Is the human blood green in colour besides being red?

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(Edited)

These are the kind of post that surely will arouse your interest if you are my kind. Today we will be discussing medics as usual but this time, it will incorporate some fundamentals and some principle that will help us arrive at a conclusion. Information here are proven facts and not speculation.

Sit tight and join me as I unveil some facts you probably don't know or must have heard but still in doubt because available information were not justifiable enough. Reading this will maybe get you convinced and well knowledgeable. I am about to add more knowledge to your repository and also wao you in the process.

It is undoubtedly true that the blood of humans is red in colour, yeah, that is definitely what anyone would answer because by mere looking at the blood, it is red. What if I told you that the blood actually has two colours - Red and green, would you believe me. Oh yes, I expected that look on your face right now, definitely you would argue, how is that, I mean, how possible is it. Well, read on, we are about to unravel some mystery and facts. Let's begin with your vision. How do you see images, differentiate and characterize images as red, blue, green, black, white etc. Isn't that something worth understanding, yes for sure it is.

Greek Phylolsophers like Plato, Aristotle and Hippocrates were the very first scholars to propose the first ever explanation on how human vision operates. They were able to describe the structure and various functions of these structures. For Aristotle, he believed that humans see as a result of the rays of light that originated from the eyes to shine or illuminate the world around it.

During the night, the air becomes so gloomy and murky that the rays are unable to pass or penetrate through and if candle is light, it will clear the opacity and then allows sight to penetrate. Quite interesting hypothesis but so far has been disproved with a better and factual principle of vision. As a layman, If we were part of their generation, we would have obviously believed it because it seems true just that it lacks factual scientific backings.

2000px-Eyesection.svg.png
Human eye section

Today we have a better understanding of the principle of vision in humans. We are able to see things as a result of the rays of light that passes through the retina. The iris which is a muscular structure has a hole known as pupil, is one of the major structure that is implicated in human vision day and night.

During the day, light rays which of course is as a result of the sun's illumination, enters the eyes through the cornea. The cornea then bends the light in such a way that it passes easily through the pupil. The pupil dilates and constricts as a result of the action of the smooth radial muscle fibers in the iris. Next is that the light rays then passes through the lens which is crytsaline and is also known to be very flexible. This flexibility enables it to adjust and it focal length. The flexibility of the lens enables it to either shorten or lengthen and this consequently enables it focus the rays of light onto the retina properly for good acuity.

The human iris naturally is pigmented and the level of its pigmentation is what determines the colour of the eyes. You would naturally observe that eye colour vary from different individuals, ranging from dark brown, black to blue. This is mainly as a result of the melanin pigmentation of the iris. People with more concentration of the pigmentation tend to have darker eyes compared to those that have lesser concentration of this pigment which makes them have blue eyes. The pigmentation though have some usefullness especially in reducing light rays.

It is important to note that, Increased intensity of light rays causes the pupil to constrict and reduce in diameter. This action limits the amount of light penetrating through the pupil to avoid damage to the photoreceptors (Rod and cone cells) which have maximum light intensity threshold it can detect. Light intensity beyond the threshold can result to problem. Reduced light intensity results to a concomitant increase in the size of the pupil. Ever wondererd why you can easily investigate death of an individual by simply pointing a torch to the eyes besides checking with stethoscope.

In dead individuals, they do have increased pupil diameter because the muscle of the iris has lost its functionality. As light passes through the lens, the next layer it meets is the vitreous humor chamber which contains gel-like in nature. The vitreous humour is what confers the eyes its shape and it is responsible for holding the content of the eyes. As the light pass through this layer, it is focused on the retina. The retina is mainly responsible for light reception. It receives light signals and converts it into neurological signals. These signal is then sent to the brain via the optic nerve for processing and visual recognition

The purpose of the retina is to receive light that the lens has focused, convert the light into neural signals, and send these signals on to the brain (the visual cortex) for visual recognition.

Explanation for vision at both day as night is mainly due to the photoreceptors found in the retina. These photoreceptors - cone and rod cells perform different functions at night and day. In the night, the rod cells are responsible for vision.

Vision at night is scientifically referred to as scotopic vision while for day, it is referred to as photopic vision. In the day time, the cones cells are more sensitive and thus responsible for colour vision. Your ability to distinguish between different colour is dependent on the correct physiological functionality of the cone cells. Individuals have three types of cones cells and in some, they may be lacking some of the cone cells. Some may lack all these three cones, and in such situations where they do not have all the three, it is referred to as colour blindness. This brings us to visible light spectrum. How do humans identify and differentiate colours?

