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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64 views

How suddenly does lactose-intolerance onset?

How quickly can the loss of lactose tolerance onset in an adult? Such as being able to process lactose normally to having notice symptoms associated with the inability to process lactose. I am not ...
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90 views

How HIV Affects and Its Treatment using Combination Therapy

Can someone please help me with the following questions. I've written my specific questions right after the text question. Human immunodeficiency virus (HIV) is a retrovirus. Its genome is a single ...
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1answer
77 views

Body's decomposition

Does a human body decompose in a completely sterile environment ? If yes, what decomposes it ? And how fast ? What happens in vacuum ? Can it remain exactly the same ? Thanks
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1answer
120 views

Need of Creatinine Phosphate

In muscle cells most of the ATP's phosphate is with creatinine phosphate. So why is the displacement of the phosphate group done ? Is it because creatinine phosphate would give it's phosphate more ...
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1answer
72 views

What stops the coagulation process?

Whenever there are minor/major injury to blood vessels, the platelets, fibrin, thrombin, etc. are recruited. They then seal the wound and block bleeding. What tells them that their job is done?
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1answer
31 views

Is it possible to suffer from hyperthermia by spending too much of time in the hot springs?

People may tend to spend time in a hot water spring. Is it possible to get hyperthermia (like a sun stroke) due to this?
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1answer
78 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 ...
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1answer
113 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. ...
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0answers
55 views

why does our voice change when we get affected by cold or cough?

Why does our voice change when we get affected by cold or cough? I observed the voice change thing in so many people including me.
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0answers
19 views

How and where do nerves share pathways to the brain?

I am interested in understanding how pain receptors send signals to the somatosensory cortex (the part of the brain that registers various nerve signals such as pain, presure, temperatures, etc). ...
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28 views

What specific sensory nerves act as receptors for “pins and needles” (neuropathy)?

According to this excellent answer, the difference between "pain" and "pins and needles" (neuropathy) is that different receptors (sensory nerves) trigger in reaction to different stimuli. Different ...
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0answers
29 views

How does proximal centriole of human sperm function?

I've read that the human's unfertilized oocyte ( stuck at metaphase 2 of meiosis ) lacks centrioles and that it completes meiosis 2 after fertilization as sperm gives its proximal centriole. Then what ...
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26 views

if woman could live to the age of 150 at what age would they go through menopause? [closed]

Ive been wondering this for a while, I watch star trek and other geeky stuff (no offense.) but i would like to my question if you could give to me, if humans could live up to 150 of age or past that ...
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36 views

Can sealed epiphyseal growth plates theoretically be restored via epigenetic or genetic methods?

I know that epiphyseal growth plates seal up once people become young adults and that it is currently impossible to restore them to actively produce new bone growth but, is it theoretically possible ...
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0answers
41 views

Does a pregnant female body treat the fetus based on gender?

I have seen on a youtube video that the female body produces antigenes and antibodies when she is pregnant with a boy. But this behaviour is not produced when she is pregnant with a girl. These means ...
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0answers
270 views

Highest Pressure Human Body Can Survive In?

One design for underwater human inhabited environments is to have equal pressure between the surrounding water and the submerged habitat, thus allowing a section of the floor to be open to the water ...
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0answers
43 views

How to stop or slow down the process of growth of hairs? [closed]

Is it possible to slow down or stop hair growth? If yes, then how is it achieved?
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0answers
52 views

Is there a difference between endorphins that are released while physical activity and sex/masturbation?

I observerd myself and I can identify two different types of "happines". First - called by me - After Pleasure : Occurs AFTER (and last long) long activity that require from me engagement focus and ...
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0answers
46 views

Can two women have a daughter? [duplicate]

In vitro fertilization is a pretty routine procedure in which a female egg is fertilized by sperm outside the body. Recently apparently there has also been something similar in which the genetic ...
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0answers
258 views

In-Ear headphones increasing nasal breathing resistance [closed]

I figure this is a rather strange question, however, I noticed this quite some time ago and wanted to make sure that this is in fact a permanent condition before posting. The situation is as follows: ...
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1answer
30 views

Role of Calcium and Magnesium in capacitation/acrosome reaction

During the acrosome reaction, the activation enzyme present in the sperm dissolves the corona radiata and zona pellucida enabling the sperm to reach the plasma membrane of the egg. Also calcium and ...
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0answers
51 views

Relationship between small and large fast-twitch motor units

When large fast-twitch motor units are temporarily fatigued, non-fatigue small motor units in the same muscle are impaired for small delicate tasks. Why? When impulses from the brain comes down, the ...
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0answers
37 views

Nearly Exhaustive List for Cholesterol Pathways

I have run across an interesting case that is similar to only two others I've encountered. What makes it interesting is the combination of undetectable (under normal testing conditions, can elaborate ...
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0answers
41 views

How can one accurately diagnose human hearing loss without surgery?

In a human, if you were to avoid a tympanotomy, how could you distinguish between a blocked Eustachian Tube, a ruptured eardrum, or Perilymph Fistula? For instance take the situation where a young ...
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30 views

Is there a homeostatic setpoint for number of hours of sleep required by a human?

