renal physiology

  • Created by: Zina_
  • Created on: 01-05-18 17:28

renal anatomy

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what are the kidneys functions?

  • regulate composition of most of the ECF and plasma ions
  • maintain water balance 
  • maintain acid-base balance,pH
  • excretion of metabolism products/blood born chemicals/foreign compounds 
  • production of hormones = erythropoietin(red blood cells) and renin(modulates blood pressure)
  • converts vitamin D into its active form 
  • regulates calcium and phosphate ions concentration 
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what are the 4 main processes performed by the kid

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what are the main blood vessels

  • inferior vena cava 
  • abdominal aorta 
  • ureter tube collecting urine from the kidneys to the bladder 
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what are nephrons?

  • functional unit of the kidney 
  •  made of bowmans capsule,proximal tubule, loop of henle, distal tubule, collecting duct 
  • vascular compoonent - afferent arteriole,glomerulus,efferent arteriole,peritobular capillaries 
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what is chronic kidney disease?

progressive/irreversible loss of kidney structure and function, symptoms only appear after disease becomes well advanced,

symptoms include; dehydration, lack of erythropoietin secretion(RBC),anemia,weakened bones due to lack of vitamin D conversion 

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what is the difference between the two types of di


  • blood cleaning outside the body 
  • blood reinjected 
  • fresh solution constantly being put in 


  • peritoneral cavity space between abdomen wall and abdominal organs 
  • artificial kidney used but inside the body 
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what happens during glomerular filtration?

  • afferent arteriole carries plasma to the capillaries of the glomerulus( cluster of nerve endings and vessels at the end of the tubule)
  • increase in pressure forces plasma from the capillaries to the bowmans capsule
  • filtered plasma enters the proximal tubule 
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what happens during tubular re absorption?

  • liquid substance goes through luminal membrane of the kidney tubular cells 
  • liq crosses cytosol of tubular cells 
  • crosses basolateral membrane of tubular cells
  • crosses interstitial fluid through diffusion 
  • goes through peritubular capillaries 
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what are the two types of tubular reabsorption?


  • follows osmotic gradient, no ATP required 
  • Cl, urea 


  • moves against conc gradient, uses ATP
  • Na,glucose 
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sodium re absorption

  • doesnt occur in descendling limb of loope of henle 
  • distial tubule/collecting duct reabsorption depends on hormonal control 
  • active sodium reabsorption depends on Na/K ATPase located in the basolateral membrane of tubular cells 
  • low intracellular Na and high Na in lateral space maintained 
  • too much sodium= no reabsorption= excreted in urine / too little sodium=most/all Na is reabsorbed 
  • lack of this system would lead to blood poisining due to accumulation of waste products 
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nephrogenic insipidus

  • diabetic disorder 
  • kidneys collecting duct dont show increase in water permeability in response to vassopressin causine dilute urine to be excreted 
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urine excretion

  • average urine made 1.25ml/min
  • no water intake=dehydration=dec ECF volume= dec blood pressure 
  • too much water intake= excess water = inc ECF volume = inc blood pressure 
  • too much salt= hypertension 
  • vertical osmotic gradient in the renal medulla enables kidneys to produce urine at a conc of 100-1200 mOsm/litre 
  • ascending loop is not permeable to water but reabsorbs Na/Cl
  • descending limb permeable to water but no sodium reabsorption 
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  • hypothalamus, secreted by posterior pituitary 
  • when vassopressin reaches capillaries surrounding the nephron 
  • binding to vassopressin receptor on collecting duct membrane 
  • more water taken in by tubule through water channels on the tubular membrane 
  • reabsorption of water into the body
  • vassopressin constantly produced producing an isotonic urine of 300mOsm/litre 
  • the more hydrated, the less vassopressin produced 
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how does alcohol intake cause dehydration?

  • alcohol inhibits vassopressin production 
  • meaning the distial tubule/collecting duct are impermeable to water and its not reabsorbed 
  • very dilute urine/dehydration 
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