Question

task 2: sequencing & process

1. put the following structures in order as air travels from the outside of the body to the alveoli: larynx, mouth/nose, bronchioles, trachea, pharynx, alveoli.
2. explain how oxygen moves from the alveoli to the bloodstream.
3. what happens to carbon dioxide in the alveoli before a person exhales?

critical thinking & application

1. why do you think the alveoli and capillaries share such a thin, close membrane?
2. what might happen to the body if gas exchange in the alveoli stopped working properly?
3. compare and contrast (what are the similarities and differences) the gas exchange we learned about yesterday when it comes to cellular respiration, at the cellular level to the gas exchange that occurs at the organ - system level.

Explanation:

1. Air enters through the mouth/nose, then passes through the pharynx, larynx, trachea, bronchioles and finally reaches the alveoli. This is the pathway for air to reach the site of gas - exchange.
2. Oxygen moves from the alveoli to the bloodstream by diffusion. The concentration of oxygen is higher in the alveoli and lower in the capillaries surrounding the alveoli, so oxygen diffuses across the thin alveolar - capillary membrane into the blood.
3. Carbon dioxide in the alveoli is collected from the bloodstream. The concentration of carbon dioxide is higher in the blood (coming from the body's tissues) than in the alveoli, so it diffuses from the blood into the alveoli before being exhaled.
4. The thin, close membrane between alveoli and capillaries is to facilitate efficient gas exchange. A thin membrane reduces the diffusion distance for oxygen and carbon dioxide, allowing for rapid and effective transfer of these gases between the air in the alveoli and the blood in the capillaries.
5. If gas exchange in the alveoli stopped working properly, the body cells would not receive enough oxygen and would accumulate carbon dioxide. This could lead to hypoxia (lack of oxygen) and respiratory acidosis (due to high levels of carbon dioxide), causing symptoms like shortness of breath, fatigue, confusion, and in severe cases, organ failure and death.
6. Similarities: Both involve gas exchange of oxygen and carbon dioxide. Differences: Cellular respiration occurs within cells and is a metabolic process to produce energy (ATP). Gas exchange at the organ - system level (in the lungs) is about getting oxygen into the body and removing carbon dioxide from the body to supply oxygen to cells for cellular respiration.

Answer:

1. mouth/nose, pharynx, larynx, trachea, bronchioles, alveoli
2. Oxygen diffuses from the alveoli into the bloodstream across the thin alveolar - capillary membrane due to the concentration gradient.
3. Carbon dioxide diffuses from the blood into the alveoli as the concentration of carbon dioxide is higher in the blood than in the alveoli.
4. To facilitate efficient gas exchange by reducing the diffusion distance for oxygen and carbon dioxide.
5. Body cells would experience hypoxia and there would be an accumulation of carbon dioxide, leading to symptoms such as shortness of breath, fatigue, confusion, and potentially organ failure and death.
6. Similarities: Both involve oxygen and carbon dioxide exchange. Differences: Cellular respiration is a metabolic process in cells for energy production; organ - system level gas exchange is for getting oxygen into and carbon dioxide out of the body to support cellular respiration.