Gland: Kidneys

THE KIDNEYS

The function of the kidneys is to filter 170,000 mL of blood daily and produce about 1200 mL of urine daily. At the same time, the kidneys are used to filter out all excessive ions such as sodium, chloride, and potassium, while maintaining glucose, amino acids, water and other substances that are essential for body metabolism. The kidneys also remove the following waste products: creatinine, BUN, and uric acid.
The two kidneys together contain about two million nephrons and each nephron is capable of forming urine by itself. Blood enters the kidneys thru the renal artery, enters the glomeruli through the afferent arteriole, and leaves through the efferent arteriole. The efferent arteriole is smaller in diameter than the afferent arteriole, therefore creating a hydrostatic (back) pressure forming the glomerular filtrate. (The glomeruli is a network of up to 50 parallel and anastomosing capillaries covered by epithelium cells and encased in Bowman’s capsule.)
The pressure of the blood into the glomeruli causes fluid to filter into Bowman’s capsule. This is known as the glomerular filtrate, which then travels to the proximal/ distal tubules in the kidney cortex. As the filtrate passes along the tubules, the capillary blood and the epithelial tubular cells add more solutes.
Interposed between the proximal and distal tubules is the loop of Henley, which has a thin descending limb, and a thin and a thick (impermeable to H20, but actively absorbs solutes causing filtrate to become hypotonic) ascending limb. It then travels through the distal tubules, through the corticoid-collecting duct, into the medullar-collecting duct, where things are absorbed or secreted. As the glomerular filtrate flows through the tubules, especially the cortical, medullary and papillary collecting ducts, over 99% of the water (via AVP) and varying amounts of its solutes are reabsorbed.
The basic function of the nephron is to clean the blood plasma of unwanted substances, particularly the end products of metabolism (organic substances) such as urea (accounts for ½ of the total dissolved solids in urine), creatinine, uric acid, urate, BUN and inorganic dissolved solids (the highest being chloride followed by sodium and potassium.) The kidney does this through two mechanisms: filtration and secretion.
Antidiuretic hormone (AVP) retains water but removes solutes. AVP binds to V2 receptor sites on renal epithelial cells of the basso lateral membrane activating protein kinase and adenylate cyclase to catalyze cAMP from ATP. The cAMP is now phosphorylated, mediating the effects of renal transport. AVP also increases transepithelial conductance and basso lateral membrane conductance of the CL ion channels. AVP also increases co transport units on other cell membranes for NA, K, and CL. Aldosterone controls potassium excretion and sodium reabsorption. Parathyroid hormone causes absorption of calcium and loss of phosphorus. The daily loss of fluid through urine is 1400 mL, 350 mL through the skin and respiratory tract, and 100 mL through sweat and feces.

The rennin-angiotensin system is stimulated by decreased blood flow through the kidneys. The purpose of which is to increase blood pressure. Rennin is a small protein enzyme released by the kidney and is stored as pro rennin. When the blood pressure drops, pro rennin is converted into rennin. Rennin also works as an enzyme on another plasma globular protein called rennin substrate 1 and 2 or angiotensin (a powerful vasoconstrictor).
Angiotensin 2 is the most powerful constrictor and is also found in the epithelium of the lungs. Angiotension decreases water and mineral loss through the kidneys while stimulating the adrenals. Aldosterone is strongly influenced by this rennin-angiotensin system (90% more than ACTH) causing strong reabsorption of sodium into the distal tubules to balance extracellular potassium ions.

The following tests indicates kidney malfunction:

1. SODIUM-Sodium is an alkaline mineral that helps maintain alkaline activity. It helps in acid-alkaline balance, which affects intracellular/extracellular fluid exchange, and osmotic pressure, via the sodium/potassium pump. It does this in conjunction with antidiuretic hormone and aldosterone. Sodium gathers and aggregates (polarizes) all substances necessary to be exchanged by semi-permeable membranes. Sodium also affects the renal tubules for the activity of discharging toxins. It literally aggregates toxins and holds them in suspension.

2. POTASSIUM-Potassium lines the inside of all cell membranes and is responsible, via the posterior pituitary, for oxidizing secondary hydrogen chloride and allowing sodium-aggregated substances to cross the cell membrane. It is the only substance that allows oxygen into unoxygenated tissue.
Potassium is necessary for proper function of mineral corticoids, (aldosterone and deoxycorticosterone) thus maintaining sodium concentration and alkaline reserve.
Therefore, potassium is of great value to the posterior pituitary (ADH/oxytocin), the pineal and the adrenal cortex, via aldosterone secretion. In turn, the kidneys are greatly affected.

