1. The respiratory system functions to facilitate the exchange of gases between the body and the environment. Its main functions include:
- Breathing: The respiratory system allows for the intake of oxygen and the removal of carbon dioxide through the process of breathing.
- Gas exchange: It facilitates the exchange of oxygen from inhaled air with carbon dioxide produced by the body's cells.
- Regulation of blood pH: The respiratory system helps regulate the acid-base balance in the body by controlling the levels of carbon dioxide.
- Voice production: The respiratory system plays a role in the production of sound and speech through the larynx.
2. The conducting zone and respiratory zone are two functional divisions within the respiratory system.
- Conducting Zone: This zone includes the structures that transport air to and from the respiratory zone. It consists of the nose, pharynx, larynx, trachea, bronchi, and bronchioles. Its main function is to filter, warm, and moisten the inhaled air, as well as to conduct it to the respiratory zone.
- Respiratory Zone: This zone comprises the structures where gas exchange occurs. It includes the respiratory bronchioles, alveolar ducts, and alveoli. Its main function is the exchange of oxygen and carbon dioxide between the air and the blood.
3. The three regions of the pharynx are:
- Nasopharynx: This region is located behind the nasal cavity and above the soft palate. It serves as a passageway for air and also houses the pharyngeal tonsils (adenoids).
- Oropharynx: Positioned behind the oral cavity, it extends from the soft palate to the epiglottis. It serves as a passage for both air and food and contains the palatine and lingual tonsils.
- Laryngopharynx: Located below the oropharynx, it extends from the epiglottis to the opening of the esophagus. It serves as a common pathway for both air and food, and its lower part is responsible for directing food into the esophagus during swallowing.
4. The larynx, also known as the voice box, is a structure in the respiratory system that plays a crucial role in breathing and voice production.
- Structure: The larynx is composed of several cartilages, including the thyroid cartilage (Adam's apple), cricoid cartilage, and epiglottis. It is also lined with vocal folds (vocal cords).
- Location: It is located in the anterior part of the neck, between the base of the tongue and the trachea.
- Functions: The larynx has multiple functions, including protecting the lower airway during swallowing (epiglottis), producing sound and speech (vocal folds), and controlling the flow of air during breathing (vocal cord movement).
5. The three large cartilages of the larynx are:
- Thyroid cartilage: It is the largest cartilage and forms the Adam's apple. It protects the vocal folds and provides structural support to the larynx.
- Cricoid cartilage: This cartilage is ring-shaped and sits below the thyroid cartilage. It provides support to the larynx and helps maintain its shape.
- Epiglottis: It is a leaf-shaped cartilage located above the glottis (the opening of the larynx). The epiglottis prevents food from entering the larynx during swallowing by covering the glottis.
6. The pleura is a membrane that surrounds the lungs and lines the thoracic cavity. It consists of two layers: the visceral pleura (attached to the lungs) and the parietal pleura (attached to the thoracic cavity). Its functions include:
- Lubrication: The pleural fluid between the layers reduces friction during breathing movements.
- Protection: The pleura provides a protective barrier for the lungs and helps maintain their shape.
- Facilitating breathing: The pleura helps in expanding and contracting the lungs during respiration.
7. The three important types of pressure in breathing are:
- Atmospheric pressure: This is the pressure exerted by the air in the atmosphere. It is usually around 760 mmHg at sea level.
- Intrapulmonary pressure: Also known as alveolar pressure, it is the pressure inside the lungs. During normal breathing, it fluctuates slightly above and below atmospheric pressure to facilitate the movement of air.
- Intrapleural pressure: It is the pressure within the pleural cavity, which is the space between the visceral and parietal pleura. Intrapleural pressure is always lower than intrapulmonary pressure and atmospheric pressure to create a pressure gradient that helps keep the lungs inflated.
8. The two major steps in pulmonary ventilation are:
- Inspiration: This involves the intake of air into the lungs. It is an active process that requires the contraction of the diaphragm and external intercostal muscles, causing the chest cavity to expand and air to be drawn into the lungs.
- Expiration: This includes the expulsion of air from the lungs. It can be either an active process (during exercise or forceful breathing) or a passive process (during normal breathing at rest). During expiration, the diaphragm and external intercostal muscles relax, and the elastic recoil of the lungs helps push air out.
9. The two divisions of the respiratory system are:
- Upper respiratory tract: It consists of the organs located above the trachea, including the nose, nasal cavity, pharynx, and larynx.
- Lower respiratory tract: It includes the organs located below the trachea, including the trachea, bronchi, bronchioles, and lungs.
10. The two sites of exchange of oxygen and carbon dioxide are:
- Lungs: The exchange of gases between inhaled air and the bloodstream occurs in the alveoli, which are tiny air sacs within the lungs. Oxygen from the air diffuses into the bloodstream, while carbon dioxide produced by the body's cells diffuses from the bloodstream into the alveoli to be exhaled.
- Tissues of the body: The exchange of gases between the bloodstream and the body's tissues occurs at the capillary level. Oxygen carried by red blood cells is delivered to the tissues, and carbon dioxide produced by the tissues diffuses into the bloodstream to be transported back to the lungs for exhalation.
