Physiology 3.1

Question 1

Describe the difference between lung volume and anatomical dead space.

Answer 1

Lung volume can vary enormously, while anatomical dead space is relatively fixed.

Question 2

What is the term used to describe the movement of air in and out of the lungs?

Answer 2

Ventilation.

Question 3

Define alveolar ventilation.

Answer 3

Alveolar ventilation describes the volume of fresh air that reaches the alveoli and participates in gas exchange.

Question 4

How is ventilation measured?

Answer 4

Ventilation is measured in litres per minute.

Question 5

Do pulmonary ventilation and alveolar ventilation have the same functional significance?

Answer 5

No, alveolar ventilation is functionally much more significant.

Question 6

Describe the impact of anatomical dead space on alveolar ventilation.

Answer 6

Anatomical dead space significantly impacts alveolar ventilation by reducing the volume of air reaching the alveoli for gas exchange.

Question 7

Do all the air exhaled during breathing come from the alveoli?

Answer 7

No, the 500 millilitres of air exhaled includes 150 millilitres from the dead space near the trachea and bronchi, and 350 millilitres from the alveoli.

Question 8

Define dead space in the respiratory system.

Answer 8

Dead space refers to the areas in the respiratory system, such as the trachea, bronchi, and bronchioles, where air can get trapped and not participate in gas exchange.

Question 9

How efficient is normal tidal volume breathing at resting values?

Answer 9

Normal tidal volume breathing is only about 70 percent efficient, with 30 percent of the fresh air inhaled getting stuck in the dead space and not reaching the alveoli for gas exchange.

Question 10

Describe the impact of changing breathing patterns on alveolar ventilation.

Answer 10

Changing breathing patterns can significantly alter alveolar ventilation, improving or worsening the efficiency of gas exchange in the lungs.

Question 11

What is the composition of the air exhaled during breathing?

Answer 11

The air exhaled includes 150 millilitres of stale air from the dead space and 350 millilitres of fresh air from the alveoli, showing that breathing is only about 70 percent efficient at normal resting values.

Question 12

Describe the respiratory pattern of the ideal man.

Answer 12

The ideal man has a respiration rate of 12 breaths per minute and a tidal volume of 500 milliliters.

Question 13

Do anxious individuals tend to have a higher or lower respiration rate?

Answer 13

Anxious individuals tend to have a higher respiration rate but a lower tidal volume, resulting in fast, shallow breaths.

Question 14

Define pulmonary ventilation.

Answer 14

Pulmonary ventilation is the total bulk movement of air in and out of the lungs, calculated by multiplying the respiration rate by the tidal volume.

Question 15

How is pulmonary ventilation calculated?

Answer 15

Pulmonary ventilation is calculated by multiplying the respiration rate by the tidal volume.

Question 16

Describe the alveolar ventilation of Homer Simpson.

Answer 16

Homer Simpson has the highest alveolar ventilation due to his slow and deep breathing pattern.

Question 17

Do all individuals in the scenario have the same pulmonary ventilation?

Answer 17

Yes, all individuals have the same pulmonary ventilation of 6000 milliliters per minute or six liters per minute.

Question 18

Describe the difference between alveolar ventilation and pulmonary ventilation.

Answer 18

Alveolar ventilation refers to the amount of air reaching the alveoli and participating in gas exchange, while pulmonary ventilation is the total amount of air moved in and out of the lungs per minute.

Question 19

Define anatomical dead space.

Answer 19

Anatomical dead space refers to the volume of air in the respiratory system that does not reach the alveoli and therefore does not participate in gas exchange.

Question 20

How is alveolar ventilation calculated?

Answer 20

Alveolar ventilation is calculated by subtracting the anatomical dead space from the tidal volume and then multiplying the result by the respiration rate.

Question 21

Do tidal volume and respiration rate both impact alveolar ventilation?

Answer 21

Yes, both tidal volume and respiration rate impact alveolar ventilation, but tidal volume has a much larger impact compared to respiration rate.

Question 22

Describe the relationship between tidal volume and anatomical dead space in relation to breathing efficiency.

Answer 22

As tidal volume changes, the proportion of air trapped in anatomical dead space changes, affecting breathing efficiency. Higher tidal volume reduces the proportion of dead space, while lower tidal volume increases it.

Question 23

What is the significance of anatomical dead space in relation to breathing efficiency?

