The respiratory system
Q1. The lungs have two membranes that surround them, the pleural membranes that enclose a fluid-filled space. Regarding this, the fluid as well as the membranes serve to protect the lungs and provide lubrication. The membranes hold a fluid called the pleural fluid. Nevertheless, if the air accumulates in between the membranes, it causes pneumothorax. Pneumothorax or a collapsed lung refers to the build-up of air in the pleural space. More importantly, when a significant amount of air accumulates in the lungs, it can compress the lungs and impede the ability of the lungs to expand.
Q2. Regarding intrapulmonary pressure, the pressure inside the lungs decreases as the volume of the lungs increases during inspiration; pressure increases during expiration. However, concerning the intrapleural pressure, the pleural cavity pressure becomes more negative as the walls of the chest expand during inspiration. Therefore, the air becomes saturated with water that has a partial pressure of 47mmHg.
Q3. The alveoli consist of two main types of cells. For instance, type I and type II cells. Concerning this, type I cells are the larger of the two types of cells (Lee et al, 2018: Knudsen & Ochs, 2018). They are thin and also have flat epithelial lining cells that always form the structure of the alveoli. Type I cells take part in the process of gaseous exchange between the blood and the alveoli. Nevertheless, the type II cells are cuboidal and smaller than type I cells (Knudsen & Ochs, 2018). The type II cells contain secretory organelles, the lamellar bodies, which fuse with the cell membranes hence secreting pulmonary surfactant. More importantly, the pulmonary surfactant is a film of fatty substances, that is, a group of phospholipids, which reduce alveolar surface tension.
The structure of the alveoli possesses various similarities with the pulmonary capillaries. For example, they both have thin walls that are approximately one cell thick. As a result, it reduces the distance to which the gases diffuse. Moreover, they both have moist walls that enable the gasses to pass across the gas exchange system. They have an extensive blood supply. In this case, they have numerous capillaries that ensure a stable exchange of gases.
Q4. Emphysema is a respiratory disease that is commonly caused by smoking. Individuals who suffer from emphysema always experiences difficulties in exchanging air from the lungs. Regarding this, cigarettes smoke damages the air sacs in the lungs to a point where they cannot undergo self-repair.
The diagnosis of emphysema cannot be made solely on symptoms. However, the spirometry and pulmonary function test (PFT) is applied. For instance, it is useful in determining airway blockage. Furthermore, spirometry tests the volume of the lungs by measuring airflow while a patient inhales and exhales. The test is done by taking a deep breath and then blowing into a tube that is hooked up to a specialized machine. The tests are compared to the normal results from the people of the same gender, height, weight, age as well as ethnic background.
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