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3

"Unaffected" is impossible. If you meant homeostasis, where fluid ingested = fluid excreted, well that happens all the time, and all "output" is not through urine. Sweat, respiration, fluid in feces, etc. are fluid loss. The body constantly needs water. Fluid regulation is a highly complex system managed by the body through a variety of osmotic gradients in ...


1

There is nothing fundamentally different about DNA of a GMO (whatever we mean by GMO) and non-GMO species. DNA has many essential nutrients and it would be a shame to waste all those nutrients. So yes, we absord DNA. More specifically we digest DNA. Digesting mean breaking down into nutrients. Once DNA has been breaking down to nutrients, there is no way to ...


2

Don't worry about picking up another human's DNA (or most other DNA) by eating it. Your digestive system is very good at chopping up free floating DNA molecules, and the large, highly charged DNA can't just diffuse through your cellular membranes. And remember that every vegtable, fruit, or animal you eat has its own DNA and you don't incorporate that DNA ...


2

There are two things happening: First melanin absorbs the energy from the UV radiation and releases it as infrared energy and thus protects the cells in the skin. This happens in all people, the deeper the skin color is, the better is the protection. What is different between people is the amount of pigment they produce, the number of melanocytes is ...


4

Some additional details on the same lines as Chris' answer: Coelho et al. have studied the short and long term effects of UV on human skin and they report that there are different stages of tanning: Immediate pigment darkening: happens in a few minutes and persists for some hours. It is most probably due to melanosome redistribution and melanin oxidation ...


12

When our skin is exposed to the sun, this can cause some damage in the upper layers of skin. This activates DNA damage repair and also induces signalling towards the melanocytes (which produce the pigment). Signalling means the excretion of signalling molecules (mostly alpha-Melanocyte stimulating hormone, aMSH) which binds to the MC1R receptor (melanocortin ...


4

First, one should mention types of skin: skin type defines how the person will tan - Second, the solar radiation (UV) absorbed by sun defines the amount of melanin produced by melanocytes of the skin to protect the skin = melanogenesis (which in turn depends on skin type). When the solar exposure diminish, the natural repair processes causes ...


0

There are controversial case reports about systemic absorption of paraffin used for constipation. These reports mention systemic effects of paraffin absorption and one of them report liquid paraffin accumulations in abdominal visceral organs. (full text article about paraffin) Liquid paraffin is indigestible and is absorbed only to a limited extent ...


0

How about gold. You can find it on foods, but it is inert and also not absorbed.


3

Simethicone is one example. It is a mixture of silica gel and dimethicone (polydimethyl siloxane); they are individually inert too. Simethicone/dimethicone is used as antigas (they help the gas bubbles coalesce). It does have a laxative effect, though.


-3

They have different genetic codes and so the alelles can make them be different colors. And the bodies have naturally thicker body hair but your hair color and ethnicity can make them be thicker or thinner.


1

Probably, it is worth to add some historic (and ironic) "perspective" to this question. It will probably explain that even without scientific research the answer to this question is probably "no" and that real use of bacterial soap should probably be reduced to hospital settings and not expanded to households as suggest promotions and commercials. The ...


2

You can search by traits (mostly diseases) for genome wide association, in these databases: Gwasdb2 Human genome variation Database: it also links to a Copy number Variation (CNV) database.


13

One important point that you might not be considering is the heat of vaporization. You may be aware that while it normally takes 4.18 J (1 calorie) of heat to raise 1 gram of water 1 °C, it takes around 2250 J of heat to raise 1 g of water from liquid at 99.5 °C to gas at 100.5 °C, due to the energy needed to go from a liquid to a gas. - What you may not ...


5

As other answers and comments have stated the reason that you feel cooler when the wind is blowing (wind chill factor often gets talked about on the news) is because evaporation is speed up by the wind. The reason that this evaporation causes cooling (explained in more detail here) is because when water evaporates, that water takes its energy with it. That ...


6

This phenomena has nothing to do with any different kinds of receptors. When we are wet, we have lots of water on our surface. The evaporation of water causes cooling. Blowing wind tends to make evaporation faster. So, even if wind blows at normal temperature, we feel cold. If we are not wet, there is some water on our body surface. This water is low in ...


5

These combination contraceptives contain two substances: Estrogen and progestin (a synthetic progesterone). Both are used together to overcome the negative effects of single substance drugs as acne or sickness. The risk for blood clots is know for quite a while (see reference 1 and 2) and is generally caused by raised levels of clotting factors (especially ...


2

Note that estimations in this answer are very very crude. I can speak with confidence that the mean pressure of ankel joint is greater than the heel and the metatarsus. However I do not trust that it can pin down the point with most pressure. @Ilan gave a very good synopsis on foot pressure distribution. However, pressure in ankles was not analyzed in his ...


