D2.2 - Breathing and Respiration

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Questions and Answers

What is the primary function of the alveoli in gas exchange?

To maintain a high concentration of carbon dioxide

To provide a large surface area for oxygen diffusion (correct)

To filter pollutants from the air

To release carbon dioxide into the blood

What prevents the lungs and respiratory pathways from collapsing?

High pressure during inhalation

Residual volume of gas (correct)

Tidal volume of air

Inspiratory reserve volume

Which respiratory volume measures the amount of air breathed in during normal breathing?

Vital capacity

Inspiratory reserve volume

Tidal volume (correct)

Expiratory reserve volume

What device is used to measure respiratory volumes?

Spirometer Signup and view all the answers

What is the total lung capacity indicated by vital capacity?

Total volume of gas that can be moved into and out of the lungs Signup and view all the answers

Which factor is NOT relevant when measuring vital capacity?

Color of hair Signup and view all the answers

What happens to the diaphragm during inhalation?

It contracts and moves downwards Signup and view all the answers

How is oxygen transported from the alveoli to the bloodstream?

Through diffusion down its concentration gradient Signup and view all the answers

What is the purpose of adaptations in respiratory structures for larger organisms?

To facilitate efficient gas exchange Signup and view all the answers

What triggers the diaphragm to start contracting?

Brain detects increased CO2 in the bloodstream Signup and view all the answers

What occurs during exhalation?

Air rushes out of the lungs as diaphragm relaxes Signup and view all the answers

How does gas exchange occur in the lungs?

By diffusion between air in alveoli and blood in capillaries Signup and view all the answers

What is the primary reason air rushes into the lungs during inhalation?

Diaphragm and intercostal muscles contract Signup and view all the answers

What concentration of CO2 is found in the blood before gas exchange?

Higher than in the alveoli Signup and view all the answers

Which action contributes to increased lung volume during inhalation?

Contraction of the diaphragm Signup and view all the answers

What happens to CO2 levels in the bloodstream after exhalation?

The levels decrease as it is expelled Signup and view all the answers

Study Notes

Breathing and Respiration

Breathing is the mechanism of gas exchange
The mechanism of breathing involves the movement of gases from an area of high pressure to an area of low pressure.
The diaphragm and intercostal muscles are crucial in achieving this.
In inhalation, the diaphragm contracts, lowering pressure inside the lungs, and air rushes in. Intercostal muscles lift the rib cage.
In exhalation, the diaphragm relaxes, raising pressure inside the lungs, and air moves out. Intercostal muscles relax allowing the rib cage to return to its normal position.

The Mechanics of Breathing

Breathing relies on the pressure difference between the chest cavity and atmosphere.
Atmospheric pressure is constant, but lung pressure changes.
An increase in lung volume decreases pressure, pulling air into lungs (inhalation)
A decrease in lung volume increases pressure, pushing air out of lungs (exhalation)

Breathing Movements

Inhalation:
- Diaphragm contracts
- Intercostal muscles contract
- Lung volume increases
- Environmental air pressure is greater than lung pressure
- Air rushes into the lungs to equalize pressure
Exhalation:
- Diaphragm relaxes
- Intercostal muscles relax
- Lung volume decreases
- Environmental air pressure is less than lung pressure
- Air rushes out of the lungs to equalize pressure

Gas Exchange

Gas exchange happens by diffusion between alveolar air and blood in capillaries.
Blood with high CO2 diffuses into alveoli to be exhaled
Alveoli with high O2 diffuses into the blood to be transported throughout the body.
Factors that facilitate gas exchange include thin, moist membranes, rich blood supply, large surface areas.

Adaptations for Gas Exchange

Small aquatic organisms diffuse gases directly between the environment and body cells.
Larger organisms need specialized respiratory structures (e.g., lungs) with thin walls, kept moist, richly supplied with blood vessels, and having large surface areas

Measuring Respiratory Volumes

Spirograph: A graph portraying respiratory volumes.
Tidal volume: Normal volume of air inhaled or exhaled during breathing cycles.
Inspiratory reserve volume: Additional air inhaled beyond tidal volume
Expiratory reserve volume: Additional air exhaled beyond tidal volume.
Vital capacity: Total volume of air that can be moved into and out of the lungs.
Residual volume: Air remaining in lungs even after maximal exhalation (essential for preventing lung collapse).
Spirometer is a device for measuring respiratory volumes.

Measuring Your Own Vital Capacity

Instructions on how to measure individual variation in lung capacity using a balloon.
Factors (age, sex, size) influence vital capacity.
Vital capacity can change due to illness
Medical professionals use vital capacity to diagnose and monitor diseases.

Summary

Gases move from areas of higher to lower pressure.
Partial pressure of gases in the atmosphere, blood, and tissues drives gas exchange.
Chemical receptors detect changes in gas levels (O2 and CO2), and send a message to adjust breathing rate.

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Description

Explore the mechanisms of breathing and respiration in this quiz. Understand how pressure changes in the lungs facilitate gas exchange, and learn the roles of the diaphragm and intercostal muscles in inhalation and exhalation.