Organisation

• Differentiation is where an unspecialised cell becomes specialised
• Differentiation only happens in multicellular organisms
• A tissue is a group of specialised cells which all perform a specific function
• Tissues can include more than one type of cell
• Tissue examples include muscular tissue, glandular tissue, epithelial tissue
• Epithelial tissue covers some parts of the body like the inside of the gut
• Tissues are organised into organs
• An organ is a group of different tissues that work together to perform a certain function
• Organs are part of organ systems which work together to perform a particular function
• The pancreas is below the stomach
• The largest internal organ is the liver
• a catalyst is a substance that increases the rate of a chemical reaction without being used up in the reaction
• enzymes act as biological catalysts
• enzymes are all large proteins and all proteins are made up chains of amino acids which are folded into unique shapes which enzymes need to do their job
• Enzymes have specific shapes so they can catalyse reactions
• chemical reactions usually involve things either being split o joined together
• enzymes have an active site with a unique shape that fits onto the substance involved in the reaction
• Enzymes use a lock and key theory
• when the substrate has binded to the active site the enzyme becomes an enzyme substrate complex
• changing the temperature change the rate of an enzyme catalysed reaction
• On a graph displaying temperature and rate of reaction with enzymes, it will start off with a gradual increase, reach an optimum temperature and then the graph will have a steep descent
• When it gets too hot an enzyme will become denatured as the bonds holding the enzyme together break and the enzyme's active site will change shape so substrate can't fit
• The lungs are in the thorax
• the thorax is just the top part of your body
• Lungs are protected by the rib cage and surrounded by pleural membranes
• Label the lung diagram

  A) Trachea

  B) Lung

  C) Bronchus

  D) Bronchiole

  E) Alveoli

  F) Diaphragm

  G) Ribs

  H) Intercostal muscle

  I) Pleural cavity

  J) Nasal cavity

  
• The trachea splits into 2 tubes called the bronchi
• Bronchi is the plural form of bronchus.
• the bronchi split into progressively smaller tubes called bronchioles
• bronchioles end up in alveoli where gas exchange takes place
• Lungs contain millions and millions of alveoli
• Alveoli are surrounded by network of capillaries
• Blood passing next to alveoli just returned from rest of body and contains lots of carbon dioxide and not much oxygen
• Oxygen diffuses out the alveoli into the bloodstream and carbon dioxide diffuses into the alveoli
• Single alveoli is called alveolus
• Humans have a double circulatory system
• the heart contracts to pump blood around the body
• the walls of the heart are mostly made of muscle tissue
• the heart has valves to make sure blood flows in the right direction
• atria is the singular version of the atrium