Respiratory Distress Syndrome and Pulmonary Volumes

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Questions and Answers

What is the consequence of decreased surfactant?

Lung collapse (atelectasis), difficult inflation and hypoxemia.

What is the cause of respiratory distress syndrome in the context of long-term inhalation of 100% oxygen?

Long-term inhalation of 100% oxygen can cause damage to the lungs and decrease surfactant production, leading to respiratory distress syndrome.

What is the cause of respiratory distress syndrome in the context of occlusion of one branch of the pulmonary artery?

Occlusion of a branch of the pulmonary artery prevents blood flow to the alveoli, which are responsible for gas exchange. This results in a failure to synthesize surfactant, leading to respiratory distress syndrome.

What is the effect of cigarette smoking on surfactant production?

Cigarette smoking negatively affects surfactant production, contributing to various lung problems. Signup and view all the answers

What specific hormone is essential for surfactant production?

Thyroxine, a hormone produced by the thyroid gland, is crucial for surfactant production. Signup and view all the answers

How does cortisol influence lung surfactant?

Cortisol accelerates the maturation of lung surfactant. Signup and view all the answers

Why is hyperinsulinism a risk factor for respiratory distress syndrome in infants?

Hyperinsulinism inhibits surfactant secretion, leading to respiratory distress syndrome, especially in infants born to diabetic mothers. Signup and view all the answers

What is the primary method for measuring lung volumes and capacities?

A spirometer is used to measure lung volumes and capacities. Signup and view all the answers

The volumes of air inspired or expired during one respiratory cycle at rest are the same for males and females.

False Signup and view all the answers

What is the maximum volume of air that can be inspired after normal inspiration?

3000 ml Signup and view all the answers

What is the maximum volume of air that can be expired by forced expiration after normal expiration?

1100 mL Signup and view all the answers

What is the volume of air remaining in the lungs after maximum expiration?

1200 mL Signup and view all the answers

What is the importance of Residual Volume?

It aerates the blood between breaths. Signup and view all the answers

What is the volume of air in the lungs at the end of normal expiration?

2300 ml. Signup and view all the answers

What is the volume of air in the lungs at the end of maximum inspiration?

5800 ml. Signup and view all the answers

What is the method used to determine FRC, RV, and TLC?

Helium Dilution Method Signup and view all the answers

Lung capacities are simply the same as lung volumes.

False Signup and view all the answers

What are the two main types of lung measures?

Lung Volumes and Lung Capacities Signup and view all the answers

Study Notes

Respiratory Distress Syndrome

Causes:
- Long-term inhalation of 100% oxygen during cardiac surgery
- Pulmonary artery blockage (thrombus)
- Cigarette smoking
- Hypothyroidism (lack of thyroxine hormone)
- Hypocorticism (reduced cortisol levels)
- Hyperinsulinism (excess insulin, common in infants of diabetic mothers)

Pulmonary Volumes and Capacities

Measured using a spirometer: Lung volumes and capacities are measured in a healthy 70 kg person, who is sitting. The volumes will be 10% smaller in a female.
Tidal Volume (TV): Volume of air inhaled or exhaled in one breath at rest, typically 500 mL.
Inspiratory Reserve Volume (IRV): Maximum volume of air inhaled after a normal breath. Approximately 3000 mL.
Expiratory Reserve Volume (ERV): Maximum volume of air exhaled after a normal breath. Approximately 1100 mL.
Residual Volume (RV): Air remaining in lungs after maximum exhalation. Approximately 1200 mL.
Functional Residual Capacity (FRC): Sum of ERV + RV; volume in lungs at end of normal breath. 2300 mL.
Inspiratory Capacity (IC): Sum of TV + IRV; maximum volume of air that can be inhaled. 3500 mL.
Vital Capacity (VC): Maximum volume of air that can be exhaled after maximum inhalation. Sum of TV+IRV+ERV. 4600 mL.
Total Lung Capacity (TLC): Total volume of air in lungs after maximum inspiration. Sum of TV + IRV + ERV + RV. 5800 mL.

Other Key Concepts

Expiratory Reserve Volume (ERV): Maximum volume of air that can be exhaled after a normal breath.
Decreased surfactant can lead to lung collapse (atelectasis) and difficulty breathing due to hypoxemia (low blood oxygen levels).
COPD: Causes an increase in residual volume (RV) and functional residual capacity (FRC), sometimes by up to 70% of total lung capacity.
Measurement and Calculation: Volume measurements can't always be completely measured by spirometry (only measures in/out of lungs). Methods like helium-dilution are used for more complete measurements.
Minimal Air: Small volume of air remains in lungs even after opening the chest wall.
Medicolegal Importance of Minimal Air: The presence or absence of minimal air can determine if an infant was born alive (if minimal air is present).

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Description

This quiz covers the causes of Respiratory Distress Syndrome as well as the measurement of pulmonary volumes and capacities. Understand key concepts such as Tidal Volume, Inspiratory Reserve Volume, and others measured with a spirometer. Test your knowledge on respiratory health and its physiological implications.