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I did my STEAM project on cystic fibrosis relating to the course objective “Analyze the effects of disease on function and structure of the respiratory system”. To understand how cystic fibrosis affects respiratory function, it is also important to understand pressure relationships and gas exchange. Gas exchange occurs where oxygen is picked up in the lungs and where carbon dioxide is released at the respiratory membrane (Betts et al., 2022). It also occurs in the tissues were oxygen is picked up and carbon dioxide released. The anatomy of the lung maximizes the diffusion of gasses, the large surface area throughout the lungs for example (Betts et al., 2022). An alveolar sac is a cluster of individual alveoli that are responsible for gas exchange. They stretch during air intake which increases surface area available for gas exchange (Betts et al., 2022). Alveoli and capillary membranes form the respiratory membrane that allows gases to cross by simple diffusion. Oxygen can then be picked up by the blood for transport and CO2 to be released into the air of the alveoli (Betts et al., 2022).
Cystic fibrosis is a multi-system and autosomal recessive disorder that results from mutations in the CFTR gene (Dickinson & Collaco, 2021). For someone to have CF, they must inherit 2 harmful CFTR variants of which there are more than 2000 CFTR variants reported. CFTR encodes for the CFTR (cystic fibrosis conductance regulator) protein. CFTR protein is an integral membrane protein that transport chloride ions out of the cell (Betts et al., 2022). In mutations of this, the cell makes a defective channel protein that is degraded in the cell instead of incorporated in the membrane. Malfunctioning chloride channels in apical membranes of the lung surface result in thick and sticky mucus that plugs the lungs resulting in inflammation, chronic infection, small airway obstruction, and bronchiectasis development (Dickinson & Collaco, 2021).
Respiratory epithelial cells secrete mucus which strap dust, bacteria, and other debris. Celia is hair-like appendages found on certain cells and they move the mucus and trapped particles away from the lungs. In order to move efficiently, the mucus must be thin and watery. Movement of chloride ions keeps the mucus watered down, but without this transport, water can’t be pulled into the mucus resulting in the thick sticky mucus that cilia struggles to move (Betts et al., 2022). This plays a huge role in defective resistance of CF patients to pathogens (Lyczak & Cannon, 2002). 80-95% of patients with CF succumb to respiratory failure brought on by chronic bacterial infection (Lyczak & Cannon, 2002). P. aeruginosa is the main cause of lung function decline and mortality in CF patients. Airways are plugged resulting in pulmonary function decline. In addition, antibiotic chemotherapy has reduced early mortality, however the ability to develop resistance to most antibiotics makes eradicating P. aeruginosa is difficult (Lyczak & Cannon, 2002). Approximately 30,000 people in the United States are affected by CF and there are ~1000 new cases a year (Betts et al., 2022). Maintaining lung health is critical and airway clearance therapy serves to remove airway mucus, reduce respiratory bacterial load along with irritants, leading to improved gas exchange and a decrease in airway obstruction (Dickinson & Collaco, 2021)! Examples of ACT include manual percussion, positive expiratory pressure devices, and high frequency cues wall oscillation which is an inflatable vest that performs chest physical therapy by vibrating at a high frequency (Dickinson & Collaco, 2021). This vest can be seen in my drawing on the left-most lung. The CF lungs are standing in a green pond to represent the thick mucous that makes it harder for gas exchange and increases susceptibility to lung infections. The lines in the pond represent the cilia that cannot effectively move mucus out and Cl- accumulation that can be seen in the pond as well. The CFTR sign is to demonstrate the mutated CFTR protein. A set of healthy lungs is standing 6 feet apart from the affected lungs. It is said that CF patients and anyone who is sick should stay 6 feet apart from other CF patients in order to avoid transmittance of infection. This is because coughing, sneezing, etc. can travel up to 6 feet (“Five Feet Apart”, n.d.). A healthy individual should be okay to stand closer than that, but the 6 feet apart reference is still added to this drawing. Lastly, in 1965 a little boy named Ricky Weiss misheard “cystic fibrosis” for “65 roses” (“65 Roses Story”, n.d.). Roses have been a symbol in the Cystic Fibrosis Foundation and this is represented in my drawing by the many flowers, and the set of healthy lungs giving the affected lungs flowers.
Works Cited
Dickinson, K. M., & Collaco, J. M. (2021). Cystic Fibrosis. Pediatrics in Review, Volume 42 (Issue 2), 55-67. 10.1542/pir.2019-0212
Lyczak, J. B., & Cannon, C. L., & Pier, G. B. (2002). Lung Infections Associated with Cystic Fibrosis. Clinical Microbiology Reviews, Volume 15 (Issue 2), 194-222. 10.1128/CMR.15.2.194-222.2002
Betts et al. (2022). Anatomy and Physiology (2nd ed.). Rice University. https://openstax.org/details/books/anatomy-and-physiology-2e
Cystic Fibrosis Foundation. (n.d.). 65 Roses Story. https://www.cff.org/about-us/65-roses-story
Cystic Fibrosis Foundation. (n.d.). Five Feet Apart.https://www.cff.org/get-involved/five-feet-apart
In progress photo:
Naomi’s STEAM project focuses on cystic fibrosis (CF) and how it affects respiratory function. She explains that gas exchange involves the diffusion of oxygen and carbon dioxide at the respiratory membrane, which consists of capillaries and alveoli. Unfortunately, CF patients often suffer from airways blockages, so gas diffusion can become impaired.
CF is caused by mutations in the CFTR (cystic fibrosis conductance regulator) gene. For this condition to present, two mutated/harmful gene variants must be inherited. The CFTR gene affects integral membrane proteins that are responsible for chloride ion transport.
Respiratory epithelial cells, in efforts to keep debris, bacteria, etc., out of the lungs, secrete mucus. Chloride ions are instrumental in maintaining proper mucus consistency because they affect the diffusion of water. The mucus is moved by cilia, which are a type of hairlike projection. Without chloride ions, the mucus becomes too thick for the cilia to move.Thick mucus, in addition to blocking airways, is known to contribute to bacterial infections.
Because CF is caused by gene mutations, it cannot be cured, however, it is managed and treated through airway clearance therapy (ACT). ACT can be performed in a variety of ways but often includes a vibrating vest. This clears mucus and consequently reduces bacterial load and improves gas exchange.
Naomi represented this artistically by drawing two sets of lungs. While one set is healthy, the other is covered in thick green mucus, wearing a vibration vest, and surrounded by chloride ions.