Answer 23

Anatomical dead space affects breathing efficiency by determining the proportion of air that does not reach the alveoli for gas exchange. Higher dead space reduces efficiency, while lower dead space increases it.

Question 24

Describe the most efficient way to breathe according to the content.

Answer 24

The most efficient way to breathe is deeply and rapidly, enhancing alveolar ventilation.

Question 25

Do rapid breathing and shallow breathing lead to hyperventilation or hypoventilation?

Answer 25

Rapid and shallow breathing usually leads to hypoventilation.

Question 26

Define hyperventilation and hypoventilation based on the content.

Answer 26

Hyperventilation is increased alveolar ventilation, while hypoventilation is reduced alveolar ventilation.

Question 27

How does exercise affect breathing according to the content?

Answer 27

Exercise increases both the rate and depth of breathing, enhancing alveolar ventilation.

Question 28

Describe the composition of normal air according to the content.

Answer 28

Normal air is mainly a mixture of nitrogen (79%), oxygen (21%), and a small amount of carbon dioxide (0.03%).

Question 29

What is the cause of increased carbon dioxide levels in the body according to the content?

Answer 29

Increased carbon dioxide levels are due to the body’s inability to exhale or eliminate carbon dioxide, not from breathing in more carbon dioxide.

Question 30

Describe the production of carbon in the human body.

Answer 30

Carbon dioxide is a by-product of aerobic respiration and is produced by the human body.

Question 31

Define partial pressure in the context of gases.

Answer 31

Partial pressure is defined as the pressure of a gas in a mixture of gases, equivalent to the percentage of that particular gas in the entire mixture multiplied by the pressure of the whole gaseous mixture.

Question 32

How is partial pressure calculated in a gas mixture?

Answer 32

The partial pressure of a gas in a mixture is calculated by multiplying the percentage of that gas in the mixture by the total pressure of the mixture.

Question 33

Describe the partial pressure of oxygen in the air we breathe.

Answer 33

The air we breathe has a partial pressure of oxygen of 160 millimetres of mercury, which is 21% of the standard atmospheric pressure of 760 millimetres of mercury.

Question 34

Do gases exert the same pressure in a mixture?

Answer 34

Yes, all gases exert the same pressure in a mixture.

Question 35

How does the partial pressure of oxygen in the alveoli compare to the air we breathe?

Answer 35

The partial pressure of oxygen in the alveoli is lower than the air we breathe due to dilution by anatomical dead space and residual volume.

Question 36

Describe the partial pressure of carbon dioxide at normal alveolar ventilation.

Answer 36

The partial pressure of carbon dioxide at normal alveolar ventilation is 40 millimetres of mercury or 5.3 kilopascals.

Question 37

What factors contribute to the dilution of the air we breathe in the alveoli?

Answer 37

The air we breathe is diluted by anatomical dead space and residual volume, reducing its effectiveness in reaching the alveoli.

Question 38

Describe the process how air becomes saturated water vapor in the system.

Answer 38

Air becomes saturated with water vapor as it passes through the respiratory system, further diluting the oxygen and needing to be in solution by the time it reaches the alveoli for diffusion into the blood.

Question 39

Define equilibrium in the context of gas exchange in the alveoli.

Answer 39

Equilibrium refers to the state where the pressure of gas in the alveoli is in balance with the pressure of gas in the blood, allowing for efficient gas exchange.

Question 40

How does hypoventilation affect the levels of oxygen and carbon dioxide in the alveoli?

Answer 40

Hypoventilation leads to a reduction in ventilation of the alveoli, causing oxygen levels to fall due to faster metabolism by peripheral tissues and carbon dioxide levels to rise as it is produced faster than it can be expelled.

Question 41

Do the values of gas partial pressures in the alveoli differ from those in systemic arterial blood in a healthy individual?

Answer 41

No, in a healthy individual, the values of gas partial pressures in the alveoli are the same as those in systemic arterial blood, as they diffuse until equilibrium is reached.

Question 42

Describe the impact of hyperventilation on the partial pressures of oxygen and carbon dioxide in the alveoli.

Answer 42

Hyperventilation leads to an increase in the partial pressure of oxygen in the alveoli, as oxygen is taken in faster than it is used, and a decrease in the partial pressure of carbon dioxide, as it is expelled faster than it is produced.

