* Inhalation: Air enters the horse's nostrils and travels through the nasal passages. The air then passes through the larynx (voice box), trachea (windpipe), and into the two bronchi, which lead to the lungs.
* Exhalation: As the diaphragm and intercostal muscles relax, air is pushed out of the lungs, reversing the path of inhalation.
* Lung Function: Inside the lungs, tiny air sacs called alveoli exchange oxygen and carbon dioxide with the bloodstream. Oxygen enters the blood, while carbon dioxide exits the body.
Specific Adaptations:
Wild horses have some adaptations that help them breathe efficiently, especially during strenuous activity like running:
* Large Lung Capacity: Horses have relatively large lungs for their size, allowing them to take in a lot of air with each breath.
* Flexible Rib Cage: Their rib cage is flexible, allowing for greater lung expansion during inhalation.
* Strong Diaphragm: The diaphragm, a dome-shaped muscle that helps with breathing, is powerful in horses, enabling them to breathe deeply and efficiently.
Other Considerations:
* Altitude: Horses living at higher altitudes have adapted to thinner air by developing larger lungs and hearts.
* Exercise: During strenuous exercise, horses breathe much faster and deeper to deliver more oxygen to their muscles.
* Disease: Respiratory diseases like pneumonia can affect a horse's ability to breathe.
Overall, wild horses have highly efficient respiratory systems that allow them to thrive in their challenging environments.