Briefly explain the main cause or mechanism of increase in respiratory rate or depth and/or respiratory difficulties in the following cases: (one to two sentences only)
1. Initiation of exercise
The main cause of increase in respiratory rate or depth during the initiation of exercise is the neural changes that send excitatory impulses to the inspiratory area in the medulla oblongata.
2. Moderate exercise
The increase in respiratory rate during moderate exercise is due to chemical and physical changes in the bloodstream, which include increased oxygen consumption, increased carbon dioxide production, and increased body temperature.
3. Asthma attack
The main cause of respiratory difficulties in asthma attacks is the smooth muscle spasms in the walls of smaller bronchi and bronchioles, edema of the mucosa of the airways, excessive mucus secretion and/or damage to the airway epithelium.
4. Abrupt ascent into high altitudes
The lack of oxygen present at high altitudes is detected by the peripheral chemoreceptors, leading to hyperventilation or the increase in breathing rate.
5. Pneumonia
Microbes that enter the lungs of affected individuals release toxins that damage alveoli and bronchial mucous membranes. Due to the inflammation and edema, the alveoli gets filled with fluid, resulting in interference with ventilation and gas exchange.
6. Paralysis of phrenic nerve
The phrenic nerve has a crucial part in breathing as it causes the diaphragm to contract and expand — which permits inhalation and exhalation of air. With this, respiratory difficulties in this case result from a paralyzed diaphragm.
7. Severe tuberculosis with resulting lung scar tissue
In severe tuberculosis, once bacteria enters the lungs, they multiply and cause inflammation. This may result in pleural effusion (a collection of fluid between the pleura, the thin membranes covering the lungs and lining the inside of the chest wall).
8. Severe anemia
Iron deficiency causes inability of the body to produce enough hemoglobin, which helps in carrying oxygen. As a result, this may result in breathing difficulties of people with severe anemia.
9. advanced COPD (chronic obstructive pulmonary disease)
COPD causes the airways and tiny sacs to lose their ability to stretch and shrink back. The walls of the airways become thick and inflamed and more mucus is produced, which may lead to clogging and blocking of the airflow.
10. Advanced pregnancy
Respiratory difficulties in a woman during advanced pregnancy may be caused by the growing uterus pressing up against the lungs, as well as change or increase in hormones.
References:
Cleveland Clinic. (n.d.). Phrenic Nerve: Anatomy & Function. Cleveland Clinic. https://my.clevelandclinic.org/health/body/22270-phrenic-nerve
Goldman, R. (2019, May 31). Symptoms and Signs of Tuberculosis | Everyday Health. EverydayHealth.com. https://www.everydayhealth.com/tuberculosis/guide/symptoms/
Medical News Today. (2022, January 20). Shortness of breath during pregnancy: Causes and management. Www.medicalnewstoday.com. https://www.medicalnewstoday.com/articles/322316#overview
Tortora, G. & Derrickson, B.(2012). Principles of anatomy and physiology. John Wiley & Sons