Friday, August 28, 2009

HYPERTENSION AND NEUROLOGY

BY GILBERT SCHMIEDEL, D.C.

Blood pressure of 140 mm Hg systolic and 90 mm Hg diastolic is now considered by many authorities to be high blood pressure—hypertension.

Why? Is this a condition unto itself or is it compensation or a normal reaction to the demands of the body? Certainly the blood pressure (controlled ultimately by the nervous system) will elevate to accommodate exercise or increased body activity or other body needs. The blood pressure is often elevated during periods of stress or anxiety. However, increased blood pressure is often associated with pathological conditions that increase the body’s demands for increased circulation; vascular disease, kidney or respiratory conditions, obesity and hormone disturbances invariably place an abnormal demand on the heart. Many of these conditions and others are, of themselves, often responsive to Upper cervical care and therefore, concomitantly, high blood pressure may be alleviated. Some of these conditions may be the subject of future articles.

I would like to specifically address what might be called idiopathic hypertension—with no apparent etiology. Toward that end, let’s consider the neurological implications of cardiac control. The heart is one of those organs mutually innervated by two major components of the autonomic nervous system: vagal and sympathetic elements.

The autonomic elements of the vagus nerve arise from the nucleus ala cinerea in the medulla oblongata. Fibers from these neurons synapse with neurons in the cardiac plexus (at the base of the heart). The fibers from these neurons are generally inhibitory for the myocardium and constrict the coronary arteries.

The sympathetic elements arise from intermedio lateral cells of cord levels T 1-4. These fibers are conducted out of the neural canal through intervertebral foramina formed by upper thoracic vertebrae and ascend via the cervical part of the sympathetic gangliated trunk to the superior cervical ganglion (lies alongside C 2-3 vertebrae), middle cervical ganglion (at juncture of C 5-6 vertebrae), and stellate ganglion (at C7–T1 vertebrae). Fibers from these cells pass through the cardiac plexus and carry impulses that are the accelerators for the myocardium and cause dilation of the coronary arteries.

In addition to the autonomic (visceromotor) elements given above, there are vaso afferent structures that reflexively influence cardiac activity. The carotid body (glomus caroticum) located near the juncture of the common carotid artery and carotid sinus, which is a dilation at the commencement of the internal carotid artery, are respectively concerned with chemoreception (CO2 and O2) and baroreception (blood pressure reception). Other chemoreceptor cells are located in the heart wall. The glossopharyngeal, vagus and sympathetics supply these specialized receptor cells. The nucleus of the tractus solitarius (which receives impulses from the baroreceptors and chemoreceptor cells), nucleus ala cinerea and reticular formation (which carries autonomic impulses from the brain centers of the hypothalamus to intermedio lateral cells of the spinal cord) are found in the medulla oblongata, specifically that part of the medulla oblongata supplied exclusively by the lateral branch of the posterior inferior cerebellar artery (a branch of the vertebral artery).

Atlanto occipital complex is most directly related to the neurovascular elements influencing cardiac function. Misalignment of the atlas or occiput may physically affect the medulla oblongata and the neuronal elements concerned with cardiac function; including the dorsal motor nucleus of the vagus (ala cinerea), nucleus solitarius (which receives vaso afferent impulses from blood pressure receptor cells and chemo receptor cells), and the reticular formation (of which some fibers synapse with intermediolateral cells in upper thoracic cord levels).

Along with neuronal elements directly affected, the vascular elements may be compromised, including the posterior inferior cerebellar artery, the lateral branch of which is the only source of blood to vital parts of the medulla oblongata. In conclusion, high blood pressure is often the consequence of many other predisposing factors—many of which are amenable to Upper Cervical care. High blood pressure may, however, be due to interference with the complex control system of the heart. In this case, interference at the atlanto occipital level is most likely and should be especially scrutinized by the Upper Cervical doctor.

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