Table of Contents
- 1 Why is it easy for gases to pass through the alveoli?
- 2 What makes alveoli suitable as a gas exchange surface?
- 3 How are alveoli and villi adapted to increase the rate of diffusion?
- 4 What structural characteristics of the alveoli make them an ideal site for the diffusion of gases?
- 5 Why is the composition of alveolar air different from that of the atmosphere?
- 6 How are the villi adapted for diffusion?
- 7 Why is gas exchange efficient in the respiratory membrane?
- 8 How is carbon dioxide released from the alveoli?
Why is it easy for gases to pass through the alveoli?
Alveoli are folded to increase their surface area to volume ratio, so more volume of air can diffuse in from the blood and and in from the bronchioles. The lining of the alveoli walls are also moist so the gases can easily dissolve. The walls are thin so the diffusion distance is short.
How does the structure of alveoli help in diffusion of gases?
It’s surrounded by networks of blood vessels called capillaries that also have thin walls. The oxygen you breathe in diffuses through the alveoli and the capillaries into the blood. The alveoli are just one cell in thickness, which allows the gas exchange of respiration to take place rapidly.
What makes alveoli suitable as a gas exchange surface?
The layer of moisture in the alveoli allows gases to dissolve so that they can diffuse quickly. The alveoli have a very large total surface area and a very good blood supply, provided by the dense network of capillaries that surround them.
Which type of alveolar cells are used for gaseous diffusion?
The alveolar type II cell is the defender of the alveolus (Figure 1). The alveolus is the anatomic site for gas exchange, the critical function of the lung. For gas exchange to take place, the diffusion distance between inhaled gas and the red cell has to be minimized.
How are alveoli and villi adapted to increase the rate of diffusion?
The villi in the small intestine provide a large surface area with an extensive network of blood capillaries. This makes the villi well adapted to absorb the products of digestion by diffusion and active transport. This increases the surface area available for diffusion even more.
What affects gas diffusion in the alveoli?
Diffusion coefficient of the gas, which is influenced by: molecular size (stable and predictable for respiratory gases) temperature (stable in most normal human lungs) fluid viscosity/chemical properties of the membrane (altered by disease, eg.
What structural characteristics of the alveoli make them an ideal site for the diffusion of gases?
Lab Study STACK
| Question | Answer |
|---|---|
| What happens when pressure is lost in the lung? | It deflates |
| What type of tissues allow the lung to deflate? | Elastic connective tissue |
| What structural characteristics of the alveoli make them an ideal site for the diffusion of gases? | Thin walls, extremely large surface area |
Why are the alveoli sometimes called the respiratory membrane?
Air ducts are minute tubes that direct air into small, thin sacs called “alveoli” (the plural of “alveolus”). Col- lectively, the alveoli are sometimes called the “respiratory membrane” because respiratory gases diffuse through these thin sacs while entering and leaving the blood.
Why is the composition of alveolar air different from that of the atmosphere?
The composition of air in the atmosphere and in the alveoli differs. In both cases, the relative concentration of gases is nitrogen > oxygen > water vapor > carbon dioxide. In addition, alveolar air contains a greater amount of carbon dioxide and less oxygen than atmospheric air.
What alveolar cell does the gas exchange?
The alveolar epithelium comprises two main cell types: the alveolar type I and alveolar type II cell. The type I cell is a complex branched cell with multiple cytoplasmic plates that are greatly attenuated and relatively devoid of organelles; these plates represent the gas exchange surface in the alveolus.
How are the villi adapted for diffusion?
Villi are specialized for absorption in the small intestine as they have a thin wall, one cell thick, which enables a shorter diffusion path. They have a large surface area so there will be more efficient absorption of fatty acids and glycerol into the blood stream.
Why are the alveoli important for the diffusion of gases?
A requirement for diffusion is that the gas (in this case oxygen) should first be dissolved. Hence, the alveoli are also moist to facilitate oxygen dissolution, and ultimately, diffusion through the membrane to be absorbed by the blood. 4. Lastly, alveoli have a good supply of blood.
Why is gas exchange efficient in the respiratory membrane?
Gas exchange is efficient due to a thin respiratory membrane, the high speed of diffusion, high surface area and lipid solubility of carbon dioxide and oxygen. To unlock this lesson you must be a Study.com Member.
How does oxygen cross the alveolar capillary membrane?
Respiratory Gases Cross the Alveolar Capillary Membrane by Diffusion. For example, oxygen diffuses across the alveolar-capillary membrane because of the difference in Po2 between the alveoli and pulmonary capillaries (Fig. 21.2). The partial pressure difference for oxygen is referred to as the oxygen diffusion gradient; in the normal lung,…
How is carbon dioxide released from the alveoli?
The exchange occurs through diffusion through the alveolar membrane. After this, the blood again circulates the body (now oxygen rich) while the carbon dioxide is released when we exhale. Diffusion in the alveoli is efficient because of some adaptations of the structure.