Sodium

ELECTROLYTES

The blood electrolytes include sodium, potassium, chloride, and the bicarbonate (HCO3) ion.
Sodium, potassium, and chloride enter the body via ingestion of food.
Carbon dioxide, on the other hand, originates within the body via the metabolic process of carbohydrates, fats, and proteins.
Normally the excretion of sodium, potassium, and water is equal to their intake. The kidneys secrete 80-90 percent of all electrolytes.
Excessive carbon dioxide stimulates the respiratory centers in the brainstem to increase respiration. Therefore, the kidneys and the lungs control sodium, chloride, potassium, water, and carbon dioxide thus exerting control over the acid/alkaline balance in the body.
There are also many other organs, and glands involved in this process, such as the posterior pituitary, adrenals, bowel, and uterus/prostate.
The purpose of electrolytes is to set up a shifting mechanism in the cell membrane via oxidation, allowing increased or decreased permeability to that membrane site.
Sodium, which is found in high concentration outside the cell, has the ability to gather up substances (foods) and bring them to active membrane sites.
Chloride is found in the cell membrane and acts as a “doorman” allowing or disallowing exchanges between the intracellular and extracellular fluids.
Potassium, which is found in high concentrations within cells, oxidizes chloride, and allows sodium, with the food to cross the cell membrane and enter the cell.
Sodium, potassium, chloride, calcium, and hydrogen are all transported via active transport.
SODIUM

Sodium is the most abundant cation (90%) and is the major base in the body. Sodium is either implanted into the food via saliva or is found in the food and has the following functions:

1. Sodium is an alkaline mineral that helps maintain alkaline activity.
Therefore, it helps in acid-alkaline balance, which affect intracellular/extracellular fluid exchange, osmotic pressure, via the sodium/potassium pump and does this in conjunction with antidiuretic hormone and aldosterone.

2. Sodium gathers, and aggregates (polarizes) all substances necessary to be exchanged by semi-permeable membranes. Sodium pumps proteins and sugars into the cell membranes.

3. Sodium also affects the renal tubules for the activity of discharging toxins. It literally aggregates toxins and holds them in suspension.

4. Sodium is controlled by the adrenal cortex and as mentioned above is extremely alkaline and therefore, can cause migration of substances towards its polarity, as well as causing these migrated substances to achieve permeability in an acid antioxidant type media known as a fatty membrane. Sodium is the substance necessary to polarize foods into storage according to that permeable membranes needs.

5. Sodium is also necessary for the transmission of neurological impulses by creating action potentials across neurological membranes.

6. Sodium concentration in and out of cells remains constant due to renal blood flow, carbonic anhydrase enzyme activity, aldosterone, and other steroids controlled by the anterior pituitary, rennin enzyme secretion, hypothalamus, and posterior pituitary control of ADH and vasopressin secretion

Potassium

ELECTROLYTES

The blood electrolytes include sodium, potassium, chloride, and the bicarbonate (HCO3) ion.
Sodium, potassium, and chloride enter the body via ingestion of food.
Carbon dioxide, on the other hand, originates within the body via the metabolic process of carbohydrates, fats, and proteins.
Normally the excretion of sodium, potassium, and water is equal to their intake. The kidneys secrete 80-90 percent of all electrolytes.
Excessive carbon dioxide stimulates the respiratory centers in the brainstem to increase respiration. Therefore, the kidneys and the lungs control sodium, chloride, potassium, water, and carbon dioxide thus exerting control over the acid/alkaline balance in the body.
There are also many other organs, and glands involved in this process, such as the posterior pituitary, adrenals, bowel, and uterus/prostate.
The purpose of electrolytes is to set up a shifting mechanism in the cell membrane via oxidation, allowing increased or decreased permeability to that membrane site.
Sodium, which is found in high concentration outside the cell, has the ability to gather up substances (foods), and bring them to active membrane sites.
Chloride is found in the cell membrane and acts as a “doorman” allowing or disallowing exchanges between the intracellular and extracellular fluids.
Potassium, which is found in high concentrations within cells, oxidizes chloride, and allows sodium, with the food to cross the cell membrane and enter the cell.
Sodium, potassium, chloride, calcium, and hydrogen are all transported via active transport.
POTASSIUM

