Tik Tok the biological clock!
- Pravneet Chadha
- Nov 19, 2023
- 3 min read
Every evening my dog Angel knows when it's time for his walk, Starting right at 4:50 pm, he starts barking to remind me that I have to take him out for a walk at 5 pm. Did he learn to read the clock I often wonder. It can't be that he JUST KNOWS that it is 4:50 pm! He is exact to that time. I mean I can relate to him in that I get up pretty much the same time every day for school and on weekends too my bladder wakes me up whether I am ready to get up or not.
Chronobiology! That is the description of today's blog.....sounds nerdy but it is the study of circadian rhythms....okay, I will break it down more. According to the National Institute of Health, "Circadian rhythms are physical, mental, and behavioral changes that follow a 24-hour cycle. These natural processes respond primarily to light and dark and affect most living things, including animals, plants, and microbes. " The term comes from the Latin phrase circa diem meaning about a day. In my science class, I learned about the biological clock and that it is affected by the hormone Melatonin. Melatonin is a hormone produced by the pineal gland that influences our sleep-wake cycle through its rhythmic synthesis. But as I started reading up more there is a whole lot more to it than just that. In 2017, researchers Jeffrey C. Hall, Michael Rosbash, and Michael W. Young won the Nobel Prize for their research on how genes affect circadian rhythms in fruit flies. Their work showed that a gene produces a protein that builds up in cells overnight, and then breaks down during the day. Similar to these humans have Period and Cryptochrome genes that code for proteins that build up in the cell’s nucleus at night and lessen during the day.
Not only are there genetic factors but environmental factors that control our biological clock. In humans, the master clock is a group of about 20,000 neurons (nerve cells) that are located in the hypothalamus which receives direct input from the eyes. So the sunlight we see as well as the light from electronic devices can affect our circadian rhythm!
Digging deeper I learned that there are scientifically defined "chronotypes" . Three different chronotypes are distinguished: Morning-types (M-types) and Evening-types (E-types), as well as Neither-types (N-types). E-types differ from M-types in their melatonin profile. No kidding! I mean I knew my brother was 100% E-type, my parents are surely M-type and I guess I am N-type (LOL!). No wonder we have an early dinner where we all get to talk and we are all awake!
There is a scientific reason why Angel needs to go to walk at a certain time and eat at a certain time.
I hope you have a Happy Thanksgiving Week! I will be blogging some more as I have this week off but first I have to go as Angel needs me to feed him dinner WOOF WOOF
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4. Reid KJ. Assessment of Circadian Rhythms. Neurol Clin. 2019 Aug;37(3):505-526. doi: 10.1016/j.ncl.2019.05.001. PMID: 31256786; PMCID: PMC6857846.
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