breathing structures - 

• visceral pleural membrane - covers outside of each lung
• parietal pleural membrane - covers inner wall of thoracic cavity
• pleural cavity - space between parietal/visceral membranes
  • filled w/ fluid, makes the 2 membranes stick together
• diaphragm - along w/ external intercostals muscles, changes thoracic volume to breathe
  • contract >> expands rib cage to inhale
  • relax >> unforced exhalation
• tidal volume - amount of air moved w/ each breath
  • anatomical dead space - areas where no exchange of air takes place
• vital capacity - maximum amount of air that is exhaled
  • reduced in emphysema, due to damaged alveoli
• hypoventilating >> not enough breathing to maintain normal blood gas
• hyperventilating >> too much breathing

breathing regulation - controlled by respiratory control center in medulla oblongata 

• automatic control of skeletal muscles in diaphragm and external intercostals muscles
  • can be overridden voluntarily
• oxygen, carbon dioxide concentrations change pH >> central/peripheral chemoreceptors in brain
  • peripheral chemoreceptors - control immediate breathing changes
  • central chemoreceptors - control sustained breathing changes
• dyspnea - difficulty in breathing
  • due to something blocking the airways
• apnea - temporary pause in breathing

hemoglobin - protein made up of 4 polypeptides, 4 heme groups 

• iron atom at center of each heme group, can bind to oxygen
• hemoglobin w/ oxygen = oxyhemoglobin
  • bright red color
• hemoglobin releases oxygen >> deoxyhemoglobin
  • dark red color, but changes tissue to blue color
• hemocyanin - found in invertebrates in place of hemoglobin
  • has copper instead of iron
• carbon monoxide poisoning - CO displaces O2 >> hypoxia (hemoglobin can’t carry oxygen)