N3 Anatomy and Physiology (1st Sem AY 2022-2023)

Briefly explain the main cause or mechanism of increase in respiratory rate or depth and/or respiratory difficulties in the following cases:

1. Initiation of exercise

• • Our muscles work harder during exercise, which results in the body’s increased consumption of oxygen and the production of more carbon dioxide. Breathing rate increases and circulation speeds up in order to cope with the use of more energy used and the release of more waste.

2. Moderate exercise

• • As the body experiences a longer duration of exercise, loss of fluid, heat, and oxygen from the respiratory system is possible to occur. Both the minute and alveolar ventilation is increased, which leads to the exchange of gases.

3. Asthma attack

• • When a person has asthma, their airways can become inflamed and narrowed, which causes difficulty in efficient air flow when inhaling and exhaling. Additionally, the airways produce an excessive amount of mucus, which can trap air and cause coughing and wheezing.

4. Abrupt ascent into high altitudes

• • Elevated heart rate and hyperventilation are the main responses of the lungs when the body is exposed to high altitudes. In high levels of altitude, our breathing rate significantly increases in order to provide a sufficient supply of oxygen to the tissues.

5. Pneumonia 

• • In the presence of pneumonia, the lungs are infected by a bacteria or virus that has entered through the body’s airway, which can stop the lungs from removing carbon dioxide and adding oxygen to the blood. This causes inflammation of the alveoli and the buildup of fluid inside and around the lungs that results in fast breathing or the feeling of not having enough oxygen.

6. Paralysis of phrenic nerve

• • The phrenic nerve provides motor function to the diaphragm, which is why phrenic nerve injury can lead to diaphragmatic paralysis or dysfunction. When this nerve is damaged, the body may experience fatigue, shortness of breath, and difficulty in sleeping.

7. Severe tuberculosis with resulting lung scar tissue

• • Tuberculosis is a bacterial infection that mainly grows in the lungs which can spread through the bloodstream and infect other organs in the body. The infection causes chest pain and severe coughing, both symptoms that lead to the destruction of tissue in the lungs and inflammation of the airways.

8. Severe anemia

• • The circulation of red blood cells to the tissues is a way of maintaining oxygen saturation. However, when diagnosed with severe anemia, the blood has an insufficient amount of red blood cells, which can lead to accelerated heart rate and shortness of breath.

9. advanced COPD (chronic obstructive pulmonary disease)

• • When diagnosed with COPD, there is an inefficient flow of air and exchange of gases caused by the inflammation of the lungs. The obstruction of airflow decreases the level of oxygen in the blood and increases carbon dioxide while also causing the breathing muscles to contract faster, resulting in shortness of breath.

10. Advanced pregnancy

• • During pregnancy, the distention of the uterus causes the compression of the lungs and elevation of the diaphragm. The uterus presses on the diaphragm, making it more difficult for the lungs to fully expand, which then causes shallow breathing.