The Respiratory System

1. The Respiratory System Parts and function

2. Acquiring Energy • ATP is the energy currency for all cells • It is required as an energy source for performing activities such as building proteins to moving to a new location, to secreting a message to other cells, or to splitting into two new cells. • Cells use energy in food molecules to build ATP • There are two ways in which a cell can do this • Fermentation or Cellular Respiration

3. Fermentation • This is a means of breaking down food into ATP without the presence of Oxygen • Fermentation is used primarily by single-celled microscopic fungi called yeast and some bacteria. • It may also occur in the muscle cells of animals when oxygen is depleted by vigorous exercise • A biproduct of this reaction is lactic acid which causes muscle cramps

4. Cellular respiration • This process requires molecular oxygen • In summary: There is an enzyme-controlled chemical reaction between the food molecules and some oxygen which results in the release of energy from the food. The energy is used to make ATP. • Reaction- • Glucose + Oxygen = CO2 + Water • The net gain is 36-38 molecules of ATP per molecule of glucose

5. The Respiratory System • In order for cellular respiration to occur, organisms must have oxygen and that oxygen must somehow get to all of the cells in the body • This is the purpose of the Respiratory System • It includes lungs, bronchi, and trachea • It also requires the circulatory system to transport gases to and from the cells

7. The alveoli are surrounded by capilaries which allow the oxygen to be moved from the lungs into the circulatory system for transport to the rest of the body

8. The Function • It draws oxygen into the body for eventual distribution to cells and to remove carbon dioxide from the body • These two gases are exchanged between the blood and the atmosphere by diffusion in opposite directions across an external surface • In fish this surface is the gills • In terrestrial animals, the surface must be inside the body or it would quickly dry out is exposed to the environment.

9. Moving oxygen in and carbon dioxide out • Because the lungs are located internally, there must be a way to get the air containing oxygen into one’s body and moving air containing carbon dioxide away from the surface • This is solved by breathing or ventilation • Lungs are able to ventilate the body through alternating expansion and contraction

10. Inhalation • Stimuli from the neurons cause the diaphragm to contract and the intercostal muscles to raise the rib cage • These actions increase the volume of the thoracic cavity, resulting in lower air pressure within the thoracic cavity • At this point there is a higher air pressure inside the lungs that outside in the thoracic cavity resulting in the expansion of the lungs and air being drawn in through the trachea

11. Exhalation • Relaxation of the diaphragm causes it to push up into a dome shape below the lungs • Relaxation of the intercostal muscles cause the ribs to come down • These actions cause the thoracic cavity to decrease in volume resulting in greater air pressure outside the lungs than inside, causing the lungs to compress, forcing air out of the lungs.

12. The Heimlich Maneuver • This is an effective way to remove food from the throat of a choking victim • Before performing, you must first determine if person is really choking • If the person can speak, do NOT use the Heimlich maneuver • If they cannot speak and have their hand at their throat, it is appropriate to perform the maneuver