Gas exchange of oxygen and carbon dioxide takes place in the alveoli. Oxygen from the inhaled air diffuses through the walls of the alveoli and adjacent capillaries into the red blood cells. The oxygen is then carried by the blood to the body tissues. Alveoli have a lot of tiny blood vessels called capillaries.

Alveoli – The bronchioles terminate in balloon-like structures known as the alveoli. Lungs – Humans have a pair of lungs, which are sac-like structures and covered by a double-layered membrane known as pleura. Air is inhaled with the help of nostrils, and in the nasal cavity, the air is cleansed by the fine hair follicles present within them.

The second reason is because the alveoli walls are only one cell thick, meaning the oxygen only has two cells to go through, the alveoli wall, and the capillary wall. They are tiny pockets in the lungs at the end of the bronchioles, where oxygen diffuses into the blood and carbon dioxide diffuses out of the blood. .

Alveoli are tiny air sacs in the shape of a balloon. During the act of breathing in and out, the alveoli are where the lungs and blood exchange oxygen and carbon dioxide. The pressure exerted by oxygen in a mixture in the alveoli of lungs is known as the partial pressure of oxygen. It is represented by pO 2. Alveoli have a pO 2 of 104 mm Hg.

Alveoli . Each bronchiole ends in spongy, tiny sacs – alveoli; each of the individual sacs is referred to as alveolus. Each alveolus fills with air when a person inhales. Together, the bronchi, bronchioles and alveoli constitute the bronchial tree. The alveoli are surrounded by tiny blood vessels referred to as capillaries.

The alveoli are thin-walled and richly supplied with a network of blood vessels to facilitate the exchange of gases between blood in the capillaries and the air inside the alveoli. These alveoli are balloon-like structures which provide the maximum surface area for the exchange of gases.

from alveoli to tissues and that of CO 2 from tissues to alveoli. Figure 17.4A Diagram of a section of an alveolus with a pulmonary capillary. Figure 17.3Diagrammatic representation of exchange of gases at the alveolus and the body tissues with blood and transport of oxygen and carbon dioxide

They occur less in the alveoli as compared to type 2 cells. They occur more in the alveoli. The ratio of type 1 cells to type 2 cells is 1:2. Surface Area Coverage . It covers almost 95% of the alveolar surface. Though they occur more often, they are less involved in lining the alveolar surface. Size of the Cell . Comparatively larger than type ...

The alveoli makes up the functional tissue of the lungs called lung parenchyma that occupy around 90% of the total lung space. The alveoli consists of two types of alveolar cells and an alveolar macrophage. The two types of cells, also known as pneumocytes, are denoted as type I and type II cells.

The enzyme carbonic anhydrase present in a high concentration in RBCs and in small quantities in the plasma facilitates this reaction in both directions. So, the bicarbonate formed in the tissues releases carbon dioxide at the alveoli. Every 100 mL of deoxygenated blood can deliver 4 mL of carbon dioxide to the alveoli.