YMCA L2 Anatomy - Respiratory System

Diffusion is the name given to the process which allows gaseous exchange to occur within the lungs. Diffusion is the movement of molecules from an area of higher concentration to an area of lower concentration. In the lungs, oxygen from the inhaled air diffuses across the thin walls of the alveoli (tiny air sacs) into the bloodstream, while carbon dioxide, a waste product, diffuses from the bloodstream into the alveoli to be exhaled. This process ensures the exchange of gases necessary for respiration to occur efficiently.

The lungs are primarily responsible for the process of respiration, which involves the exchange of gases between the air and blood. Inhalation and exhalation are the main actions involved in this process, allowing for the intake of oxygen and the removal of carbon dioxide. Gaseous exchange refers to the transfer of oxygen from the lungs to the bloodstream and the removal of carbon dioxide from the bloodstream to the lungs. Circulation, on the other hand, is the function of the heart and blood vessels, responsible for transporting oxygenated blood from the lungs to the rest of the body and deoxygenated blood back to the lungs. Therefore, circulation is not a function of the lungs.

Gaseous exchange takes place in the alveoli. These tiny air sacs are located at the end of the bronchioles in the lungs. They are surrounded by a network of capillaries, allowing for the exchange of oxygen and carbon dioxide between the lungs and the bloodstream. The large surface area and thin walls of the alveoli facilitate the diffusion of gases, ensuring efficient oxygen uptake and carbon dioxide removal.

The tiny air sacs where gaseous exchange takes place within the lungs are called alveoli. These small structures are located at the end of the bronchioles and are surrounded by capillaries. Oxygen from the inhaled air diffuses into the bloodstream through the thin walls of the alveoli, while carbon dioxide, a waste product, passes from the capillaries into the alveoli to be exhaled. The large number of alveoli in the lungs provides a large surface area for efficient exchange of gases, ensuring that oxygen is taken in and carbon dioxide is expelled effectively.

The correct answer is "Pharynx, larynx, trachea, bronchi, bronchioles, alveoli." This sequence accurately describes the passage of air through the respiratory tract, starting from the pharynx (throat) and passing through the larynx (voice box), trachea (windpipe), bronchi (large airways), bronchioles (smaller airways), and finally reaching the alveoli (tiny air sacs in the lungs where gas exchange occurs). This order reflects the anatomical structure of the respiratory system and the pathway that air follows during inhalation and exhalation.

The diaphragm is a large dome-shaped muscle located below the lungs. It plays a crucial role in the process of inhalation by flattening and contracting, which increases the volume of the thoracic cavity and allows the lungs to expand. This movement creates a pressure gradient that draws air into the lungs. The other options listed, such as the intercostal muscles, internal obliques, and abdominals, are not directly involved in the process of inhalation.

The lungs are located within the chest cavity on either side.

The lungs are located above the diaphragm. The diaphragm is a muscle located at the bottom of the ribcage that separates the chest cavity from the abdominal cavity. The lungs are situated within the chest cavity, above the diaphragm. They are protected by the ribcage and surrounded by the pleural membranes.

The correct answer is 21%. This is because the air we inhale is composed of various gases, with oxygen being one of them. Oxygen makes up approximately 21% of the air we breathe.

Oxygen is the correct answer because it diffuses into the capillaries surrounding the alveoli to be taken back to the heart. Oxygen is inhaled into the lungs and then diffuses across the thin walls of the alveoli into the surrounding capillaries. From there, it binds to hemoglobin in red blood cells and is transported to the heart to be pumped to the rest of the body.

The intercostal muscles are responsible for lifting the ribs to expand the chest cavity. These muscles are located between the ribs and play a crucial role in the process of breathing. When they contract, they elevate the ribs, allowing for the expansion of the chest cavity and the inhalation of air. This action is essential for increasing lung capacity and facilitating efficient breathing. The diaphragm also plays a significant role in breathing, but its main function is to contract and flatten, causing the chest cavity to expand downward rather than lifting the ribs. The internal obliques and abdominals are muscles involved in core stability and trunk rotation, but they do not directly contribute to expanding the chest cavity.

Approximately 16% of oxygen is exhaled from the lungs after gaseous exchange.

The correct answer is 0.04%. This is because the concentration of carbon dioxide in the Earth's atmosphere is approximately 0.04%. When we inhale air, we breathe in a mixture of gases including oxygen, nitrogen, and carbon dioxide. While oxygen is the most important gas for our bodies, carbon dioxide is present in a much smaller percentage.

During exhalation, the diaphragm relaxes and moves up. The diaphragm is a dome-shaped muscle located below the lungs. When we inhale, the diaphragm contracts and moves down, creating more space in the chest cavity for the lungs to expand. This allows air to enter the lungs. During exhalation, the diaphragm relaxes and moves up, reducing the space in the chest cavity and causing the lungs to deflate, pushing air out of the body.

The bronchi are responsible for transporting air in and out of the lungs. They are the main passageways that connect the trachea to the lungs, allowing air to flow in during inhalation and out during exhalation. The bronchi branch out into smaller tubes called bronchioles, which further distribute the air to the alveoli, where oxygen is transferred to the blood. Therefore, while the bronchi do supply air to the alveoli and transport air to the lungs, their primary role is to transport air in and out of the lungs.