Excretion

• What are the two main functions of the kidneys?

  Excretion and osmoregulation
• Where are the kidneys located in the body?

  Just behind the abdominal cavity in the lower back
• What is the main function of the kidneys?


  To produce urine
• What is urine?

  An excretory product stored in the bladder
• How do the kidneys vary the amount of urine produced?


  By adjusting the volume based on the body's needs
• How do the kidneys filter blood?

  Blood enters through an arteriole and spreads throughout the kidney tissues for filtration
• What happens to toxins and waste products during kidney filtration?

  They are removed from the blood and turned into urine
• What is the pathway of urine after it is produced in the kidneys?

  It flows down the ureter
• What are the two main purposes of the kidneys?

  Cleaning the blood of toxins and controlling water potential
• What is the definition of excretion?

  Excretion is the removal of unwanted products of metabolism.
• Why is it important to remove metabolic wastes from the body?

  It prevents the accumulation of toxic substances like carbon dioxide and nitrogenous waste.
• What are the main products of excretion?

  Carbon dioxide, urea, and bile pigments.
• Why is it important to maintain water potential in the body?

  To ensure cells have the right fluid amount and consistency
• Where does urea come from?

  Urea is produced from the breakdown of amino acids.
• How is carbon dioxide produced in the body?

  It is produced in every living cell during aerobic respiration.
• How is carbon dioxide transported in the blood?

  It is carried in three ways: 5% in solution, 10% as carbaminohaemoglobin, and 85% as hydrogen carbonate ions.
• What role does carbonic anhydrase play in carbon dioxide transport?

  It catalyzes the reaction between carbon dioxide and water to form carbonic acid.
• What happens to carbonic acid in the blood?

  It dissociates into hydrogen ions and hydrogen carbonate ions.
• What is the chloride shift?

  It is the movement of chloride ions into red blood cells to balance the charge as hydrogen carbonate ions diffuse out.
• What happens if the water potential in the blood is too high?

  Water enters the cells, causing them to burst
• What are the consequences of not excreting carbon dioxide?

  It can lead to respiratory acidosis and symptoms like headache and confusion.
• Where is the liver located in the human body?

  The liver lies below the diaphragm and just to the right of center.
• What are the two blood supplies to the liver?

  The hepatic artery and the hepatic portal vein.
• How many lobes is the liver divided into?

  The liver is divided into two principal lobes.
• What are liver lobules composed of?

  Liver lobules are composed of specialized epithelial cells called hepatocytes.
• What is the function of Kupffer cells in the liver?

  Kupffer cells destroy worn-out blood cells, bacteria, and foreign matter.
• What occurs if the water potential of the blood is too low?

  Water leaves the cells, causing them to shrink
• What do hepatocytes secrete into bile canaliculi?

  Hepatocytes secrete bile from the breakdown of hemoglobin.
• What is urea produced from in the liver?

  Urea is produced from excess amino acids.
• What is the ornithine cycle?

  The ornithine cycle is the process by which ammonia is converted into urea in the liver.
• What happens to ammonia during deamination?

  Ammonia is formed and is highly soluble and toxic.
• What is the role of insulin in carbohydrate metabolism?

  Insulin stimulates hepatocytes to convert glucose into glycogen when blood glucose levels rise.
• What is urea a product of?

  The breakdown of amino acids
• What is the function of catalase in the liver?

  Catalase detoxifies hydrogen peroxide into water and oxygen.
• How is alcohol detoxified in the liver?

  Alcohol is broken down into acetic acid by alcohol dehydrogenase and aldehyde dehydrogenase.
• What happens in fatty liver disease?

  Fatty acids accumulate in the liver when NAD is reduced and cannot oxidize them.
• What is cirrhosis?

  Cirrhosis is the replacement of damaged hepatocytes with fibrous tissue, disrupting blood flow.
• What is the primary function of the kidney?

  The primary function of the kidney is to filter blood and produce urine.
• How is urea formed in the liver?

  Excess amino acids are turned into ammonia, which is then converted into urea
• What is the structure of the nephron?

  The nephron consists of Bowman’s capsule, proximal convoluted tubule, loop of Henle, distal convoluted tubule, and collecting duct.