Colour differentiation by human eyes

Very importantly is imperative we establish some basic facts, Objects do not have inherent or intrinsic colours. What determines the colour of any object is solely dependent on three important factors such as:

• The color content of the incident light that is illuminating the object;
• The way the object reflects, absorbs, and transmits the incident colors of light; and lastly,
• The way in which the detector such as your eye or a camera detects and interprets the colors of light coming from the object.

The human eyes has the ability of detecting all the visible light spectrum - a subset of the electromagnetic spectrum. light from the sun or a white bulb contains all the wavelengths of visible light spectrum. Note that they usually of equal distribution and together they are seen as white light.

2000px-Light_dispersion_conceptual_waves.gif
White Light Dispersion by glass Prism

This can be seen practically through a simple experiment using a glass prism which refracts and disperses them based on their speed. It has been well established that the prism is known to slow their respective speed and causes them to bend their path (refraction).

Our eyes is only able to see the colour that bounces off from the object on which an incident light falls on. If the object is seen as green, the indication is that, all other colours were absorbed by the object thus, resulting to the reflection of only green light. Wavelength that do not bounce off, are absorbed as heat. Not every wavelength can be detected by the human eyes and this is one of the reasons why infrared lights detectors can be used to detect and visualize pigmentations behind paint drawings.

Is human blood green in colour aside red?

The answer is an emphatic yes. Human blood besides being red is also green in colour. Before you doubt, the three fundamental principles we earlier talked about above. Let's start with some scientific research findings. In 2005, Martina Meinke and colleagues investigated the spectrum of human blood by measuring it's reflectance. It was discovered that it mainly reflected two colours - predominant red and then green colour.

The predominant red coloured spectrum below is the readily visible colour of the blood when we look at it. This is so because it reflects more of the red colour than the green spectrum. As they would say, "out of sight is out of mind". That the green colour spectrum of the blood is not readily visible doesn't mean that speaking the blood is only green in colour. Hope it is now making more sense here.

blood_spectrum.png
Diffuse reflectance of human blood with a hematocrit of 33%, oxygen saturation of 100%, and mean cell volume of 83 fentoliters; Public Domain Image, data source: M. Meinke, image source: Christopher S. Baird

They further measured the reflectance spectrum of different blood with different haematological values like the haematocrit and oxygen saturation values and still discovered that the graph though slightly changed but was still generally the same for all the haematological parameters. By implication, the green and red spectrum was always present and reflected, with the dominant reflected spectrum being the green, as depicted from the graph above.

Logically, anyone would always believe that the only colour of the blood is red, because when you shine light on it, it reflects only red colour since it is more of red by virtue of the iron content that make up haemoglobin. The haemoglobin in turn gives the blood the shade of red. Remember that the normal light we mostly use are white in colour and if you recall, we established for a fact that, the white light is mad up of the visible light spectrum which together form the white light.

What if we isolate specifically only the green visible light spectrum and shine it on the human blood, what do you think would be the result? Ever thought of that? Infact the blood would not even reflect or be seen as red, should a light source containing all other visible light spectrum with the exception of red be shined on it. It would only reflect green.

If you would recall, from the three factors we earlier stated, the third factor took into consideration the property and nature of the light source as it also determines the colour of an object, our illustration here depicts that singular factor. This is just one of once case experiment that would prove the existence of green visible light spectrum in human blood. Another case scenario is seen scuba divers.

Deep ocean water is slightly coloured blue not because of the sky but because it is able to absorb some of the red light emanating from the sun that is passing through it. Note that, as light descends or travel down the ocean, the visible light spectrum is gradually absorbed one after the other, with the red light being the very first because of its low energy. At depth of about 1000 feet below sea level, there is total darkness. That is to say, at this depth, all the visible light spectrum has been absorbed.

Gráfica_de_luz_color_vision.jpg
Scuba Diver in deep ocean reflecting green

As scuba divers descend deeper into the ocean, at depth of 15feet, there is total absorption of the red light by the ocean water while the other visible light spectrum penetrates. At this point, they notice a change in the colour of their body to green. Even underwater photographers at this point use red colour filters in their camera to restore the red colour.

Remember, since the red light which we have fundamentally established as part of the visible light spectrum is no longer available, the second colour of the blood that had been masked by the dominant red colour becomes clearly visible abd thus reflects green. This however, doesn't mean that the blood changed physiologically, the blood is still predominantly red but by virtue of the red colour disappearance, the green spectrum authomatically rules the day.

