respiratory system

• the respiratory system involves a group of organs responsible for transporting oxygen from the air to the lungs, then into the bloodstream. it's also responsible for removing the waste product carbon dioxide
• components of respiratory system:

  • nose
  • pharynx (throat)
  • trachea (windpipe)
  • bronchi (tubes that connect trachea to lungs)
  • lungs (main organ of respiratory system)
• we need oxygen so our cells can carry out a process known as aerobic respiration
• aerobic respiration:

  • within our cells, the energy contained in food is converted into muscle growth, movement, a heartbeat, heat (to keep us at a temp of ~37.8 degrees)
  • to create energy, fuel is needed > to burn fuel, oxygen is needed > fuel for animals is glucose, and oxygen is needed to burn this fuel > this is why we breathe
  • chemical process where oxygen is used to make energy from glucose
• aerobic respiration equations:

  
  

  glucose + oxygen = carbon dioxide + water + energy

  C6H12O6 + 6O2 → 6CO2 + 6H2O + energy (ATP)
• roles of respiratory system:

  • provides oxygen to cells for cellular respiration
  • removes carbon dioxide from blood
  • air passes through the nose to provide sense of smell, assists with sense of taste, air passing through throat assists with providing sounds for speech
  • helps regulate amount of h20 in system
  • helps to cool body
• lungs are about the size of a pair of footballs
• lungs are made up of 5 sections/lobes

  • right lung is larger > 3 lobes
  • left lung is smaller > 2 lobes
• in a lifetime, a person will breathe ~ 300,000,000 L of air
• the lungs are the only organs light enough to float on water
• the respiratory system is made up of a number of air passages
• air travels through the path:

  nostrils > pharynx > larynx > trachea > bronchus > bronchioles > alveoli (lungs)
• alveoli : tiny sacs that are only one cell thick, surrounded by capillaries (where gas exchange occurs)
• diffusion: oxygen/co2 will move from high concentration to lower concentration
• the lungs are situated in a space inside the chest called the thoracic cavity:

  • the walls of this are supported by the ribs
  • the floor of this is a sheet of muscle called the diaphragm
• most air enters the respiratory system through the nose. the air breathed in through the nose is:

  • warmed
  • moistened
  • filtered (by nostril hairs, cilia, mucus)
• air is moved in and out of the lungs by actions of the:

  • diaphragm (tough sheet of muscle separating the organs of the chest from those of the abdomen)
  • intercostal muscles (muscles in between each rib)
• inspiration: breathing in
• expiration: breathing out
• in inspiration:

  • the diaphragm contracts and flattens out
  • the intercostal muscles contract
  • pulls the ribs upwards
  • these movements cause an increase in chest volume
  • causes a decrease in pressure; air rushes in to the lungs and fills the extra space
• lower pressure means air fills in lungs
• in expiration:

  • the diaphragm relaxes and regains its dome shape
  • the intercostal muscles relax
  • ribs return to their original position (move down and in)
  • these movements reduce the volume of the thoracic cavity
  • lungs are squeezed, forcing the air out
• each breath is ~ 500 mL of air
• vital capacity: the maximum amount of air you can exhale after inhaling
• breathing is an automatic process and is controlled by a part of the brain (which controls all our important bodily functions)
• to breathe, nerve impulses are sent down to the spinal cord to the diaphragm and intercostal muscles, instructing them to contract regularly
• the rate at which you breathe is controlled chemically; the control centre of the brain can detect an increase in co2 and step-up the rate of breathing to compensate
• getting winded involves creating a muscular spasm of the intercostals which interferes with inhalation and exhalation