The Adrenal Medulla

The cells of the adrenal medulla, called chromaffin cells, are homologous with sympathetic postganglionic neurons. The adrenal medulla may in fact be considered a modified sympathetic ganglion. The adrenal medulla secretes two hormones. One is norepinephrine, which is also the primary neurotransmitter of sympathetic post-ganglionic neurons. The other medullary hormone is epinephrine.

General activation of the sympathetic system during stress, fear, or anxiety is accompanied by increased secretion of adrenal medullary hormones, which consist primarily of epinephrine in the human. The secretory activity of the adrenal medulla is regulated by the CNS.

Some blood-borne substances of endogenous origin, such as histamine, angiotensin, and bradykinin, can directly stimulate the chromaffin cells to secrete epineph-rine and norepinephrine. A variety of exogenously administered drugs, such as cholinomimetic agents and caffeine, can directly stimulate the secretion of adrenal medullary hormones. The neuronally induced secretion of medullary hormones is antagonized by ganglionic blocking agents.

Free Yourself from Panic Attacks

Free Yourself from Panic Attacks

With all the stresses and strains of modern living, panic attacks are become a common problem for many people. Panic attacks occur when the pressure we are living under starts to creep up and overwhelm us. Often it's a result of running on the treadmill of life and forgetting to watch the signs and symptoms of the effects of excessive stress on our bodies. Thankfully panic attacks are very treatable. Often it is just a matter of learning to recognize the symptoms and learn simple but effective techniques that help you release yourself from the crippling effects a panic attack can bring.

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