6.4 Gas exchange

Description

Nature of science:
Obtain evidence for theories—epidemiological studies have contributed to our understanding of the causes of lung cancer. (1.8)

Understandings:

Ventilation maintains concentration gradients of oxygen and carbon dioxide between air in alveoli and blood flowing in adjacent capillaries.
Type I pneumocytes are extremely thin alveolar cells that are adapted to carry out gas exchange.
Type II pneumocytes secrete a solution containing surfactant that creates a moist surface inside the alveoli to prevent the sides of the alveolus adhering to each other by reducing surface tension.
Air is carried to the lungs in the trachea and bronchi and then to the alveoli in bronchioles.
Muscle contractions cause the pressure changes inside the thorax that force air in and out of the lungs to ventilate them.
Different muscles are required for inspiration and expiration because muscles only do work when they contract.

Applications and skills:

Application: Causes and consequences of lung cancer.
Application: Causes and consequences of emphysema.
Application: External and internal intercostal muscles, and diaphragm and abdominal muscles as examples of antagonistic muscle action.
Skill: Monitoring of ventilation in humans at rest and after mild and vigorous exercise. (Practical 6)

Guidance:

Ventilation can either be monitored by simple observation and simple apparatus or by data logging with a spirometer or chest belt and pressure meter. Ventilation rate and tidal volume should be measured, but the terms vital capacity and residual volume are not expected.
Students should be able to draw a diagram to show the structure of an alveolus and an adjacent capillary.

Utilization:
Syllabus and cross-curricular links:
Biology
Topic 1.4 Membrane transport
Topic 1.6 Cell division
Topic 6.2 The blood system
Physics
Topic 3.2 Modelling a gas

Aims:

Aim 8: The social consequences of lung cancer and emphysema could be discussed.

