Renal Physiology - Urine Formation PDF

Secretion 3. ➔ filtrate) Direction of ~vmt ( e.g. plasma form urine Location @ nephron Plasma Filtrate Plasma 1. Filtration 2. Reabsorption 3. Secretion filtrate plasma filtrate ➔ ➔ ➔ PCT, LoH, OCT, CD PCT, LoH, OCT, CD Glomerulus -------------------------------~ Process Reabsorption 2. water, elect...

Secretion 3. ➔ filtrate) Direction of ~vmt ( e.g. plasma form urine Location @ nephron Plasma Filtrate Plasma 1. Filtration 2. Reabsorption 3. Secretion filtrate plasma filtrate ➔ ➔ ➔ PCT, LoH, OCT, CD PCT, LoH, OCT, CD Glomerulus -------------------------------~ Process Reabsorption 2. water, electrolytes, nutrients Filtration OF BLOOD - Glomerulus 1. Three distinct processes Afferent arterioles Basic processes of urine formation School of Medicine and Dentistry Queensland, Australia ~UI Ciriffith uNIVERSITY Peritubular capil laries To interlobular ---?"-f--.MI'--- Glomerular capillaries Efferent arterioles Plasma 3. Secretion retained as cannot filter More detail provided in upcoming Lecture on GFR cells and proteins Large molecules (e.g., cells and proteins) are retained at glom, producing glomerular filtrate free of blood pressure forces water and solutes across glomerular filtration membrane to Bowman's capsule PCT, LoH, DCT, CD Water and most solutes, freely filtered into BC filtrate ➔ PCT, LoH, DCT, CD plasma ➔ Glomerulus ~20% of plasma entering glom is filtered filtrate ➔ Efferent arterioles , 7, School of Medicine and Dentistry Queensland, Australia ~UJGriffith uNIVERSITY To interlobular Glomerular capillaries Peritubular capil laries I " ll!!ff urine production starts Filtration Filtrate 2. Reabsorption Secretion 3. Plasma Reabsorption 2. 1. Filtration Filtration 1. Three distinct processes Afferent arterioles Basic processes of urine formation ➔ filtrate) Location @ nephron Plasma 3. Secretion selective via diffusion and carrier proteins once filtrate has left Glomerular corpuscle Return to venous system via peritubular capillaries PCT, LoH, OCT, CD filtrate ➔ PCT, LoH, OCT, CD Selective movement of water and solutes from tubular fluid into peritubular capillaries plasma ➔ Reabsorption Filtrate 2. Reabsorption -------------------------------1. Filtration Plasma ➔ filtrate Glomerulus Direction of ~vmt Secretion 3. ( e.g. plasma Reabsorption 2. Process Filtration 1. Three distinct processes Afferent arterioles Basic processes of urine formation.....,._ School of Medicine and Dentistry Queensland, Australia ~UI Ciriffith uNIVERSITY Type text here where reabsorbed _ Periffll bular capi laries To interlobular ~ - +--.Ml'- Glomerular capillaries Efferent arterioles ➔ filtrate) Location @ nephron Plasma 3. Secretion remove unwanted substances in blood prepare drgus for excrete "Back-up" for filtration , i.e., a secondary route for substances to enter renal tubules from blood PCT, LoH, OCT, CD filtrate ➔ PCT, LoH, OCT, CD Selective movement of solutes from peritubular capillaries into tubular fluid plasma ➔ Secretion Filtrate 2. Reabsorption -------------------------------1. Filtration Plasma ➔ filtrate Glomerulus Direction of ~vmt Secretion 3. ( e.g. plasma Reabsorption 2. Process Filtration 1. Three distinct processes Afferent arterioles Basic processes of urine formation School of Medicine and Dentistry Queensland, Australia ~UI Ciriffith uNIVERSITY Peritubular capil laries To interlobular ~ - +--.Ml'- Glomerular capillaries Efferent arterioles facilitated diffusion and co-transport allows osmotic reabsorption of water creates a concentration gradient filtrate osmolarity will decrease - reabasorb ions Water Ions: Na+, K+, Ca 2+, Mg 2+, Cl- , HC0 3- urea, small lipid soluble molecules unwanted products Ions: W {depending on acid/base balance) Drugs, toxins (e.g. penicillin, aspirin, morphine) Urea, creatinine, ammonium Secretion reabsorbs 70% of filtrate volume produced by glomerulus bound to plasma proteins too large - cannot rely on filtration to remove waste toxins and drugs reabsorb 108L/day decrease in filtrate volume -s~,11 ,o.~0-1 ~Bilff'1111fll?OII....,...,ac,cj. - i!(N'l'le~ GkH:o,e HCO, H'. u,.,. H:() Organic nutrient molecules (almost everything!); glucose, amino acids, vitamins, lactate, Reabsorption PCT reabsorption and secretion....,.... Noel 11co,· H,() ~':iolult