What is Pathogenesis?
It belongs to the category of pathology, that is, a pathological process in which the body is affected by the internal and external environment and an imbalance occurs. The reason it is called a mechanism is that each disease has its own pathogenesis and manifests a systemic or local (system, tissue, organ, cell, etc.) pathological response.
Pathogenesis explained
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- It belongs to the category of pathology, that is, a pathological process in which the body is affected by the internal and external environment and an imbalance occurs. The reason it is called a mechanism is that each disease has its own pathogenesis and manifests a systemic or local (system, tissue, organ, cell, etc.) pathological response.
- Pathogenesis
- The pathogenesis of essential hypertension is unclear. A large number of experimental studies and clinical observations have confirmed that essential hypertension is closely related to heredity. Parents with primary hypertension have a greater chance of developing hypertension in their children, and children with or without hypertension have a significantly higher blood pressure response in the sodium load test than children without family history of hypertension, suggesting intake Too much salt is good for high blood pressure. Studies have found that somatic membrane ion transport is abnormal in patients with essential hypertension and is closely related to genetics. Whether the pathogenesis of essential hypertension remains to be confirmed. Weight is an important factor affecting children's blood pressure. Children with hypertension are more obese. Lowering weight often decreases blood pressure.
- Others, such as high excitability of sympathetic nerves, nervousness, and lack of sleep, increase blood pressure due to excessive production of adrenaline and norepinephrine, but there is no definitive evidence for direct hypertension. Arterial pressure depends on the stroke volume and total peripheral vascular resistance. Any factor that causes an increase in stroke volume, such as increased blood volume and increased myocardial contractility after water and sodium retention, or increased peripheral vascular resistance, such as peripheral arterial contraction caused by nerve or endocrine factors, can increase blood pressure. The former increased the systolic blood pressure, while the latter increased the diastolic blood pressure significantly. There are also some indirect factors that cause high blood pressure, including mental nerve activity and certain endocrine hormones. These factors change blood pressure through the above direct determinants, the most important of which is the renin-angiotensin-aldosterone system. Renal disorders, particularly renal vascular disorders, reduce renal blood perfusion pressure, or reduce effective circulating blood volume, or increase sympathetic nerve activity, which stimulates the juxtaglomerular cells to secrete a large amount of renin.
- Renin is a proteolytic enzyme that catalyzes the hydrolysis of angiotensinogen (an 2 globulin) produced by the liver to angiotensin I. Angiotensin I is not active. It flows through various vascular beds, especially During the pulmonary circulation, it is converted into active angiotensin II by the action of converting enzymes. The latter has a strong vasoconstrictive effect, leading to high blood pressure, and indirectly stimulates the adrenal cortex to secrete aldosterone, which causes sodium in the renal tubules to expand blood volume and increase blood pressure (see the section of Renal Hypertension in the Urinary System). In children with acute glomerulonephritis and most renal parenchymal diseases, hypertension is mostly related to increased blood and sodium retention blood volume. Blood renin measurement is mostly in the normal range. When advanced glomerulosclerosis can also occur, high vasoconstriction and high reninism. blood pressure.
- Adrenal disorders cause hypertension through its secreted hormones, such as: primary hyperaldosteronism, which has the mechanism of producing hypertension as described above; cortisol, a large number of glucocorticoids cause water and sodium retention and stimulate angiotensin Caused by high blood pressure; pheochromocytoma, the tumor cells secrete too much epinephrine and norepinephrine. Epinephrine increases systolic blood pressure by increasing myocardial contractility and heart rate to increase cardiac output. In addition to the above-mentioned effects, norepinephrine causes strong contraction of peripheral blood vessels and increases systolic and diastolic blood pressure. Aortic constriction is caused by mechanical obstruction in upper extremity hypertension, but in a few advanced cases, blood pressure does not decrease after surgical relief of constriction, which may be related to increased renin or peripheral vascular resistance. Takayasu arteritis causes high renal renin hypertension due to renal artery stenosis or severe anterior descending aorta stenosis which affects renal blood perfusion.
- Central nervous system disorders such as polyradiculitis, polio, intracranial hemorrhage, tumors, and encephalitis can occasionally cause severe hypertension. The pathogenesis is thought to be due to the disease affecting the stability of the autonomic nervous system, resulting in sympathetic nervous excitement. Increased intracranial pressure may be a predisposing factor.