Name
Western Governors University
D313 Anatomy and Physiology II with Lab
Prof. Name
Date
What are the primary functions of the nasal cavity mucosa?
The mucosa lining the nasal cavity serves essential protective roles for the respiratory system. It primarily acts as a filter by trapping dust, allergens, and microorganisms, thereby preventing harmful particles from entering the lower respiratory tract. Additionally, it humidifies and warms the air before it reaches the lungs, which is critical to avoid irritation and dryness of the respiratory tissues. These functions together help maintain a stable environment that supports efficient gas exchange within the alveoli (Marieb & Hoehn, 2018).
Why does the trachea contain cartilaginous rings?
The trachea is reinforced by C-shaped cartilaginous rings that provide structural integrity while allowing flexibility. These rings prevent the trachea from collapsing during breathing by maintaining an open airway. The open part of these rings faces the esophagus, enabling the esophagus to expand when swallowing food without compressing the trachea (Tortora & Derrickson, 2017).
What is the pathway of oxygen from the nares to the body tissues?
Oxygen enters through the nares and flows into the nasal cavity, then passes through the pharynx, larynx, and trachea. It continues down the bronchi and bronchioles until reaching the alveoli in the lungs. At the alveoli, oxygen diffuses into pulmonary capillaries, binds with hemoglobin in red blood cells, and is transported via the bloodstream to various tissues where it supports cellular respiration (Marieb & Hoehn, 2018).
How is asthma characterized?
Asthma is a chronic inflammatory disorder of the airways characterized by bronchoconstriction, swelling, and excess mucus production. These changes lead to symptoms such as wheezing, coughing, and difficulty breathing. Management typically involves inhaled corticosteroids to reduce inflammation and bronchodilators to ease airway constriction. Environmental factors like allergens, cold air, and stress can trigger or worsen asthma attacks (National Heart, Lung, and Blood Institute, 2020).
| Structure | Description |
|---|---|
| Trachea | A flexible tube supported by cartilage and lined with pseudostratified ciliated columnar epithelium containing goblet cells that secrete mucus to trap airborne particles. |
| Lung | A spongy, elastic organ with a grayish hue responsible for gas exchange between air and blood. |
Post-Lab Questions
Label the components indicated by arrows in microscopic slides:
A: Goblet cells
B: Basement membrane
C: Connective tissue of lamina propria
D: Cilia
E: Bronchiole
F: Bronchi
G: Alveoli
H: Capillaries
What features of alveoli facilitate gas exchange?
Alveoli are specialized for gas exchange through their extremely thin epithelial walls formed by Type I pneumocytes, an extensive surrounding capillary network, and a large surface area. The moist environment inside alveoli supports efficient oxygen and carbon dioxide diffusion. Type II pneumocytes secrete surfactant, which reduces surface tension to prevent alveolar collapse during breathing (Tortora & Derrickson, 2017).
Why is mucus present in the trachea?
Mucus in the trachea traps dust, microbes, and other particles, preventing them from reaching the lungs. It also keeps the airway moist and contains antibodies and antimicrobial agents that help neutralize pathogens (Marieb & Hoehn, 2018).
What role do cilia play in the trachea?
Cilia lining the trachea move rhythmically upward, pushing mucus and trapped debris toward the pharynx for expulsion or swallowing. This mucociliary escalator mechanism is crucial for airway cleanliness and infection prevention (Tortora & Derrickson, 2017).
| Question | Answer |
|---|---|
| How does diaphragm contraction affect thoracic pressure and lung volume? | Diaphragm contraction increases thoracic cavity volume, decreasing internal pressure and allowing air to enter the lungs (inhalation). Relaxation reverses this, raising pressure and pushing air out (exhalation). |
| Where does deoxygenated blood become oxygenated? | Oxygenation occurs in the alveoli of the lungs through gas exchange between alveolar air and capillary blood. |
| Is the trachea located superior or inferior to the diaphragm? | The trachea is positioned superior (above) the diaphragm. |
| Which is more medial: the right lung or the tracheal bifurcation? | The tracheal bifurcation is more medial than the right lung. |
| What is the most inferior organ of the respiratory system? | The diaphragm is the most inferior respiratory structure. |
| Observation | Description |
|---|---|
| Squeezed Bottle (Step 3) | Internal balloon inflates as air is drawn in, simulating lung expansion during inhalation. |
| Released Bottle (Step 4) | Balloon deflates as air exits, replicating exhalation. |
Post-Lab Questions
What causes the balloon to inflate?