5

You may be interested to look into the Old friends hypothesis, since this is related to how the human immune system may respond to reduced biodiversity in the microbiota. The basic idea is that the human immune system is developed by exposture to the microbiota, and without exposture to organisms from our evolutionary past, immune system regulation might ...


6

It is logically clear that the ankle could only partly be analyzed in the group of joints that are below its height. There is no direct way to measure the pressure on ankle joint (on talus bone), but from the logic it is clear that it should be the point of highest pressure in the group of points lister in the question, however the pressure is distributed ...


-1

Human immune defense response is primed by cell damage products as it does not have prior knowledge about bacterial or viral "malware". The whole purpose of disinfectant substances is damaging cells and potential organic disease carriers. As those substances are not discriminating, frequent use of them will prime your immune defense against benign organic ...


44

Short answer: There is no benefit for their use in households. Long answer: These soaps (see here for the complete list) contain the so called quaternary ammonium compounds Benzalkonium chloride and Cetrimonium chloride which indeed have antimicrobial properties. While they do not promote resistance to these compounds (see reference 1), their use is still ...


14

Chris has correctly identified the antibacterial agent in the hand soap depicted in the image in the question, and therefore his answer is superior as a direct answer. Nevertheless, other members of the Softsoap series of hand soap uses triclosan, 0.15% as their antibacterial agent, as seen in an image of their ingredient list on the reverse of the bottle. ...


8

Short answer In terms of visual function, the low-tier primary visual cortex and high-tier frontal cortex are inactivated. The activity of the intermediate ventral stream and limbic regions are increased, apparently uncoupling low- and high-level vision processing from the system. Background The sleep stage where visualizations (dreaming) occur is called ...


5

Both your linked fact from the University of Arkansas When you sneeze, the intrathoracic pressure in your body momentarily increases. This will decrease the blood flow back to the heart. The heart compensates for this by changing its regular heart beat momentarily to adjust. However, the electrical activity of the heart does not stop during the sneeze. ...


-1

kmm gives what is likely the best possible answer, as it is argued from causality rather than teleology. As my ninth grade biology teacher used to say, "there is no 'why' in biology, only 'how'". On the other hand, it is fun to speculate! Here's my two cents in the form of a Bad ad hoc Hypothesis: Holes going into the body are an expensive and risky ...


0

I would just modify the excellent previous by pointing out that the embryology describes a local maxima of fitness whose barrier to change is higher than any selective pressure. The re-use of the "logic" of the intermediate mesoderm was either initially a bifurcation from one or the other, or, was of enough selective advantage to have the two developmental ...


3

There don't appear to be many robust studies on this, but this study by De Longe et al in 2004 suggests that, whilst the volume of the ejaculate is increased after 5-days of abstinence (in most participants), for many this did not increase further after 8-days [1]. Here are the 11 participant included (along the x-axis), and for each participant there are ...


9

Developmentally, the urinary and genital systems (typically you will hear them referred to as "urogenital system") are derived from the same embryonic tissue, the intermediate mesoderm. The embryonic kidneys are drained by the mesonephric duct in both females and males. This embryonic tissue also gives rise to the ovaries and testes. The mesonephric duct ...


3

In order to clear some issues with the question and answers I add this one. The question itself was "will a heart keeps beating if it is separated from the body?" The answer to this question as it was asked: No, the heart removed from the body "as is" will stop beating almost immediately. Denervation and stopping oxygen and electrolytes supply will cause ...


4

You don't get hydrated by breathing moist air. That may at best hydrate your respiratory tract. You should drink more water in dry weather because the body gets dehydrated more. Humid weather is not hotter, it just feels more uncomfortable but dry heat is actually more harmful because it dehydrates you (not in the sense of extreme heat).


4

I was wondering if a heart keeps beating if it is separated from the body? Yes, it does. Here's a video showing it (don't click if you're squeamish!): https://www.youtube.com/watch?v=NEuSCPifKhA It's a classical physiology experiment to remove a heart and keep it beating for some time in a jar with liquid solution. In fact, acetylcholine, the first ...


22

Short version The heart has the ability to beat independently of the brain as long as it has oxygen. The heart will eventually stop beating as all bodily systems begin to stop working shortly after brain death. Remember the heart can beat, but your diaphragm and lungs wont. hence the cardiac muscles undergo asphyxiation and die off. However, immediately ...


8

Sydney Ringer showed in 1882 that when the heart, when separated from the body and immersed in lactated Ringer's solution, or even isotonic saline solution, will beat because it has its own pacemaker systems at the level of the Sinoatrial node and Atrioventricular node. This activity will continue until there is insufficient ATP to support it energetically. ...


