Question

when the diaphragm relaxes, it moves_____, compressing the lungs and pushing waste gases out.
1. outward
2. inward
3. downward
4. upward

2. How does the vast majority of oxygen travel in the blood?
1. as oxygen associated with hemoglobin
2. as bicarbonate
3. as dissolved oxygen in the plasma
4. as carbaminohemoglobin

3. what occurs when air moves from the atmosphere of high pressure into the lower pressure of the lungs?
1. gas exchange
2. exhalation
3. expiration
4. inspiration

4. in your own words, describe the process of inspiration

5. In pneumonia, fluid collects in the alveoli. What conclusion can you draw regarding the efficiency of gas exchange in this state?

6. for a person who has or is currently hyperventilating, why does breathing into a paper bag restore normal blood chemistry more rapidly than continued breathing into the atmosphere?

7. identify the separate volumes that make up the total lung capacity.

Answer 1

1. 4) Upward

Explanation: when the diaphragm contracts, it moves downward and become flat shaped so as to increase the volume of the thoracic cavity. When the diaphragm relaxes, it aasumes its original dome shaped structure and move upward causing decrease in thoracic volume.

2. 1) as oxygen associated with hemoglobi

3. 4) inspiration

4)

Mechanics of breathing :

Following three types of pressures are observed in breathing mechanics.
1) Intrapleural pressure:
It is the pressure in the space between lungs and chest wall.
Normally it is negative around - 2.5 mmHg at the start of inspiration.

2) Intra alveolar pressure:
It is the pressure inside the alveoli.
It becomes negative during inspiration resulting in sucking of the air in the lungs and become positive during expiration resulting I exhalation of air out.

3) Transpulmonary pressure :
It is the pressure difference between intra alveolar pressure and Intrapleural pressure.

During inspiration :
- Intra alveolar pressure decreases to - 1 mmHg at the end of inspiration.

- Intrapleural pressure reaches - 6 mmHg at the end of inspiration

- Transpulmonary pressure is highest at the end of normal inspiration

- Air flows into the lungs

During Expiration :

- Intra alveolar pressure increases to + 1 mmHg at the end of expiration.

- Intrapleural pressure reaches the Normal value of -2.5 mmHg

- Air flows out of the lung

5) Due to collection of the fluid in the pneumonia, the thickness of the air and blood interface increases which reduces the diffusion of the gases. This leads to hypoxemia.