What happens if the blood is green under white light?

All things being equal, physiologically, you should only be able to see the blood as red. In situations where on a normal day, the blood turns green, without you being inside the deep ocean or using visible light spectrum devoid of the red spectrum, then this becomes a pathological condition known as Sulfhemoglobinemia (SulfHb). This is though a very rare condition that is caused by excessive sulfhemoglobin concentration in the blood. In sulfhemoglobinemia, instead of iron binding to the haemoglobin which is responsible for transporting oxygenated blood to organs, sulfur binds, consequently making it difficult for haemoglobin to effectively transport blood around the human body.

Report has it that sulfhemoglobinemia is caused by excessive exposure to sulfur containing compounds and actually the treatment is simple and easy. Human blood have 3 months life span after which they are destroyed and recycled. So invariably, this set of blood are destroyed along the process provided the patient desist from using or getting further exposure to the causative agents, they will be fine after 3 months.

We can conclusively infer that the blood is not only red in colour but also reflects green. Obviously if you are in an examination condition and it happens that the question is thrown - The human blood is physiologically also green in colour besides being red, discuss". This article is enough for you as a student to get a very good A.

Until I come your way again, stay awesome.

References

How Does The Human Eye Work?
Principles of Vision
Structure and function of photoreceptors
Post-mortem Human Iris Recognition
Retina Function, Anatomy & Anatomy
Rods & Cones
Seeing colour
There’s a condition that can cause human blood to turn green
PUBMED - The Diagnosis of Sulfated Hemoglobin (SulfHb) Secondary to Sulfur Dioxide Poisoning Using Matrix-Assisted Laser Desorption Time-of-Flight Mass Spectrometry (MALDI-ToF MS)—A Novel Approach to an Unusual Clinical Problem
Is human blood ever any color other than red?
Chemometric Determination of Blood Parameters Using Visible–Near-Infrared Spectra



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Interesting! This is the first time I hear anything about a green blood. Of course, it started to make sense while reading the post ;)

Funnily, when I read your description of how the colours of the objects around us arose, I couldn’t prevent myself from thinking about the fact that some colours are actually not colours in terms of the electromagnetic spectrum, but are only colours because of our “detectors” (i.e. our eyes). I in particular regularly tease some friends who like pink with the fact that pink is not a colour (that’s an abusive shortcut, but that’s a good one ;) ).

Cheers, and thanks for the nice blog!

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I couldn’t prevent myself from thinking about the fact that some colours are actually not colours in terms of the electromagnetic spectrum, but are only colours because of our “detectors”

Very true.

As we age, we keep learning. It's a privilege to pass the knowledge here in a clearer ad more simplified way.
🙏

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Portions of your writing do not appear to be original. Your text appears to originate from multiple articles. You cite these sources at the end of your article, but the intent of citation isn't to copy/paste or spin information from them as your original work:

I have listed an example below, but there are others.

Your ArticleSourceOriginal Author
The purpose of the retina is to receive light that the lens has focused, convert the light into neural signals, and send these signals on to the brain (the visual cortex) for visual recognition. Explanation for vision at both day as night is mainly due to the photoreceptors found in the retina.Healthline-RetinaThe purpose of the retina is to receive light that the lens has focused, convert the light into neural signals, and send these signals on to the brain for visual recognition.
Greek Phylolsophers like Plato, Aristotle and Hippocrates were the very first scholars to propose the first ever explanation on how human vision operates. They were able to describe the structure and various functions of these structures. For Aristotle, he believed that humans see as a result of the rays of light that originated from the eyes to shine or illuminate the world around it. During the night, the air becomes so gloomy and murky that the rays are unable to pass or penetrate through and if candle is light, it will burn off the opacity in the air which then allows sight to penetrate.NIH - Principles of VisionIt was the Greek philosophers (Hippocrates, Aristotle, Plato) who provided the first known theories concerning the eye, its function, anatomy, and treatment. Originally, the Aristotelian idea was that rays of light emanated from the eyes to illuminate the world around. When it was dark, the air became murky so the rays could not penetrate, but a candle could burn off the opacity in the air, allowing sight to penetrate.

I'd look forward to reading your review on this matter. For example, the second example I provide seems to be just paraphrased commentary that originated from the sources you provided.

