How Our Biological Clock Works (The Circadian Rhythm) and How it Control Our Activity

Biological Clock and how it works:

Our body has a clock of its own, often called our Biological clock. It controls everything. From feeling hungry, to feeling active or sleepy, all are controlled by this one clock.

Not only us, all the animals has a body clock which controls their basic necessities i.e. eating, sleeping and mating.  That clock is called circadian rhythm or circadian clock. Now, this clock is old sun-dial. So, day-night cycle influences the circadian clock.

Regulator of circadian clock or circadian is in Hypothalamus, deep inside our brain.

SCN in Hypothalamus control Circadian Rhythm

 Group of cell in hypothalamus known as Suprachiasmatic nucleus or SCN control this clock. SCN  is connected optic nerves of eyes. Hence it adjusts our body clock with day-night cycle.

SCN tries to sync our Biological clock with Day-Night cycle

In morning, with exposure to light SCN instruct our body to increase temperature, heart beat and blood pressure and get ready to for action. Then it gradually stops melatonin secretion, the hormone which makes us feel sleepy. With melatonin gone, we gets into top gear in late morning between 10 to 11 am.After sunset, in absence of natural light SCN instruct to release melatonin. As melatonin rises during night we feel less active.

Circadian Rhythm

Consequences altering body Clock:

But, our body clock can be altered by ourselves. Like people who does night shift can stay awakes whole night. But circadian circle doesn’t only control sleep cycle, it also controls many other functions in body. So, changing your sleep pattern can put sleep cycle out of sync with other activities. So, when you try altering body clock you just mess up the synchronization between brain and other organs. That is why people who do shift works often experience a sleeping disorder named “Shift Work Sleeping disorder”.

Shift Work Sleeping Disorder

Shift Work Sleeping Disorder:

Because of changing shift they get obliged to sleep in different times on different days. Hence, their body often has to adjust against the scheduled made by their Biological clock. So, feel active or sleepy on abnormal times as their circadian cycle gets messed up because of their changing schedules.

They experience some drastic consequences of it.

Symptoms:

• Feeling tired when they need to stay awake
• Inability to sleep or being sleepy suddenly
• Difficulty in concentration
• Irritation, depression
• Difficulty in coping up with situations and peoples

Jet Lag:

People who fly across the time zones frequently experiences sleeping issues, tiredness, lack of concentration etc. That condition is called Jet Lag. It is considered a circadian rhythm sleep disorder as it is caused by disturbance in the internal body clock. 

Reason of Jet Lag:

Say, you live in USA and you visit Japan. During your natural sleeping time, it is daytime in Japan. So your brain try to make adjustment to keep you awake but your body wants sleep. Then again you change your time zone. Say, you go to India. Again your body clock tries to make adjustment for the 5-6 hour change in time because of sudden change of time zone. But this adjustments are not as easy to make as it sounds. This adjustments requires resetting times of secretions of many hormones (like melatonin ) , synchronizing all organ clocks with the change and that can’t be accomplished in just few hours. So, you end up feeling fatigued, confused, having sleeping issues.

Messing up with body clock is never a good idea.

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Why we feel pain and how pain is produced? How pain killer works?

Pain is not a very good feeling. In fact, we hate pain. But just like other feelings pain is also product of our Mr.Brain’s magnificent electro-chemical expertise. Why the hell brain creates such an intense unpleasant feeling which we hate so freaking much.

But pain may not be good but it is necessary. 

You are feeling pain means brain is informing you that your body is taking some damage. If we touch a hot thing or press our hand against a tip of needle unconsciously, our hand moves away from it by itself. These automatic involuntary reflexes are for protection of our body from harm.

Now, when you get a cut, brain creates feeling of pain to draw your attention to that damaged part. Its brain’s way to tell, ‘Your body suffered some damage and do something about it!’

And pain is very compelling; if there were no pain, we wouldn’t even bother treat a cut or even worse. Few people has reduced sensation of pain because of mutation in SCN9A gen and they can walk

around with broken ankle or deep wound without feeling much pain but that injury becomes more serious over time. Luckily that condition is found very rarely; so almost all us have our brain warn us through pain about damages in our body.

Pain is for informing you of damage or something wrong about in your body that is why in most of the diseases we feel pain as our brain responds to unpleasant changes inside our body.

Now, how pain is generated?

Our nerve receptors are constantly picking up signals from outside world. There is a specialized receptor called nociceptors for feeling of pain.

If you touch blunt edge of a thing, you don’t feel pain as it is not doing any damage like penetrating your skin to make nociception fire a signal. But if you touch pointy needle and it penetrates your skin, that stimulation hits the nociceptive threshold and then ‘ouch’. The nociceptor’s work is like sending SOS in distress and it makes brain aware that “body is taking damage”.

Then some of your tissues are damaged brain sends some tuning chemical at that place to lower the nociceptve threshold of that area. That’s why a simple touch on a bruise hurts like hell.