Directly related questions

17N.2.SL.TZ0.01e:
Elastin is also an important component of other tissues such as arteries and ligaments. Evaluate how these other sources of elastin could affect the interpretation of the biomarker as an indicator of COPD.
17N.2.SL.TZ0.01e:
Elastin is also an important component of other tissues such as arteries and ligaments. Evaluate how these other sources of elastin could affect the interpretation of the biomarker as an indicator of COPD.
17N.2.SL.TZ0.e:
Elastin is also an important component of other tissues such as arteries and ligaments. Evaluate how these other sources of elastin could affect the interpretation of the biomarker as an indicator of COPD.
17N.2.SL.TZ0.01h:
Discuss whether measurements of desmosine concentration would be useful for monitoring changes in the health of a patient.
17N.2.SL.TZ0.h:
Discuss whether measurements of desmosine concentration would be useful for monitoring changes in the health of a patient.
17N.2.SL.TZ0.01h:
Discuss whether measurements of desmosine concentration would be useful for monitoring changes in the health of a patient.
17N.2.SL.TZ0.01g:
Other studies on pulmonary diseases have shown a wide variety of results. Apart from age, sex and severity of COPD, list two other factors that may explain the inconsistent results between studies.
17N.2.SL.TZ0.01g:
Other studies on pulmonary diseases have shown a wide variety of results. Apart from age, sex and severity of COPD, list two other factors that may explain the inconsistent results between studies.
17N.2.SL.TZ0.g:
Other studies on pulmonary diseases have shown a wide variety of results. Apart from age, sex and severity of COPD, list two other factors that may explain the inconsistent results between studies.
17N.2.HL.TZ0.01c:
Using the data presented in this question, explain the effect of hypoxia on the body.
17N.2.HL.TZ0.01c:
Using the data presented in this question, explain the effect of hypoxia on the body.
17N.2.HL.TZ0.c:
Using the data presented in this question, explain the effect of hypoxia on the body.
17N.2.HL.TZ0.01e.i: Outline the effect of hypoxia on the force of contraction of the diaphragm.
17N.2.HL.TZ0.01e.i: Outline the effect of hypoxia on the force of contraction of the diaphragm.
17N.2.HL.TZ0.e.i: Outline the effect of hypoxia on the force of contraction of the diaphragm.
17N.2.HL.TZ0.01e.ii:
Hypoxia caused a 13 % increase in the surface area to volume ratio of the diaphragm. Suggest a reason for this change.
17N.2.HL.TZ0.01e.ii:
Hypoxia caused a 13 % increase in the surface area to volume ratio of the diaphragm. Suggest a reason for this change.
17N.2.HL.TZ0.e.ii:
Hypoxia caused a 13 % increase in the surface area to volume ratio of the diaphragm. Suggest a reason for this change.
17N.2.HL.TZ0.01g:
Discuss the advantages and disadvantages of using rats as models in this investigation.
17N.2.HL.TZ0.01g:
Discuss the advantages and disadvantages of using rats as models in this investigation.
17N.2.HL.TZ0.g:
Discuss the advantages and disadvantages of using rats as models in this investigation.
21M.1.SL.TZ2.27: Which is an adaptation to increase rates of gas exchange in the lung? A. Small surface area B....
21M.1.SL.TZ2.27: Which is an adaptation to increase rates of gas exchange in the lung? A. Small surface area B....
21M.2.SL.TZ1.7a:
Outline the process of inhalation.
21M.2.SL.TZ1.7a:
Outline the process of inhalation.
21M.2.SL.TZ1.a:
Outline the process of inhalation.
21N.1.SL.TZ0.27: What occurs during inhalation?
21N.1.SL.TZ0.27: What occurs during inhalation?
21N.2.SL.TZ0.2c: Outline the action taken by the diaphragm during inhalation.
21N.2.SL.TZ0.2c: Outline the action taken by the diaphragm during inhalation.
21N.2.SL.TZ0.c: Outline the action taken by the diaphragm during inhalation.
21N.2.HL.TZ0.4c: Outline the action taken by the diaphragm during inhalation.
21N.2.HL.TZ0.4c: Outline the action taken by the diaphragm during inhalation.
21N.2.HL.TZ0.c: Outline the action taken by the diaphragm during inhalation.
22M.1.SL.TZ2.27: Pressure changes inside the thorax cause the movement of air in and out of the lung alveoli...
22M.1.SL.TZ2.27: Pressure changes inside the thorax cause the movement of air in and out of the lung alveoli...
18N.2.SL.TZ0.1g: State two respiratory diseases, other than lung cancer, caused by smoking.
18N.2.SL.TZ0.1g: State two respiratory diseases, other than lung cancer, caused by smoking.
18N.2.SL.TZ0.g: State two respiratory diseases, other than lung cancer, caused by smoking.
18N.2.SL.TZ0.1b: Compare and contrast the trends in smoking behaviour between males and females between 1950 and...
18N.2.SL.TZ0.1b: Compare and contrast the trends in smoking behaviour between males and females between 1950 and...
18N.2.SL.TZ0.b: Compare and contrast the trends in smoking behaviour between males and females between 1950 and...
18N.2.SL.TZ0.1d: Describe the relationship between the incidence of lung cancer and stopping smoking.
18N.2.SL.TZ0.1d: Describe the relationship between the incidence of lung cancer and stopping smoking.
18N.2.SL.TZ0.d: Describe the relationship between the incidence of lung cancer and stopping smoking.
18N.3.HL.TZ0.1c: Suggest how the total lung volume at rest would differ for a patient with emphysema.
18N.3.HL.TZ0.1c: Suggest how the total lung volume at rest would differ for a patient with emphysema.
18N.3.HL.TZ0.c: Suggest how the total lung volume at rest would differ for a patient with emphysema.
18M.3.SL.TZ2.3c: Predict, with a reason, the effect of exercise on the rate of cell respiration.
18M.3.SL.TZ2.3c: Predict, with a reason, the effect of exercise on the rate of cell respiration.
18M.3.SL.TZ2.c: Predict, with a reason, the effect of exercise on the rate of cell respiration.
18M.3.HL.TZ1.2a : State the apparatus used to measure the tidal volume.
18M.3.HL.TZ1.2a: State the apparatus used to measure the tidal volume.
18M.3.HL.TZ1.a: State the apparatus used to measure the tidal volume.
18M.3.HL.TZ1.2c: Compare and contrast the effect of increasing treadmill speed on the ventilation rate and tidal...
18M.3.HL.TZ1.2c: Compare and contrast the effect of increasing treadmill speed on the ventilation rate and tidal...
18M.3.HL.TZ1.c: Compare and contrast the effect of increasing treadmill speed on the ventilation rate and tidal...
19M.2.SL.TZ1.4b: Explain how gases are exchanged between the air in the alveolus and the blood in the capillaries.
19M.2.SL.TZ1.4b: Explain how gases are exchanged between the air in the alveolus and the blood in the capillaries.
19M.2.SL.TZ1.b: Explain how gases are exchanged between the air in the alveolus and the blood in the capillaries.
19M.1.SL.TZ2.26: In premature babies born earlier than the 30th week of pregnancy, type II pneumocytes are usually...
19M.1.SL.TZ2.26: In premature babies born earlier than the 30th week of pregnancy, type II pneumocytes are usually...
19M.3.SL.TZ2.3b: Compare and contrast the effect of increasing exercise intensity at sea level and at an altitude...
19M.3.SL.TZ2.3b: Compare and contrast the effect of increasing exercise intensity at sea level and at an altitude...
19M.3.SL.TZ2.b: Compare and contrast the effect of increasing exercise intensity at sea level and at an altitude...
19N.2.SL.TZ0.6c: Explain how ventilation and lung structure contribute to passive gas exchange.
19N.2.SL.TZ0.6c: Explain how ventilation and lung structure contribute to passive gas exchange.
19N.2.SL.TZ0.c: Explain how ventilation and lung structure contribute to passive gas exchange.
19N.1.HL.TZ0.23: Which factors could cause emphysema? I. Air pollution II. Genetic predisposition III. Tobacco...
19N.1.HL.TZ0.23: Which factors could cause emphysema? I. Air pollution II. Genetic predisposition III. Tobacco...
22N.1.SL.TZ0.28:
The graph shows the concentration of the lipid lecithin in the amniotic fluid surrounding the fetus during normal gestation. This lipid is produced in the lungs of the fetus and acts as a surfactant.

