Excretion

    Cards (77)

    • What is excretion?
      Removal of metabolic waste products
    • Why is excretion important for homeostasis?
      It prevents tissue damage from waste accumulation
    • What does the liver break down amino acids into?
      Urea
    • What are the main functions of the liver?
      • Breaks down amino acids into urea
      • Detoxifies the blood
      • Stores glycogen
      • Makes bile for lipid digestion
    • What is the process called that converts ammonia into urea?
      Ornithine cycle
    • What happens to organic acids after amino acids are deaminated?
      They are respired or stored as glycogen
    • Why is ammonia converted into urea?
      Ammonia is toxic and needs to be neutralized
    • Where is urea released after being formed in the liver?
      Into the bloodstream
    • What is the function of the hepatic artery?
      Delivers oxygenated blood to the liver
    • What does the hepatic portal vein connect?
      The liver to the intestines
    • What are liver lobules made up of?
      Cylindrical structures of hepatocytes
    • What role do Kupffer cells play in the liver?
      They break down old red blood cells
    • What are the two main parts of the kidney?
      Medulla and cortex
    • What is the function of nephrons in the kidneys?
      Filter blood and remove waste products
    • What substances do kidneys remove from the blood?
      Excess water, ions, and urea
    • What are the two processes involved in removing substances from the bloodstream in the kidneys?
      1. Ultrafiltration
      2. Selective reabsorption
    • What surrounds the glomerulus in the kidney?
      Bowman's capsule
    • Why is blood pressure high in the glomerulus?
      The efferent arteriole is smaller than the afferent
    • What is glomerular filtrate?
      Substance formed from small molecules pushed out
    • What layers do small molecules pass through to enter the Bowman’s capsule?
      Capillary endothelium, basement membrane, epithelium
    • What occurs during selective reabsorption in the nephron?
      • Useful substances are reabsorbed into capillaries
      • Glucose is reabsorbed in the PCT
      • Water is reabsorbed in the loop of Henle, DCT, and collecting duct
    • What structure in the nephron has microvilli for reabsorption?
      Proximal convoluted tubule (PCT)
    • How is water reabsorbed in the nephron?
      By osmosis in various nephron parts
    • What is the final product of the nephron after filtration?
      Urine
    • What hormone regulates water reabsorption in the kidneys?
      ADH (antidiuretic hormone)
    • What is the role of the ascending limb of the loop of Henle?
      Permeable to ions, pumps sodium ions
    • What happens in the descending limb of the loop of Henle?
      Water moves out by osmosis
    • How do organisms in dry conditions adapt their kidneys?
      They have an extra-long loop of Henle
    • What triggers the release of ADH?
      Low water levels in blood plasma
    • What is the effect of ADH on the collecting duct?
      Increases permeability to water
    • What is kidney failure?
      When kidneys stop filtering toxic substances
    • What can cause kidney failure?
      Infection or high blood pressure
    • What is measured to diagnose kidney failure?
      Glomerular filtration rate (GFR)
    • What problems can arise from kidney failure?
      • Build-up of waste products
      • Ion imbalance
      • Accumulation of fluids in tissues
      • Anaemia
      • Mortality if untreated
    • What is dialysis?
      Connecting blood supply to a dialysis machine
    • What happens to urea during dialysis?
      It diffuses out of the blood into fluid
    • What is a disadvantage of dialysis?
      It requires multiple hospital visits
    • What is a kidney transplant?
      Replacing a damaged kidney with a new one
    • What is a risk associated with kidney transplants?
      Rejection of the new kidney by the body
    • What are the uses of urine testing?
      • Detecting drugs
      • Pregnancy tests for hCG
      • Monitoring health conditions
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