Organisation

• What is a tissue

  A group of cells working together with the same functions
• What is the mouths purpose?

  Chew food and break it down to more digestible food
• What is an organ?

  A group of tissues that work together to perform a specific function in the body.
• What is a organ system?

  Organs working in groups to do a specific job
• What is the salivary glands function?

  Produce salive to turn food into a paste. Release enzymes which begin to break down food
• What is the oesophagus job?

  Provide a track for food to travel to the stomach through
• What does the stomach do?

  Enzymes released begin the digestion of proteins. Contains strong hydrochloric acid and the churning motion of the stomach turns the food to fluid which increases the surface area and makes it easier for enzymes.
• What is the pancreas function?

  It releases enzymes which break down starch and proteins and begin the digestion of lipids.
• What is the livers function?

  It releases bile which emulsifies lipids and neutralises acid from the stomach
• What do small intestines do?

  Release enzymes which help digest lipids and proteins, absorb nutrients from the food in to the blood stream
• What do the large intestines do?

  Absorb water into blood stream leaving faeces
• What are enzymes?

  • Biological catalysts
  • Large protein molecules
  • They have an active site which is where substrate attaches to enzymes
  • The substrate are specific - lock and key
• How are proteins broken down?

  Proteins -> protease -> amino acids
• How is starch broken down?

  Starch -> amylase -> glucose
• How are lipids/fats broken down?

  Lipids -> lipase -> glycerol + fatty acids

  (Emulsified by bile)
• Where is lipase released and made?

  Pancreas small intestine
• Where is amylase made?

  Salivary glands and pancreas
• Food test for starch

  Iodine

  blue black = starch

  Orange = no starch
• food test for glucose

  Benedict’s solution + heat

  Brick red/ orange, glucose present

  Blue green, no glucose present
• Food test for protein

  Biurets

  Purples / lilac protein is present

  No change, no protein
• Food test for lipids

  Ethanol + shake

  White /cloudy , lipids are present

  No change, no lipids are present
• What adaptations does the small intestine have for absorption?

  • Very long
  • Huge surface area
  • Villi
  • Microvilli
• How does villi have rapid diffusion?

  • capillary mean very good blood supply - high concentration gradient
  • Thin membrane means short diffusion pathways
  • Micro villi mean huge surface area
• The heart & circulation

  The hearts job is to pump blood around the body

  
• Arteries

  • High pressure blood
  • Move oxygen blood away from heart (apart from pulmonary artery)
  • Thick muscular walls to withstand pressure
  • Elastic fibres allow stretch during surges
• Capillaries

  • Diffuse blood to cells
  • Thin walls, short pathways mean rapid diffusion
  • Transfer co2 and oxygen
• Veins

  • Thin walls
  • Low pressure
  • Carry deoxygenated blood to heart (except pulmonary vein)
  • Valves stop blood flowing backwards
• What is the blood made up of?

  Plasma, red blood cells, white blood cells, platelets
• What does plasma transport?

  CO2 glucose digestive products and urea
• Red blood cells

  Contain haemoglobin

  No nucleus

  Bio concave disc, oxygen diffuses in and out rapidly
• White blood cells

  Have a nucleus which holds dna holds instructions for their job

  Part of the immune system, anti bodies
• platelets

  Tiny fragments of cells and it is there job to help the blood clot
• Cardiovascular diseases

  Diseases of the heart and blood vessels. They are non communicable and non infectious
• What is coronary heart disease?

  Layers of fatty material build up in the arteries. This causes them to narrow and reduces blood flow.
• What are statins?

  A pill you can take to reduce the level of cholesterol in the blood, it slows the rate of fat build up. It reduces the effects of coronary heart disease but can have side effects like liver problems.
• What is a stent?

  A tube which is inserted into an artery to keep it open so blood can flow normally, this does not however treat underlying causesl
• How does the trachea not collapse when your inhaling?

  It has rings of cartilage
• how Are gasses diffused in and out the blood stream?

  Alveoli
• What are the adaptations of the alveoli?

  • Millions of alveoli mean a huge surface surface area
  • Very thin walls mean a short diffusion pathway
  • Very good blood supply
  • Concentration gradient is steel as breathing means constant changes
• What is cancer?

  Uncontrolled division of mutated cells resulting in a tumour