Respiratory System - - Meet the Lungs: The Adam’s apple is also known as the voicebox and air passes through here Acts as the entryway into the trachea Right lung has 3 lobes (upper, middle, and lower) and the left lung has 2 lobes (also has a cardiac notch because this is where the heart sits) Diaphragm makes up the floor of the thorax while the ribs make up the walls Alveoli (~500 million) are sacs that collect oxygen from the air and let it diffuse into the blood while waste gets thrown back into the alveoli Wrapped by elastin which allows them to expand during inhalation Inhaling & Exhaling: O2 is about 20% of air composition Basically air goes from high to low pressure and equilibrates (also remember relationship of PV = nRT) - - How does lung volume change?: Intercostal muscles are in between the ribs External intercostal muscles expand the thorax for inspiration Internal intercostal muscles lower the volume of the thorax for exhalation O2 and CO2 Solubility: Henry’s Law states that the higher kH is (a constant), the less soluble it is in that particular solvent (KH = Pressure/Concentration) CO2, is way more soluble in water than O2 because of the carbonic acid buffer system The higher the temperature, the higher the KH because the gas has more energy to leave the liquid Fick’s Law of Diffusion: V is the rate at which the particles move D is the diffusion constant ( 𝑘𝐻 √𝑀𝑜𝑙𝑒𝑐𝑢𝑙𝑎𝑟 𝑤𝑒𝑖𝑔ℎ𝑡 ) T is thickness Oxygen Movement from Alveoli to Capillaries: O2 in the lungs have to go through a layer of fluid, epithelial cells, a basement membrane of the alveoli, connective tissue, another basement membrane of the capillary, an endothelial cell (makes the wall of the capillary), the plasma, and finally the RBC. The Respiratory Center: Respiratory center is an area in the medulla and pons that send signals to the muscles that control breathing Central chemoreceptors are cells that gather information based on CO2 levels and pH (NOT O2 levels) Peripheral chemoreceptors are cells that gather information based on different things (located outside of the brain) → detects - O2, CO2 and pH levels Aortic body uses CN 10 (vagus nerve) in order to communicate with the respiratory center Carotid body uses CN 9 (glossopharyngeal nerve) in order to communicate with the respiratory center Mechanoreceptors send information with regards to pressure (nose, lungs, GI tracts) The cerebrum controls breathing patterns (i.e. singing, playing an air instrument, yelling, etc.)