biology unit 1 - respiration

• aerobic respiration - gluclose + oxygen --> carbon dioxide + water
• aerobic respiration - the process of releasing energy in cells when oxygen is available
• respiration -the process of breathing in and out of the body to release energy from food
• ATP - the energy-carrying molecule used in cell as it releases energy very quickly
• water and carbon dioxide are waste products that must be removed
• anaerobic respiration - gluclose + oxygen --> lactic acid + energy
• anaerobic respiration - occurs when there is no oxygen available. oxygen debt and lactic acid is released
• lactic acid - caused by anaerobic respiration. it is harmful to the body and causes muscle aches/cramps.
• oxygen debt - this is the amount of oxygen that is required to remove lactic acid and. lactic acid is broken down to water and carbon dioxide
• a fit person can; breathe a greater volume of air , break down lactic acid faster , produce less lactic acid
• respiratory system - transports oxygen from the air we breathe into our bodies, into our lungs, and diffuses it into our blood steam. while carbon dioxide does the opposite and leaves our bodies.
• Air enters the body


  Warmed through the nasal cavity
• The trachea is divided


  1. Into 2 bronchi

  2. One of each bronchus enters each of the lungs
• Each bronchus branches out

  1. Into smaller tubes called bronchioles

  2. Air travels through the bronchioles
• At the end of the bronchioles


  1. Air enters the many million alveoli

  2. Gaseous exchange takes place
• breathing in - inspiration - the intercoastal muscle contract and the rib cage moves up and out - the diaphragm contracts, moving up and down - the volume of the thorax increases the pressure of the thorax increases - lungs inflate and draws air into the lungs
• breathing out - expiration - intercostal muscle relaxes and rib cage moves out and in - diaphragm relaxes and moves up - volume of thorax decreases - pressure inside thorax decreases - air is pushes out of lungs
• Bell jar model

  • Same shape as ribcage - no muscle attached to rib
  • Balloon inflates and deflates - not filled with alveoli
  • Rubber sheet acts like diaphragm - domed up when exhaling - has to be pushed out and in by hand
  • Tube acts like trachea - windpipe conducts air into balloon/lungs - not supported by rings of cartilage
• The bell jar model is used to demonstrate similarities and differences with the human respiratory system
• rings of cartilage - prevents trachea from collapsing.
• inspired air - breathed in air
• expired air - air we breath out
• testing for carbon dioxide - limewater turns cloudy if present
• alveoli - tiny air sacs at the end of the bronchioles filled with air, where the lungs and blood exchange oxygen and carbon dioxide during breathing in and out
• alveoli adaptions for gas exchange - good blood supply; more gases can be exchanged. large surface area - increases gaseous exchange. thin walls - easier for the diffusion of gas
• difference between inspired and expired air 1. expired air has less oxygen 2. expired air has more carbon dioxide 3. expired air has more water vapour
• cilia - hair like structure that moves in the trachea to move mucus upwards
• cleaning the lungs

  • the air we breathe contains dust and bacteria. the alveoli are delicate so must be cleaned beforehand
  • cilia are scattered with goblet cells that produce mucus. the mucus traps the bacteria in the air
  • The cilia moves the mucus up the trachea and to the back of the throat
  • the mucus is swallowed to the stomach where the acid destroys the bacteria
• effects of smoking tobacco smoke from tobacco paralyzes the cilia in the trachea dey dust and chemicals in smoke irritate the lungs and clog up mucus cilia usually sweep the mucus away but it has become paralyzed mucus build up and can become infected causing bronchitis coughing causes damage to the alveolar walls which reduces the surface area for gas exchange and results in shortage of oxygen.
• tobacco chemicals

  tar - a dark, brown sticky substance that collects in the lungs as the smoke cools. contains carcinogens which is a chemical that causes cancer carbon monoxide - a gas that combines with hemoglobin and reduces the oxygen-carrying capacity of the blood nicotine - an addictive drug that makes smoking a hard habit to give up, nicotine makes blood pressure rise
• smoking diseases


  lung cancer - 90% of lung cancers are from smoking emphysema - the chemical in tobacco smoke that damages walls of alveoli and eventually breaks down. this reduces the surface area for gas exchange and results in oxygen shortage
• keeping lungs clean - the air we breathe contains dust & bacteria. the alveoli is delicate so air must be cleaned before hand, by cilia
• cilia - hair-like structures that move in airways to sweep mucus away, up through the trachea for it to be swallowed and the bacteria to be destroyed by acid in the stomach