Tuesday, January 31, 2012

Pathophysiology of Hypertension

Pathophysiology of Hypertension Pathway
Pathophysiology of Hypertension

Mechanisms that control the constriction and relaxation of blood vessels located in the vasomotor center, the medulla in the brain. Of the vasomotor center, the sympathetic nerve pathway begins, which continues down the spinal cord and the spinal cord out of the column to the sympathetic ganglia in the thorax and abdomen. Central vasomotor stimulation delivered in the form of impulse which moves downward through the sympathetic nervous system to the sympathetic ganglia. At this point, preganglionic neurons, releasing acetylcholine, which will stimulate post-ganglion nerve fibers to blood vessels, where the release of norepinephrine resulting in constriction of blood vessels. Various factors such as anxiety and fear can affect the response to stimuli vasoconstriction of blood vessels.

Individuals with hypertension is very sensitive to norepinephrine, although it is not clear why this could occur.

At the same time in which the sympathetic nervous system stimulates the blood vessels in response to emotional stimuli, the adrenal glands are also stimulated, resulting in additional vasoconstriction activity. Adrenal medulla secretes epinephrine, which causes vasoconstriction. Adrenal cortex to secrete cortisol and other steroids, which can strengthen the vasoconstrictor response of blood vessels. Vasoconstriction resulting in decreased flow to the kidneys, causing the release of renin. Renin stimulates the formation of angiotensin I is then converted into angiotensin II, a powerful vasoconstrictor, which in turn stimulates the secretion of aldosterone by the adrenal cortex. This hormone causes retention of sodium and water by kidney tubules, causing increased intra-vascular volume. All these factors tend to trigger a state of hypertension.

For consideration of Gerontology. Structural and functional changes in the peripheral vascular system are responsible for changes in blood pressure that occurs in the elderly. These changes include atherosclerosis, loss of elasticity of the connective tissue and a decrease in vascular smooth muscle relaxation, which in turn lowers the ability of distention and tensile strength of blood vessels. Consequently, the aorta and large arteries decreases its ability to accommodate the volume of blood pumped by the heart, resulting in decreased cardiac cheating and increased peripheral resistance. Pathophysiology of Hypertension (Brunner & Suddarth, 2002).

Hypertension Nursing Care Plan : Assessment, Diagnosis and Interventions
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