Biology pertaining to humans
3
votes
1answer
103 views
Can Naegleria fowleri enter through the eyes ( example rinsing/splashing eyes with water)
I understand that it primarily enters the body through the nose by by "feeding on the olfactory neurons in the nose" as answered here in a different question. Would the nerve cells in the eyes present ...
1
vote
1answer
51 views
What could cause hairs to gray at the tips but not the roots?
I have noticed that some of my sporadic gray hairs are gray at the tip side but oddly, not near the roots. Some are even only gray in the middle. I find all of this very counter intuitive, and I ...
1
vote
0answers
39 views
Are there nutritional benefits to drinking diluted urine?
I know that urine drinking is a widespread practice (with a long history). The main reason that people give today involves there being nutrients in urine.
If there are nutrients to be gained, why is ...
1
vote
1answer
30 views
Is there an optimal illumination level for human habitats/workplaces?
I know of melanopsin, a photo pigment in mammal eye that helps regulate circadian rhythms. It responds most strongly to blue spectrum light. There have been experiments that demonstrated that ...
17
votes
4answers
2k views
Death because of distilled water consumption
One of my friends said that I would die if I drank distilled water (we were using it in a chemistry experiment) I gave it a go and surprisingly did not die.
I did a bit of Googling and found this
...
2
votes
1answer
64 views
What controls the breast size?
I am not a biology student, just a curious person. To be specific, I'm talking about humans and specifically about females. I know that it might apply to other mammals.
What controls the size of ...
3
votes
2answers
194 views
Why is that all the animals can swim in water without learning to swim but humans cannot?
I had a question since I was a child. I was always curious that all the animals can swim in water. They don't need any training or to learn swimming. But humans need to learn to swim. Why ?
I am a ...
2
votes
1answer
37 views
Are (baseline) high blood levels of melatonin associated with either circadian rhythm or mood disorders?
(Exogenous) melatonin is administered at night for treatment of circadian rhythm disorders, but melatonin taken during the day is linked with depression.
I would like to know if high blood levels of ...
1
vote
1answer
44 views
Relation between goose bumps and temperature
As we all know, cold weather will cause us to have goose bumps. I honestly don't know why (1), because our skin contracts?
Apart from that something quite contradicting happened this morning. I was ...
7
votes
2answers
164 views
Do hormone drugs affect whether a person feels sexual attraction to males or females?
I know that ingesting testosterone and other hormonal drugs may stimulate libido and increase sexual desire.
But I wonder, if a man ingests female hormones such as estrogen, will he experience sexual ...
1
vote
1answer
57 views
Agony, Hydrophobia and viruses in the light of evolutionary principles
I'm undergraduate physics student, but I've always been interested in biology. So I have a couple of questions about an application of the evolutionary principles to practice.
Agony as the last ...
9
votes
1answer
73 views
Does sleep in humans re-structure based on the expected sleep time?
I've read about anecdotal evidence that human brain has a fairly good internal clock that can be used to judge the amount of time that has passed. I'm wandering if there are any mechanisms in the ...
0
votes
1answer
78 views
Are there any viruses or bacteria which have evolved to withstand higher temperatures due to fever
My question was raised after receiving this information:
The primary reason the body raises its temperature (via the Hypothalamus in this case) is that bacteria and viruses tend to optimally ...
4
votes
1answer
129 views
If fever is a natural immune defense, why do people take drugs to lower it?
If fever is a natural defense against pathogens, why do sick people take NSAIDs to reduce the fever?
-3
votes
1answer
39 views
How much can be said about behaviour (future) based on bloodgroup?
My bloodgroup for example is A+. How much information is knowing my bloodgroup? How much information can be known from a blood sample? I expect you to be able to clone if known a complete DNA sequence ...
5
votes
1answer
66 views
Can cirrhosis be caused by physical compression of the body?
On a random forum, a member speculated that their cirrhosis was caused by wearing tight-fitting clothing such as a girdle or corset. This leads me to the following question:
Question: Can ...
4
votes
1answer
67 views
Why do sneezes come in pairs or more?
