Humans

• Amylase breaks down carbohydrates into maltose.
• What is ingestion?

  Food is taken into the body
• What is digestion?

  Large (insoluble) food molecules are broken down into smaller, soluble molecules.
• What is absorption?

  Digested food molecules are absorbed into the cell.
• What is assimilation?

  Some absorbed food substances are converted into new cytoplasm or used to provide energy.
• What is egestion?

  Undigested food is removed from the body.
• What is alimentary canal?

  Digestive track
• What is the function of the mouth?

  1. Teeth chews food from larger pieces to smaller pieces to increase surface area to volume ratio.
  2. Contains salivary glands.
• How does food travel from the mouth to the oesophagus?

  Peristalsis
• What is peristalsis?

  Muscles that help to push down food.
• What is the function of the stomach?

  1. Churning occurs, breaks down bigger pieces into smaller pieces to increase surface area to volume ratio.
  2. Gastric glands releases gastric juice.
  3. Hydrochloric acid converts pepsinogen into pepsin and kills bacteria.
  4. Pepsin converts protein into polypeptide.
• What is the function of the small intestine?

  Pancreas secrets...

  1. Amylase converts starch into maltose
  2. Pancreatic lipase converts fats into glycerol + fatty acids
  3. Trypsin converts protein into polypeptide
• What is the function of the gall bladder?

  1. Stores & releases bile
  2. Emulsifies big fat droplets into small fat droplets
• Intestinal juice is secreted by intestinal glands and it digests..

  1. Intestinal fats digests fats into glycerol + fatty acids
  2. Maltase digests maltose into glucose
  3. Peptidases digests polypeptides into amino acids
• What is physical digestion?

  Involves mechanical break-up of food into smaller particles.
• What is chemical digestion?

  1. Involves break-down of large molecules of food into small soluble molecules that can be absorbed.
  2. Involves hydrolytic reactions catalysed by digestive enzymes
• What are the adaptations of absorption in the small intestine?

  1. Villi and microvilli to increase surface area to volume ratio for increased rate of absorption.
  2. Walls are one cell thick to decrease distance and increase speed of absorption.
  3. 6m long to increase time for absorption.
  4. Richly supplied with blood capillaries to maintain concentration gradient for diffusion. (carry absorbed nutrients quickly)
• Type 1 diabetes

  1. Occurs when the pancreas is unable to produce enough insulin
  2. Tends to develop at a young age
  3. Cannot be prevented
  4. Requires insulin therapy
• Type 2 diabetes

  1. Occurs due the insulin resistance
  2. Tends to develop at an older age
  3. Can be prevented with lifestyle changes
  4. Can be managed with lifestyle modifications if diagnosed early
• What is the similarity between type 1 and type 2 diabetes?

  Both share symptoms of frequent urination, increased thirst, extreme hunger, unintentional weight loss, fatigue, blurry vision, sores or wounds that heal slowly, and numbness and tingling sensation in hands and feet.
• Which vein carries blood from the intestines to the liver?

  Hepatic portal vein
• How are nutrients utilised in the liver?

  1. Glucose releases energy during aerobic respiration
  2. Amino acids synthesis enzymes
  3. Fats are a storage form of energy
• What happens to the excess food products in the liver?

  1. Glucose is converted into glycogen and stored in the liver and muscles
  2. Amino acids cannot be stored and it is deaminated in the liver
  3. Fats are stored in fat tissues or adipose tissues
• What are the functions of the liver?

  1. Produces bile
  2. Regulation of glucose
  3. Detoxification (alcohol is converted into harmless substances)
  4. Protein synthesis (make fibrinogen)
  5. Remove excess amino acids (demination to covert excess amino acids into urea)
• What does excess glucose convert into?

  Glycogen in liver for storage (controlled by insulin)
• What happens when there is a lack of glucose in the liver?

  Glycogen converts back into glucose (by glycagon)