| The horse's respiratory system is large and | | | | Infection-fighting white blood cells are also found |
| complex, precisely suited to provide the right | | | | along the respiratory tract as well as deep inside |
| amount of oxygen for both ordinary and | | | | the lungs. These cells are crucial for defense |
| extreme conditions. It begins at the large nostrils | | | | against viruses, bacteria, and other organisms. |
| that can expand to take in large amounts of air | | | | However, they also cause inflammation that, left |
| when the horse, a prey animal, has that "need for | | | | untreated, can lead to development of serious |
| speed," and lined with a sophisticated defense | | | | lung disease. |
| system to keep out dust and airborne pathogens | | | | Since most of our horses no longer run wild in the |
| like bacteria and fungal spores. | | | | great outdoors, good environmental management |
| The intake of air starts at the nostrils and moves | | | | is needed to keep lung disease from developing. If |
| through a long network of thin bones called | | | | your horse is stabled, make sure the barn has |
| turbinates. From there, it moves through the | | | | excellent ventilation, and keep doors, half-doors, |
| sinuses, located in the front part of the skull, and | | | | and windows open as much as possible. If the |
| into the main airway, the trachea. At its lower | | | | weather is cold, it is better to blanket the horse |
| end inside the chest, the trachea splits into two | | | | than to close off sources of fresh air. Good stable |
| branches (one to each lung), which then subdivide | | | | hygiene (frequent removal of damp or soiled |
| many times until reaching the air sacs in the lungs, | | | | bedding) is also important. |
| where oxygen is transported into the | | | | All feeds should, of course, be as clean and as |
| bloodstream. | | | | high quality as possible. It's best if hay is stored |
| The respiratory system resembles an | | | | away from horse stalls and kept as dry as |
| upside-down tree, where the nostrils are the | | | | possible to prevent mold growth.While stalls are |
| roots, the trachea is the trunk, and the branches | | | | being cleaned, the horse should be removed to an |
| (airways) multiply and get smaller (from large | | | | outdoor run or other secure area until the dust |
| bronchi to tiny bronchioles) until reaching the | | | | settles. |
| leaves (air sacs), where gas exchange with the air | | | | These simple precautions will help keep your |
| takes place. | | | | horse safe and sound and performing at its best! |
| The respiratory tract is lined with specialized cells | | | | Trivia: Here's a little respiratory trivia for |
| that perform many functions. The nostrils are | | | | you...Quarter horses got their name because they |
| lined with skin, which becomes a moist mucous | | | | are extremely fast runners for 1/4 of a mile. |
| membrane as it progresses inward. Olfactory cells | | | | They're even faster than Thoroughbreds, but only |
| that sense odor are numerous in the turbinates. | | | | for that distance. Why 1/4 mile? Because that's |
| Much of the tract is also lined with cilia. The nasal | | | | how far they can run on one breath. Other |
| passages and sinuses warm and moisten the air | | | | breeds, as well as horses running for longer |
| as it flows toward the lungs, while the mucus and | | | | distances, take more breaths, and it slows them |
| cilia trap small particles. The cilia move rhythmically | | | | down. By not taking a breath, Quarter horses can |
| to move mucus and particles upward and | | | | put 100% of their energy into running; but once |
| outward. The horse will then blow (snort) or | | | | they run out of oxygen from that first breath, |
| cough to force these particles out of the system. | | | | the effort of breathing slows down their pace. |
| These normal defenses help keep the lungs safe | | | | Now that's the ultimate sprinter! |
| and healthy. | | | | |