Question 43

Explain the role of diffusion in maintaining the values of gas partial pressures in the alveoli and systemic arterial blood.

Answer 43

Diffusion ensures that in a healthy individual, the values of gas partial pressures in the alveoli are reflected in the values in systemic arterial blood, as they diffuse until equilibrium is reached.

Question 44

Describe the effect of hyperventilation on the levels of oxygen and carbon dioxide in the blood.

Answer 44

Hyperventilation leads to a rise in oxygen levels and a fall in carbon dioxide levels in the blood.

Question 45

Do people find it easy or difficult to hyperventilate for an extended period of time? Why?

Answer 45

It is difficult for people to hyperventilate for any period of time because carbon dioxide is the primary stimulus for breathing.

Question 46

Define the primary driving force for breathing and its relationship to carbon dioxide levels.

Answer 46

The primary driving force for breathing is carbon dioxide, and as carbon dioxide levels rise, it stimulates centers in the brain and makes us breathe.

Question 47

How does the brain respond to falling carbon dioxide levels during hyperventilation?

Answer 47

As carbon dioxide levels fall, the brain subconsciously relaxes the stimulus for breathing, as it is hypersensitive to carbon dioxide and less sensitive to oxygen.

Question 48

Describe the difficulty in maintaining chronic hyperventilation and the role of the brain in this process.

Answer 48

Chronic hyperventilation is difficult to maintain as the brain constantly tells the individual to relax, as there is no carbon dioxide to get rid of, thus overcoming the brain’s signals is challenging.

Question 49

Explain the relationship between alveolar ventilation and transpulmonary pressure during breathing.

Answer 49

As intrapleural pressure becomes more negative during inhalation, transpulmonary pressure increases, resulting in a bigger change in volume at the base of the lung compared to the apex of the lung.

Question 50

What are the expected values of gases in the alveoli and systemic arterial blood of a healthy individual breathing normally?

Answer 50

The expected values of gases in the alveoli and systemic arterial blood of a healthy individual breathing normally are reflected in the partial pressures of oxygen and carbon dioxide.

Question 51

Describe the sensitivity of the brain to carbon dioxide and oxygen levels during hyperventilation.

Answer 51

The brain is supersensitive to carbon dioxide and less sensitive to oxygen during hyperventilation, leading to the difficulty in maintaining prolonged hyperventilation.

Question 52

Explain the difficulty in voluntarily hyperventilating for an extended period of time.

Answer 52

Voluntarily hyperventilating for an extended period of time is difficult as the brain signals the individual to relax due to the absence of carbon dioxide to get rid of, making it challenging to overcome the brain’s natural response.

Question 53

Describe the relationship between change in volume and pressure in the lungs.

Answer 53

The change in volume in the lungs is much bigger for any given change in pressure at the base of the lung than it is at the apex of the lung.

Question 54

Define alveolar ventilation and how it varies from the base to the apex of the lung.

Answer 54

Alveolar ventilation is greater at the base of the lung and declines with height from the base to the apex due to lower compliance at the apex.

Question 55

How does compliance vary between the apex and the base of the lung?

Answer 55

Compliance is lower at the apex of the lung than it is at the base, resulting in less capacity for alveoli at the apex to expand on inspiration.

Question 56

Describe the effect of gravity on alveolar ventilation and compliance in the lungs.

Answer 56

Gravity affects alveolar ventilation and compliance, causing the greatest alveolar ventilation and compliance at the base of the lung and the least at the apex when the subject is upright.

Question 57

Do changes in body position affect alveolar ventilation and compliance in the lungs?

Answer 57

Yes, lying down increases compliance and alveolar ventilation at the back of the lung, while hanging upside down increases compliance and alveolar ventilation at the apex.

Question 58

Define compliance in the context of lung physiology.

Answer 58

Compliance refers to how much volume the lungs can achieve for any given change in pressure.

Question 59

Describe the impact of lung positioning on alveolar ventilation and compliance.

Answer 59

Lung positioning affects alveolar ventilation and compliance, with the greatest alveolar ventilation and compliance at the base of the lung and the least at the apex when the subject is upright.

Question 60

How does the weight of the lung affect alveoli at the base and apex?

Answer 60

The weight of the lung compresses the alveoli at the base more than it compresses the alveoli at the apex, effectively stretching the alveoli at the apex and squashing the alveoli at the base.