Excretion

• What is excretion?

  Removal of toxic waste from the body
• How do the lungs contribute to excretion?

  They excrete carbon dioxide through breathing
• What waste product do the kidneys produce?

  Urine containing urea
• Why is excretion important for homeostasis?

  It prevents accumulation of metabolic waste
• What metabolic waste do mammals produce due to high metabolic rates?

  Carbon dioxide and nitrogenous waste
• What is ammonia produced from?

  Deamination of excess amino acids

  
• What happens if metabolic waste accumulates in the body?

  It can change pH and affect enzyme efficiency

  
• Which organ produces metabolic wastes except carbon dioxide?

  The liver
• What is the role of the hepatic artery?

  It supplies oxygenated blood to the liver
• How does the liver receive nutrient-rich blood?

  Through the hepatic portal vein
• What is the function of the gall bladder?

  Stores and releases bile
• What are hepatocytes?

  Cells that perform liver functions
• How is blood supplied to liver lobules?

  Through branches of the hepatic artery and portal vein

  
• What is the main function of the nephron?

  Formation of urine
• What are the two stages of urine formation?

  Ultrafiltration and selective reabsorption

  
• What triggers glycogenesis in the liver?

  Insulin after increased blood glucose
• What is deamination?

  Removal of the amino group from amino acids

  
• What is the ornithine cycle?

  Conversion of ammonia to urea
• What is the toxic effect of ammonia?

  It can damage the body if accumulated
• What substances undergo detoxification in the liver?

  Alcohol, hydrogen peroxide, lactate, drugs
• What happens to ethanol in the liver?

  Converted to ethanal by alcohol dehydrogenase
• What condition can result from continuous alcohol detoxification?

  Fatty liver due to fat storage
• What is histology?

  Study of microscopic anatomy of tissues
• How can liver histology be studied?

  By staining and viewing tissue sections
• How many kidneys do humans have?

  Two kidneys
• What is the function of the renal pelvis?

  Where the ureter joins the kidney
• What is the functional unit of the kidney?

  The nephron
• What is the role of the glomerulus?

  Filters blood in the nephron

  
• What is the role of the afferent arteriole?

  Supplies blood to the glomerulus

  
• What happens to blood after it leaves the efferent arteriole?

  Flows into capillaries alongside the nephron
• What is the process of ultrafiltration?

  Blood is filtered in the glomerulus

  
• What is selective reabsorption?

  Reabsorption of useful substances from filtrate

  
• What happens to urine after formation?

  Flows to the bladder for storage
• What substances are reabsorbed during urine formation?

  Amino acids, water, glucose, ions
• What is the fibrous capsule?

  Tough outer layer surrounding the kidney
• What is the cortex of the kidney?

  Outer region containing nephron structures

  
• What is the medulla of the kidney?

  Inner region containing loop of Henle

  
• What is the renal pelvis?

  Area where ureter joins the kidney

  
• What is the role of the collecting duct?

  Collects urine from nephrons

  
• What is the function of the proximal convoluted tubule?

  Reabsorbs nutrients and water from filtrate