biology organisation

• organ systems


  A group of organs that work together in performing vital body functions.
• tissues


  a group of similar cells that work together to carry out a particular function
• musucalar tissue


  contracts to move whatever its attached to

  
  

  - moves the stomach wall to churn up the food
• glandular tissue


  makes and secretes chemicals like enzymes and hormones

  
  

  - makes digestive juices to digest food
• epithelial tissues


  protective covering for some of the internal and external surfaces of the body

  
  

  - covers the inside and outside of the stomach
• organs


  a group of different tissues that work together to perform a certain function
• enzymes


  Catalysts produced by living things
• catalyst


  substance which increases the speed of a reaction without being changed or used up in the reaction
• how enzymes work


  an active site with a unique shape that fits onto the substance involved in the reaction
• Factors that effect enzymes


  temperature and pH
• digestive enzymes


  3 types are amylase , protease , lipase

  
  

  they break down big molecules
• amylase


  amylase breaks down starch into glucose

  
  

  made in pancreas , small intestine and salivery glands
• lipase


  lipase breaks down lipids into fatty acids and gylcerol

  
  

  made in pancreas and small intestine
• protease


  protease breaks down proteins into fatty acids

  
  

  made in pancreas , small intestine and stomach (called pepsin)
• salivary glands


  produce amylase in saliva
• gullet


  the esophagus; throat
• stomach


  it pummels the food with its muscular walls

  produces pepsin

  produces hydrochloric acid to kill bacteria and to give the right ph so protease can work
• liver


  where bile is produced

  
  

  bile neutralises stomach acid and emulsifies fats
• gall bladder


  Where bile is stored before it's released into the small intestine
• pancreas


  produces protease , amylase and lipase and releases them to small intestines
• small intestine


  Digestive organ where most chemical digestion and absorption of food takes place
• large intestine


  where excess water is absorbed from the food
• rectum


  where the feaces are stored before they exit the anus
• lungs


  in the thorax

  proteced by ribcage and surrounded by pleural membranes
• breathing in


  the air that you breathe in goes through the trachea. this splits into two tubes called bronchi ( each one is a bronchus ) one going to each lung
• bronchi


  the bronchi splits into progressively smaller tubes called bronchioles
• alveoli


  the bronchioles finally end at the small bags called alveoli where gas exchange happens
• gas exchange


  the lungs contain millions of alveoli. the bloody going to the alveoli has just returned from the rest of the body so it has very little oxygen and lots of carbon dioxide.

  
  

  co2 diffuses out of the blood into alveolus and is breathed out. and oxygen diffuses out if alveolus into blood
• circulatory system


  made up of the heart, blood vessels, and blood
• circulatory system - the heart

  the right ventricle pumps deoxygenated blood to the lungs to take in oxygen. this blood returns to the heart

  
  

  the left ventricle pumps oxygenated blood around all the other organs of the body
• pump blood around body

  body —————> vena cava -> right atrium -> right ventricle-> pulmonary artery-> lungs

  
  

  lungs ————> pulmonary vein -> left atrium-> left ventricle -> aorta -> body
• circulatory system - blood vessels

  arteries , veins, capillaries
• arteries


  carry blood away from the heart

  
  

  heart pumps blood at high pressure so the artery walls are strong and elastic

  walls are thick compared to the lumen

  thick layers of muscle
• capillaries


  exchange of materials at the tissues

  
  

  arteries branch out into capillaries

  capillaries are really tiny and carry blood very close to every cell to exchange surfaces

  permeable walls so substances can diffuse in and out

  walls are 1 cell thick
• veins


  take blood back to the heart

  
  

  formed from capillares. . blood is at a lower pressure so the walls dont need to be as thick

  bigger lumen to help blood flow

  have valves to keep blood flowing in the right direction
• circulatory system - blood

  there are 4 main things in blood

  
  

  red blood cells

  white blood cells

  plasma

  platelets
• red blood cells


  carry oxygen from lungs to all cells in the body

  
  

  they dont have a nucleus and have a biconcave disk shape for more surface area

  they get the red pigment from haemoglobin which binds to the oxygen in the lungs and then to release oxygen cells they split up
• white blood cells


  phagocytes engulf unwanted microorganisms

  
  

  lymphocytes produce antibodies to fight against disease
• platelets


  they help blood clot at a wound to stop blood flowing out and microorganisms coming in
• plasma


  liquid that carries everything in the blood

  
  

  red white blood cells/ platelets

  carbon dioxide

  urea

  hormones

  proteins

  antibodies and antitoxins