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 rate and depth of our breathing immediately increase as soon as an exercise is initiated mainly due to the proprioceptors of our body monitoring our movements. These, along with our motor neurons, send impulses to our instipatory area of the DRG in our medulla resulting to immediate reaction of our respiratory efforts.
2. Moderate exercise
- Increased external stimulus leads us to fall further in hyperpnea and a ventilatory pump is highly utilized to maintain an effective homeostasis of the arterial blood gases and hydrogen ion concentration by increasing alveolar ventilation. The target is to regulate breathing in the level of the external efforts to minimize the work performed by the respiratory muscles and prevent it from fatigue.
3. Abrupt ascent into high altitudes
- In hypoxic hypoaxia, an abrupt ascent to high altitudes may cause an effective impediment in the oxygen transport between our lungs and our blood due to a low PO2 in arterial blood. As altitude increases, oxygen gets farther apart and partial pressure continues to decrease, thus explain our difficulty in breathing.
4. Paralysis of phrenic nerve
- As the phrenic nerve provides sensory information to various respiratory organs and is the only nerve to provide primary motor supply to the diaphragm, its paralysis (unilaterally or bilaterally) may cause multitude of challenges ranging from shortness of breath to pneumonia or even death when not treated. The diaphragm's contraction and relaxation are the major initiator of breathing, thus its paralysis will cause a major gap in our pulmonary ventilation.
5. Severe anemia
- With low-functioning hemoglobin streamlining our blood, fewer binding sites means oxygen cannot be effectively transported to various cells and tissues of our body. Increased capillary perfusion, arteriolar dilation, and viscosity reduction all are needed to maintain normal oxygen consumption.
10. Advanced pregnancy
- As a pregnant woman's uterus progressively takes up space, the anatomical and lung volume changes it brought primarily leads to greater resistance to air flow and greater risk of airway obstruction thus leading to episodes of shortness of breath. The diaphragm cannot fully descent, rib cage expands, chest height lowers, tidal volume and respiratory rates increase, TLC and FRC decrease — all contributing simultaneously.
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• Cleveland Clinic. (2022). Phrenic Nerve: Anatomy & Function. Cleveland Clinic. https://my.clevelandclinic.org/health/body/22270-phrenic-nerve
• LoMauro, A., & Aliverti, A. (2015). Respiratory physiology of pregnancy. Breathe, 11(4), 297–301. https://doi.org/10.1183/20734735.008615
• Lumen Learning. (2019). The Process of Breathing | Anatomy and Physiology II. Lumenlearning.com. https://courses.lumenlearning.com/suny-ap2/chapter/the-process-of-breathing-no-content/
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• Pittman, R. N. (2011). Oxygen Transport in Normal and Pathological Situations: Defects and Compensations. In www.ncbi.nlm.nih.gov. Morgan & Claypool Life Sciences. https://www.ncbi.nlm.nih.gov/books/NBK54113/#:~:text=Anemic%20hypoxia%20occurs%20when%20the
• Respiratory changes during pregnancy | Deranged Physiology. (n.d.). Derangedphysiology.com. https://derangedphysiology.com/main/required-reading/pregnancy-obstetrics-and-gynaecology/Chapter%20114/respiratory-changes-during-pregnancy
• Tortora, G. J., & Derrickson, B. (2017). Principles of Anatomy and Physiology (15th ed.). Wiley.
POST-LECTURE ACTIVITY: RESPIRATORY SYSTEM
BONAJOS, Ayumi M.
The due date for posting to this forum was Thursday, 26 October 2023, 11:59 PM.