1. Control of Breathing

2. Control of respiration Neural regulation: -The activity of the respiratory muscles (diaphragm and external intercostals) is regulated by nerve impulses transmitted to them from the brain by the phrenic and intercostal nerves -The neural centers that control respiratory rhythm and depth are located in the medulla and pons

3. Medulla and Pons The medulla sets the basic rhythm of breathing, contains a self-exciting inspiratory center, as well as other respiratory centers The pons centers appear to smooth out the basic rhythm of inspiration and expiration set by the medulla Medulla and pons maintain a impulse of 12-15 respirations/min

4. Factors influencing respiratory rate/depth Physical factors: talking, coughing, body temperature and exercise Volition (conscious control): Respiratory centers will ignore messages from the brain when the oxygen supply in the blood is getting low or blood pH is failing Emotional factors: fear, happiness, surprise

5. Chemical factors: the levels of carbon dioxide (more important) and oxygen in the blood -Increased level of CO 2 and decreased level of pH leads to increase in the rate and depth of breathing -Changes in O 2 concentration in the blood are detected by chemoreceptors in the aorta and carotid artery Factors influencing respiratory rate/depth

6. pH factors Low pH: breathe more deeply and more rapidly- this action blows off more CO 2 and decrease the amount of carbonic acid High pH: breathe more shallow and slow- this action allows CO 2 to accumulate in the blood

7. Hyperventilation Fast, deep breathing Often brought on by anxiety attack, frequently leads to brief period of apnea, brief stop of breathing, until CO 2 builds up in the blood again Cyanosis: when breathing stop for a extended period of time

8. Nonrespiratory Movement Sneezing: Involves using the uvula to close the oral cavity off from the pharynx in order to clear the upper respiratory passages Coughing: Blast of upward rushing air that clears the lower respiratory passages

9. Hiccupping: Sudden inspirations resulting from spasms of the diaphragm Yawning: A very deep inspiration formerly believed to be triggered by low oxygen Nonrespiratory Movement

10. Crying: Primarily an emotionally induced mechanism that involves release of air in a number of short breaths Laughing: An emotionally induced response that produces air movements similar to crying Nonrespiratory Movement