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)
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