Digestive System

• What does the epiglottis do?

  Covers windpipe during swallowing
• What is mechanical digestion?

  Where the teeth in the mouth break down the food for easier swallowing and the stomach walls churn food down.
• What is chemical digestion?

  Starch into maltose via salivary amylase (mouth)

  Proteins into polypeptides via pepsin (stomach)

  Bile emulsifies fats

  Fats into fatty acids and glycerol via lipases (small intestine)

  Alkaline salts neutralise acidic chyme
• What does pancreatic juices do?

  They neutralise acidic chyme because they are alkaline
• What does bile do?

  Emulsifies fats and neutralises stomach acid
• What is absorption?

  Movement of nutrients.

  Large surface area created by villi

  One cell thick short diffusion distance

  Network of blood capillaries transports glucose and amino acids into blood
• What is assimilation?

  Movement of digested food into cells. Travels across the hepatic portal vein to liver, which stores glucose as glycogen. Also stores fats, vitamins and minerals and distributes to required cells.
• What is IBS?

  Symptoms stomach pain and cramping mucus passing from anus

  Causes Increased sensitivity of gut to certain foods by something we eat or drink

  Muscles in the large intestine move too quickly or slowly causing constipation or diarrhoea.

  Cut down on high fibre foods

  Gastroscopy endoscope in mouth investigates abdominal pain

  Avoid sorbitol
• What are gallstones?

  Symptoms Jaundice Diarrhoea

  Explanation High levels of cholesterol or bilirubin causes tiny crystals to form in bile and they grow into small stones

  Causes over 40 years, family history or obese

  Reduce fat intake

  Lithotripsy uses endoscope to shatter gall stones

  Single incision keyhole surgery removes gall bladder
• What is coeliac disease?

  Symptoms Indigestion Diarrhoea

  Explanation Autoimmune disease which causes damage to villi

  Causes Family history, introducing gluten to babies less than 6 months

  Give up gluten, vaccinations, vitamin and minerals supplements
• Structure

  A) Buccal cavity

  B) Liver

  C) Gall Bladder

  D) Pancreas

  E) Salivary glands

  F) Oesophagus

  G) Stomach

  H) Small intestine

  I) Large intestine

  J) Rectum

  K) Anus

  
• Buccal cavity

  Opening which food enters
• Liver

  Produces bile which emulsifies fats
• Gallbladder

  Stores bile
• Pancreas

  produce pancreatic juices
• Salivary glands

  Produces saliva which makes food easier to swallow
• Oesophagus

  Transports food from mouth to stomach
• Stomach

  Walls churn the food down and produces pepsin to break proteins into peptides and amino acids
• Small intestine

  Absorbs nutrients from faeces
• Large intestine

  Balance water levels in faeces
• Rectum

  Stores faeces
• Anus

  Expels faeces