9

Short answer People with androgen insensitivity syndrome do not have a functional uterus and cannot bear a child. Background Androgen-insensitive genetic males may develop female genitalia and internal female reproductive organs. However, in both partial androgen insensitivity syndrome (PAIS) and complete androgen insensitivity syndrome (CAIS) the uterus is ...


7

The yellow color comes from the accumulation of Bilirubin in the body. Bilirubin is a breakdown product of hemoglobin (contained in erythrocytes, also known as red blood cells, and responsible for the oxygen transport in the body). (This is also the reason why bruises get colored, as the blood which was released into the skin gets removed.) As erythrocytes ...


3

Short answer External stimuli can drive autonomic responses. Background The autonomic nervous system is a visceral sensory and motor system. The viscera are the internal organs. Virtually all visceral reflexes are mediated by local circuits in the brain stem or spinal cord (Fig. 1). It is one of two major subdivisions of the nervous system; the other being ...


9

Short answer Various inhalants, most notably organic solvents including those used in paint and glue suppress appetite. Background From the Division of Alcohol and Drug Abuse I learned the following: Initial effects [of various inhalants] include nausea [...], and a loss of appetite. And the Humanitarian Irin News reports the following on Nepali ...


17

Speaking of your DNA in general, you have alleles from all four of your grandparents. The 22 pairs of autosomes (non-sex chromosomes) can receive DNA from all four with random mixing. On a few chromosome pairs you may be missing alleles from one of your grandparents due to the randomness, but on average you will have about a quarter of your autosomes from ...


5

Short answer Water of 180 oF (82 oC) causes immediate scalding (thermal burn wounds). Background The severity of a scald injury depends on the temperature to which the skin is exposed, and for how long. Residential water heaters warm up tap water typically to 120 oF (48 oC). At this temperature, the skin of adults requires an average of five minutes of ...


1

Remember: A and B are genetic markers that might be linked to the disease gene. Neither A nor B are actually the hemophilia disease mutation (or gene), A or B are proxies, or substitutes for the mutation in the disease gene. Since it is an X-linked recessive, it is only the Mother's two X chromosomes that are candidates. You can completely ignore the ...


2

At the moment, the youngest diagnosed Huntington's case was 2 years of age. This paper appears to discuss not only this boy's onset, but also the diagnosis of symptoms in the early-onset disease. Here they research a link between age-of-onset and the length at which the repeats are. The thing is that these repeats won't just constantly get longer. There ...


0

The lacrimal gland, the major source for tear production, is situated just above the eye. It sends it's secretions to the eye via the lacrimal duct. Tears secreted collect in the conjunctiva of the upper lid. There is also a nasolacrimal duct which drains the tears from the eye into the nasal cavity. Hence the sniffles when we cry. How is it controlled? The ...


1

Since there are 2 alleles of each gene and 3 different genes, 2EE3 = 8? Let's test this by making a table, for 1 gene there are two different kinds of gametes, so 2EE1 = 2, for 2 genes there are 4 different kinds of gametes (AB, Ab, aB, ab) so 2EE2 = 4, and you already did the calculation yourself for 3 genes, and 2EE3 = 8. Why don't you try working it ...


0

Your illustration is wrong. During second meiosis the sister chromosomes go to each their cell, not the same cell. This would correspond to switching the colors up in your illustration like this:


0

A genetic marker is, by empirical definition, something that you can unequivocally place on a genetic map. A genetic marker may be an allele of a known gene that confers either a dominant, or a recessive phenotype. Alternatively, a genetic marker could be either a restriction fragment length polymorphism--whose segregation can be detected by either a ...


1

Chromosomal aberrations have defined notations you can find here. The notation rule for multiple genetic abnormalities is to concatenate them. In the presence of an unbalanced translocation two abnormalities will be indicated as you have both a translocation and another event (e.g. deletion, duplication, ...). In your example, as no other ...


1

Genetic markers don't cut the DNA. They're simply regions of DNA sequence that happen to be variable between individuals (see my answer to your previous question). They might be measured using restriction enzymes (i.e. RFLP) to identify the exact difference, but it's not the marker that's cutting DNA. Furthermore, they don't necessarily cause disease. ...


1

This translocation is balanced: if it was not there was a specific sign for specific unbalanced event, for example "del" for deletion or "+" and "-" signs etc.


1

Indeed, a paper was published in 2011 regarding the same for humans by using a magnetic resonance spectroscopy to measure carnosine content. A significant positive correlation was found between muscle carnosine, measured by 1H-MRS, and percentage area occupied by type II fibers. Explosive athletes had ∼30% higher carnosine levels compared to a reference ...



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