To discuss:
How the PCT reabsorbs NaCl, other electrolytes, glucose, urea, and water; why the reabsorption of water and solutes depends directly or indirectly on the sodium-glucose transporter (SGLT) and sodium reabsorption.
Introduction:
In the whole of the glomerular filtrate, about 65% are reabsorbed by the proximal convoluted tubule. The proximal convoluted tubule removes wastes present in the blood and excretes them through the urine. Due to the presence of microvilli (its greater length), the proximal convoluted tubule has the benefits of increasing its surface area for absorption. Proximal convoluted tubule cells are equipped with a rich source of large mitochondria that produce ATP, which supports active transport. Of all the calories that are consumed in a day, only 6% of ATP is needed by the proximal convoluted tubule.
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Chapter 23 Solutions
ANATOMY AND PHYSIOLOGY THE UNITY OF FORM
- Why in the initial phase of fluid replacement is rapid in both isotonic and hypotonic dehydration, but it is contraindicated in hypertonic dehydrationarrow_forwardHow the renal system regulates acid-base balance of our body.arrow_forwardSodium ion reabsorption from the filtrate into peritubular blood across the cells of this component of the nephron (marked by the black asterisk) Choose from the following: (A) is regulated by the binding of the hormone aldosterone (B) is not regulated by any hormone, but is determined by sodium ion concentration and filtrate flowarrow_forward
- The presence of either protein or glucose in a urinalysis is abnormal but they end up in the urine for different reasons. For each of these molecules, briefly describe where in the urine production process (i.e., glomerular filtration, tubular reabsorption or tubular secretion) the problem occurs, and why it might happen. please helparrow_forwardRenal Physiology (human) The foot processes of podocytes surround the peritubular capillaries of both cortical and juxtamedullary nephrons. Vasa recta are long, straight blood vessels associated with juxtamedullary nephrons. Canagliflozin is a therapeutic drug that acts on the collecting duct to decrease glucose reabsorption.arrow_forwardRenal tubules cannot reabsorb HCO3–; yet HCO3–concentration in the tubular fluid falls while in the blood plasma itrises. Explain this apparent contradiction.arrow_forward
- It is specifically in the______________ of the kidneys where ADH stimulates water reabsorption to conserve water.arrow_forwardAs the text noted, two-thirds of the water and solutes that the body reclaims by reabsorption in nephrons occurs in the proximal tubule. Proximal tubule cells have large numbers of mitochondria and demand a great deal of oxygen. Explain why.arrow_forwardTrue or false When a substance gets actively reabsorbed, ATP is spent to power the movement of that substance without any carrier molecule from the nephron back into the blood stream. (explain why)arrow_forward
- Physiology of angiotensin II in humans Angiotensin I is enzymatically converted to angiotensin II by ACE. Angiotensinogen II acts on the adrenal cortex to cause the release of storage vesicles containing aldosterone. Angiotensin II is a peptide hormone that is made in advance and stored in vesicles. Physiology of angiotensin II in humans Question 24 options: Angiotensin I is enzymatically converted to angiotensin II by ACE. Angiotensinogen II acts on the adrenal cortex to cause the release of storage vesicles containing aldosterone. Angiotensin II is a peptide hormone that is made in advance and stored in vesicles.arrow_forwardosmoregulation homeostasisarrow_forwardA patient has essential hypertension, and with a healthy lifestyle and medication, he is able to maintain normal blood pressure on a single antihypertensive medication. The medication he takes is called an angiotensin converting enzyme inhibitor, or ACE inhibitor, which blocks the activation of angiotensin II. Describe at least two mechanisms by which angiotensin II targets the kidneys to increase extracellular fluid volume and, therefore, increase blood pressure.arrow_forward
- Human Biology (MindTap Course List)BiologyISBN:9781305112100Author:Cecie Starr, Beverly McMillanPublisher:Cengage LearningHuman Physiology: From Cells to Systems (MindTap ...BiologyISBN:9781285866932Author:Lauralee SherwoodPublisher:Cengage Learning
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