Guided Notes for the Control of Respiration

1. The activity of the respiratory muscles, the diaphragm and external intercostals, is regulated by nerve impulses transmitted to them from the brain by the phrenic and intercostal nerves.

2. The medulla oblongata sets the basic rhythm of breathing. Impulses from the pons and medulla maintain a rate of 12 to 15 respirations per minute. This normal rate is called eupnea.

3. During exercise, the brain centers send more impulses to the respiratory muscles. This pattern is called hypernea.

4 Factors That Affect the Rate and Depth of Respiration 1.Talking 2.Coughing 3.Exercise 4.Increased body temperature

5. Voluntary control of breathing is limited, and our respiratory centers will simply ignore messages from the cortex when oxygen supply in the blood is too low or blood pH is falling.

6. The most important factors that modify respiratory rate and depth are chemical—the levels of carbon dioxide and oxygen in the blood.

7. Although every cell in the body must have oxygen to live, it is the body’s need to rid itself of carbon dioxide (not take in oxygen) that is the most important stimulus for breathing in a healthy person.

8. What is the purpose of hyperventilation? It blows off more carbon dioxide and decreases the amount of carbonic acid in the blood, returning its pH to normal levels.

Name the 4 features common to COPD’s 1.Patients almost always have a history of smoking 2.Dyspnea—difficult or labored breathing 3.Coughing and frequent pulmonary infections 4.Most COPD patients are hypoxic, retain carbon dioxide, and have respiratory acidosis

10. In emphysema, the alveoli enlarge as the walls of adjacent chambers break through, and chronic inflammation promotes fibrosis of the lungs. Emphysema patients use an incredible amount of energy to exhale, and they are always exhausted.

11. In chronic bronchitis, the mucosa of the lower respiratory passages becomes inflamed and produces excessive amounts of mucus. The pooled mucus impairs ventilation and gas exchange and dramatically increases the risk of lung infections.

12. Cystic fibrosis, which is the most common lethal genetic disease in the U.S, causes oversecretion of a thick mucus that clogs the respiratory passages and puts the child at risk for fatal respiratory infections.

13. Asthma is caused by chronically inflamed, hypersensitive bronchial passages that respond to many irritants with dyspnea, coughing, and wheezing.