Stretch receptors activated sufficiently‐Detrusor muscle contraction of occurs‐Internal sphincter may open‐(upon strong contraction)‐Stretch receptor activity inhibits neuronsprojecting to both sphincters‐Couples with contracting detrusormuscle (bladder empties)
Micturition29‐A spinal reflex regulates micturition‐Can be overridden by trainedindividual‐Purely reflexive in infants
Kidney Stones (renal lithiasis)30‐Common affliction in western culture‐males 4X more often‐Minerals become concentrated in the kidneys‐precipitate out of solution, form crystals‐crystals attach to renal epithelium‐enlarge, usually < 1 cm‐dislodge and enter ureter‐Calcium oxalatemost common substance‐uric acid, cysteine, struvite also involvedFluid intake and diet can befactors‐high protein, low fiber may cause them‐high vitamin C and D‐Magnesium and citrate, increased fluid intakemay help prevent kidney stone formation
Ch 19 – Fluid and Electrolyte Balance31‐Materials that are exchanged affect plasma content
Water Balance32Body WaterIntake + metabolically produced = output + any used in chemical rxns.Water Intake/Production‐digestive tract‐cellular metabolismWater Exiting the Body‐insensible loss‐(respiration, skin)‐sweating‐feces‐urine‐Only the kidneys regulate the rate of water loss for the purpose ofmaintaining water balance.
Water Reabsorption – Proximal Tubule33Na+is the primary solute in the ECF‐Most of the filtered Na+is reabsorbed in theproximal tubuleNa+‐produces the osmotic gradientdriving water reabsorption‐always actively transportedacross the basolateral membraneinto the peritubular fluid‐diffuses into plasma of capillariesOther solutes‐also contribute to the gradient‐water flows with the solutes
Water Balance‐Medullary Osmotic Gradient34Loop of Henle‐Descending and Ascending limbs differing propertiesWater reabsorption from thecollecting ductviaaquaporins‐vasopressin (ADH) influences quantity of aquaporins in membranes
Medullary Osmotic Gradient‐The Countercurrent Multiplier35
Medullary Osmotic Gradient‐The Countercurrent Multiplier36
Medullary Osmotic Gradient‐The Countercurrent Multiplier37
Medullary Osmotic Gradient‐The Countercurrent Multiplier38
Medullary Osmotic Gradient‐The Countercurrent Multiplier39
Water Reabsorption – ADH and Aquaporins40‐Vasopressin (Antidiuretic Hormone, ADH) controls quantity ofaquaporins indistal tubuleandcollecting ducts(apical membrane)
Medullary Osmotic Gradient – Urea’s Role41‐Additional solute is required tomaintain the established gradient fromthe countercurrent multiplier‐Urea (waste product) from the liveracts as a soluteUrea‐40% of solutes in glomerular filtrate‐Membrane transporters (UT‐A, B, C)‐Highly Soluble‐Utilized to prevent massive water loss‐Transport out of collecting duct for use‐40% of osmolarity of medullary osmoticgradient
Medullary Osmotic Gradient – The Vasa Recta42Vasa recta capillaries‐supply blood flow (nutrients)to the renal medulla‐
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- Fall '12
- Physiology, Glomerulus, loop of Henle, Bowman's capsule, medullary osmotic gradient