Biology pertaining to humans.

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What is the inlet/outlet speed of air going in/out of our mouth during inhalation/exhalation

During inhalation, your alveoli expand, creating a pressure difference between the atmosphereic pressure and our lung sacks and therefore air will flow into the repspiratory airways. I am trying to ...
11
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3answers
925 views

Where does the 'C' in exhaled CO2 mostly come from?

When a human being exhales $CO_2$, what is, by the numbers, the main source of carbon atoms exiting the body in this way? I mean what class of cells, or which tissues are the biggest on a pie chart of ...
8
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2answers
352 views

Do memories have mass?

If it were possible to live forever, would our brains grow infinitely with the number of memories that we store? Or would we remove old memories as we create new ones?
8
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2answers
424 views

How much weight/volume do microbes occupy within the human body?

Microorganisms constitute the bulk of all the biomass on Earth. I weighed myself yesterday, and wondered how much less I would weigh if I were completely free of bacteria and microbes, inside and out. ...
7
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1answer
88 views

What happens when we know that there is something that we forgot but we can't remember what it was?

I think it happens for everyone that sometimes we go to a room and forget why we went there. Is there any research or article on this?
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2answers
2k views

Is nicotine toxic to humans?

More specifically, is nicotine in the concentrations that smokers receive when smoking cigarettes toxic? I know that in great enough concentrations it can be toxic (but then, so can just about ...
6
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2answers
186 views

How does the body measure dehydration?

What, physically, does the body do to measure it? I assume it's measured by how how turgid or plasmolysed certain 'sample cells' are, or water concentration in the blood, What is the way they use to ...
2
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1answer
44 views

Is it more likely to develop a throat-ache at night?

I have noticed that I rarely develop phlemmy throat-aches in the daytime, but often notice them after I have been sleeping. Is this a recognised phenomenon? Could it be because viruses or bacteria ...
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0answers
47 views

Do humans have chemosensors for nutrients or chemicals?

I'm reading about chemoreceptors on Wikipedia, and see that the typical ones are mentioned: taste, smell, co2. I would like to learn more about the other kinds of chemoreceptors that humans may ...
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2answers
385 views

Would exposure to a strong magnetic field have deleterious effect on the human?

This article states of a 25T magnet, ".. If are ever caught in one of these devices, let’s just say you probably won’t live to tell the tale." Is the above statement in order? What effect would ...
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0answers
93 views

Functionality of vitamin A, Bx, C, D, E, K as used in cosmetics for the skin?

I was wondering if someone can compare the functionality of vitamin A, Bx (x means numbers, such as 1, 2, 3, ...), C, D, E, K in the skin? They are used in cosmetics but what is their actual effect? ...
3
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1answer
257 views

Do adipose cells divide in adults?

I have a dim recollection of having heard that when humans gain weight, adipose cells just get larger, rather than dividing. True?
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1answer
57 views

In a human, what non-germline cells have the highest/lowest mass?

I'm just curious which cells are largest/smallest in the human body other than sperm/ova.
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3answers
427 views

What makes urine smell acrid?

Occasionally, after someone's been, there is an awful acrid smell lying about long after them. What causes this? The food that they've eaten? Urea less dilute due to dehydration? If it helps I've ...
6
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1answer
4k views

Will a bone marrow transplant change one's blood type?

Will a bone marrow transplant change one's blood type? Or is the donor blood type matched with the person before transplant?
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3answers
355 views

Is there such thing as “half-life” of dopamine?

If a dopamine is released at T=0 and binds to receptor D2, what determines the time when the concentration of this neurotransmitter bound to the receptor reaches half of the original concentration? In ...
4
votes
1answer
247 views

Do effects of caffeine on human body change with habitual use?

I've been reading about homeostatic nature of a lot of neurobiological processes - the brain is trying to maintain a balance by desensitizing receptors, re-uptaking and breaking down ...
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4answers
12k views

What is the armpit hair for?

Modern human beings, especially women, cut their armpit hair. It seems to me the armpit hair is trivial/useless. Shortly speaking, what is the armpit hair for?
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1answer
153 views

Are inflammation and anxiety connected?

I've been reading a curious paper about the use of cannabis, and one of the passages piqued my interest: There’s also been a lot of work done on another constituent of marijuana, cannabinoid, ...
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2answers
285 views

Does the brain and the body use the same energy source (glucose/ATP)?

I've heard that the brain consumes quite a lot of oxygen and energy, compared to the rest of the body. What I'm interested in is if this is the kind of energy and oxygen that the rest of the body ...
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0answers
114 views

Virucides - Herbal and otherwise, for HHV6 type virus or any inner-cell virus

Does anyone know where I can find a reliable list of virucides (not anti-virus) that can be used by humans? This virucide must be able to affect viruses that are already inside the cells. St John's ...
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2answers
89 views

Is there any biological reason for humans to rest after x days of work?

A lot of people live in a 7 day cycle, where 5 days of work are followed by 2 days of "rest". Vacations and holidays can increase the time available for resting. Is there any biological reason for ...
4
votes
3answers
322 views

The probability of indirect human fertilization?

What is the probability of conception in situations when sperm isn't directly ejaculated into the woman's vagina, like: The man's or the woman's hands come into contact with sperm, for example when ...
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2answers
4k views

Does sour food cause sweating?

While eating sour food or candy, I start to sweat if it's sour enough. My body feels much hotter although my actual temperature is the same, my forehead starts sweating a lot and I feel like it just ...
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2answers
188 views

How does fever physically work?

