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Respiratory System Gross and Microscopic Anatomy

See how long you can hold your breath as you continue reading…How long can you do it? Chances are you are feeling uncomfortable already. A typical human cannot survive without breathing for more than 3 minutes, and even if you wanted to hold your breath longer, your autonomic nervous system would take control. This is because every cell in the body needs to run the oxidative stages of cellular respiration, the process by which energy is produced in the form of adenosine triphosphate (ATP). For oxidative phosphorylation to occur, oxygen is used as a reactant and carbon dioxide is released as a waste product.

Figures (10)

Alveoli and their capillary networks
The lungs as main part of respiratory tract
On inhalation, air travels to air sacs near the back of a bird. The air then passes through the lungs to air sacs near the front of the bird, from where the air is exhaled.
The left lung
The right lung
Chest CT (axial lung window)
Cross-sectional detail of the lung
Thick elastic fibres from the visceral pleura (outer lining) of lung
TEM image of collagen fibres in a cross sectional slice of mammalian lung tissue
A lobule of the lung enclosed in septa and supplied by a terminal bronchiole that branches into the respiratory bronchioles. Each respiratory bronchiole supplies the alveoli held in each acinus accompanied by a pulmonary artery branch.

Key Points

  • The larynx is also called the voice box and has the associated cartilage that produces sound.
  • The trachea is the largest tube in the respiratory tract and consists of tracheal rings of hyaline cartilage.
  • The bronchi in the conducting zone are reinforced with hyaline cartilage in order to hold open the airways.
  • The respiratory bronchioles and the alveolar ducts are responsible for 10% of the gas exchange.
  • The alveoli are tiny air sacs in the lungs where gas exchange takes place.
  • The inner visceral pleura covers the surface of the lungs, and the outer parietal pleura is attached to the inner surface of the thoracic cavity.

Terms

Tap a term for a plain-language explanation.

Sources & licensing(4)