[Source: Gluck, L. and Kulovich, M., n.d. [Concentrations of phospholipids]. [graph online] Available at:
http://www.columbia.edu/itc/hs/medical/humandev/2004/Chpt12-LungDev.pdf [Accessed 28 October 2021].]

What problem may occur in a baby born before 34 weeks gestation?

A. Type I pneumocytes do not produce sufficient surfactant for lungs to inflate.

B. There are no type II pneumocytes.

C. The alveolar walls stick together.

D. The alveoli are too large.
22N.1.SL.TZ0.28:
The graph shows the concentration of the lipid lecithin in the amniotic fluid surrounding the fetus during normal gestation. This lipid is produced in the lungs of the fetus and acts as a surfactant.

[Source: Gluck, L. and Kulovich, M., n.d. [Concentrations of phospholipids]. [graph online] Available at:
http://www.columbia.edu/itc/hs/medical/humandev/2004/Chpt12-LungDev.pdf [Accessed 28 October 2021].]

What problem may occur in a baby born before 34 weeks gestation?

A. Type I pneumocytes do not produce sufficient surfactant for lungs to inflate.

B. There are no type II pneumocytes.

C. The alveolar walls stick together.

D. The alveoli are too large.
17N.2.SL.TZ0.01a: State the level of COPD that has the lowest FEV.
17N.2.SL.TZ0.01a: State the level of COPD that has the lowest FEV.
17N.2.SL.TZ0.a: State the level of COPD that has the lowest FEV.
17N.2.SL.TZ0.01b:
Explain how a low FEV can be used to indicate emphysema.
17N.2.SL.TZ0.01b:
Explain how a low FEV can be used to indicate emphysema.
17N.2.SL.TZ0.b:
Explain how a low FEV can be used to indicate emphysema.
17N.2.SL.TZ0.01c: State the disease severity group that has the highest range of plasma desmosines.
17N.2.SL.TZ0.01c: State the disease severity group that has the highest range of plasma desmosines.
17N.2.SL.TZ0.c: State the disease severity group that has the highest range of plasma desmosines.
17N.2.SL.TZ0.01d:
Evaluate which of the two biomarkers would be the most useful indicator of COPD severity.
17N.2.SL.TZ0.01d:
Evaluate which of the two biomarkers would be the most useful indicator of COPD severity.
17N.2.SL.TZ0.d:
Evaluate which of the two biomarkers would be the most useful indicator of COPD severity.
17N.2.SL.TZ0.01f: State the relationship between diffusion capacity and urine desmosines.
17N.2.SL.TZ0.f: State the relationship between diffusion capacity and urine desmosines.
17N.2.SL.TZ0.01f: State the relationship between diffusion capacity and urine desmosines.
17N.2.HL.TZ0.01a: Outline the effect of hypoxia on body mass and erythrocyte percentage.
17N.2.HL.TZ0.01a: Outline the effect of hypoxia on body mass and erythrocyte percentage.
17N.2.HL.TZ0.a: Outline the effect of hypoxia on body mass and erythrocyte percentage.
17N.2.HL.TZ0.01b:
Using the data in the graph, deduce whether hypoxia increases or decreases the endurance of the rats’ diaphragm muscle.
17N.2.HL.TZ0.01b:
Using the data in the graph, deduce whether hypoxia increases or decreases the endurance of the rats’ diaphragm muscle.
17N.2.HL.TZ0.b:
Using the data in the graph, deduce whether hypoxia increases or decreases the endurance of the rats’ diaphragm muscle.
17N.2.HL.TZ0.01d.i:
Analyse the graph to obtain two conclusions about the concentration of sodium–potassium pumps.
17N.2.HL.TZ0.01d.i:
Analyse the graph to obtain two conclusions about the concentration of sodium–potassium pumps.
17N.2.HL.TZ0.d.i:
Analyse the graph to obtain two conclusions about the concentration of sodium–potassium pumps.
17N.2.HL.TZ0.01d.ii:
Muscle fibres are stimulated to contract by the binding of acetylcholine to receptors in their membranes and the subsequent depolarization.

