Biology pertaining to humans
4
votes
1answer
96 views
Is a raised baseline between T and QRS normal in any ECG lead?
Here are excerpts from an unknown ECG lead. I find it weird that the "baseline" changes after the T wave and doesn't return until after the following QRS complex. Is that normal/expected for any lead?
...
10
votes
1answer
172 views
What are the clotting factors' effect on avascular necrosis development?
Do clotting factors tpa and pai-1 lead to degenerative osteoarthritis in the same way that lupus anticoagulant and prothrombin might? Is one of these pathways particularly detrimental during formation ...
16
votes
2answers
234 views
Can an adult without genetic lactase persistence still develop a tolerance for dairy foods?
While investigating the rise of adult lactose tolerance, I came across the news that China has been encouraging its citizens to drink more milk, even though most of the Asian population lacks the SNP ...
14
votes
3answers
308 views
Are human fetuses more likely to be male?
Question: From a physiological point of view, when sex is determined in a human fetus, is it equally likely to be male or female?
Studies in this area typically measure age at birth, where the data ...
3
votes
1answer
739 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 ...
1
vote
1answer
108 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 ...
9
votes
2answers
194 views
Where do the bacteria within the vagina originate from?
I understand that it's feasible the bacteria within the gastrointestinal tract originate from the food we eat and air we breath, but where does this population of microbes originate from?
1
vote
0answers
70 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 ...
0
votes
0answers
25 views
Are there different metabolic pathways leading to “sleep”?
First of all, I apologize if this question does not belong on biology.stackexchange.
I've long been interested in sleep and recently postulated this question in light of reading about ...
1
vote
0answers
19 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 ...
0
votes
0answers
91 views
Can the sleep/wake cycle be influenced by non-visible spectrum electro-magnetic radiation?
I've been reading a few papers on Melanopsin and Suprachiasmatic Nucleus (SCN), and see that the sleep/wake transition is ...
10
votes
1answer
125 views
Why do most breast cancers occur in women?
According to Korde et al. (2010):
Male breast cancer accounts for less than 1% of all cancers in men and less than 1% of breast cancers.
This raises the question: Why do most breast cancers ...
4
votes
1answer
185 views
In the vacuum of space would death be instantaneous?
I was arguing with my colleague about this matter (I'm not going to mention which side I fall on).
Would death be immediate in the vacuum of space? For example, if I was suddenly teleported into the ...
3
votes
0answers
72 views
What is the effect of garlic on intestinal flora?
Now that we can compare whole microbiomes, has there been investigations on the effect of garlic (or diallyl disulfide, its main ingredient) on intestinal flora? From the proven antimicrobial ...
3
votes
1answer
69 views
How are melatonin levels measured in humans?
I'm wondering how it is possible to measure diurnal variations of melatonin levels in humans. I keep reading that there should be a large difference in amplitude between melatonin levels measured at ...
4
votes
1answer
35 views
Are there yearly variations in HIOMT (HydroxyIndole-O-MethylTransferase) availability?
I'm reading a booklet on melatonin published in 1996, titled "Melatonin and the Biological Clock". And see the following statement:
HIOMT (HydroxyIndole-O-MethylTransferase), one of enzymes of ...
4
votes
0answers
44 views
What light intensity determines the start/end of a photoperiod in humans?
I'm reading this article, which discusses the influence of Long Photoperiod (LP) and Short Photoperiod (SP) on melatonin production:
HIOMT drives the photoperiodic changes in the amplitude of the ...
4
votes
1answer
154 views
Is there a relationship between Melatonin, Norepinephrine and depression in humans?
I'm reading a booklet on melatonin published in 1996, titled "Melatonin and the Biological Clock". This particular paragraph caught my attention and I would like to better understand what it means:
...
5
votes
1answer
136 views
Influence of alcohol on brain cells
As I am not related to biology, I would appreciate if you can keep your answers as simple as possible.
