Renal | Proximal Convoluted Tubule

Official Ninja Nerd Website: https://ninjanerd.org Ninja Nerds! In this renal physiology lecture, Professor Zach Murphy takes you on a detailed tour of the Proximal Convoluted Tubule (PCT)—the first major segment of the nephron responsible for the bulk of solute and water reabsorption. This lecture builds on your understanding of glomerular filtration and lays the groundwork for mastering how the kidney fine-tunes the composition of filtrate in early tubular processing. We begin by reviewing the histological features of the PCT, including its brush border, mitochondria-rich epithelial cells, and tight junctions, all designed for efficient reabsorption. You’ll learn how approximately 65–70% of filtered sodium, water, chloride, potassium, and bicarbonate are reabsorbed here, along with essential nutrients like glucose and amino acids. The lecture dives deep into the key transport mechanisms: Na⁺/K⁺ ATPase, sodium-glucose cotransporters (SGLT2), bicarbonate reabsorption via carbonic anhydrase, and organic acid/base secretion, including the handling of drugs and toxins. We also discuss isosmotic reabsorption, the concept that water follows solutes to maintain osmotic balance in this segment. Clinical correlations include disorders like Fanconi syndrome, glycosuria in diabetes mellitus, and the mechanism of acetazolamide, a carbonic anhydrase inhibitor. These tie physiology directly to pathology and pharmacology, reinforcing the importance of the PCT in maintaining fluid, electrolyte, and acid-base balance. Enjoy the lecture and support us below! 🌐 Official Links Website: https://www.ninjanerd.org Podcast: https://podcast.ninjanerd.org Store: https://merch.ninjanerd.org 📱 Social Media   / ninjanerdlectures     / ninjanerdlectures     / ninjanerdlectures   https://x.com/ninjanerdsci/   / ninja-nerd   💬 Join Our Community Discord:   / discord   #ninjanerd #ProximalConvolutedTubule #Renal