Suggest a reason for increasing the concentration of sodium–potassium pumps in the membranes of diaphragm muscle fibres.
17N.2.HL.TZ0.01d.ii:
Muscle fibres are stimulated to contract by the binding of acetylcholine to receptors in their membranes and the subsequent depolarization.

Suggest a reason for increasing the concentration of sodium–potassium pumps in the membranes of diaphragm muscle fibres.
17N.2.HL.TZ0.d.ii:
Muscle fibres are stimulated to contract by the binding of acetylcholine to receptors in their membranes and the subsequent depolarization.

Suggest a reason for increasing the concentration of sodium–potassium pumps in the membranes of diaphragm muscle fibres.
17N.2.HL.TZ0.01f:
Using all relevant data in the question, evaluate the effectiveness of the rats’ adaptation to hypoxia.
17N.2.HL.TZ0.01f:
Using all relevant data in the question, evaluate the effectiveness of the rats’ adaptation to hypoxia.
17N.2.HL.TZ0.f:
Using all relevant data in the question, evaluate the effectiveness of the rats’ adaptation to hypoxia.
17N.1.HL.TZ0.23: Which type of cell is specialized to facilitate gas exchange? A. Type I pneumocytes B. Type II...
17N.1.HL.TZ0.23: Which type of cell is specialized to facilitate gas exchange? A. Type I pneumocytes B. Type II...
18M.1.SL.TZ1.28: How are the insides of alveoli prevented from sticking together?
18M.1.SL.TZ1.28: How are the insides of alveoli prevented from sticking together?
18M.2.SL.TZ1.6a:
Outline the role of the parts of an alveolus in a human lung.
18M.2.SL.TZ1.6a:
Outline the role of the parts of an alveolus in a human lung.
18M.2.SL.TZ1.a:
Outline the role of the parts of an alveolus in a human lung.
18M.2.HL.TZ2.6b: Outline how ventilation in humans ensures a supply of oxygen.
18M.2.HL.TZ2.6b: Outline how ventilation in humans ensures a supply of oxygen.
18M.2.HL.TZ2.b: Outline how ventilation in humans ensures a supply of oxygen.
18M.3.HL.TZ1.2b:
Calculate the total volume of air inhaled during one minute during the highest velocity of the treadmill in this test, giving the units.
18M.3.HL.TZ1.2b:
Calculate the total volume of air inhaled during one minute during the highest velocity of the treadmill in this test, giving the units.
18M.3.HL.TZ1.b:
Calculate the total volume of air inhaled during one minute during the highest velocity of the treadmill in this test, giving the units.
18M.3.SL.TZ2.3a: Determine the ventilation rate after exercise.
18M.3.SL.TZ2.3a: Determine the ventilation rate after exercise.
18M.3.SL.TZ2.a: Determine the ventilation rate after exercise.
18M.3.SL.TZ2.3b: Describe how the mean tidal volume after exercise could be determined using the graph.
18M.3.SL.TZ2.3b: Describe how the mean tidal volume after exercise could be determined using the graph.
18M.3.SL.TZ2.b: Describe how the mean tidal volume after exercise could be determined using the graph.
18M.3.SL.TZ2.3d: Identify a muscle responsible for increasing the volume of the chest cavity.
18M.3.SL.TZ2.3d: Identify a muscle responsible for increasing the volume of the chest cavity.
18M.3.SL.TZ2.d: Identify a muscle responsible for increasing the volume of the chest cavity.
18M.1.SL.TZ2.28: What is the role of type II pneumocytes? A. To carry out gas exchange B. To keep the alveoli...
18M.1.SL.TZ2.28: What is the role of type II pneumocytes? A. To carry out gas exchange B. To keep the alveoli...
18N.2.SL.TZ0.1a: Calculate the change in the percentage of the male population that smoked from 1950 to 2000.
18N.2.SL.TZ0.1a: Calculate the change in the percentage of the male population that smoked from 1950 to 2000.
18N.2.SL.TZ0.a: Calculate the change in the percentage of the male population that smoked from 1950 to 2000.
18N.2.SL.TZ0.1c: Evaluate the evidence provided by the data in the graphs for smoking as a cause of lung cancer.