I've heard this TED.com talk about dieting and it mentions that there's a very definitive setpoint within the human brain about how much a human should weight. The speaker mentions that after as much ...
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0answers
62 views

How many blood types are there? [duplicate]

In total how many blood types are there? And why do people normally know only 8 of them? (A+, B+ , AB+ and O+ and Rh- counterparts)
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46 views

Why does the ovum prefers to be arrested at metaphase 2 of meosis before fertilization? What is the possible advantage of this process?

Why does the human ovum prefers to be arrested at metaphase 2 of meosis before fertilization? What is the possible advantage of this process??Please help me with it.
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103 views

Why do we feel pain in knees when we are facing fear [closed]

Just for information: I was watching Resident Evil, and every time I saw a zombie, I shook and then after a few minutes or just a few moments, I felt my knees ache! It was like someone is squeezing ...
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69 views

Harmful effects of radiation from cell phone towers? [closed]

As per this article - http://www.thehindu.com/news/national/mumbai-citizens-link-cancer-to-cell-phone-towers/article5139166.ece , people living adjacent to cell phone towers claim to have developed ...
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0answers
159 views

What naturally produced drug causes 'a tingleing euphoric rush' [closed]

What naturally produced drug causes a 'tingleing euphoric rush' through your body, as well as a 'wave of goosebumps'? I've always been interested in this sensation, two of the last times i can ...
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0answers
44 views

What parts of the brain are involved in regulating blood pressure in mammals?

I'm reading this Wikipedia article on blood pressure and its regulation, and it mentions that medulla is involved. however, I vaguely remember reading another article on Wikipedia and it mentioned ...
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1answer
105 views

copper spiral birth control not toxic?

I Always thought that copper was toxic to the human body. So how can it be safe to place a copper object (birth control spiral) into a uterus for a duration of 5 years?
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274 views

Size order of human organs [closed]

Wikipedia states that the liver is the largest internal organ in the human body. How does it relate to the sizes of ex. the lungs and small intestines? I've been having this personal image for years ...
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88 views

Why do ion concentrations change with different secretion rates in pancreatic juice?

Why is it that when secretory rate increases in the pancreas the concentration of chloride ions decreases, and the concentration of bicarbonate increases in the production of isotonic NaCl secretion? ...
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1answer
1k views

What would be the best design for spike-and-recovery and linearity-of-dilution validation experiments in one 96-well ELISA plate?

I have searched in the web for a detailed explanation of doing such validation experiment, but unfortunately couldn't find a satisfactory one. I came across the following sources: Thermo ...
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1answer
145 views

Perception of distant lights without glasses

I am fairly short-sighted and wear glasses pretty much all the time. Naively, I would expect that when I take my glasses off, the image I see should look very much the same as as a photograph that's ...
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0answers
33 views

Are anti-inflammatories useful for tendinosis? [closed]

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 ...
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2answers
206 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?
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1answer
34 views

What are studies linking dietary choices over life with probability of reaching higher ages? [closed]

Are there big studies that link diet and lifestyle choices with the probability of reaching a certain age? What are their conclusions?
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59 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 ...
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0answers
41 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 ...
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58 views

Are the intestinal flora substantially different within a diverticulum of the colon?

From the Wikipedia page for the vermiform appendix: This proposal is based on a new understanding of how the immune system supports the growth of beneficial intestinal bacteria, in combination ...
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1answer
74 views

Any relevant knowledge/studies about voluntary goose bumps [duplicate]

I'm not entirely sure how normal this is, but since I was a child, I've been able to produce myself voluntarily a "chill" sensation that seems to start on my head and traverse the rest of my body, ...
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3answers
135 views

Why is it better to drink room temperature water instead of cold water? [closed]

My teacher told me that drinking water that is room temperature is better for you then drinking cold water, but she did not tell me why that is. I want to know because I often drink cold water (with ...
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4answers
377 views

Strictly from a biological perspective, what is the functional expectation of a human being [closed]

Just like the title says: Strictly from a biological perspective, what is the functional expectation of a human being. No religious or philosophy-based answers will be accepted, we are talking ...
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2answers
725 views

What part of food gives the blood red color?

Roughly, what I know is, when we eat food it goes into our: Stomach > Small Intestine > Large Intestine > Rectum. So, it just moves through a digestive pipe. What I don't understand is, what part of ...
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3answers
963 views

How come that we “feel” it when someone's watching us [closed]

The question is relatively easy (the answer however..). We all know this feeling "being watched" and more often than not this is a real thing. If someone is staring at us from the side or from the ...
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1answer
254 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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486 views

Are there examples of the green beard effect in humans?

Green-beard effects are genes that: Produce an effect that can be detected Produce preference to others with the same effect Are there any examples of this in humans?
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28 views

Clarification on BMI formula

In the BMI formula= (Weight) X 703) / (Height^2) , what does 703 represent? What is a reliable source that I can cite for this answer? weight= lbs height= inches