There are different types of nociceptors :

Thermal nociceptors are activated by too much heat or cold

Mechanical nociceptors reacts when too much pressure or mechanical force doing damage like when someone use you as punching bag.

Chemical nocicpetor responses to unpleasant chemical changes  like you being poisoned or some bacteria is doing chemical party inside you.

And sleeping nociceptor which only activates when you are really injured and when this silent daddy shouts shout in pain too.

Inflammation:

Generally damage cell releases arachidonic acid.

It interacts with two cyclo-oxygenase enzymes, COX1 and COX2.

And we get prostaglandin which is culprit for inflammation, increased heartbeat.

Actually, in this case, inflammation is our immune system’s response to presence of prostaglandin.

How pain killer works?

We get prostaglandin when arachidonic acid reacts with COX enzymes.

So, common painkillers have chemicals which neutralize either arachidonic acid or COX enzyme.

Like aspirine has salacin which produce salicylic acid and blocks cox 1.

Ibuprofen derived from propionic acid blocks arachidonic acid.Paracetamol takes charge after arachidonic acid merges with cox enzymes and it blocks effect of created compound.

That is all for now. Please watch the video for simpler and complete explaination.

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I am Saphyaire,
Signing off for now and take care

Why science can't make human biologically immortal like bacteria

We were told that all living organisms are made to die, which is not exactly the truth. Unicellular life forms like bacteria don't have to suffer that fate. An amoeba or a bacterium becomes old and then divides, yielding two newborn cells. Nothing has died. So, they are biologically immortal. Biological aging is named senescence. Bacteria and many unicellular organisms and even simple multi-cellular organisms like hydra has negligible senescence as their cells keep dividing. They get killed by other organisms or harsh environment like high temperature.

Bacteria are biologically immortal

If those creatures can keep their internal structures intact and working indefinitely, why can't human cells do so?

Let us understand why humans can’t be immortal and why we die.

First, as our cells get nutrition, they divide and we grow. Eventually cells lose their ability to multiply. Biologist Hayflick found that human cells can be grown in the laboratory for only about 40 to 60 rounds of cell division.

Our body cells can't divide after 40-60 round of division

So, after that they don’t renew and we know, whatever doesn’t renew decays.

Mouse lives for 3 years and its cell can go through 14 to 28 divisions.

The tortoise can live really long, averaging 100 years and its cells keep dividing for 90 to 120 rounds. So, how long an organism would live appears to be related to the number of cell divisions its cells can sustain.

But why can't a cell keep dividing?

Because, each time a cell divides, the telomeres of chromosome get shorter. When telomeres get too short, the cell can no longer divide. If you are wandering what is telomere, a telomere is the end part of a chromatid, which protect our genetic data and doesn’t allow chromosome to fuse with its neighbor chromosome. Telomeres are really important.

Telomere gets shorter and shorter with every round of division

  

When cell divides, chromosome replicates itself, new chromosome gets little shorter telomere, then that cell again divides and length of telomere gets shorter. When telomere becomes too short, cell can’t replicate that chromosome anymore.

And if cell can’t replicate its chromosomes it can’t divide anymore.

 

Why does a cell die?

There are many theories as there are many reasons.

Our cells are chemical plant where lots of chemical reactions taking place continuously.

All products of those reactions are not exactly good for the cell. Sometimes unstable compound or ions with unpaired electrons are produced. Those are called free radicals. Free radicals can also be produced because of light and heat radiation.

These electron hungry free radicals break apart other molecules. Then those molecules who lost electrons try to steal electrons from another molecules, thus a chain reaction may start which destroy the whole work-flow inside cell chemical plant and plant shuts down, cell dies.

But we often heard of antioxidant which is good for us and this is the thing which can stop free radicals. Antioxidants give electrons to free radicals but it doesn’t turn to a harmful substance itself after giving electrons.

Vitamin C, E etc are excellent anti-oxidant.

But anti-oxidants can’t keep a cell alive for ever, though it can extend the life of cells.

But still you have to die because many cells which are given specialized functions can’t get renewed by division. Like nerves and most of muscle. 

Just think, our nerves make circuit in brain to retain memories, information of things we have learned. If they divide then those circuits or connection would be destroyed.

The maintenance credit goes to lysosomes in cells. Lysosomes produces enzyme to recycle old parts of cells to renew the cells. But many indigestible debris (lipofuscin) get accumulated inside lisosome and just like an old machine it loses its ability. Then cell dies as it can’t get renewed. 

As your body is made of cells, even the healthiest person of the earth has to die.

But many other factors like pollution, increase of light and heat radiation because of global warming also contribute a lot to produce free radicals in our cells.

Unhealthy diet can disturb the delicate work-flow in the chemical plant of our body and thus it reduces your life.

So, a healthy diet in a healthy environment can increase your life-span but you will die one day.

 

 

To understand better please watch the full video.

I am Saphyaire, Signing off for now

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