18N.2.SL.TZ0.1c: Evaluate the evidence provided by the data in the graphs for smoking as a cause of lung cancer.
18N.2.SL.TZ0.c: Evaluate the evidence provided by the data in the graphs for smoking as a cause of lung cancer.
18N.2.SL.TZ0.1e: Explain evidence from the data in the table that could be used to persuade a smoker to give up...
18N.2.SL.TZ0.1e: Explain evidence from the data in the table that could be used to persuade a smoker to give up...
18N.2.SL.TZ0.e: Explain evidence from the data in the table that could be used to persuade a smoker to give up...
18N.2.SL.TZ0.1f: Among 75-year-old lifelong non-smokers the percentage incidence of lung cancer was 0.01 %....
18N.2.SL.TZ0.1f: Among 75-year-old lifelong non-smokers the percentage incidence of lung cancer was 0.01 %....
18N.2.SL.TZ0.f: Among 75-year-old lifelong non-smokers the percentage incidence of lung cancer was 0.01 %....
18N.2.HL.TZ0.6c: Adult humans may absorb more than five hundred litres of oxygen per day. Explain how gas exchange...
18N.2.HL.TZ0.6c: Adult humans may absorb more than five hundred litres of oxygen per day. Explain how gas exchange...
18N.2.HL.TZ0.c: Adult humans may absorb more than five hundred litres of oxygen per day. Explain how gas exchange...
18N.3.SL.TZ0.2a: Calculate the ventilation rate at rest, giving the units.
18N.3.SL.TZ0.2a: Calculate the ventilation rate at rest, giving the units.
18N.3.SL.TZ0.a: Calculate the ventilation rate at rest, giving the units.
18N.3.SL.TZ0.2b: Explain the changes in ventilation after 35 seconds.
18N.3.SL.TZ0.2b: Explain the changes in ventilation after 35 seconds.
18N.3.SL.TZ0.b: Explain the changes in ventilation after 35 seconds.
18N.3.SL.TZ0.2c: Suggest how the total lung volume at rest would differ for a patient with emphysema.
18N.3.SL.TZ0.2c: Suggest how the total lung volume at rest would differ for a patient with emphysema.
18N.3.SL.TZ0.c: Suggest how the total lung volume at rest would differ for a patient with emphysema.
18N.3.HL.TZ0.1a: Calculate the ventilation rate at rest, giving the units.
18N.3.HL.TZ0.1a: Calculate the ventilation rate at rest, giving the units.
18N.3.HL.TZ0.a: Calculate the ventilation rate at rest, giving the units.
18N.3.HL.TZ0.1b: Explain the changes in ventilation after 35 seconds.
18N.3.HL.TZ0.1b: Explain the changes in ventilation after 35 seconds.
18N.3.HL.TZ0.b: Explain the changes in ventilation after 35 seconds.
18N.3.HL.TZ0.1d: Outline the function of pneumocytes in the lungs.
18N.3.HL.TZ0.1d: Outline the function of pneumocytes in the lungs.
18N.3.HL.TZ0.d: Outline the function of pneumocytes in the lungs.
19M.1.HL.TZ1.23: What is produced by type II pneumocytes? A. Epinephrine B. Elastase C. Pulmonary...
19M.1.HL.TZ1.23: What is produced by type II pneumocytes? A. Epinephrine B. Elastase C. Pulmonary...
19M.2.SL.TZ1.4a: Outline the functions of type I and type II pneumocytes.
19M.2.SL.TZ1.4a: Outline the functions of type I and type II pneumocytes.
19M.2.SL.TZ1.a: Outline the functions of type I and type II pneumocytes.
19M.2.HL.TZ1.6a: Outline the process of inspiration in humans.
19M.2.HL.TZ1.6a: Outline the process of inspiration in humans.
19M.2.HL.TZ1.a: Outline the process of inspiration in humans.
19M.3.SL.TZ2.3a: State one other variable that should have been controlled in this study.
19M.3.SL.TZ2.3a: State one other variable that should have been controlled in this study.
19M.3.SL.TZ2.a: State one other variable that should have been controlled in this study.
19M.3.SL.TZ2.3c:
Outline how ventilation rate could have been monitored in this study.
19M.3.SL.TZ2.3c:
Outline how ventilation rate could have been monitored in this study.
19M.3.SL.TZ2.c:
Outline how ventilation rate could have been monitored in this study.
20N.1.SL.TZ0.28:
The graph shows a spirometer trace of oxygen consumption when breathing at rest and during exercise.

