The circadian rhythm keeps an organism’s body in sync with night and day in order to keep the body systems in order. The word circadian comes from the latin word circa diem, which means about a day (JCI). It was first identified in 1729 by Jean Jacques d’Ortuous de Marian, a french astronomer, geophysicist, and more importantly, a chronobiologist. Chronobiology is a type of science that examines the natural phenomenons and rhythms such as the circadian rhythm (Serendip). He was born on November 26, 1678 and died on February 20, 1771. With his interest in chronobiology, the study of day and night’s effects on living organisms, he proved the existence of circadian rhythm in plants. To come to this conclusion, he observed that the a type of plant, the Mimosa pudica, still opened its leaves during the day and closed them at night when put in a completely dark environment. With this shocking discovery, he “concluded circadian rhythms persist[s] without environmental cues” (The Guardian).
“A circadian rhythm is a roughly 24 hour cycle in the physiological processes of living beings, including plants, animals, fungi and cyanobacteria” (Science Daily). The biological clock that the circadian rhythm relies on to function is regulated by the suprachiasmatic nucleus (SCN), which is also called the pacemaker in the hypothalamus portion of the brain. The hypothalamus controls a variety of functions in the body from the nervous systems to the endocrine system. It is located in the center base of the brain and encloses the ventral part of the third ventricle. Located inside the hypothalamus, the suprachiasmatic nucleus (SCN) connects to the optic nerve which receives light and is made up of a cluster of nerve cells, around 20,000 neurons, that react to light and dark signals. Certain genes have been discovered to be linked with circadian rhythm and directing the rhythm (NIH). In humans up to 15% of genes may be regulated by this process. The connection means that circadian rhythm is majorly affected by light levels (ColoState). This mainly affects the eating, sleeping, and mating habits of living organisms from prokaryotes to the most complex animals.
The circadian rhythm’s effects on metabolism on living organisms is extremely significant. In humans, “a high-fat diet affects the molecular mechanism controlling the internal body clock that regulates metabolic functions in the liver” (UCI). This circadian rhythm disruption could lead to illnesses such as obesity, diabetes, and high blood pressure. A balanced, low-fat diet can help reset the rhythm. Not only does the liver have a specific circadian rhythm that functions best at around 1-3 a.m., but there are also other organs in the body that use a circadian rhythm as well. The lungs function best at 3-5 a.m., the large intestines at 5-7 a.m., the stomach at 7-9 a.m., the heart at 11 a.m.-1 p.m., the small intestines at 1-3 p.m., and the kidneys at 5-7 p.m. (Organic Authority).
In humans, the...