Chronobiology

The life and times of Time and Life.

Introducing Biological Rhythms: a primer on the temporal organization of life, with implications for health, society, reproduction and natural environment
by Willard L. Koukkari & Robert B Sothern

Ch 1 – the study of the biology of rhythms

“Life moves in synchrony to the beat of locks and calendars, some outside he body, some within the very cells of all living things.”

“By definition, a rhythm is a change that is repeated with a similar pattern.”"

see also
Crowds and Power,
Language and Feet,
Cadence, Ratio and Ratiocination

“Accidents, catastrophes, and illnesses are inevitable when the time cycle of society does not heed the biological rules that underlie the rhythms of humans or other organisms.”

Three-Mile Island’s nuclear accident, Bhopal’s methyl isocyanate leak, the Exxon Valdez’ oil spill and Chernobyl’s nuclear disaster as well as a train collision in Western Canada on February 8th 1986 – all attributed to human error due to disrupted rhythms resulting from shift-work.

< 1 second – EEG (delta waves) & ECG
4 – 15 minutes – reaction time
75 – 100 minutes – pupillary motility
90 – 100 minutes – REM – NREM sleep
24 hours – body temperature, sleep-wake
7 days – organ transplant rejection
27 – 34 days – menstrual cycle

Ch 2 –

Equivalency

time frequency time label spectrum wavelength
1 second ultradian ultraviolet 4 x 10 (17) s
1 minute
1 hour
1/2 day
1 day Circadian visible spectrum 4 – 8 x 10 (14) s
1/2 week infradian infrared 5 x 10 (11) s
1 week
1 month
1 year ultrasound 1 x 10 (9) s
11 years audible sound 1 x 10 (5) s
1 century infrasound 1 x 10 (3) s

Human rhythms:
core temperature – 64 +/- 8 minutes
sleep EEG – 80-120 minutes
insulin – 6-10 & 140 minutes

Superchiasmatic Nuclei (SCN)

“Anatomically, this area [SCN] is located above the optic chiasm where the two optic nerves cross and include two clumps of nuclei, each containing about 10, 000 neurons.”

rhodopsin – opsin based visual pigment of rods & cones
melanopsin – same mRNA in it & SCN & retinal ganglion

Retinohypothalamic Tract (RHT)
terminates at the SCN
glutamate & PACAP (a polypeptide) involved

Ch 3 -

“Time has no divisions to mark its passage, there is never a thunderstorm or blare of trumpets to announce the beginning of a new month or year. Even when a new century begins, it is we mortals who ring bells and fire pistols.”
Thomas Mann

bases for calendars:

Sun, Moon, stars & planets
River flooding
Shadows (sundials)
water flow

Prime Meridian and Time Zones introduced in 1884
Daylight Savings Time introduced with WWI
US moved up the Spring Daylight Savings Date in 1986

Ch 4 –

“Time is very bankrupt and owes more than he’s worth to season.
Nay, he’s a thief too: have you not heard men say,
that Time comes stealing on by night and day?”
William Shakespeare

“Today, the trends of urbanization and the utilization of electrical power and rapid transportation shield most of us from witnessing much of the seasonal biological diversity found in nature.”

photoperiodism – seasonal changes to light
“response of an organism to the timing and duration of light and dark.”

Ch 5 –

“Time, space, and causality are only metaphors of knowledge, with which we explain things to ourselves.”
Friedrich Nietzsche

attractor
bifurcation
unstable, neutrally stable and stable focus
isochron
saddle point
node
singularity

Ch 6 –

12.4 hour circatidal cycle
24.8 hour circalunidian (lunar day)
29.5 days circalunar

Ch 10 -

“The clock, not the steam engine, is the key machine of the modern industrial age…even today no other machine is so ubiquitous.”
Lewis Mumford

Ch 11 –

observe one’s own:
body temperature, mood, vigor, perception of elapsed time, heart rate, blood pressure, speed of adding, short-term memory.

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