[Source: Courtesy of Dr. Dafang Wang for his work at University of Utah.]

What explains the difference between the traces at regions X and Y on the graph?

A. At X, the internal intercostal muscles contract more than the external intercostal muscles.

B. At Y, the ribcage moves up and out more than at X.

C. At X, the diaphragm flattens more per breath than at Y.

D. At Y, the intercostal muscles contract more slowly than at X.
20N.1.SL.TZ0.28:
The graph shows a spirometer trace of oxygen consumption when breathing at rest and during exercise.

[Source: Courtesy of Dr. Dafang Wang for his work at University of Utah.]

What explains the difference between the traces at regions X and Y on the graph?

A. At X, the internal intercostal muscles contract more than the external intercostal muscles.

B. At Y, the ribcage moves up and out more than at X.

C. At X, the diaphragm flattens more per breath than at Y.

D. At Y, the intercostal muscles contract more slowly than at X.
21M.2.SL.TZ1.7b:
Explain the process of gas exchange taking place in the alveoli.
21M.2.SL.TZ1.7b:
Explain the process of gas exchange taking place in the alveoli.
21M.2.SL.TZ1.b:
Explain the process of gas exchange taking place in the alveoli.
21M.1.HL.TZ1.21: Which process results in the exchange of gases across the membrane of pneumocytes? A. Active...
21M.1.HL.TZ1.21: Which process results in the exchange of gases across the membrane of pneumocytes? A. Active...
21M.1.SL.TZ2.28: Where in the body are type I pneumocytes found? A. Alveoli B. Nephrons C. Capillaries D. Trachea
21M.1.SL.TZ2.28: Where in the body are type I pneumocytes found? A. Alveoli B. Nephrons C. Capillaries D. Trachea
22M.1.SL.TZ1.27: A cell from the lungs, observed under the microscope, contains a large number of secretory...
22M.1.SL.TZ1.27: A cell from the lungs, observed under the microscope, contains a large number of secretory...
22N.1.HL.TZ0.22:
The diagram shows a section through an alveolus.

[Source: Bergman, Ronald A., Ph.D., and D'Alessandro, Michael P., M.D. Pulmonary alveoli, “Anatomy Atlases”. Available online: http://www.anatomyatlases.org/ [Accessed 02/01/2023].]

What are the functions of the following labelled structures?
22N.1.HL.TZ0.22:
The diagram shows a section through an alveolus.

[Source: Bergman, Ronald A., Ph.D., and D'Alessandro, Michael P., M.D. Pulmonary alveoli, “Anatomy Atlases”. Available online: http://www.anatomyatlases.org/ [Accessed 02/01/2023].]

What are the functions of the following labelled structures?
23M.3.HL.TZ1.8:
Explain how breathing is controlled by the brain.
23M.3.HL.TZ1.8:
Explain how breathing is controlled by the brain.
23M.1.HL.TZ2.19: What occurs during inspiration? A. Internal intercostal muscles contract, increasing the...
23M.1.HL.TZ2.19: What occurs during inspiration? A. Internal intercostal muscles contract, increasing the...
23M.1.HL.TZ2.39: At what stage of spermatogenesis does the first division of meiosis occur? A. Spermatogonium to...
23M.1.HL.TZ2.39: At what stage of spermatogenesis does the first division of meiosis occur? A. Spermatogonium to...
23M.1.HL.TZ2.40: Which statement applies to the placenta? A. Carbon dioxide diffuses from fetus to mother across...
23M.1.HL.TZ2.40: Which statement applies to the placenta? A. Carbon dioxide diffuses from fetus to mother across...

Sub sections and their related questions

None

6.4 Gas exchange

Description

Directly related questions

Sub sections and their related questions

Confirm action