Excretion

• What is the process of excretion in the liver?

  Removing metabolic waste products from the body
• What are some metabolic waste products removed by the liver?

  CO2, bile pigment, nitrogenous waste
• How does the liver maintain homeostasis?

  By keeping blood substance levels constant
• What does the liver store to control blood glucose concentration?

  Glycogen
• What happens to ethanol in the liver?

  It is broken down into acetic acid
• What condition can excess alcohol cause in the liver?

  Cirrhosis
• What can excess paracetamol in the blood lead to?

  Liver and kidney failure
• How does the liver handle excess amino acids?

  By removing the amine group through deamination
• What is produced from the deamination of amino acids?

  Ammonia and organic acids
• What happens to ammonia in the liver?

  It is converted to urea through the Ornithine cycle

  
• What is the function of the hepatic artery?

  Supplies oxygenated, nutrient-poor blood
• What does the hepatic portal vein supply?

  Deoxygenated, nutrient-rich blood
• What is the role of the hepatic vein?

  Takes deoxygenated blood away from the liver
• What is the structure of liver lobules?

  Cylindrical structures made of hepatocytes

  
• What connects the hepatic artery and portal vein to the central vein?

  Capillaries called sinusoids
• What do Kupffer cells do?

  Remove bacteria and break down old erythrocytes
• What do hepatocytes produce?

  Bile
• What is the main function of the kidneys?

  Filter blood and produce urine
• What is the role of nephrons in the kidneys?

  They filter blood and produce urine
• What is the structure that encapsulates the glomerulus?

  Bowman's capsule

  
• What is ultrafiltration?

  Filtering substances from blood into tubules
• Why is blood pressure high in the glomerulus?

  Due to the smaller diameter of the efferent arteriole
• What structures must substances pass through to enter Bowman's capsule?

  Endothelium, basement membrane, podocytes
• What is glomerular filtrate?

  Small substances that enter the nephron
• What happens during selective reabsorption?

  Useful substances are reabsorbed into the blood
• How do Na ions facilitate the reabsorption process?

  They create a concentration gradient for diffusion
• What adaptations do proximal convoluted tubule cells have?

  Large mitochondria, microvilli, co-transport proteins

  
• What is the counter-current mechanism?

  Filtrate moves in opposite directions in limbs
• What happens in the Loop of Henle?

  Na+ is transported out, creating a gradient
• How does the body regulate urine concentration?

  By adjusting permeability of collecting ducts
• What is the composition of urine?

  Water, dissolved salts, urea, hormones
• What is the renal capsule?

  A thin, strong membrane covering the kidney
• What is the renal hilum?

  The indented area where tubes exit the kidney
• What are renal pyramids?

  Cone-shaped structures in the medulla
• What is the role of osmoreceptors in the hypothalamus?

  Detect changes in blood's water potential
• What triggers the release of ADH?

  Changes in the blood's water potential
• How does ADH affect the collecting duct cells?

  Increases permeability to water
• What is the result of increased ADH secretion?

  Smaller volume of concentrated urine