LS1.2 - Respiratory System

Structures:

• Nasal Cavity: The space inside the nose.

• Oral Cavity: The mouth.

• Pharynx: The throat; common passageway for air and food.

• Larynx: The voice box; contains the vocal cords.

• Epiglottis: Flap of cartilage that covers the trachea during swallowing.

• Trachea: The windpipe; cartilaginous tube leading to the lungs.

• Bronchi (singular: bronchus): The two main branches of the trachea that enter the lungs.

• Bronchioles: Smaller branching airways within the lungs.

• Alveoli (singular: alveolus): Tiny air sacs in the lungs where gas exchange occurs.

• Capillaries (pulmonary): Small blood vessels surrounding the alveoli.

• Lungs: The primary organs of respiration.

• Pleura: Membranes surrounding the lungs.

• Diaphragm: Large, dome-shaped muscle at the base of the chest cavity that helps with breathing.

• Rib Cage: Bony structure protecting the lungs and aiding in breathing.

• Intercostal Muscles: Muscles between the ribs that help with breathing.

Processes and Concepts:

• Ventilation: The process of moving air into and out of the lungs (breathing).

• Inhalation (Inspiration): The process of taking air into the lungs.

• Exhalation (Expiration): The process of releasing air from the lungs.

• Gas Exchange: The diffusion of oxygen and carbon dioxide between the alveoli and the blood.

• Diffusion: The movement of molecules from an area of high concentration to an area of low concentration.

• Partial Pressure: The pressure exerted by a single gas in a mixture of gases (important for understanding gas exchange).

  • Partial Pressure of Oxygen (PO₂)

  • Partial Pressure of Carbon Dioxide (PCO₂)

• Respiratory Rate: The number of breaths taken per minute.

• Tidal Volume: The volume of air inhaled or exhaled during a normal breath.

• Vital Capacity: The maximum volume of air that can be exhaled after a maximum inhalation.

COVID-19 can cause lung complications such as pneumonia and, in the most severe cases, acute respiratory distress syndrome, or ARDS. Sepsis, another possible complication of COVID-19, can also cause lasting harm to the lungs and other organs. Newer coronavirus variants may also cause more airway disease, such as bronchitis, that may be severe enough to warrant hospitalization.

COVID-19 Pneumonia

In pneumonia, the lungs become filled with fluid and inflamed, leading to breathing difficulties. For some people, breathing problems can become severe enough to require treatment at the hospital with oxygen or even a ventilator.

The pneumonia that COVID-19 causes tends to take hold in both lungs. Air sacs in the lungs fill with fluid, limiting their ability to take in oxygen and causing shortness of breath, cough and other symptoms.