My question is about the influence of alcohol on the brain. As far as I know, drinking alcohol ...
2
votes
1answer
2k views
What is the functional difference between hemoglobin and ferritin?
I read that both hemoglobin and ferritin are for storing iron in the body. So, what is the difference between them in terms of storing/binding iron?
10
votes
2answers
260 views
Could an “overactive” brain increase the chances of Alzheimer's Disease?
From Raichle ME. 2010. Two views of brain function. Trends in cognitive sciences 14: 180–90:
Alzheimer’s disease (AD) is the most common cause of progressive
cognitive decline and dementia in ...
16
votes
2answers
235 views
Why would diffusion be faster across a non-specialised tissue?
The standard protocol for a person experiencing chest pains is to chew a 300mg aspirin tablet, the argument being that chewing rather than swallowing the tablet results in the aspirin entering the ...
4
votes
2answers
118 views
Does age affect the frequency of flatus?
Is there any relation between age and the frequency of flatus? I often have this feeling that older people f*** more often than younger ones. Is this feeling scientifically correct?
3
votes
1answer
76 views
What is the relationship between Homocysteine and Norepinephrine metabolic cycles?
I've been researching neuromodulators and have taken a look at the Norepinephrine/Noradrenaline system.
The diagram of biosynthesis of Norepinephrine is presented in the wikipedia article:
...
22
votes
3answers
3k views
How does the brain's energy consumption depend on mental activity?
What is the impact of mental activity on the energy consumption of the human brain?
I am most interested in intellectually demanding tasks (e.g., chess matches, solving a puzzle, taking a difficult ...
10
votes
2answers
157 views
Can a color-deficient person be made to visualize the missing colors?
Hope this is within the scope of this site.
Color-deficient persons lack the cells in their retina needed for differentiating some (or all) colors.
However, the part of the brain that actually ...
0
votes
1answer
125 views
From which ancestor species did humans inherit orgasm?
From what ancestors did humans inherit orgasm?
Do fish experience orgasm?
Are the male and female orgasm the homologues that can be traced to the time when there was no difference in sex between ...
4
votes
1answer
102 views
Are there any effects of elevated Cysteine levels on cognitive function?
I'm looking at this diagram of homocysteine metabolism and see two distinct pathways that the amino acid may get metabolized to: with vitamin B12 it gets converted back into methionine, while with B6 ...
7
votes
2answers
93 views
How was the guided daily amount (GDA) calculated?
We are constantly shown nutritional information on food packaging stating this food contains "x" amount of your guided daily amount. A linked to the values is here. How were these values calculated? ...
11
votes
3answers
413 views
What happens to dextrorotatory amino acids in humans?
As indicated by this question, most of the amino acids in the human body have the L-chirality. As enzymes also have handedness, what happens to the D-amino acids that end up within the human body? Are ...
8
votes
2answers
150 views
Do twins “run in the family”?
My wife and I recently found out that we are going to have twins and so nearly everyone asks if we have a family history of twins. Now I know that the answer for me is that it doesn't matter—as ...
4
votes
1answer
248 views
What does vitamin B6 and B12 absorption depend upon?
I'm looking at my question about homocysteine metabolism and am doing a followup inquiry into vitamins B6(Pyroxidine) and B12(Cyanocobalamin). I've found this interesting bit about vitamin B12 and am ...
1
vote
1answer
41 views
What is the role of Homocysteine in cognitive function?
I'm looking at this link : Homocysteine and cognitive impairments and am looking for more information on specific cognitive impairments associated with elevated levels Homocysteine. That article is ...
7
votes
3answers
163 views
What alternatives are there to the amyloid hypothesis?
Given the recent failure of the Bapi clinical trial, there is a lot of questions that have arised from he amyloid hypothesis. However, I can't really think of many other mechanisms that don't involved ...
4
votes
2answers
168 views
Does making yogurt from non-pasteurized milk work against possible disease bacteria?
