To discuss:
How tubular reabsorption is limited by the transport maximum (Tm); how this relates to glycosuria in diabetes mellitus.
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 & PHYSIOLOGY THE UNITY OF FORM A
- Diabetic nephropathy typically does NOT present as hematuria. Come up with a hypothesis why not (hint: this should involve the filtration membrane).arrow_forwardRenin is an important proteolytic enzyme produced by the kidney, involved in the control of salt/water balance in the body. Explain the source of renin, how it is secreted and how it acts to ultimately influence plasma volume. A separate hormonal system exists for directly controlling kidney water reabsorption. Explain how this hormone is released and how it exerts its renal effects.arrow_forwardExplain how his headinjury resulted in these effects on urinaryfunction and thirst. Why would a sphenoidfracture be more likely than an occipitalbone fracture to cause diabetes insipidus?What hormone imbalance resulted from thisaccident? Would you expect to find elevatedglucose in the urine of this diabetic patient?Why or why not?arrow_forward
- How the kidneys metabolize carbohydrates, lipids, ans proteins and the effects that these three micromolecules have on renal functions. Examine how the gross and histological structure of the kidney facilitates urine production during 1) glomerular filtration, 2) tubular reabsorption, and 3) tubular secretion.arrow_forwardThose with chronic renal failure often have issues with anemia because the kidney cannot secrete sufficient levels of renin.arrow_forwardKIDNEY FUNCTION IN REGULATION OF RENAL BLOOD FLOW, FLUIDS VOLUME AND REGULATION OF ENDOCRINEarrow_forward
- Some tumors of the adrenal cortex secrete excess aldosterone and may cause paralysis. Explain this effect andidentify the electrolyte and fluid imbalances you wouldexpect to observe in such a casearrow_forwardTrue or false activation of the angiotensin in Cascade increases blood volume by increasing the reabsorption of NA+ CL- in the kidneysarrow_forwardIndicate whether the following sentence is True or False Aldosterone is required to restore water from loop of Henle, and reabsorption of Na+ from this segment is increased by ADH, allowing equilibration of water with the hyperosmotic interstitiumarrow_forward
- The syndrome of inappropriate secretion of antidiuretic hormone (SIADH) is a disorder of impaired water excretion caused by the inability to suppress the secretion of antidiuretic hormone. Why does the patient experience serum hypernatremia (high sodium), polyuria and polydipsia (excessive thirst)? Explain.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_forwardWhat happen to the cortical and medullary duct value in the absence of vasopressinarrow_forward
- Human Physiology: From Cells to Systems (MindTap ...BiologyISBN:9781285866932Author:Lauralee SherwoodPublisher:Cengage Learning
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