7.3 - Measuring the process of ventilation

Question 1

What factors affect the amount of gaseous exchange needed in the lungs?

Answer 1

The amount of gaseous exchange depends on your size and level of activity.

Question 2

Why must the gaseous exchange system be adaptable?

Answer 2

The gaseous exchange system must respond to the varying demands of the body to meet oxygen requirements and remove carbon dioxide efficiently.

Question 3

What are the four main ways that breathing can be scientifically measured?

Answer 3

1. vital capacity
2. tidal volume
3. breathing rate
4. oxygen uptake

Question 4

What is vital capacity?

Answer 4

Vital capacity is the maximum volume of air that can be breathed in after the strongest possible exhalation followed by the deepest possible inhalation.

Question 5

What is tidal volume?

Answer 5

Tidal volume is the volume of air that is breathed in or out during normal breathing at rest, with each resting breathe.

Question 6

What is the tidal volume in most adults at rest?

Answer 6

It is around 500 cm³ in most adults at rest, using about 15% of the vital capacity.

Question 7

What is breathing rate?

Answer 7

Breathing rate is the number of breaths taken in one minute. One breath includes inhaling and exhaling.

Question 8

What is oxygen uptake?

Answer 8

Oxygen uptake is the volume of oxygen used by someone in a given time.

Question 9

What are the 3 ways of measuring the capacity of the lungs?

Answer 9

1. A peak flow meter
2. Vitalographs
3. Spirometer

Question 10

What does a peak flow meter measure? Who is it used by, and what does it monitor?

Answer 10

A peak flow meter measures the rate at which air can be expelled from the lungs. It is often used by people with asthma to monitor lung function.

Question 11

What is a vitalograph, and how does it differ from a peak flow meter? What does it produce?

Answer 11

A vitalograph is a more sophisticated version of a peak flow meter. It produces a graph of the amount of air a patient can breathe out and the speed of exhalation.

Question 12

What is the forced expiratory volume in 1 second (FEV1)?

Answer 12

The forced expiratory volume in 1 second (FEV1) is the volume of air a person can breathe out in one second, measured using a vitalograph.

Question 13

What does a spirometer measure?

Answer 13

A spirometer measures different aspects of lung volume and investigates breathing patterns. breathing measurements such as vital capacity, tidal volume, breathing rate, and oxygen uptake.

Question 14

Are there different types of spirometers?

Answer 14

Yes, there are many forms of spirometers, but they all function on the same basic principle.

Question 15

How is carbon dioxide managed in a spirometer?

Answer 15

Soda lime absorbs carbon dioxide from the exhaled air to prevent its concentration from becoming too high, which could cause respiratory distress.

Question 16

How does a spirometer record breathing patterns?

Answer 16

As the subject breathes through the spirometer, a trace is either drawn on a rotating drum of paper or produced digitally for analysis.

Question 17

How does a spirometer measure oxygen uptake?

Answer 17

As the subject breathes, oxygen is extracted from the air in the spirometer. The total volume of air in the spirometer decreases, and this change in volume is used to calculate oxygen uptake.

Question 18

What measurements can be obtained using a spirometer?

Answer 18

A spirometer can measure:
1. Vital capacity
2. Tidal volume
3. Breathing rate
4. Oxygen uptake

Question 19

What does a spirometer trace represent?

Answer 19

A spirometer trace represents breathing patterns and measurements in the form of a graph drawn on paper or digitally created by a computer.

Question 20

What is residual volume?

Answer 20

Residual volume is the small amount of air that is always retained in the lungs, even after forceful exhalation. This cannot be measured directly.

Question 21

Why is residual volume important?

Answer 21

Residual volume prevents the lungs from collapsing and ensures that gas exchange continues between breaths.

Question 22

What aspects of lung volume can be measured?

Answer 22

1. Tidal volume
2. Vital capacity
3. Inspiratory reserve volume
4. Expiratory reserve volume
5. Residual volume
6. Total lungs capacity

Question 23

What is inspiratory reserve volume?

Answer 23

The maximum volume of air you can breathe in over and above a normal inhalation.

Question 24

What is expiratory reserve volume?

Answer 24

The extra amount of air you can force out of your lungs over and above the normal tidal volume.

Question 25

How is the total lung capacity calculated?

Answer 25

The sum of the vital capacity and the residual volume.

Question 26

What is the breathing rate?

Answer 26

The number of breaths taken per minute.

Question 27

What is the ventilation rate?

Answer 27

The total volume of air inhaled in one minute.

Question 28

How is ventilation rate calaculated?

Answer 28

Ventilation rate = tidal volume × breathing rate (per minute)

Question 29

How does the tidal volume change during exercise?

Answer 29

The tidal volume can increase from 15% to as much as 50% of the vital capacity to meet the body's oxygen demands.

Question 30

What happens to the breathing rate during increased oxygen demands (e.g., exercise)? Why?

Answer 30

The breathing rate increases to facilitate higher ventilation and oxygen uptake.

Question 31

How does the body meet increased oxygen demands?

Answer 31

By increasing tidal volume and breathing rate, which enhances ventilation and oxygen uptake during gaseous exchange.

Question 32

How do you convert tidal volume from cm³ to dm³?

Answer 32

Divide the tidal volume in cm³ by 1,000. e.g., 500cm³ --> 0.5dm³

Question 33

EXAMPLE QUESTION: A person took 15 breaths in a minute, and their tidal volume was 500 cm³. What is their ventilation rate in dm³ min⁻¹?

Answer 33

1. Convert tidal volume to dm³: 500cm³ = 0.5dm³ 2. Substitute values into the formula: Ventilation rate = 0.5dm³ × 15min⁻¹ 3. Calculate ventilation rate: Ventilation rate= 7.5 dm³ min⁻¹

Question 34

Why is it important to convert tidal volume from cm³ to dm³ when calculating ventilation rate?

Answer 34

To ensure the units match for consistent calculations, as ventilation rate is expressed in dm³ min⁻¹.

Question 35

Describe how you would investigate breathing rates in a school library. (3 marks)

Answer 35

1. Measure breathing rate by counting the number of breaths taken by individuals in one minute. 2. Ensure participants are at rest and comfortable in a quiet environment. 3. Record results and repeat the measurements for multiple individuals to ensure reliability.

Question 36

Describe the relationships between tidal volume, breathing rate, and oxygen uptake. (4 marks)

Answer 36

1. Tidal volume is the volume of air inhaled or exhaled in a single breath. 2. Breathing rate is the number of breaths taken per minute. 3. Oxygen uptake depends on the total ventilation rate, which is calculated as Tidal volume × Breathing rate 4. During exercise or increased oxygen demand, both tidal volume and breathing rate increase to meet the body's needs.

Question 37

A dog is under stress during a visit to the vet and pants, but the ventilation rate remains steady. Suggest a possible explanation for these observations. (2 marks)

Answer 37

1. Panting involves rapid, shallow breaths that do not significantly increase tidal volume. 2. As a result, although the breathing rate increases, the ventilation rate remains steady because the overall volume of air moved per minute does not change.