Respiratory System and Smell
The horse's respiratory system consists of the nostrils, pharynx, larynx, trachea, diaphragm, and lungs. Additionally, the nasolacrimal duct and sinuses are connected to the nasal passage. The horse's respiratory system not only allows the animal to breathe, but also is important in the horse's sense of smell (olfactory ability) as well as in communicating. The soft palate blocks off the pharynx from the mouth (oral cavity) of the horse, except when swallowing. This helps prevent the horse from inhaling food, but also means that a horse cannot use its mouth to breathe when in respiratory distress—a horse can only breathe through its nostrils. For this same reason, horses also cannot pant as a method of thermoregulation. The genus Equus also has a unique part of the respiratory system called the guttural pouch, which is thought to equalize air pressure on the tympanic membrane.Located between the mandibles but below the occiput, it fills with air when the horse swallows or exhales.
Read more about this topic: Equine Anatomy
Famous quotes containing the words system and/or smell:
“In the course of the actual attainment of selfish ends—an attainment conditioned in this way by universality—there is formed a system of complete interdependence, wherein the livelihood, happiness, and legal status of one man is interwoven with the livelihood, happiness, and rights of all. On this system, individual happiness, etc. depend, and only in this connected system are they actualized and secured.”
—Georg Wilhelm Friedrich Hegel (1770–1831)
“The worst of crimes. All the other crimes are virtues beside it: all the other dishonors are chivalry itself by comparison. Poverty blights whole cities; spreads horrible pestilences; strikes dead the very souls of all who come within sight, sound, or smell of it.”
—George Bernard Shaw (1856–1950)