Discuss three hormones that regulate sodium ion concentration in the extracellular fluid (ECF)
What will be an ideal response?
The two main hormones that increase sodium ion retention are angiotensin-II and aldosterone. A low extracellular sodium ion concentration is one of the major stimuli that trigger the renin-angiotensin-aldosterone system (RAAS). Angiotensin-II increases the reabsorption of sodium ions from the proximal tubule and stimulates aldosterone secretion, which causes sodium ion reabsorption from the distal tubule. These actions indirectly increase water reabsorption, as water follows sodium ions by osmosis. When secretion of both hormones decreases, the number of sodium ions (as well as the amount of water) reabsorbed decreases. Another hormone that influences sodium ion balance is atrial natriuretic peptide (ANP), which decreases sodium ion (and water) reabsorption. Together, these three hormones maintain a relatively stable plasma sodium ion concentration despite significant changes in intake.
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The parathyroid glands produce a hormone that
A) stimulates the formation of white blood cells. B) increases the level of calcium ions in the blood. C) increases the level of sodium ions in the blood. D) increases the level of potassium ions in the blood. E) increases the level of glucose in the blood.
Which branch(es) of the right coronary artery extends toward the apex along the anterior surface of the right ventricle and continues across the posterior surface of the heart?
A) circumflex branch B) posterior interventricular branch C) atrial branches D) right marginal branch E) anterior interventricular branch
Which of the following is/are functions of the human nervous system?
A. receiving, storing, and processing information on the internal and external environments B. bringing about changes in physiology and/or behavior to ensure optimal functions of homeostatic mechanisms C. secretion of hormones D. coordination of movement E. All of the choices are correct.
The predominant lipid in the cell membrane is a
A. triglyceride. B. glycolipid. C. phospholipid. D. prostaglandin. E. cholesterol.