digestive system

• Carbs


  ratio 1:2:1

  
  

  CH2O

  
  

  glucose c6h12o6

  
  

  act as an energy source

  help control blood glucose and insulin metabolism
• Protein


  C, H, O, N

  
  

  amino acids (20) sequence

  
  

  build and repair muscles and bones to make hormones and enzymes

  
  

  provide structural support in cm

  
  

  broken down in alimentry canal as peptides and peptones and then into amino acids
• Fats


  C H O

  1:2:<1

  glycerol and fatty acids

  fatty compounds that help withmoving and storing energy, absorbing vs making h's
• Vitamins


  group of substances that are required for cf, growth and development
• minerals


  Building materials influencing nerve function and regulating body water balance
• water


  restore fluids lost through metabolism and removal of waste
• Monosacchardies


  simple sugars

  
  

  glucose, fructose
• Disaccharide


  double sugars

  
  

  sucrose, lactose, maltose
• Polysacchardies


  many sugars

  
  

  starch, glycogen and cellulose

  
  

  most complicated
• enzymes


  made up of proteins

  
  

  act to reduce amount of energy required to start reaction (activation energy)

  
  

  Lock and key theory
• factors affecting enzyme action

  1. higher concentration = faster rate of chemical reaction

  2. rate of most chemical reactions increase as temperature increases

  3. all enzymes have optimum ph levels, if inappropriate, it may denature

  4.enzyme reaction will increase with increase in concentration of substrate

  5. inhabitors are substances that slow or interfere enzyme activity
• digestion


  breakdown of large insoluble food compounds into small water soluble components so they can be absorbed in blood plasma
• mechanical digestion


  physically breaking down food into smaller pieces

  
  

  e.g. teeth, churning in stomach
• chemical digestion


  uses certain enzymes to break down nutrients

  
  

  e.g. proteins, carbs, fats in smaller molecules

  
  

  e.g. maltose, lipase, sucrase
• Ingestion


  taking in food from mouth
• peristalsis


  moves food and water through stages of digestive process
• digestion


  convert food we eat into simplest form
• absorption


  transfer of nutrients from diet into circulation
• defecation


  expelling feces from digestive tract via anus
• alimentry canal


  continuous tube running from the mouth to the anus
• mouth


  bounded by cheeks, tongue, hard and soft palate

  
  

  sensitive to heat, cold, pain pressure, taste

  
  

  jaws and teeth begin mechanical digestion to increase sa

  
  

  3 pairs of salivary glands begin chemical digestion

  
  

  salivary amalyse (break starch down to maltose)
• four incisors


  chisel shaped teeth for biting and cutting

  
  

  e.g. eating an apple
• four premolars


  two on each side of jaw

  
  

  crushing and grinding
• two canines


  used for taring
• six molars


  crushing and grinding food
• Stomach


  found beneath diaphragm

  
  

  mechancial digestion occurs due to 3 muscle layers acting to store, mix and empty food in small intestine

  
  

  stomach absorbs water, glucose, alcohol

  
  

  top of stomach = cardiac sphincter

  
  

  rugae act to increase sa

  
  

  gastric glands found in rugae produce gastric juice ph 1-3
• gastric juice


  hydrochloric acid - kill bacteria and provides environment to make protease enzyme active

  
  

  mucus - act to protect stomach lining from acid

  
  

  protease enzyme - digests proteins into peptides and peptones
• liver


  largest gland in body found right sife of abdomen beneath diaphragm

  
  

  regulate blood sugar levels

  
  

  generate body heat

  
  

  make blood proteins

  
  

  store iron and vitamins a and d

  
  

  detoxify alcohol and drugs
• pancrease


  produces digestive enzymes

  
  

  ph 7 acts to neutralise acid from stomach in small intestine

  
  

  pancreatic amalyse - break down starch to maltose

  pancreatic lipase - break down fat into fatty acid and glycerol

  protease - break down protein into peptides

  deoxy and ribonucleases - break down rna and dna
• small intestine


  highly convuluted and broken into 3 sections

  
  

  duodenum (25cm), jejenum (350cm) and ileum (250cm)

  
  

  aids in chemical digestion by producing

  
  

  intestinal protease - protein into aa

  amalyse - carbs into glucose

  lipas - fats, fatty acids and glycerol

  
  

  nutrients absorbed by diffusion, osmosis and AT