Excretion

    Cards (63)

    • 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 process involves the conversion of ammonia into urea?
      The ornithine cycle
    • What is one function of the liver?
      Detoxifies the blood
    • How does the liver detoxify the blood?
      By breaking down alcohol, drugs, and hormones
    • What does the liver store?
      Glycogen
    • What is the role of bile produced by the liver?
      Aids lipid digestion by emulsifying fats
    • What is the first step in the ornithine cycle?
      Deamination of amino acids
    • What happens to organic acids after deamination?
      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 vein do?
      Takes deoxygenated blood away from the liver
    • What is the role of the hepatic portal vein?
      Connects the liver to the intestines
    • What are liver lobules made up of?
      Hepatocytes
    • What are sinusoids in the liver?
      Capillaries connecting the central vein and vessels
    • What do Kupffer cells do?
      Break down old red blood cells and remove bacteria
    • What are the two parts of the kidney?
      Medulla and cortex
    • How does blood flow to 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 are the two processes involved in the removal of substances from the bloodstream?
      Ultrafiltration and selective reabsorption
    • What surrounds the glomerulus?
      Bowman's capsule
    • Why is blood pressure high in the glomerulus?
      Due to the smaller diameter of the efferent arteriole
    • What is glomerular filtrate?
      Substance formed from small molecules pushed out of blood
    • What layers do small molecules pass through to enter the Bowman’s capsule?
      Capillary endothelium, basement membrane, epithelium
    • Where does selective reabsorption primarily occur?
      In the PCT, loop of Henle, and DCT
    • 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 the remaining filtrate become after reabsorption?
      Urine
    • What additional substances may be found in urine?
      Hormones, excess vitamins, drug breakdown products
    • Where does water reabsorption regulation primarily occur?
      DCT, loop of Henle, and collecting duct
    • What hormone regulates water reabsorption in the kidneys?
      ADH
    • How does ADH affect the collecting duct?
      Increases permeability to allow more water reabsorption
    • What triggers the release of ADH?
      Low water levels in blood plasma
    • What is the role of osmoreceptors in the hypothalamus?
      Detect drops in blood water potential
    • What happens when ADH is secreted?
      More water is reabsorbed, producing concentrated urine
    • What is kidney failure?
      When kidneys stop filtering toxic substances