D313 Lab 13 The Respiratory System

Student Name

Western Governors University

D313 Anatomy and Physiology II with Lab

Prof. Name:

Date

Lab 13: The Respiratory System

Student Name: ____________
Access Code: [Located on the lid of your lab kit]

Pre-Lab Questions

1. What are two main functions of the nasal cavity mucosa?

The mucosa lining the nasal cavity serves a dual purpose: it filters incoming air by trapping dust, allergens, and other particulates, and it humidifies the air by adding moisture. This ensures that the respiratory tract remains protected from drying out and potential irritation, creating optimal conditions for efficient gas exchange further down the respiratory tract.

2. Why does the trachea have cartilaginous rings?

The trachea is reinforced with cartilaginous rings to maintain its structural integrity. These rings prevent the trachea from collapsing during breathing, ensuring that the airway remains open for unimpeded airflow to the lungs.

3. What is the pathway of oxygen from the nares to body tissues?

Oxygen follows a specific path starting at the nares, passing through the nasal cavity, then the pharynx, trachea, bronchi, bronchioles, and finally reaching the alveoli where gas exchange occurs. From the alveoli, oxygen enters the bloodstream and is transported to body tissues.

4. How is asthma characterized?

Asthma is a chronic respiratory disease marked by inflammation and narrowing of the airways. This leads to symptoms such as difficulty breathing, coughing, and wheezing. Management typically requires long-term medication to control inflammation and acute treatment during flare-ups.

Experiment 1: Microscopic Anatomy of the Respiratory System

Table 1: Observations of Respiratory Structures

Structure	Description
Trachea	A long U-shaped tube connecting to the voice box; lined with ciliated epithelium and goblet cells producing mucus.
Lung	Spongy, grayish organ responsible for gas exchange.

Post-Lab Questions

1. Label the arrows in the microscopic slide images:

A: Goblet cells
B: Basement membrane
C: Connective tissue of lamina propria
D: Cilia
E: Bronchiole
F: Bronchi
G: Alveoli
H: Capillaries

2. What alveolar features facilitate gas exchange?
Alveoli have thin walls composed of a single layer of epithelial cells, a large surface area, a rich network of blood capillaries, and a moist environment. These characteristics optimize the diffusion of oxygen into blood and carbon dioxide out of the blood.

3. Why is mucus present in the trachea?
Mucus in the trachea traps airborne particles, humidifies inhaled air, protects airway tissues, and supports immune defense by preventing harmful agents from reaching deeper lung structures.

4. What is the function of cilia in the trachea?
Cilia on the tracheal walls move rhythmically to sweep mucus, along with trapped particles, upward toward the pharynx for expulsion, thus helping maintain a clean respiratory tract.

Experiment 2: Virtual Model of the Respiratory System

Insert screenshot of the epiglottis (Note: user to provide)

Post-Lab Questions

1. How does diaphragm contraction affect thoracic cavity pressure and lung volume?

When the diaphragm contracts, the volume of the thoracic cavity increases, causing a decrease in internal pressure. This negative pressure draws air into the lungs (inhalation). When the diaphragm relaxes, pressure increases, and air is expelled (exhalation).

2. Where does deoxygenated blood become oxygenated?

Deoxygenated blood becomes oxygenated in the lungs, specifically within the alveoli.

3. Is the trachea located superior or inferior to the diaphragm?

The trachea is located superior (above) to the diaphragm.

4. Which structure is more medial: the right lung or the tracheal bifurcation?

The tracheal bifurcation is more medial compared to the right lung.

5. What is the most inferior organ of the respiratory system?

The diaphragm is the most inferior structure associated with the respiratory system.

Experiment 3: Understanding Lung Mechanics

Table 2: Lung Mechanics Observations

Observation	Description
Squeezed Bottle (Step 3)	Balloon inside increases in size as air enters, simulating inhalation.
Released Bottle (Step 4)	Balloon slowly decreases in size, simulating exhalation.

Post-Lab Questions

1. What happens to the balloon and why?
The balloon inflates as it fills with air from the straw, representing the lungs expanding during inhalation.

2. What if the bottle’s seal leaks?
If the seal leaks, the balloon will not inflate fully or may fail to inflate, disrupting normal lung mechanics.

3. What causes a collapsed lung?
A collapsed lung, or pneumothorax, occurs when air enters the pleural space, breaking the negative pressure required to keep the lung inflated.

4. Is a collapsed lung functional? Why or why not?
No, a collapsed lung cannot function properly because it cannot expand to allow gas exchange, impairing oxygen delivery to the body.

Experiment 4: Spirometry Data Analysis

Patient Spirometry Data Summary

Patient	FVC (L)	FEV1 (L)	FEV1/FVC (%)	Interpretation
A	4.93	4.10	83.3	Effective asthma management
B	2.16	1.93	89.7	Asthmatic symptoms present
C	2.74	2.08	76.1	Candidate for lung surgery
D	2.53	2.00	78.95	Likely airway obstruction
E	2.29	2.03	88.6	No asthma detected

Post-Lab Questions

1. Is Patient A managing asthma effectively?
Yes, Patient A’s spirometry values are within predicted ranges, indicating good asthma control with inhaler use.

2. Is Patient B suffering from asthma?
Yes, the reduced FEV1 during exercise suggests airway obstruction consistent with asthma.

3. Should Patient C undergo lung surgery?
Yes, due to significantly compromised lung function, Patient C may benefit from surgical intervention.

4. What is the likely cause of Patient D’s symptoms?
Patient D’s low FEV1 suggests airway obstruction, possibly from chronic conditions like COPD or asthma.

5. Is Patient E asthmatic?
No, Patient E’s spirometry results do not indicate asthma.

6. What are some limitations of spirometry in diagnosing respiratory diseases?
Spirometry results can be influenced by patient effort, technique variability, and external factors like smoking or air pollution. It may also produce false positives or negatives and has limited scope in diagnosing complex lung conditions.

Experiment 5: Fetal Pig Dissection

Post-Lab Questions

1. Describe the interior lining of the trachea.
The trachea’s interior is lined with ciliated respiratory epithelial cells that propel mucus and trapped particles upward. Goblet cells produce mucus, while the submucosa contains blood vessels and glands supporting the lining.

2. Are there many blood vessels between the lungs and heart? Why?
Yes, numerous blood vessels connect the lungs and heart to ensure efficient oxygen transport and carbon dioxide removal, facilitating effective systemic oxygenation.

3. What is the function of the diaphragm during breathing?
The diaphragm is a vital involuntary muscle that contracts to increase thoracic volume during inhalation and relaxes to reduce volume during exhalation, thus driving normal breathing.

References

Marieb, E. N., & Hoehn, K. (2018). Human Anatomy & Physiology (11th ed.). Pearson.
Tortora, G. J., & Derrickson, B. (2017). Principles of Anatomy and Physiology (15th ed.). Wiley.