MED 2030 Lecture Notes - Lecture 3: Proximal Tubule, Carbonic Anhydrase, Peritubular Capillaries
12 Dec 2017
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Acid-base balance: the kidney reabsorbs hco3- (in the. Proximal convoluted tubule) (image credit: dr. mclaughlin may 4th 2012 lecture) Reabsorbs 1 na+ while secreting 1 h+ into tubule. This is how hco3- reabsorption is linked to na+ reabsorption. Hco3- wasting (i. e. in vomiting) also means na+ will be wasted, urine [na+] Stimulates nhe3 directly, to absorb more na+ and water proximally. Nhe3 activity (pump more h+ out of cell: the secreted h+ binds to the hco3- that was filtered into the tubule; an extracellular carbonic. Anhydrase (ca) converts them into water and co2. The h+ is re-secreted back into the lumen by nhe3 to facilitate na+ reabsorption. Type 2 renal tubular acidosis: metabolic acidosis due to the failure to reabsorb hco3- in the pct, can be due to dysfunctional nhe3-antiporters, ca, or na/hco3-symporters. Yan yu, 2012 (www. yanyu. ca) glucose, amino acids, uric acid, and phosphate, as well as bicarb) 2- is filtered into the tubule: hpo4.
