Gland: Adrenal Medulla

THE ADRENAL MEDULLA

The adrenal glands, or “suprarenal glands” as they are sometimes referred to, sit on top of the posteromedial surface of the kidneys. The adrenal glands weigh approximately 4 grams, are 2cms wide, 5cms long, and 1 cm thick. The adrenal glands are composed of the adrenal cortex and the adrenal medulla. Each has specific hormones and functions, which will now be discussed.

Under the capsule, you have the cortex, which is divided into 3 zones:

1. ZONA GLOMERULOSA-makes up 15% of the cortex and this depends on sodium intake
2. ZONA FASCICULATE-makes up 75% of the cortex is large and lipid-laden
3. The innermost zone, which is sharply demarcated from the other two zones, is called the ZONA RETICULARIS

Blood supply for the cortex comes from 12 arteries off the aorta, phrenic, renal and intercostals. They form a subcapsular plexus, which radiate and penetrate the cortex zones. At the reticular zone, a sinusoidal plexus empties into the inferior vena cava on the right and the renal vein on the left.
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THE ADRENAL MEDULLA

The adrenal medulla is part of the sympathetic portion of the autonomic nervous system. The principal secretion of the sympathetic nervous system is norepinephrine (which builds up glycogen) from the peripheral nerves and the CNS and epinephrine (which breaks down glycogen), from the adrenal medulla. Peripheral sympathetic nerves also secrete catecholamines and dopamine. Preganglionic neurons synapse in the sympathetic chain, preaortic, celiac and superior/inferior mesenteric ganglion, and can ascend via the sympathetic chain to the pons, medulla and then to the hypothalamus.
Lower thoracic and upper lumbar preganglionic innervate the adrenal medulla and secrete acetylcholine in the ganglion synapses, whereas postganglionic innervations can be cholinergic, noradrenergic or both. Androgenic nerves can also secrete substance P, neuropeptide Y and somatostatin. The adrenal medulla is derived from the nervous system, specifically from chromatin tissue, which is an extension of the sympathetic nervous system. It is also found everywhere along the sympathetic chain. You can live without the adrenal medulla, but not without the cortex. The arterial blood supply is from the aorta to the inferior phrenic, and renal artery and drains via the renal vein on the left, and the vena cava on the right. Glucocorticoids influence the production of epinephrine (which is stored in the adrenal medulla) by the enzyme phenylethanolamine N-Methyl transferase. Norepinephrine is synthesized and stored in the nerve endings.
Catecholamines are formed by the hydroxylation and decarboxylation of tyrosine via tyrosine hydroxylase. The adrenal medulla has an affinity for chromium, which is a blood sugar regulator. These two hormones also help regulate the sympathetic and parasympathetic nervous systems controlling fat and fatty acid metabolism in the following way.
It is the acid depositing mineral chloride, from the stomach (HCL) that attaches to the food substance, which stores the food (fats and fatty acids) in the cell membrane. Food then is stored in the membrane and needs chloride to shift out of the way, allowing the foods to enter the cell and the toxins to leave. In order for the chloride shift to occur, epinephrine must be present. Epinephrine is then necessary for fatty acid combustion, is sympathetically controlled and is a daylight phenomenon (catabolism).
Norepinephrine is the nighttime phenomenon (anabolism) for fat/hormone growth/storage and is controlled via the parasympathetic nervous system.

The following blood tests are used to determine adrenal dysfunction:

1. CHLORIDE-as mentioned above, chloride is the regulatory mechanism for food storage in cell membranes to increase the potency for body utilization. It is the epinephrine and nor-epinephrine effect on chloride that regulates the shift.

2. SODIUM-as mentioned above, is controlled by the adrenal cortex and is extremely alkaline. Therefore, it causes 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. This is the substance necessary for polarizing substances into storage, according to the needs of the membrane.

3. POTASSIUM-which has prime importance in controlling membrane permeability by displacing the chloride ion as well as epinephrine for the next stage, which permits sodium aggregated substances to cross the cell membrane. It is the only substance necessary to allow oxygen into unoxygenated tissue.

4. ALKALINE PHOSPHATASE-is an enzyme that affects phosphorus. Therefore, we are looking at the phosphoric acid component of the alkaline phosphatase. There are high concentrations found in the intestinal mucosa, liver, and bone. Alkaline phosphatase aids in maintaining the alkaline pH of the blood and works best at a pH of ten (10).
Alkaline phosphatase is a member of a family of metalloid protein enzymes that split off phosphate groups from organic phosphate esters. The enzyme activity usually occurs in the brush borders of the proximal convoluted tubules of the kidneys, the intestinal mucosa, the hepatic sinusoidal membranes and the vascular endothelial cells of the osteoblasts. Since the adrenals are responsible for mineral/alkaline and sugar/acid pH balance, you can see how pH levels may affect, and are affected by, alkaline phosphatase, since it is a very powerful alkaline enzyme.

Alkaline Phosphatase

ALKALINE PHOSPHATASE

Bone osteoblasts, liver cells, and the placenta all produce high levels of alkaline phosphatase, with some activity in the kidneys and intestines.
Alkaline phosphatase is called alkaline because it aids in maintaining and works best in an alkaline pH of 9-10.
From a pathological perspective, alkaline phosphatase levels rise in liver disease due to impaired excretion of this enzyme from obstruction in the biliary tract, and bone disease via increased osteoclastic activity due to bone breakdown as in cancer.

From a physiological perspective alkaline phosphatase is responsible for the balancing of water, and mineral metabolism controlled by the glands below. This exchange of water and mineral metabolism occurs at the cell membranes of ligaments, tendons and disc structures.
The balance is created by, setting the minerals involved with electrolyte balance into motion. These minerals, along with proper neurological control, cause the shifting of food thru the membranes.
The glands responsible for this balance are as follows:
• The adrenal cortex via mineralocorticoids causes excretion of sodium and potassium by the kidney.
• The adrenal medulla via epinephrine and norepinephrine increase metabolism, and cellular exchange via the chloride shift at the level of the membrane.
• The posterior pituitary via antidiuretic hormone and its effect on potassium (oxidizer) and the water content within the cell.
• Prostate/uterus via selenium acts as an oxidative mineral to insure proper membrane exchange in conjunction with the above.

Alkaline phosphatase is a member of a family of zinc metalloprotein enzymes whose purpose is to split off a terminal phosphate group from an organic phosphate ester.
Enzyme activity is localized in the brush border of the proximal convoluted tubules of the kidney, intestinal mucosal epithelial cells, hepatic sinusoidal membranes, vascular endothelial cells and osteoblasts of bone as mentioned above.

It is the introduction of an alkaline media for bone growth. When there is an increased alkaline phosphatase you have too much acidity. In “bone pathology” there is usually a hyper-acidic state, since the foundation of a cell, is nucleic acid.
The nucleic acid is composed of phosphoric acid. Phosphoric acid is a component of alkaline phosphatase, therefore, the adrenals regulate the acid/alkaline balance for energy, and growth.
Alkaline phosphatase controls the alkaline substance, which controls energy, and the acid substance, which controls growth.
Over the years, the laboratory low range has been steadily decreasing from 60, down to 40 now down to the mid 20's. Since this test does measure metabolic output of the adrenals, going to low is not the answer. I recommend that the low range is 70.