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(Edited)

Okay, thanks for the observation @scholaris.pob . I stand corrected at this point if I am wrong...There is never a virgin topic or discussion in research. Majority of we know today is a a product of what others might have done and then to improve them, we borrow their ideas, build on them, and in exchange, reference and give credit to whom it is due. This has always been my practice and I have never failed to do. Even in the course of writing my scientific papers on journals.

You would agreed with me that no man is an island of knowledge. Never have I Said all the content of my articles are solely mine. That would obviously make me a very big lier. We only borrow ideas, hence the essence of referencing. Discussing science without stating facts the way they are maybe impossible, how it is said may differ but they sure must contain the necessary content to make them valid. Sometimes, you need scientific words to buttress points. If an author used some word and I also used it, but in another way to explain well known facts, kindly want to know if it would make it a spinned or plagiarized word? Anyone can easily write from inspiration without having to borrow concepts provided they are not discussing science.

In blogging, I try as much as possible to look for unique concepts that would require better explanation, then I pass them the best possible way. Communicating ideas the way you understand it, is the key and as much I try, I always do that and If I can't, I quote the source. My intents are pure and never with intent of spinning articles. There might be areas that might look alike but doesn't make them plagiarized content. There will always be clashes in words when discussing science, hence the reason 20-30% allowance is allowed in writing, to my Best of knowledge. Explaining things the way you understand them after reading cannot be judged as spinning. If no allowance is given, then it expected the individual must discover a novel explanation without having to borrow from a preexisting facts and laws (obviously impossible). It's just like asking someone to explain the Newton laws of motion without inputting key words that make the law valid.

One of the area you highlighted possibly needs quotation which I will admit is an oversight on my part and the needful will be done. The other part as you would observe clearly has the in-text reference attached to it. However, I do not write articles with intent of spinning.

Quick condemnation as speedy downvote makes it look personal without getting my view on the matter first. It's fine regardless.

Thanks.

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(Edited)

Quick condemnation as speedy downvote makes it look personal without getting my view on the matter first. It's fine regardless.

You're not wrong. It looks personal, but perhaps it is to a degree. I review a lot of articles. Not many people respond. And I can't always go back to check on whether or not the author corrects the issue. So, I'm thankful you did.

One of the areas I highlighted definitely needed quotations otherwise it's copy/paste. The other example is just paraphrasing what was already available.

Also, I've written research papers before. I've never heard of a "20-30% allowance".

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Make him cite where that 20-30% allowance came from, one of the sources probably came from his ass.

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(Edited)

By 20-30% allowance, I meant plagiarism score checks before paper submission.

The necessary correction has been effected.

I appreciate your critical review of the article regardless and I apologize for that omission.

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You might want to revisit the notion that 20-30% plagiarized content is acceptable to anyone, @cyprianj.

From the Editage Insights website -

Q: What is the acceptable percentage of plagiarism [in a] report?

Answer: There is a lack of consensus or clear-cut-rules on what percentage of plagiarism is acceptable in a manuscript. Going by the convention, usually a text similarity below 15% is acceptable by the journals and a similarity of >25% is considered as high percentage of plagiarism.

But even in case of 15% similarity, if the matching text is one continuous block of borrowed material, it will be considered as plagiarized text of significant concern. On the other hand, text similarity due to the usage of common terminologies and method related details in ‘Methodology’ part of a manuscript should not raise a serious ethical concern.

And to be clear, "usage of common terminologies" certainly doesn't cover taking entire sentences verbatim, or even slightly rewording to make them harder to detect by plag checkers seem original.

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All I read is ok sorry for the misunderstanding here are my elaborate reasons to justify why I spun some parts cause I may have forgot. If you've been doing this for a long time, there's a good chance some old posts had it too. Scholaris highlighted the specific parts where you just changed some words which is just spinning content.

However, I do not write articles with intent of spinning.

You don't intend to spin but it came out spun. And it is spun.

If no allowance is given, then it expected the individual must discover a novel explanation without having to borrow from a preexisting facts and laws (obviously impossible). It's just like asking someone to explain the Newton laws of motion without inputting key words that make the law valid.

Newton invented calculus because current math during his time couldn't explain his theories.

Quick condemnation as speedy downvote makes it look personal without getting my view on the matter first. It's fine regardless.

I don't care if the downvotes look personal, I don't wait for the author's opinion when I am free to upvote their post. The safest method you could've gone was just quoting the lines instead of botching the word smithing. I don't see the value in trying so hard to repack the idea when you can just link people to something that explains it better.

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