Why might the special senses of smell and taste be important for helping to maintain homeostasis in the body?
The French scientist Claude Bernard first suggested the concept of homeostasis in the 19th century. He defined homeostasis as the fact that all living things maintain a constant internal environment. Homeostasis is the tendency of the body to maintain a relatively consistent internal state. The nervous system sends and receives signals about temperature, hydration, blood pressure and other factors, and the endocrine system carries chemical messengers to adjust bodily functions. The body is composed of billions of cells that require precise temperatures to function properly. Cellular metabolism and reproduction require access to hormones, nutrients and signals from other cells. When conditions in the body change too much, cells can't function properly. This is especially noticeable in sport or in extreme conditions. In sport, during jogging, the blood pressure and pulse increase to provide blood to the body's tissue, and body temperature increases. Homeostatic processes allow these increases to remain at a manageable level and provide the body with a mechanism for returning internal conditions to normal when you're finished jogging. In extreme conditions, such as hypothermia, the body’s negative feedback systems will quickly trigger muscular reactions (such as shivering) in an attempt to generate heat to warm-up the body and maintain homeostasis. In the reverse situation - where the body’s core temperature is rising (for example in the desert, or when exercising in extreme heat and/or humidity) – the body starts to sweat in order to dissipate some of the heat and help cool the body.
Taste and smell functions are absolutely critical to maintain a homeostatic balance in the body: a. Taste works as a guardian of what we eat before something enters a person’s gastrointestinal tract b. Smell works to guard guardian our lungs and the respiratory tract
These senses allow us to eat foods and to drink beverages that are both non-toxic and nourishing, and breathe air that is free from pollutants and contaminants.
The Sense of Taste: Taste buds are the sensory structures for taste and are located primarily in the oral cavity. We have 10,000 or more taste buds and most of them are located on our tongue, a few on the inner surface of the cheeks and a couple on the soft palate, pharynx and epiglottis.
The sense of taste declines as we age. We are born with around 10,000 taste buds, but as we age the number slowly declines. At the age of 50 the decline becomes much more rapid. That is probably why older people sometimes complain that the food “just doesn’t taste as good as it used to”! The Sense of Smell: The sense of smell is governed by paired olfactory organs which are located on either side of the nasal septum in the upper portion of the nasal cavity. These cells are specialized endings of the fibers that make up the olfactory nerve. They are surrounded by specialized epithelial cells that each end in a tuft of cilia. Chemicals will bind to the cilia and stimulate the transmission of nerve impulses that are transmitted directly to the olfactory bulb of the cerebral cortex. The senses of taste and smell complement each other. They are jointly interpreted by the cerebral cortex.
1. Thibodeau, G.A., & Patton, K.T. (2012). Structure & Function of the Body (14th edition) St. Louis, MO: Elsevier Mosby