What is the physical mechanism that causes temperature to rise during a fever? I know that somehow the hypothalamus "orders" to increase the standard body temperature regulation, and this should ...
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2answers
1k views

Preferred Aspect Ratio for Human Eyes

Our eyes are spherical, our retina is circular, but still our eyes can see more in the horizontal direction than in vertical direction. Why is it so, why is the preferred aspect ratio not square? ...
6
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1answer
89 views

Does artificial heat (shower/tea) affect diurnal rhythms in humans?

I've been reading that over the course of the day, human body temperature follows diurnal rhythm with the lowest body temperature observed some time close to the middle of the sleep episode, while the ...
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1answer
45 views

PGC-1β Sod2 limiters/blockers

I'd like to block a percentage of PGC-1β or Sod2 expression. According to the following paper's figure beta-blockers inhibit some expression of PGC-1α. Are there any medicines/chemicals which safely ...
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2answers
97 views

Is there some branch of biology that deals with the entire organism?

I'm reading about various parts of the human body and brain and started to wander if there's a branch of biology that deals with the entire human? I know that there are branches various -biologies, ...
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2answers
2k views

How does sodium in one's diet affect blood pressure?

Due to high blood pressure, my doctor has recommended I go on a low-sodium diet. So, that got me wondering what it is about sodium that drives this recommendation? What does sodium do to a body ...
4
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1answer
195 views

What is the molecular basis of hangovers?

Well, most of us have experienced the wonderful feeling of the dreaded hangover. How does it work exactly? I imagine it has something to do with dehydration but what are the underlying mechanisms? ...
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0answers
48 views

Does Dorsal Raphe Nuclei firing pattern change in response to voluntary breathing?

I'm reading this paper, which discusses how Serotonin may be involved in motor functions of mammals: 5-HT and motor control: a hypothesis . The paper includes the following diagram of the Dorsal ...
2
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1answer
86 views

What triggers creative thought in humans?

Creativity, innovation and ideation. Is there something in the brain that makes the brain think that way, as opposed to "normal baseline". What triggers creative thought in humans?
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2answers
56 views

Is there a circadian component to hunger?

I'm wondering what produces the feeling of hunger in humans. Checking Wikipedia revealed that leptin and ghrelin are two hormones involved. I've also read that the digestive system produces its own ...
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1answer
1k views

Slow-oxidative fibres vs fast-glycotic fibres

Why do slow oxidative muscle fibres contain more mitochondria compared to fast-glycolytic muscle fibres?
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1answer
158 views

How quickly can the human heart rate rise and fall?

How quickly can the human heart rate rise and lower? For example lets say a human heart rate is rested and is at 60BPM and that person is suddenly scared to trigger their fight or flight reaction. ...
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2answers
121 views

Can children restore brain cells?

By "children" I mean young people at the age of 10 or lower. I know that the adult brain cannot restore brain cells, but what about children? I mean, the brain must develop from a few cells to a 90 ...
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0answers
20 views

How to seek information on the duration of biological entrainment processes in mammals?

This is a question that is a little bit hard to define for me. I'm interested in learning more about times of "attractor/entrainment" processes that may take place in the body/brain of mammals, and ...
3
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1answer
209 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 ...
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2answers
4k views

Which shades/hues of color are easiest to distinguish for humans?

I'm trying to represent data graphically and am using a variation of hue/lightness to distinguish one data point from the next. I would like to use a color that would allow me to convey most ...
2
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1answer
97 views

Where are -HCl supplements absorbed in the human digestive system?

I see that quite a lot of drugs and dietary supplements sold in the USA have -HCl(hydrochloride) added to their name. For example pyridoxine hydrochloride for Vitamin B6. I'm interested in knowing ...
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3answers
2k views

Why do the two hemispheres of the brain control the opposite sides of the body?

Why does the left hemisphere control the right and the right hemisphere control the left? I googled it but didn't find a good answer regarding this. Could someone explain? Does this adaptation help ...
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1answer
204 views

Why is offspring of identical twins not identical?

When identical twins marry identical twins, the children of the couples will be full genetic siblings but why are they not genetically identical?
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3answers
103 views

Adipocyte Density

People who are overweight and wish to lose weight, often do so because they are concerned about looking too big. Their increased size is attributed to an increased volume of fat. When people try to ...
10
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1answer
107 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 ...
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5answers
310 views

Are there any substance that are more dangerous at low dose than at higher dose?

It is commonly admitted that The dose makes the poison which means as a person, the more I take a substance, the more risk I take for my health. There is even an indicator called LD50 (see ...
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1answer
3k views

Does mixing alcoholic drinks really make you more drunk?

There is plenty of anecdotal evidence ("beer after wine and you'll feel fine, wine after beer will make you feel queer") that mixing alcoholic drink types leads to a stronger effect, but I can't find ...
2
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1answer
131 views

Can a person die instantaneously from internal damage to the brain?

Given the human heart is autonomous, can a person die instantly from internal damage to the head/brain? I would expect the heart to continue to pulse until it ran out of energy ... My contention is ...
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1answer
240 views

Why is membrane potential not zero at equilibrium?

For the squid giant axon, the membrane potential computed by the Goldman equation is -60mV. And the Nernst potentials are (the differences between the K+ and the Na+'s Nernst potential and the ...
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0answers
29 views

Can we make any judgements about sleep or readiness to sleep from a heart rate metric and/or pulse oxymetry?

I'm looking at inexpensive and un-intrusive ways to quantify the state of human body/mind . One of these is Actigraphy, which is a study of human motion over time. This can be done with an iPhone ...