The balloon inflates because air pressure enters through the straw, mimicking lung expansion when the diaphragm contracts during inhalation.
What happens if the bottle seal leaks?
A leak disrupts negative pressure formation, preventing proper balloon inflation and simulating conditions like pneumothorax where lung expansion is impaired.
What causes a collapsed lung?
A collapsed lung occurs when air enters the pleural cavity, eliminating the pressure difference necessary for lung expansion, resulting in lung collapse (pneumothorax).
Is a collapsed lung functional? Why or why not?
No, a collapsed lung cannot expand or perform gas exchange, leading to inadequate oxygen supply to body tissues.
| Patient | FVC (L) | FEV1 (L) | FEV1/FVC (%) | Interpretation |
|---|---|---|---|---|
| A | 4.93 | 4.10 | 83.3 | Asthma well controlled |
| B | 2.16 | 1.93 | 89.7 | Mild asthma symptoms |
| C | 2.74 | 2.08 | 76.1 | Reduced lung capacity; potential surgery candidate |
| D | 2.53 | 2.00 | 78.95 | Possible airway obstruction |
| E | 2.29 | 2.03 | 88.6 | Normal respiratory function |
Post-Lab Questions
Is Patient A managing asthma effectively?
Yes, Patient A exhibits normal FEV1/FVC ratios, indicating well-controlled asthma.
Does Patient B have asthma?
Yes, the spirometry data suggest airway resistance consistent with mild asthma symptoms.
Should Patient C consider lung surgery?
The reduced lung function suggests surgery might be necessary, pending further evaluation.
What might be the cause of Patient D’s symptoms?
Symptoms likely result from airway obstruction related to chronic respiratory illnesses such as asthma or COPD.
Is Patient E asthmatic?
No, Patient E’s spirometry values indicate normal lung function.
What are some limitations of spirometry in diagnosing respiratory diseases?
Spirometry depends on patient cooperation and technique, which can influence results. It cannot always distinguish among different pulmonary diseases, often requiring supplementary imaging and tests for accurate diagnosis (American Thoracic Society, 2023).
Describe the internal lining of the trachea.
The trachea is lined with pseudostratified ciliated epithelium containing goblet cells that produce mucus. The cilia move mucus upward toward the pharynx to clear debris. Beneath this layer lies a vascular submucosa that supplies nutrients and oxygen to the tracheal tissue (Marieb & Hoehn, 2018).
Are there many blood vessels between the lungs and heart? Why?
Yes, numerous pulmonary arteries and veins connect the lungs and heart, facilitating rapid and efficient gas exchange—oxygenating the blood and removing carbon dioxide.
What role does the diaphragm play during breathing?
The diaphragm is the main muscle involved in respiration. Its contraction enlarges the thoracic cavity, allowing air to flow into the lungs (inhalation), while its relaxation decreases cavity volume, pushing air out (exhalation) (Tortora & Derrickson, 2017).
American Thoracic Society. (2023). Spirometry. https://www.thoracic.org/patients/patient-resources/resources/spirometry.pdf
Marieb, E. N., & Hoehn, K. (2018). Human Anatomy & Physiology (11th ed.). Pearson.
National Heart, Lung, and Blood Institute. (2020). Asthma. https://www.nhlbi.nih.gov/health-topics/asthma
Tortora, G. J., & Derrickson, B. (2017). Principles of Anatomy and Physiology (15th ed.). Wiley.