In the past, when there was no pasteurization, could making yogurt from milk lower the chance of getting infected by bovine tuberculosis (or other diseases from infected milk)?
For example, would ...
0
votes
0answers
25 views
What's a good way to think of how a biological organism operates? [closed]
I'm a programmer and deal with computers a lot. I can write code and make computers do things, using conditional logic and algorithms. Not so long ago I started to research sleep and am trying to get ...
3
votes
1answer
62 views
Is there an advantage to having cellulite
There are many ads nowadays advertising cellulite removal, and it causes me to wonder if there is an advantage to having cellulite or if it is just a result of too much fat unevenly spread? Is it ...
18
votes
2answers
220 views
Why is rabies incurable?
I'm still not sure about the mechanics that lead to rabies being incurable. I know that it can be treated before any symptoms show up, but why is it that once symptoms show the person is a dead man ...
6
votes
1answer
78 views
Why are pilots under the illusion of gaining altitude without doing so?
We had a lecture about the balancing systems of the body (mainly the otolith organ / semilunar canals) in which a case was described where a pilot crashed into a ship. He was supposed to keep his ...
3
votes
1answer
145 views
Why do rod cells not recover after bleaching upon exposure to bright light?
I'm confused as to why, when exposed to bright light, rod cells cease to function.
I understand that exposure to bright light bleaches all of the rhodopsin, but...so what?
Why doesn't the bleached ...
4
votes
1answer
43 views
During human ageing, which immune cell sub-types are most affected?
It is now well established that human ageing is accompanied by an increase in systemic, low-grade (chronic) inflammation, sometimes termed inflammaging (Franceschi, 2007). This is in part due to more ...
6
votes
1answer
124 views
What is Mendelian Randomization, and how is it used to infer causality in epidemiology?
Studies of human traits and diseases are inherently confined to observational studies, known as epidemiological studies. This can make it very hard to determine what actually causes a particular ...
16
votes
2answers
2k views
What causes fingerprints to form and why is the pattern formed unique?
I've found research that suggests that the reason we develop fingerprints is because they aid us with feeling surfaces (Scheibert, et al. 2008) and not to increase friction and help with the gripping ...
2
votes
1answer
187 views
How does the brain instinctively know the math behind Newtonian Physics?
A 10 year old child does not have the intellectual power to accurately calculate the energy required to throw a ball an arbitrary distance. Yet they are able to accurately throw a ball at a ...
8
votes
1answer
120 views
A timeline of the odds for survival for fertilized eggs and fetuses
I'm looking for data to build a timeline of the odds for survival of a fertilized egg, i.e.,
What are the odds it'll last a week?
What are the odds it'll last a month?
2 months?
(and so on ...
26
votes
1answer
2k views
Why Does Salt Water Help Sore Throats?
I am having some trouble understanding how salt water, a simple solution, could so effectively remove the pains of a sore throat.
I do believe that the answer is closely related to hypo/hyper-tonic ...
4
votes
1answer
186 views
When is the lactase in lactose-free milk active?
Recently we have started suspecting that one of our children has hypolactasia (lactose intolerance), and so accordingly I have had my first exposure to lactose-free dairy- and dairy-like products. In ...
7
votes
1answer
136 views
How fast do different organs turn over cells?
It is said that the human body turns over all cells or molecules in 7 year cycles. This is not quite correct, because there are different organs changing at different speeds. My interest is what is ...
6
votes
1answer
260 views
Is there a biological basis to physical attraction?
Is there something encoded within us that makes us attracted to, e.g., someone
taller or shorter
with blonde or brunette hair
with green or blue eyes?
Or, is this phenomenon completely based on ...
5
votes
1answer
81 views
What is the biological mechanism linking temperature and probability to be infected with a virus?
It is common knowledge that when you're cold you could get a cold.
What is the mechanism linking temperature and viral infection?
