Nephron
Nephron * Basic structural and functional unit of kidney * Regulate concentration of water and soluble substances * FUNCTION: Eliminates waste, regulates blood pressure, regulates blood PH, controls levels of electrolytes and metabolites
A. Urine Formation
FILTRATION - plasma filtered from glomerulus into Bowman’s capsule * Blood pressure forces filtrate through filtration slits between podocytes of Bowman’s capsules. * Approx 20% of blood plasma is non-selective filtered into capsule * What does this? * Renal Corpuscle * Glomerulus – capillaries! Blood supply is from the afferent arteriole. Water and solutes are filtered out from the blood into Bowman’s capsule. * Bowman’s capsule – Glomerular capsule, surrounds glomerulus. Inner layer (Visceral) formed by podocytes, outer layer (Parietal) simple squamous epithelium. Fluids from blood in glomerulus filtered through podocytes. glomerular filtrate further processed along nephron to urine * In the filtrate: Water, nitrogenous waste (urea, uric acid), ions, nutrients, small molecules * NOT: Plasma proteins, large molecucles (kung meron sa urine, there is something wrong with your glomerulus!)
REABSORPTION – Moved from tubule lumen back into blood system * Bowman’s capsule, proximal tubule, descending loop of henle, ascending loop of henle, distal tubule, collecting duct * Passive: No energy required, down their concentration gradient into blood * Water, Urea and many ions including bicarbonate and salt * Active: Needs energy! Against concentration gradient into blood. * Glucose, amino acids, Na+ * Na+ is actively reabsorbed in proximal tubule, ascending loop, and distal tubule!! * Drives reabsorption of other substances * Proximal tubule * Active reabsorption: NaCl, HCO3, Glucose, Amino Acids * Early proximal tubule: Reabsorbs Na and H20 with HCO3, glucose, amino acids, phosphate, and lactate.
A. Urine Formation
FILTRATION - plasma filtered from glomerulus into Bowman’s capsule * Blood pressure forces filtrate through filtration slits between podocytes of Bowman’s capsules. * Approx 20% of blood plasma is non-selective filtered into capsule * What does this? * Renal Corpuscle * Glomerulus – capillaries! Blood supply is from the afferent arteriole. Water and solutes are filtered out from the blood into Bowman’s capsule. * Bowman’s capsule – Glomerular capsule, surrounds glomerulus. Inner layer (Visceral) formed by podocytes, outer layer (Parietal) simple squamous epithelium. Fluids from blood in glomerulus filtered through podocytes. glomerular filtrate further processed along nephron to urine * In the filtrate: Water, nitrogenous waste (urea, uric acid), ions, nutrients, small molecules * NOT: Plasma proteins, large molecucles (kung meron sa urine, there is something wrong with your glomerulus!)
REABSORPTION – Moved from tubule lumen back into blood system * Bowman’s capsule, proximal tubule, descending loop of henle, ascending loop of henle, distal tubule, collecting duct * Passive: No energy required, down their concentration gradient into blood * Water, Urea and many ions including bicarbonate and salt * Active: Needs energy! Against concentration gradient into blood. * Glucose, amino acids, Na+ * Na+ is actively reabsorbed in proximal tubule, ascending loop, and distal tubule!! * Drives reabsorption of other substances * Proximal tubule * Active reabsorption: NaCl, HCO3, Glucose, Amino Acids * Early proximal tubule: Reabsorbs Na and H20 with HCO3, glucose, amino acids, phosphate, and lactate.