activity originated by activation of the baroreflex Renin converts

Activity originated by activation of the baroreflex

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activity originated by activation of the baroreflex. Renin converts angiotensinogen into angiotensin I. Thereafter, angiotensin converting enzyme (located on pulmonary capillary endothelial cells) converts angiotensin I into angiotensin II, which stimulates the release of aldosterone. Aldosterone affects principal cells of the late distal tubule and collecting ducts by increasing the number and open sodium channels in the apical membrane and increasing the number of Na + /K + pumps in the basolateral membrane. This results in an increased reabsorption of sodium. In addition, angiotensin II affects blood pressure by 1) its vasoconstrictive properties, 2) altering thirst at the hypothalamus, and 3) stimulating ADH release. ANP is counterregulatory to aldosterone and is released in response to stretch of the atria (increased blood pressure). Once released, ANP decreases glomerular filtration rate by decreasing glomerular capillary pressure through concomitant dilation of the afferent arteriole and constriction of the efferent arteriole. In addition, ANP decreases the number of open sodium channels in the apical membrane and decreases the release of ADH. The primary stimulation for the release of ADH is an increase in osmolarity within the hypothalamus. Secondarily, the release of ADH is modified by angiotensin II (increased) and ANP (decreased). ADH increases blood pressure by altering the reabsorption of water. This occurs through the insertion of aquaporin - 2 into the membrane of cells within the collecting ducts. ADH also increases the number of sodium channels in the apical membrane of principal cells. Finally, erythropoietin is stimulated by a decrease in blood flow to the kidneys, which induces a hypoxia within the kidneys. Since erythrocytes make up about 45% of the volume of blood, any changes in their production will affect blood volume. 25
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151) The balance of acid and base within the blood plays an important role in a number of bodily functions. How do changes in the pH of the blood affect bodily functions? Answer: Typically, blood remains within the pH range of 7.35 to 7.45. As the concentration of hydrogen ions moves outside of this normal range, they can affect amino acids, resulting in conformational changes of proteins that can affect their functions. At the same time, the activity of the nervous system is altered by pH. Acidosis can cause a decrease in the excitability of neurons; a severe acidosis can lead to confusion, coma, and even death. Alkalosis causes an increase in the excitability of neurons. This can lead to the generation of action potentials in sensory or motor neurons. A disturbance in acid - base balance can also lead to a potassium imbalance. Acidosis results in potassium retention, whereas alkalosis results in potassium depletion. These alterations in potassium are caused by electrochemical interactions and competition for carrier proteins. Acidosis can also lead to cardiac arrhythmias and vasodilation of blood vessels due to an impaired sympathetic activity.
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