This tag is for questions about the general biological features of human beings (as opposed to the biology of non-humans).

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How many species of mites live on the human body?

How many known species of mites regularly live on the human body? I've always heard that most people have eyebrow mites. This source mentions 2 species of face mites, Demodex folliculorum and D. ...
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25 views

What are the most efficient sources of nutrition to add lean mass? [closed]

In conjunction with an exercise routine, what sources of nutrition will best help increase lean body mass. Most non-hormonal exercise supplements risk causing liver damage and gout due to excess urea ...
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1answer
78 views

Does our brain contain an innate function about closing only one eye?

I wasn't sure where to post this, but biology seemed fitting for me. Sorry if I'm wrong. I was wondering why, when we close both our eyes and look at light, it is clear we can see the light even ...
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2answers
5k views

Is it possible that by mutation a human could see infrared or other 'colours'?

Incoming light reacts with the several types of cone cells in the eye. In humans, there are three types of cones sensitive to three different spectra, resulting in trichromatic color vision. Each ...
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2answers
71 views

Metabolic activity postmortem

I read some papers about studies on metabolism in post-mortem tissues in human, but I do not exactly the reason about why our brain continues to have activity after death.
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1answer
250 views

What biological functions does crying serve?

Tears suddenly start flowing out of our eyes when we find our long lost friend or when someone unexpectedly decides to break up with us. Do tears really save us from harm? Or are they just the reflex ...
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1answer
37 views

How fast is the patellar reflex?

I have found a lot of content on the patellar reflex, but I cannot find any studies on how fast the reflex is, from onset of stimulus to innervation of muscles. Does anyone know of either a study or ...
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1answer
73 views

What were the main discoveries in Biology? [closed]

What were the greatest achievements in Biology? Can you please provide a short list of discoveries that you would consider as being the most important discoveries of the history of Biology.
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2answers
117 views

Are humans evolving since their first appearance? [duplicate]

Is the evolution a very prolonged progress, or are we going to witness further evolution of the human species? If so, in which direction? Are there any widely predicted changes for humans?
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1answer
65 views

What is the correlation between hand and neck flexibility? [closed]

I am trying to understand this statement in the book, Mudras, Yoga in your Hands by Gertrud Hirschi: There is a direct relationship between the hands and the neck since the nerve paths run through ...
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1answer
41 views

What's the mixture of plasma and haemoglobin called [closed]

I know of oxyhaemoglobin but the mixture of plasma and haemoglobin in the blood gives what?
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1answer
51 views

What's the mixture of carbon and haemoglobin called [closed]

I know of oxyhaemogloblin , the mixture of oxygen and haemoglobin , but carbon and haemoglobin combination is what's confusing
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1answer
62 views

Can someone help me answer or explain how to answer questions about DNA coding capabilities? [closed]

How is it that a DNA coding system with only 4 bases can yield so many possibilities? Also, how many unique coding sequences can there be with a DNA code that is 8 base pairs long? Hint: 4^n ...
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78 views

Why does the Vas Deferens detour over the pubic bone?

I was surprised to learn that the vas deferens detours over the pubic bone instead of taking the obviously more direct path. https://human.biodigital.com/widget?be=u1P&uaid=1ly5V Because I would ...
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0answers
52 views

What is the function of the kidney in terms of osmoregulation and excretion [closed]

Also include the role that ADH plays I am fully aware that ADH has a role in osmoregulation but does it also play a role in exretion?
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0answers
51 views

Could a human heart really pump fuel up to a jet engine?

In Parks and Recreation, Chris is told his heart was strong enough to "pump fuel to a jet engine". What I'm wondering is the following: Does an extremely healthy human heart have the power to do ...
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0answers
45 views

What is meningitis? [closed]

I know that meningitis is the inflammation of the meninges surrounding the brain and the spinal cord. But I still don't understand this definition. If you can broaden the definition, please do.
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0answers
42 views

How long does it take for blood to travel from the lungs to the fingertips?

I've noticed that a pulse oximeter at my fingertip lags my breathing effort by a noticable amount. I conclude that it takes some time for freshly oxygenated blood to travel from the lungs to the ...
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1answer
80 views

What causes anorexia nervorsa?

I've heard of anorexia nervosa being a severe loss of appetite. I'm wondering what causes such disease in humans?
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1answer
131 views

Is an athlete's heart rate after exercise greater than a non-athlete [closed]

I was just wondering And if it is greater or lower how does this benefit an athlete Also what is the averaged number of heart beats per minute
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1answer
3k views

What is the speed of blood?

The speed of blood may vary from one place to another and may be quite low in the tinyest vessels compared to the biggest one. What is the speed of blood while exiting a normal human heart?
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0answers
22 views

is there any relationship between shape of the nucleus and the function of the cell?

is there any relationship between the shape of the nucleus and the function of the cell, like in the case of leukocytes, all of them have different shapes.
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0answers
64 views

Why doesn't hair grow all over your face?

Why doesn't hair grow all over your face? Surely hair on a face would have blocked the sun and kept it warm. Or perhaps through natural selection we opted for hairless faces over hairy ones?
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2answers
105 views

Are human beings evolved to eat meat? [duplicate]

I know humans can cook, and prepare almost anything, but are humans specifically adapted to eat meat. One of my doubts humans are not particularly well adapted to eat meat because they lack canine ...
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1answer
140 views

Would urination continue after death?

If someone was urinating, and they were to hypothetically suddenly "fall dead" (the brain is unconscious and all muscles / organs are unfunctional), would they continue urinating or would it stop?
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39 views

What happens to the mold spores we inhale?

