Ventilation and Breathing Mechanisms

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Questions and Answers

How does chronic endurance exercise training affect lung volumes?

It has no impact on lung volumes. (correct)

It only affects tidal volume.

It decreases lung volumes over time.

It significantly increases lung volumes.

Which sport is known to change lung volumes due to its demands?

Swimming (correct)

Cycling

Running

Weightlifting

What is the primary mechanism for increasing lung capacity in swimming?

Increased carbon dioxide retention.

Holding breath underwater. (correct)

Increased tidal volume during rest.

Descending below sea level.

What happens to barometric pressure as one ascends above sea level?

It decreases. Signup and view all the answers

What is the partial pressure of oxygen at sea level?

160 mmHg Signup and view all the answers

What initiates inspiration at rest?

Contraction of the diaphragm Signup and view all the answers

Which muscle is NOT involved in the process of expiration at rest?

Sternocleidomastoid Signup and view all the answers

What role does the diaphragm play during expiration?

Relaxes to decrease thoracic volume Signup and view all the answers

Which of the following activities occurs during inspiration during exercise?

Contraction of the diaphragm Signup and view all the answers

How does constricting the abdominal region affect the thoracic cavity size?

It decreases the size of the thoracic cavity Signup and view all the answers

What is the primary function of pressure in ventilation?

To establish a pressure gradient for airflow Signup and view all the answers

Which statement describes the system used for ventilation?

A closed system that creates pressure changes Signup and view all the answers

What happens to the intercostal muscles during active expiration?

They contract to pull the rib cage inwards Signup and view all the answers

What is dead space ventilation (VD)?

Ventilation that is unused and does not participate in gas exchange Signup and view all the answers

Where does oxygen diffusion into the blood primarily occur?

Alveoli Signup and view all the answers

What does surfactant do in the lungs?

Helps alveoli to not collapse Signup and view all the answers

How does acute exercise affect tidal volume?

Increases by cutting into inspiratory reserve volume Signup and view all the answers

What is the equation for total ventilation?

V = VA + VD Signup and view all the answers

What is the maximal volume breathed in after a normal inhalation called?

Inspiratory reserve volume Signup and view all the answers

Why is the air left in the lungs considered dirty?

It contains metabolic byproducts that are diluted Signup and view all the answers

What mechanism allows intrapleural fluid to help the lungs expand?

The pleura moving against the thoracic lining when pressure is applied Signup and view all the answers

What effect does swimming have on the alveoli during breath-holding?

Changes in size to hold breath for longer periods Signup and view all the answers

What is the relationship between barometric pressure and altitude?

Barometric pressure decreases as one ascends above sea level Signup and view all the answers

Which description best defines absolute pressure?

The barometric pressure in the atmosphere Signup and view all the answers

What primarily facilitates the diffusion of O2 and CO2 in the respiratory system?

Pressure gradient differences Signup and view all the answers

How is the partial pressure of oxygen in the lungs calculated?

Barometric pressure multiplied by the percentage of oxygen in the air Signup and view all the answers

What is the main function of surfactant in the alveoli?

Prevents alveoli from collapsing Signup and view all the answers

What happens to tidal volume during acute exercise?

It increases by utilizing inspiratory and expiratory reserve volumes Signup and view all the answers

How is total lung capacity (TLC) defined?

Volume in the lung after maximal inspiration Signup and view all the answers

What is the primary reason why residual lung volume cannot be expelled from the lungs?

It maintains alveolar structure Signup and view all the answers

What is the definition of dead space ventilation (VD)?

Unused air volume in the respiratory system Signup and view all the answers

Which lung volume is measured by spirometry?

Tidal volume Signup and view all the answers

What is the role of the diaphragm during normal breathing?

To help expand the thoracic cavity Signup and view all the answers

What impact does acute exercise have on breathing frequency?

Breathing frequency increases Signup and view all the answers

What occurs to the diaphragm during expiration at rest?

It relaxes and moves upwards Signup and view all the answers

Which of the following muscles are primarily engaged during inspiration in exercise?

Sternocleidomastoid and external intercostals Signup and view all the answers

What happens to the thoracic cavity size during contraction of abdominal muscles?

It decreases as abdominal organs push upward Signup and view all the answers

What is the outcome of relaxing the diaphragm during expiration?

Decreased volume of the thoracic cavity Signup and view all the answers

How does pressure change facilitate ventilation?

It creates a pressure gradient for air to flow in and out Signup and view all the answers

What happens to the pressure in the thoracic cavity during inhalation at rest?

It decreases below atmospheric pressure Signup and view all the answers

What role does the rib cage play during inspiration?

It expands the thoracic cavity Signup and view all the answers

Which of the following describes a closed system in relation to ventilation?

It maintains pressure changes to cause air movement Signup and view all the answers

Study Notes

Ventilation

Air movement in and out of the lungs is called ventilation.
The diaphragm contracts during inspiration, pulling it down, increasing thoracic cavity volume and decreasing pressure.
Relaxation of the diaphragm during expiration reverses this process.
Muscle contractions like those of the intercostals or abdominal muscles also affect thoracic cavity size.
Exercise increases the rate of ventilation through increased contractions of secondary respiratory muscles.
Ventilation is a closed system with pressure changes causing air to move into and out of the lungs.

Inspiration and Expiration at Rest and During Exercise

Inspiration at rest involves diaphragm and intercostal muscle contraction.
Expiration at rest involves diaphragm relaxation.
Exercise increases inspiration via use of accessory muscles (e.g., sternocleidomastoid, scalenes, external intercostals).
Exercise increases expiration via use of abdominal muscles.

Mechanisms of Ventilation

Inspiration involves diaphragm contraction and rib cage expansion.
Expiration involves diaphragm relaxation and rib cage contraction.
Surface tension in the alveoli is reduced by surfactant.

Lung Volumes

Tidal volume (TV) is the volume of air inhaled and exhaled during a normal breath.
Inspiratory reserve volume (IRV) is the maximal volume of air that can be inhaled beyond the tidal volume.
Expiratory reserve volume (ERV) is the maximal volume of air that can be exhaled beyond the tidal volume.
Residual volume (RV) is the volume of air remaining in the lungs after a maximal exhalation.
Inspiratory capacity (IC) = TV + IRV.
Functional residual capacity (FRC) = ERV + RV.
Vital capacity (VC)= IRV + TV + ERV
Total lung capacity (TLC)= IRV +TV +ERV +RV or VC + RV.

Ventilation During Exercise

Exercise increases the rate and depth of breathing.
Tidal volume increases.
Inspiratory reserve volume reduced.
Exhaled air during exercise is no longer 'clean'.

Partial Pressure

The pressure exerted by individual gases in a mixture of gases.
Oxygen diffuses from area of higher partial pressure to area lower partial pressure to be absorbed into the blood.
Carbon dioxide diffuses from area where it has higher partial pressure in the blood to the lungs where partial pressure is lower.

Other factors

Dead Space Ventilation (VD) - portion of inhaled air in the conducting zone and not involved in gas exchange
Alveolar ventilation (VA) - volume of inspired gas reaching respiratory zone
Spirometry - measures lung volume.
Examples: tidal volume (tidal inspired/expired volume per breath), inspiratory reserve volume (maximal additional inspiratory volume), expiratory reserve volume (maximal additional expiratory volume), residual volume.

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Description

This quiz covers the mechanisms of ventilation, including the roles of the diaphragm and intercostal muscles during inspiration and expiration. It also explores how exercise affects the rate of ventilation and the use of accessory muscles. Test your knowledge on how these processes occur at rest and during physical activity.