I very rarely sneeze just once, usually there's two coming in a row, and I've noticed the same thing in other people and even in animals. Is there any reason for this?
3
votes
1answer
155 views
How does prolonged exposure to high frequency noise affect hearing?
Is there any research showing how prolonged exposure to background noises, particularly high frequency noises, affect hearing abilities? Does constant high pitched noise cause damage even a low ...
9
votes
2answers
375 views
Will humans and animals be harmed by frequencies outside their hearing range?
The human ear (for example) is sensitive to frequencies from 20Hz to 20kHz. Any sound beyond that limit would not be heard by us naturally.
Will it harm us (effect our ability to hear) when we hear ...
3
votes
0answers
30 views
Can a sound frequency 'not' within human hearing (20 Hz - 20 kHz) damage hearing when it is of high volume? [duplicate]
We can't hear sounds outside the range of 20 Hz - 20 kHz. However, if an inaudible sound is played at high volume, will one's hearing be affected?
2
votes
1answer
74 views
What in soy are people allergic to and will these allergens be passed along if an animal that has eaten soy is consumed?
I have two related questions about soy allergies and possible reactions.
What is it that are humans who have soy allergies actually allergic to? What is the allergen?
If an animal eats soy, are ...
1
vote
0answers
17 views
Are anti-inflammatories useful for tendinosis?
I am wondering why some doctors prescribe anti-inflammatory treatments for conditions that are supposedly not inflammatory such as tendinosis.
From my understanding, only tendinitis a swollen tendon ...
3
votes
0answers
629 views
What causes random long white body hairs?
I'm sure many of you have experienced this - you scratch your back or brush your hand over your arm and find a ridiculously long thin white hair, sometimes as long as 3 or 4 inches. I know a few ...
8
votes
1answer
98 views
What prevents a pregnant woman's immune system from recognizing her fetus as nonself (and attacking)?
I'm familiar with the scenario of Rh- mother with Rh+ fetus having complications (more so after her first child), but that's not what I'm curious about. I want to know mechanistically why a pregnant ...
13
votes
8answers
3k views
Why have humans evolved much more quickly than other animals?
Humans have, in a relatively short amount of time, evolved from apes on the African plains to upright brainiacs with nukes, computers, and space travel.
Meanwhile, a lion is still a lion and a ...
1
vote
1answer
34 views
Are there any studies of epigenetic difference between twins during their lifespan?
Are there any studies of epigenetic difference between twins during their lifespan ? I ask because I wonder if there exist phases during lifespan, when environmental factors plays major role ...
2
votes
2answers
63 views
Lactose Intolerance
What nutrition is given to infants who are lactose intolerant? I understand, in today's day and that age we have non-lactose formula milk, but what happened, before lactose-free milk was created, to ...
2
votes
0answers
19 views
HSL Lightness vs Eye sensitivity
In a monochromatic spectrum, is the human eye equally able to distinguish between lighter colors just as it is in distinguishing between darker colors? I mean is there really a linear relationship ...
5
votes
1answer
49 views
Does frequency of eye blinking reveal anything about human biology/nervous system?
I'm looking at an output of a single dry sensor EEG headband with the sensor positioned above left eye. As a side effect of it's placement, the device picks up eye blinks, and some eye motion as ...
6
votes
3answers
75 views
What are the limitations of commercial-grade DNA genotyping compared to full sequencing?
I've heard about services like 23andme, which offer genetic testing to the general public. As a person who knows very little about genetics, I'm interested in the subject and would like to know what ...
7
votes
2answers
103 views
Does every human eye see the same visible spectrum?
It is said that human eye can see light with wavelength approximately between 400nm and 700nm.
Are these upper and lower bounds same for every human? If not, what are the means and standard ...
3
votes
0answers
150 views
Can a person really die quickly from biting their tongue?
A common trope in certain circles (like Eastern martial fiction), is someone committing quick suicide by biting his or her tongue. But is this really possible?
The internet turns up millions of ...
3
votes
1answer
50 views
How can the child and the mother have different blood types?
