The Kidney
Teacher recommended
?- Created by: khodnett
- Created on: 08-02-16 11:51
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- The kidney
- homeostasis
- maintenance of a constant environment
- set point is desired norm
- receptor detects deviation
- coordinator communicates with effector to correct deviation
- detector turns off after correction
- structure
- blood received by renal artery and sent to renal vein
- ureter carries urine from kidney to bladder
- nephrons have close association with blood vessels
- afferent arteriole ->glomerulus-> capillaries
- serves proximal and distal convoluted tubules
- vasa recta along loop of henle
- ultra filtration
- filtration under pressure
- separates small soluble molecules from blood plasma in bowmans capsule
- glomerular filtration rate is the rate at which fluid passes from blood to glomerular capillaries into bowmans capsule
- basement membrane of capillary is a selective barrier
- lies between blood and nephron and filters solutes
- hydrostatic pressure forces molecules through filter, amplified by the narrowness
- Selective reabsorption
- useful products are reabsorbed such as glucose and water and salts in the proximal convoluted tubule
- remaining water is taken in by collecting duct
- loop of henle
- high conc of salts in medulla causes osmotic flow of water out of ducts concentrating urine so hypertonic to blood
- ascending limb walls impermeable to water actively transporting Na+ and Cl- out into tissue fluid between the 2 limbs to lower the water potential
- descending limb walls are permeable to water Na+ and Cl-
- fluid flows down and water passes out by osmosis while Na+ and Cl+ diffuse in losing lots of water
- loop is most concentrated at the bottom
- counter current multiplier
- maximum concentration is built up inside and outside the apex of the loop
- collecting duct fluid runs back down to medulla through the low water potential causing more water to pass out into the vasa recta
- osmoreceptors
- osmoreceptors detect changes in solute concentration in blood to regulate osmoregulation on a negative feedback principle
- ADH
- affects permeability of collecting ducts and distal convoluted tubules
- increased ADH makes walls more permeable to reabsorb more water
- decreased ADH makes walls less permeable to absorb less water
- excretory products
- fish produce ammonia, highly soluble so diffuse out across gills and dilute to non toxic levels
- birds and insects excrete uric acid, insoluble, needs high energy but little water, useful when water is scarce
- mammals excrete urea, less toxic than ammonia can be stored for short time needs energy
- desert mammals
- live on metabolic water produced from oxidising food reserves
- live underground as cooler to reduce water loss by evaporation
- longer loops of henle for greater water potential gradient
- reabsorb more water
- homeostasis
- hypothalmus
- pituitary gland
- ADH
- wall of collecting duct
- ADH effect
- concentration of urine
- volume of urine
- normal
- increased
- volume of urine
- normal
- volume of urine
- decreased
- volume of urine
- decreased
- concentration of urine
- increased
- decreased
- increased
- concentration of urine
- increased
- concentration of urine
- more permeable
- ADH effect
- decreased
- increased
- decreased
- ADH effect
- less permeable
- ADH effect
- less adh
- wall of collecting duct
- more permeable
- less permeable
- more permeable
- wall of collecting duct
- more adh
- wall of collecting duct
- ADH
- increased conc
- pituitary gland
- ADH
- less adh
- more adh
- less adh
- ADH
- pituitary gland
- decreased conc
- pituitary gland
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