Excretion

    Cards (62)

    • 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 is the process called that converts amino acids into urea?
      Deamination followed by the ornithine cycle
    • What does the liver detoxify?
      Alcohol, drugs, and hormones
    • What does the liver store?
      Glycogen
    • What is the function of bile produced by the liver?
      Aids lipid digestion by emulsifying fats
    • What happens to excess amino acids in the liver?
      They are converted into urea
    • What is ammonia converted into in the liver?
      Urea
    • What is the hepatic artery's function?
      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 is the role of Kupffer cells in the liver?
      Break down old red blood cells and bacteria
    • What are the two main parts of the kidney?
      Medulla and cortex
    • How does blood reach the kidneys?
      Via the renal artery
    • What are the structures that filter blood in the kidneys called?
      Nephrons
    • What substances do kidneys remove from the blood?
      Excess water, ions, and urea
    • What is ultrafiltration?
      Process where blood is filtered under high pressure
    • What surrounds the glomerulus?
      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 during filtration?
      Capillary endothelium, basement membrane, epithelium
    • Where does selective reabsorption occur in the nephron?
      Proximal convoluted tubule, loop of Henle, distal convoluted tubule
    • How is glucose reabsorbed in the PCT?
      By active transport and facilitated diffusion
    • What feature of the PCT epithelium aids reabsorption?
      Microvilli provide a large surface area
    • How is water reabsorbed in the nephron?
      By osmosis in various nephron parts
    • What does urine contain?
      Excess water, salts, and urea
    • What regulates water reabsorption in the nephron?
      Hormones such as ADH
    • What are the two limbs of the loop of Henle called?
      Ascending and descending limb
    • What is the permeability of the ascending limb?
      Permeable to ions, impermeable to water
    • What happens at the top of the ascending limb?
      Sodium ions are actively pumped into the medulla
    • How does water move out of the nephron?
      By osmosis from the descending limb
    • What happens to the filtrate as water moves out?
      It becomes more concentrated
    • How does the nephron's water potential change?
      It lowers as sodium ions move out
    • What is the role of ADH in urine concentration?
      Increases water reabsorption in collecting duct
    • How does ADH affect the collecting duct wall?
      Makes it more permeable to water
    • What triggers the release of ADH?
      Low water levels in blood plasma
    • What do osmoreceptors in the hypothalamus detect?
      A drop in blood water potential
    • What is kidney failure?
      When kidneys stop filtering toxic substances
    • What can cause kidney failure?
      Infection or high blood pressure