The equine respiratory system allows them to take oxygen in to sustain life processes, and also plays a part in the horses amazing athletic abilities. This article reveals how this system works.
Respiration and breathing are easily confused. Respiration is the chemical reaction of producing energy, wherein glucose and oxygen are transformed into carbon dioxide, water and an energy form called adenosine triphosphate (ATP). The mechanical action of breathing is called ventilation.
Air is drawn in through the nostrils (horses can’t breathe through their mouths!). These become highly flared during strenuous exercise, to increase air intake. The air travels into the nasal cavity, and through the larynx (voice box), which is made up of cartilage, and held in place by small bones called the hyoid apparatus.
The front of the larynx (situated behind the tongue) has a flap called the epiglottis, which covers the trachea during swallowing to prevent choking. The air travels down the back of the throat, into the windpipe, or, trachea. The trachea consists of rings of cartilage that help keep it open. The trachea divides into two branches called bronchi. Each of these travels to a separate lung. The bronchi divide into smaller and smaller passages called bronchioles, which end in bunches of small, rounded structures called alveoli. Each of these is adorned by a capillary, a small blood vessel with a wall only one cell thick. This is where gaseous exchange takes place with the blood.
The trachea constantly produces mucus which cleans it and tiny hairs called cilia assist with the process by moving the mucus up and back to the pharynx where it is swallowed. The lungs are contained in sacs of tissue called the pleurae, which become infected during a chest infection.
The capillaries carry deoxygenated blood to the alveoli of the lungs, and the oxygen from the inhaled air is drawn into the blood, and transported by the red blood cells. Carbon dioxide diffuses into the alveoli, from the sodium hydroxide dissolved in the plasma of the blood, and expelled.
The equine respiratory system is highly effective, and this allow horses to perform highly effectively too – Looking after your horses lungs allows him to reach his full potential!
Dusty hay, dusty bedding and working a horse too hard when unfit are three ways to damage your horses lungs. Therefore, to maximise potential, train and fitten your horse slowly, and avoid overworking. Feed haylage, soaked hay, or low dust hay to keep his airways clean, and avoid old, dusty straw bedding, or shavings that are not dust extracted.