Potassium is intracellular, lining the inside of all cell membranes and affecting intracellular fluids, osmotic pressure, buffering viscosity (potassium bicarbonate is the primary intracellular inorganic buffer). When there is a decrease in potassium bicarbonate you have acid cells, which excites the respiratory centers so the patient hyperventilates. Metabolic acidosis or diabetic ketoacidosis drives potassium out of the cells, affecting electrolyte balance, water retention and carbon dioxide transport in red blood cells. Potassium is responsible via the posterior pituitary for oxidizing secondary hydrogen chloride (affecting adrenal function), allowing the sodium-aggregated substances to cross the cell membrane by affecting the membranes permeability.
Potassium is the only substance, which allows oxygen into unoxygenated tissue. About 90% of the body’s potassium supply is intracellular with only a small percent in the serum.
80% of that is found in the muscles (used for muscular contraction) and in the bones. Potassium levels are regulated by the Na/K ATPase pump which requires magnesium for proper function.
Potassium is necessary for proper function of mineralocorticoids, (aldosterone and deoxycorticosterone) thus maintaining sodium concentration and alkaline reserve.
Therefore, potassium is of great value to the posterior pituitary (ADH/oxytocin), the pineal, and the adrenal cortex via aldosterone secretion.
Potassium along with sodium regulate renal acid-base balance, by substituting hydrogen ions for sodium and potassium in the renal tubules.
Potassium also facilitates oxygen to the myocardium and oxidizes the S.A. node of the heart.
The heart has the highest potassium concentration in the body. Potassium along with calcium and magnesium controls the rate and force of contraction in heart muscle.
It is the primary oxidizer of the body capable of expressing all cellular needs.
Potassium also regulates neurological impulses via osmotic pressure gradients throughout the nervous system.
Potassium directs carbohydrate digestion by polarizing minerals associated with carbohydrate digestion, from the time the carbohydrate enters the body until the cell utilizes it.
Potassium also makes proteins soluble and regulates protein synthesis.
80-90 percent of potassium in the cells is excreted by the kidneys (resulting in the loss of 40-50 mEq/L per day even during fasting) with the remainder excreted by the stool and through sweating

POTASSIUM IS LOW WHEN
General considerations:

¬ Increase water intake
¬ Increase magnesium intake
¬ Decrease calcium intake
¬ Increase potassium intake
¬ Decrease carbohydrate intake

Albumin

ALBUMIN

In pathological levels albumin is used to evaluate:
1. Liver and renal disease
2. Blood osmotic pressure
3. Chronic disease states, which most patients have
4. Dehydration
5. Albumin decreases in acute inflammatory infectious processes

From a physiological standpoint, albumin is produced in the liver and is a primary byproduct of sterols and waxes. Its function is used to build and repair tissue. Albumin is responsible for 80 percent of the colloidal osmotic pressure between body tissues and blood cells. 75% of this control occurs inside the cells since most of the protein is intracellular.
When you have a decrease in albumin, the osmotic pressure becomes disturbed resulting in fluid transfer and edema. Since albumin influences water movement, it will also influence nutrient and mineral movement.

Albumin creates the permeability of the membrane to the osmolarity of the membrane. Therefore, substances can pass from a lesser concentration to a greater concentration. The flow is from the arterial capillaries to extracellular fluid, then from the extracellular fluid to the intracellular fluid, then from the intracellular fluid to the mitochondria. Then back via the same pathway in reverse via osmotic absorption into the veins.

Albumin is also a part of a complex buffer system, which accounts for 75% of things that need to be buffered to maintain acid-alkaline balance in the body. The most powerful buffer system out of the four including, the bicarbonate system (HCO3-), the phosphate buffer system, and the liver (nitrogen/urea), the proteins of the cells and plasma, rein supreme. The protein buffer system works by controlling blood Hydrogen (H+) ion homeostasis. Both intracellular and extracellular proteins have negative charges and can serve as buffers for alterations in hydrogen ion concentration. However, because most proteins are inside cells, this primarily is an intracellular buffer system.

Hemoglobin (Hb) a globular protein is an excellent intracellular buffer because of it's ability to bind with Hydrogen ions forming a weak acid and carbon dioxide (CO2) bond. After oxygen is released in the peripheral tissues, hemoglobin binds with CO2 and H+ ions. As the blood reaches the lungs these actions reverse themselves. Hemoglobin binds with oxygen, releasing the CO2 and H+ ions. The H+ ions then combine with bicarbonate (HCO3) ions to form carbonic acid (H2CO3). The H2CO3 breaks down to form water (H2O) and carbon dioxide (CO2), which are excreted via expiration through the lungs.
Increases in albumin cause arteries to sclerose and a decrease in albumin causes veins to sclerose.
Albumin is also a transporter of minerals and accounts for 70% of the bound calcium.
Magnesium also binds to albumin and since it has a lower specificity for the receptors it creates more free magnesium in the plasma.
Calcium, magnesium, and phosphates continuously enter the plasma via the kidneys, the intestinal brush borders and the ruffled border of the bone.
Albumin is also responsible for transporting copper, zinc, and nickel.
By controlling the transport of these minerals, albumin is the carrier of choice.

The following glands are associated with albumin:
1. The parotids
2. The head of the pancreas
3. The endo-reticular portion of the liver
4. Kidneys
Therefore, the function or malfunction of anyone of those glands/organs or combinations thereof can lead to imbalances in albumin levels.