Formation of Urine Formation of Urine

Steps in forming urine Three steps to forming urine: Filtration Reabsorption Secretion

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1) Filtration Label Glomerulus and Bowman’s Capsule Function: -Moves waste from glomerulus to the Bowman’s capsule -Done using the high blood pressure that occurs in the kidney Moves: - Water, Urea, Uric acid, glucose, Hydrogen ions, amino acids, salt,

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2) Reabsorption Label Proximal Convoluted Tubule Function: - Moving molecules back to the blood from the nephron. - The molecules returned to blood are the ones needed by the body Moves: Active (Using ATP): Glucose and Amino acids, Na ions, Osmosis: Moves water Passive (Diffusion): Some Urea

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3) Reabsorption of NaCl Label Loop of Henle Function: Some NaCl moves back to the blood from the Loope of Henle Moves: - NaCl

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4) Tubular Excretion Label Distal Convoluted Tubule Function: -Molecules move from the blood to the nephron Moves: - Uric Acid, Ammonia, H ions

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5) Excretion Label Collecting Duct Function: -Urine is formed and travels to the ureter Moves: - Water, Salt, Urea, Uric Acid,

Water Balance Need to Balance Water: Increased water intake = increases urine production Increased exercise or decreased water intake = decreased urine formation Making the adjustments: Nervous System Endocrine System

Regulating (ADH) ADH = antidiuretic hormone: A hormone that helps regulate the osmotic pressure of the body fluids How: Can increase the amount of water reabsorbed into the kidney (produces more concentrated urine) which hydrates the body

ADH ADH Production - Produced in the brain by nerve cells Moves from the hypothalamus to the pituitary gland where it is stored until it is needed. ADH Release control: 1) Osmoreceptors in the hypothalamus trigger the release of ADH if... There is a decrease in water intake There is an increase in water loss

Physiological response to Osmotic Pressure Increase 2) The increase of ADH = more concentrated blood 3) The highly concentrated blood pulls water out of the hypothalamus causing it to shrink 4) The shrinking hypothalamus sends a nerve impulse to the brain causing the release of ADH 5) ADH travels in the blood stream to the kidney causing it to reabsorb water

Behavioural response to Osmotic Pressure increase Behavioural response: Shrinking hypothalamus leads to the sensation of being thirsty = Drinking

ADH and the Nephron Normal Osmotic pressure: 85% of the water absorbed into the nephron will be reabsorbed into the blood at the proximal tubule. Loop of Henle and Water Reabsorption: Down (descending) part of loop = Permeable to water and ions Up (Ascending) part of loop = Only permeable to ions (more )

ADH and the Kidney cont... Distal Convoluted Tubule and Collecting duct: Impermeable to water (all water stays in kidney and goes out into urine). Distal Convoluted Tubule and Collecting Duct + ADH: Both permeable to water so water can be reabsorbed into the blood stream

Assignment Pg 808 7-11 Urinary System-the nephron elcheguevarra