PRODUCTION OF URINE Mladen Tomas Mentor: A. Žmegač Horvat

Urine production: 1. filtration 2. reabsorption 3. secretion

FILTRATION renal artery → afferent arterioles blood - passes through the membranes of Bowmann’s capsule: 1. osmosis 2. diffusion glomerular filtrate consists of: water excess salts → Na + and K + glucose urea

GFR = glomerular filtration GFR = glomerular filtration rate rate ↓ 125 ml/minute 125 ml/minute amount of water removed from the blood each day amount of water removed from the blood each day ↓ 180 L/day!! 180 L/day!!

REABSORPTION movement of substances out of renal tubules back into blood capillaries located around the tubules movement of substances out of renal tubules back into blood capillaries located around the tubules proximal convoluted tubules → loop of Henle → distal convoluted tubules → collecting tubules proximal convoluted tubules → loop of Henle → distal convoluted tubules → collecting tubules

3 main substances reabsorbed: 1. WATER = passive reabs l/day returns = 99% 2. GLC = actively transported - limitations – DM 3. Na = actively transported - ↓salt intake = ↑ reabsorption = excretion ↓

substances move into distal and collecting tubules from blood in the capillaries around these tubules substances move into distal and collecting tubules from blood in the capillaries around these tubules mechanisms: 1. active transport mechanisms: 1. active transport 2. diffusion 2. diffusion substances: substances: –hydrogen ions (H+) –potassium ions (K+) –ammonia (NH3) –certain drugs S ECRETION

CONCENTRATION OF URINE signal signal ↓ hypotalamus hypotalamus ↓ ↓ ↓ ↓ pituitary gland pituitary gland ↓ ADH ADH ↓ water reab. water reab. ↓ highly concentrated urine

URINE PATHOLOGY HEMATURIA HEMATURIA PYURIA PYURIA GLYCOSURIA GLYCOSURIA PROTEINURIA PROTEINURIA

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