A. ACTIVITY
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 most important reason for an elevation in both the rate and depth of breathing at the beginning of exercise is the increased need for oxygen by the engaged muscles, as well as the need to expel accumulating carbon dioxide. These factors all together activate the respiratory centers in the brain, causing an increase in breathing to match up with the increased metabolic demands of the body.
2. Moderate exercise
- During a session of moderate physical activity, the exertion placed on your muscles intensifies, demanding for a higher supply of oxygen and resulting in an increased production of carbon dioxide; this causes your inhalation and exhalation to quicken, reaching a rate of around 40-60 breaths per minute (2016). Additionally, your blood flow quickens to ensure sufficient delivery of oxygen to the engaged muscles in order to maintain their functionality while efficiently eliminating carbon dioxide.
3. Abrupt ascent into high altitudes
- The human body faces significant challenges when exposed to high altitudes, mostly coming from the gradual decrease in barometric pressure and consequent decline in oxygen pressure, this situation results in crucial physiological reactions that allow people to withstand hypoxia and ensure a sufficient oxygen supply to bodily tissues [known as the process of acclimation] (Cogo, 2011). The altered oxygen accessibility instigates an elevation in respiratory rate and volume, compensating for the lowered oxygen levels in order to sustain an appropriate oxygen delivery to the body's tissues.
4. Paralysis of phrenic nerve
- The impairment of diaphragmatic function caused by the paralysis of the phrenic nerve results in a reduction in the depth of respiration and often necessitates the engagement of accessory muscles to facilitate breathing, thereby giving rise to respiratory challenges. During physical examinations, observations may reveal diminished breath sounds on the affected side, dullness on percussion of the affected area of the chest, as well as a concomitant movement of the epigastrium towards the thoracic cavity during inhalation.
5. Severe anemia
- In cases of severe anemia, characterized by a notable decline in the blood's ability to transport oxygen due to reduced levels of hemoglobin, the body reacts by increasing both the frequency and magnitude of respiration so as to improve the supply of oxygen to tissues, thereby mitigating the diminished oxygen transport capability of the blood. Individuals afflicted with considerably severe anemia experience manifestations of exaggerated respiration and an accelerated heart rate, as their bodies persistently endeavor to restore oxygen levels to a state of equilibrium.
10. Advanced pregnancy
- During advanced pregnancy, the expanding uterus exerts upward force on the diaphragm, constraining its ability to contract fully. Consequently, taking deep breaths becomes troublesome, resulting in respiratory challenges; this process brings about notable modifications in the diaphragm, such as heightened tension generation due to lengthening of muscle fibers, an increased surface area of contact with the lower ribcage, and a larger radius of curvature caused by the gradual enlargement of the lower ribcage to accommodate the lungs (LoMauro & Aliverti, 2015).
References:
Anemia disrupts respiratory system activity. (n.d.). Retrieved from https://www.biron.com/en/education-center/specialist-advice/anemia-breathing/
Cogo, A. (2011). The lung at high altitude. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3463062/#:~:text=In%20fact%2C%20high%20altitude%20is,the%20oxygen%20supply%20to%20tissues.
LoMauro, A., & Aliverti, A. (2015). Respiratory physiology of pregnancy: Physiology masterclass. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4818213/
Phrenic Nerve. (n.d.). Retrieved from https://www.physio-pedia.com/Phrenic_Nerve
Your lungs and exercise. (2016). Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4818249/#:~:text=When%20you%20exercise%20and%20your,litres%20of%20air