chronic diseases as arthritis or spinal pains, he will have to discuss the case with the doctor, seeking to find a way to overcome pains without endangering the kidneys.
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