Lung

Definition

The lung is a vital organ in the respiratory system responsible for gas exchange, allowing oxygen to enter the bloodstream and carbon dioxide to be expelled. This process is essential for maintaining the body's oxygen levels and removing waste gases, highlighting the lung's critical role in breathing and overall respiratory function.

5 Must Know Facts For Your Next Test

1. Each human lung consists of lobes; the right lung has three lobes while the left lung has two, allowing for space for the heart.
2. Lungs are surrounded by a double-layered membrane called the pleura, which provides lubrication and reduces friction during breathing.
3. The process of breathing involves two phases: inhalation, where air enters the lungs, and exhalation, where air is expelled from the lungs.
4. Gas exchange occurs in the alveoli, where oxygen diffuses into the blood and carbon dioxide diffuses out to be exhaled.
5. The lungs receive blood from two sources: oxygen-poor blood from the heart via the pulmonary arteries and oxygen-rich blood returning to the heart through pulmonary veins.

Review Questions

• How do the structure and function of alveoli contribute to efficient gas exchange in the lungs?
  • Alveoli are tiny air sacs that provide a large surface area for gas exchange due to their numerous and clustered arrangement. Their thin walls allow oxygen to easily diffuse into the surrounding capillaries while facilitating the removal of carbon dioxide from the bloodstream. The surfactant produced by alveolar cells reduces surface tension, preventing alveoli from collapsing and ensuring that gas exchange remains efficient during both inhalation and exhalation.
• Discuss how the diaphragm works with other structures to facilitate breathing.
  • The diaphragm is a key muscle involved in breathing that contracts and flattens during inhalation, increasing thoracic cavity volume and drawing air into the lungs. This action is coordinated with the intercostal muscles, which lift and expand the rib cage. Together, these muscles create a pressure difference that allows air to flow in during inhalation and expel air out during exhalation, demonstrating an intricate collaboration between respiratory structures.
• Evaluate the impact of lung diseases on respiratory efficiency and overall health.
  • Lung diseases such as asthma, chronic obstructive pulmonary disease (COPD), or pneumonia significantly impair respiratory efficiency by reducing airflow, gas exchange, or causing inflammation. These conditions can lead to symptoms like shortness of breath, chronic cough, and decreased oxygen levels in the blood. The impact extends beyond respiratory health; systemic effects include reduced exercise capacity, lower quality of life, and increased risk for other health issues like cardiovascular disease. Thus, maintaining lung health is crucial for overall well-being.

Related terms

Alveoli: Tiny air sacs in the lungs where the exchange of oxygen and carbon dioxide occurs.

Diaphragm: A dome-shaped muscle located beneath the lungs that plays a crucial role in the process of inhalation and exhalation.

Bronchi:

The major air passages that branch from the trachea into each lung, facilitating the flow of air during breathing.