A&P2 Week 6: Pulmonary Ventilation

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Questions and Answers

Define pulmonary ventilation.

Pulmonary ventilation, otherwise known as breathing, is inhalation (inflow) and exhalation (outflow) of air between the atmosphere and the alveoli of the lungs.

Define external respiration.

External respiration is the exchange of gases between the alveoli of the lungs and the blood in the pulmonary capillaries across the respiratory membrane. Pulmonary capillary blood gains O₂ and loses CO₂.

Define internal respiration.

Internal respiration is the exchange of gases between blood in systemic capillaries and tissue cells. Blood loses O₂ and gains CO₂. Cellular respiration is the metabolic reactions within cells that consume O₂ and produce CO₂.

What are the basic differences between pulmonary ventilation, external respiration, and internal respiration?

Pulmonary ventilation involves breathing (air moving in and out of the lungs). External respiration involves gas exchange at the alveolar level (O₂ in, CO₂ out). Internal respiration involves gas exchange at the tissue level (O₂ out of blood, CO₂ in). Signup and view all the answers

What does Boyle's law state?

Boyle's law states that the pressure of a gas in a closed container is inversely proportional to the volume of the container: increasing container size decreases pressure, and decreasing container size increases pressure. Signup and view all the answers

How does lung volume affect pressure and air movement?

Differences in pressure caused by changes in lung volume force air into the lungs when inhaling and out when exhaling. Signup and view all the answers

What happens to pressure when volume is increased during inhalation?

When the lungs expand, lung volume increases and lung pressure decreases, causing atmospheric pressure to be higher, resulting in air moving into the alveoli. Signup and view all the answers

What happens to pressure when volume is decreased during exhalation?

When the lungs relax, lung volume decreases and lung pressure increases, causing atmospheric pressure to be lower, resulting in air moving from the alveoli to the external atmosphere. Signup and view all the answers

Describe what happens to alveolar pressure as the diaphragm flattens and the intercostal muscles contract.

As the diaphragm flattens and the intercostal muscles contract, lung volume increases and lung pressure decreases, allowing for inhalation. Signup and view all the answers

Why is expiration referred to as a 'passive' process?

Expiration is referred to as a 'passive' process because no muscular contractions are involved; it occurs due to lung recoil. Signup and view all the answers

Describe what happens to alveolar pressure when the muscles relax and the lungs recoil.

When the muscles relax and the lungs recoil, lung volume decreases and lung pressure increases, leading to exhalation. Signup and view all the answers

Compare what happens during quiet versus forceful pulmonary ventilation.

During quiet inspiration, the diaphragm and external intercostal muscles contract, slightly enlarging the thoracic cavity. Deep breathing uses forceful contractions of inspiratory muscles and accessory muscles to produce larger changes in thoracic cavity volume during both inspiration and expiration. Signup and view all the answers

Study Notes

Pulmonary Ventilation

Defined as breathing; involves inhalation (inflow) and exhalation (outflow) of air between the atmosphere and the alveoli.

External Respiration

The exchange of gases between the alveoli and blood in pulmonary capillaries across the respiratory membrane.
Oxygen (O₂) enters the blood, while carbon dioxide (CO₂) is expelled.

Internal Respiration

The exchange of gases between blood in systemic capillaries and tissue cells.
Blood loses O₂ and gains CO₂; cellular respiration occurs within cells, consuming O₂ and producing CO₂ during ATP production.

Differences between Pulmonary Ventilation, External and Internal Respiration

Pulmonary ventilation entails breathing (air influx and efflux).
External respiration is gas exchange at the alveoli level (O₂ in, CO₂ out).
Internal respiration occurs at the tissue level (O₂ out of blood, CO₂ in).

Boyle's Law

States that the pressure of a gas in a closed container is inversely proportional to the volume of the container.
Increasing container size decreases gas pressure; decreasing container size increases gas pressure.

Lung Volume and Air Movement

Variations in lung volume create pressure differences that drive air into the lungs during inhalation and out during exhalation.

Increasing Volume

Inhalation occurs when lung volume increases and lung pressure decreases, leading to air moving into the alveoli where atmospheric pressure is higher.

Decreasing Volume

Exhalation happens when lung volume decreases and lung pressure increases, causing air to move from the alveoli to the external atmosphere where pressure is lower.

Alveolar Pressure Changes

As the diaphragm flattens and intercostal muscles contract, lung volume increases and pressure decreases, facilitating inhalation.

Expiration as a Passive Process

Refers to exhalation as a passive process because it occurs without muscular contractions.

Alveolar Pressure During Muscle Relaxation

When muscles relax and the lungs recoil, lung volume decreases and pressure increases, leading to exhalation.

Quiet versus Forceful Pulmonary Ventilation

Quiet inspiration involves the diaphragm and external intercostal muscles contracting, slightly enlarging the thoracic cavity.
Deep breathing incorporates forceful contractions of inspiratory muscles and accessory muscles, achieving larger volume changes during inspiration and expiration.

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Description

This quiz covers key concepts related to pulmonary ventilation and external respiration. It defines important terms such as breathing and gas exchange within the lungs. Test your understanding of these fundamental respiratory processes.