As far as I know the fetus is fed by the umbilical cord which basically connects his/her circulatory system with the mother's in order to supply oxygen and nutrients. But how is this possible if they ...
0
votes
1answer
43 views
Are lactic acid and prolactin rise after exercise connected?
I've been reading about prolactin, a human hormone. Apparently it's levels within the brain can raise after exercise, although the mechanism is not clear to me. I'm interested of there is any ...
1
vote
1answer
54 views
Is it possible to give a person an allergic reaction in a very specific place?
Can I give a person an allergic reaction at a very specific spot in a tissue?
And if so, how accurate can i get?
1
vote
2answers
46 views
Why does throat 'burn' when you've got a common cold?
Apart from pain when swallowing, there's also a persistent feeling of throat 'burning' in the same area.
What causes it and why does it feel that way?
4
votes
1answer
114 views
Which sex has higher variance of reproductive rate in modern societies - male or females?
Who has a more varied reproduction rate in modern western societies - men or women? The average rate is the same of course, but I wonder which sex have higher variance - higher variance means that ...
2
votes
1answer
38 views
Trigger allergic reaction in non-allergic people?
Is there a proven way to trigger an allergic or allergic-like reaction in non-allergic people? I have wondered if this is possible, since allergies are basically just a form hypersensitivity - so ...
3
votes
1answer
73 views
Does an allergic reaction kill body cells?
I have wondered what actually happens in an allergic reaction that causes the symptoms such as pain, rash etc.
Is it possible that the human body actually kills its own cells in the process?
0
votes
0answers
40 views
Why does strenous exercise cause vision of “lights”?
I had a hard climb a week ago. I got so tired then any time I closed my eyes I saw these lights inside my head. I see these lights almost every time that I run fast or some thing like that. What are ...
0
votes
2answers
39 views
Manipulating Gut flora in vivo
I am tasked with designing an in vivo experiment in humans that requires manipulating the gut flora in one sample group to gauge its effect. Please suggest ways of doing this besides administering ...
10
votes
3answers
221 views
Athletes: nature vs. nurture?
Having watched a lot of olympians the last few weeks, I was struck by how many of them have actually spent their wholes lives/careers training for their one event (be in running a marathon, or ...
5
votes
1answer
119 views
Can you consider a human as alive, or is it the cells on the body that are alive?
Sorry if this question seems strange, but in the recent time I have been interested in the question of what life is and how you can define life.
My question:
How long can individual cells live on a ...
3
votes
0answers
48 views
How does healing work?
I stacked my bike and split my head right open. About three weeks later the scab falls off and the skin is sealed over, like magic! How does it all work? How does the brain know that part of the ...
1
vote
1answer
51 views
Interlocus Contest Evolution means suicide?
I was reading Matt Ridley's "Genome" book. I am trying to understand the Interlocus Contest Evolution in his X-Y chapter. I do not understand why the X and Y chromosome would want to kill each other. ...
5
votes
2answers
208 views
What is the relationship between migraines and histamine?
A family member suffers from migraines so I have been reading a little around the subject.
There seem to be any number of "triggers", but I have seen mention several times of the role of histamine ...
5
votes
1answer
47 views
Why do we yawn?
I've read a new study which suggests that yawning may help you keep a cool head. Also, the findings might hold some hope for sufferers of insomnia, migraines, and even epilepsy.
Is there any ...
3
votes
1answer
42 views
The fundamental importance of R.E.M. Sleep. (Rapid Eye Movement)
Question:
I know that experiments have been conducted to determine the importance of R.E.M. sleep in our sleep cycle. It is particularly important for learning, information synthesis, and recovery ...
1
vote
1answer
20 views
Why do cells have an average 'life span'
I've heard of Henrietta Lacks. As a result of a genetic mutation, her cells never died. I've heard/read that overtime, our cells stop multiplying as much, (as an effect of aging). Why? Why do we age? ...
6
votes
1answer
38 views
Is there a normal human melatonin concentration to light level curve?
I'm looking for a graph or a curve that would show the typical concentration of melatonin in blood or saliva for humans over 24 hours. It would be good to know the photoperiod for the same human as ...
