Parasympathetic paragangliomas are mainly located in the head and neck and do not usually secrete adrenaline/noradrenaline but may grow and spread locally. Paragangliomas can also be referred as ‘extra-adrenal pheochromocytomas’ which can lead to confusion. Paragangliomas (PG) are rare neuroendocrine tumours that arise from ‘paraganglia’ outside the adrenal glands and can be parasympathetic or sympathetic. Pheochromocytomas affect men and women equally with a peak age at diagnosis between 40-50 years, but 20% of all pheochromocytomas are found in children and adolescents. 40% do not secrete these hormones and are asymptomatic, remaining undiagnosed for many years. 60% of these tumours produce excessive amounts of catecholamines (adrenaline and noradrenaline) which produce symptoms of high blood pressure, sweating, headaches. They arise from the adrenal (adrenal medulla) glands that lie atop the kidneys. Pheochromocytomas (PH) are rare neuroendocrine tumors with an annual incidence of 1–4 cases per millionpopulation. The actions of the parasympathetic system are opposite or antagonize that of the sympathetic system and cause increased secretions, slowing of the heart rate, relaxation of smooth muscles and constriction of pupils etc. The parasympathetic nervous system has nerve fibres running from the brain and the lower part of the spinal cord and sends nerves out to blood vessels, glands and the majority of internal organs (heart,lungs, abdominal organs etc). They cause the reflex of ‘fight or flight’ in response to a stress (dry mouth, increased heart rate, constriction of blood vessels and increased blood pressure, increased breathing rate, dilated pupils etc).
It sends our nerves to blood vessels, the heart, lungs, abdominal organs, skin and controls functions by reflex action. The sympathetic nervous system has nerve fibres running from the brain via a chain of ganglia (a structure containing a collection of nerve cell bodies) in the thoracic and lumbar regions. The adrenal glands are essential for life, but if they are surgically removed the hormones can be replaced with daily medications.
The adrenals are made up of two parts – an outer cortex which produces androgens (sex hormones), cortisol and aldosterone (causes kidneys to retain salt) and an inner medulla, which is made up of chromaffin cells which produce and secrete catecholamines- adrenaline and noradrenaline which are humans stress response hormones. The adrenal glands in humans lie atop the kidneys and receive hormonal and nervous system messages and responds by secreting hormones.
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