What happens to the mold spores we inhale? I'm guessing when we exhale, many of them are expelled back out to the environment. But given that disease can be caused by mold exposure, I'm also ...
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1answer
90 views

What are the highest and lowest amplitude values in ECG for humans?

I'm currently trying to parse the records captured from an ECG device and display them on a mobile application. I am wondering what the highest and lowest possible amplitude values for ECGs are in ...
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1answer
77 views

When you take a very cold or hot bath how is that influencing your breath?

It looks like when you take a cold shower or bath your veins get smaller and when you take hot shower your veins get wider. But is that right and do you need to breath more in both cases because you ...
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1answer
348 views

What is the function of the polar bodies produced during oogenesis?

Why are polar bodies produced during oogenesis in human females? I read that polar bodies are produced during meiosis so that the oogonium (or gamete mother cell) can be converted into a haploid ...
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25 views

Does the source of caffeine affect the biological impact?

I've recently decided to give up my morning coffee in lieu of a caffeine pill. Both are around 200mg (my Tim Horton's XL 4x4 was 240 mg of caffeine) of caffeine. We were talking about the various ...
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2answers
60 views

How does the mechanism which controls blood pressure in the brain work? [closed]

I've heard that the blood pressure in the brain is organised by a special mechanism. What is that and how does it work?
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0answers
16 views

Is the efferent arteriole a pathway for filtrate through the nephron ?

I am studying the urinary system. I have to identify what part of the nephron is not a pathway for filtrate. I believed the collecting duct is not a pathway for filtrate because once the filtrate ...
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0answers
10 views

how to see prefrontal cortex works normally by a test?

Is there a test to see if the Prefrontal cortex of someone works normally? especially a simple test like a questionnaire that you give the individuals to fill out and based on their answer you obtain ...
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1answer
97 views

What causes swelling after impact?

Why does the head swell after getting hit by something hard? What is the liquid that forms after impact?
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2answers
88 views

Crossing over and exon shuffling?

Campbell Biology 10e, in discussing the functions of introns, writes: The presence of introns in a gene may facilitate the evolution of new and potentially beneficial proteins as a result of a ...
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22 views

Did the number of rods changed from ancient time?

Correct me if I am wrong, but I know that rods work under limited light conditions only. But now we are in a world that always have lights everywhere unlike ancient time when humans had to deal with ...
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1answer
36 views

Difference between the spinal cord and vertebrae column [closed]

What is the difference between the spinal cord and the vertebrae column, they both run through from the head to the abdomen. Does any one have any idea.
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15 views

What is the difference between chloride shift and Bohr shift?

Does anyone know the difference between chloride shift and Bohr shift? Is it that Bohr shift happens in respiring tissues when CO2 concentration is low, and that Chloride shift happens in the blood ...
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2answers
1k views

How long do viruses, such as Zika, stay in the body?

Can a virus stay in your body (after recovery) in a concentration that is sufficient to infect someone? Is it known how long the Zika virus persists in the body?
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51 views

Model for Oxygen diffusion into tissue? [closed]

Currently I have an idea and want to research it's feasibility. I want to know how oxygen or any other particle could diffuse into the body through small holes in the skin. is it possible to ...
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1answer
38 views

The impossibility of making a human in a lab [closed]

Am I right if I say that the only place where the right conditions exist for developing a human being is the womb, so that people will never be able to make a human being in a lab? In order to develop ...
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0answers
32 views

In the life-cycle of the HIV virus, how does the created DNA enter the nuclear membrane?

I am in a high school biology class, so I cannot truly attest to how accurate the information I am given is, but as far as I know only RNA and very small molecules can enter the nuclear membrane ...
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65 views

When and why did humans start disliking the way we naturally smell? [closed]

Like many animals, humans produce a myriad of scents from sweating, bacteria, possibly pheromones, etc. Many of these scents are used throughout the animal kingdom for mate choice, recognition of ...
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1answer
45 views

What is a catalytic domain?

I have to answer a few questions from an article I'm reading, and I am just really confused on defining "catalytic domain." I have to relate it to the antibiotic Teixobactin. Is catalytic domain the ...
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1answer
50 views

Do the antibodies in a patient suffering from Hashimoto's, attack the thyroid hormones or the thyroid gland (or both?)?

If oral thyroid hormone supplement is administered, is the attack stopped or does it just create an excess of thyroid hormones so that even after a lot of it is destroyed by the antibodies, there is ...
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0answers
39 views

Why are eye defects so common? [duplicate]

The title says it all, what makes eye defects so common in the world? Whereas defects of any other body part is quite uncommon, I searched online and one of the articles said that 6 out of 10 people ...
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1answer
95 views

Short dated spontaneous ringing in ear [closed]

What causes very high pitched sound in one's ear?
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2answers
197 views

Growth factors vs. mitogens

According to Campbell Biology, A growth factor is a protein released by certain cells that stimulates other cells to divide. and according to Wikipedia, A mitogen is a chemical substance ...
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1answer
30 views

Advantage of GCPRs over RTKs or other receptor protein kinases

My book lists two important differences between GCPRs and receptor protein kinases: GCPRs do not directly activate a signal transduction pathway. It only does so indirectly, via a G protein. On the ...
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0answers
66 views

Can one eye affect the other eye's low-light adaption?

This previous question addresses how long eyes need to adapt to darkness and reach full contrast. My question is how does one eye affect the "transition" and/or efficacy of this "night vision" of the ...