Digestive system

• Basic unit of carbohydrates

  Monosaccharide
• Basic units of proteins

  Amino acid
• Basic units of lipids

  triglyceride
• Carbohydrates role in the body

  Energy source
• Proteins role in the body

  Repair damaged tissue and used for energy
• Lipids role in the body

  Provide energy, keeps body warm(through insulating) and protects organs.
• What is the role of the digestive system?

  To break down food and absorb nutrients for use by cells.
• 6 basic functions of the digestive system?

  1. Ingestion of food and water
  2. mechanical digestion
  3. chemical digestion
  4. movement of food along the alimentary food
  5. absorption of ingested food and water in lymph and blood
  6. elimination of material that is not absorbed
• What is mechanical digestion?

  The physical breakdown of food into smaller pieces.
• What is chemical digestion?

  Breakdown of food by enzymes and acids in the digestive system.
• What enable chemical digestion to occur?

  Enzymes
• Whats surrounds the digestive organs and keeps them in place?

  Peritoneum
• What is the role of digestive enzyme in the digestive system?

  Degrade fats, proteins and carbohydrates.
• How does mechanical digestion occur in the mouth?

  By teeth grinding food into smaller pieces in a process called mastication.
• Why is it important for food to be physically broken up in the mouth?

  Increases surface area for chemical digestion and makes it easier to swallow.
• 4 types of teeth?

  1. Molars
  2. Premolars
  3. Canines
  4. Incisors
• Teeth shape and function

  Incisors: chisel-shaped for biting and cutting

  Canines: conical (cone-shaped) for tearing

  Molars & Premolars: broad crowns with rounded cups for crushing and grinding.
• How does chemical digestion occur in the mouth?

  When food is chewed it mixes with saliva containing a digestive enzyme (salivary amylase) as well as mucus to lubricate the food.
• What are the 3 salivary glands?

  1. Parotid gland
  2. Sublingual gland
  3. submandibular gland
• Whats the lump of food swallowed called?

  Bolus
• What are the 2 types of muscle located in the oesophagus?

  1. Circular muscle
  2. Longitudinal muscle
• Circular muscle

  Has muscle fibires arranged in a circle
• Longitudinal muscle

  Has muscle fibres arranged along the length of the canal
• What is peristalsis?

  Contraction and relaxation of longitudinal and circular muscles through the digestive tract in order to move the bolus along.
• What aides food down the oesophagus?

  Saliva. Moistens food so it moves easily through the oesophagus.
• What does the bolus have to pass through to get into the stomach?

  Oesophagus
• What role does the oesophagus have within the digestive system?

  Transports food from the mouth to the stomach. Via peristalsis
• Why is peritoneum important?

  It supports the organs of the abdomen and acts as a conduit for the passage of nerves, blood vessels and lymphatics.
• What is peritoneum?

  The peritoneum is a thin membrane that lines the abdominal cavity and covers the organs within it.
• What surrounds the digestive organs and holds them in place?

  Peritoneum
• What forces the bolus down the oesophagus?

  Peristalsis
• What are the functions of the stomach?

  1. Store food and liquid
  2. Digest food and liquid
  3. Chemical digestion
  4. Mechanical digestion
  5. Produces hydrochloric acid and enzymes
  6. Kills unwanted bacteria
• What are the causes if indigestion and heart burn?

  Diet, stress, smoking, and certain medications.
• What is the lining of the stomach called?

  The mucosa
• What does the mucosa secrete and what does it contain?

  The mucosa secretes mucus and the mucosa is made up of layers of epithelial tissue.
• Gastric cell: Mucous neck cell


  Secretes: Mucous

  Function of secretion: Protects the stomach lining from being destroyed.
• Gastric cell: Parital cells


  Secretes: Hydrochloric acid

  Function of secretion: Activates pepsinogen to form pepsin, kills bacteria and denatures proteins.

  Secretes: Hormones

  Function of secretion: Stimulates/regulates digestion
• Gastric cell: Chief cells


  Secretes: Pepsinogen - inactive form of pepsin

  Function of secretion: Pepsin when activated breaks proteins into polypeptides.

  Secretes: Gastric lipase

  Function of secretion: Splits short chain triglycerides into fatty acids and monoglycerides.
• 3 types of gastric glands - Exocrine

  • Mucous neck cell
  • Parietal cells
  • Chief cells
• What are the two roles of the small intestine in digestion?


  Absorption of nutrients (carbohydrates and proteins) and digestion