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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2answers
147 views

Growth factors vs. mitogens

According to Campbell Biology, A growth factor is a protein released by certain cells that stimulates other cells to divide. and according to Wikipedia, A mitogen is a chemical substance ...
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0answers
128 views

How does geography affect morphological features of the human body

I've seen many times how a person born in one place, goes to another country for a long time, and then they start looking more like the people there, but I never found out how it works. This report ...
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0answers
66 views

Can one eye affect the other eye's low-light adaption?

This previous question addresses how long eyes need to adapt to darkness and reach full contrast. My question is how does one eye affect the "transition" and/or efficacy of this "night vision" of the ...
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1answer
63 views

Is there a blood panel lab test that measures all the hormone-producing glands?

I understand that there are gland-specific hormone tests, such as: Secretin: for the pancreas; and Prolactin/ACTH: for the pituitary; and PTH: for the payathyroid, etc. However, are there any ...
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1answer
37 views

What is the best way to block cigarette smoke from the body? [closed]

Would it be better to hold your breath after smelling the presence of it or quickly inhale and exhale to get rid of it in your system(body)? EDIT: Changed from carbon monoxide to cigarette smoke.
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2answers
331 views

How efficient is the human body at metabolizing food?

My friend and I were having a discussion over how "efficient" human digestion is. If a human ate a 1000 calorie hamburger, how many of those calories (how much energy) does the body process into ...
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0answers
14 views

What fills the spaces between non-fused sacral vertebrae?

What is in between the sacral vertebrae before they are fused? I have looked and found no specific descriptions. If it is simply cartilage, what type of cartilage?
6
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1answer
383 views

Is there any scientific evidence that a human has ever grown a third set of teeth?

This is about the possibility (or lack thereof) for a person to re-grow a new "permanent tooth" or set of teeth, to replace the teeth that grew after their milk teeth fell out. I had earlier seen ...
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0answers
40 views

Does medication make the body dependent? [closed]

First of, I know of course that certain medication can cause an addiction if incorrectly used. But as far as I understand it, drugs prone to cause addiction have some agent in it, that makes them ...
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0answers
27 views

Are there fundamental differences between the adaptive immune systems of higher primates and other mammals?

I recently attended a Leukemia and Lymphoma Society lecture in which one of the lecturers indicated that there are fundamental differences between the adaptive immune systems of higher primates and ...
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1answer
44 views

What is 'noise'?

In both my psychology, biology and neuroscience classes, professors are constantly talking about 'noise'. For instance, our perception is limited due to 'sensory noise' in our neurons. I am utterly ...
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1answer
75 views

Does evolution thinks? [closed]

I understand evolution as survival of the fittest rule , where its the nature and surroundings that shapes the life by extinction of species which are not fit to survive the nature at that period. To ...
6
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2answers
211 views

At any given moment, how much energy is stored in the human body as ATP?

At any given moment, approximately how much energy is stored in the human body as ATP in the ADP-P-bond? This of course depends on what type of cell it is and the activity of the individual in ...
2
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2answers
66 views

Skull size of Homo naledi

I want to 3D print the skull of the newly discovered Homo naledi. The printing data can be found here: http://morphosource.org/index.php/Detail/MediaDetail/Show/media_id/7300 Where can I find the ...
5
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1answer
253 views

What is the maximum altitude where humans can survive?

What is the highest altitude that a human can survive without being pressurized? Let's assume that oxygen and heat/insulation are not the limiting factors? Why I asked.
5
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1answer
97 views

Can we artificially increase human growth using HGH?

Robert Pershing Wadlow was a man who lived in the first half of the twentieth century. He had hyperplasia of his pituitary gland, which caused him over-produce human growth hormone (HGH), and as a ...
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0answers
30 views

Why is exocrinous pancreatic cancer so lethal when compared to others?

I know it seems far fetched, but I would really like to understand why an interference with the regulation of production of pancreatic exocrine products (and which are they) is so lethal. I know that ...
5
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1answer
29 views

Constant or variable number of chiasmata during recombination?

During recombination, is the number of chiasmata consistent for each gamete and are the chiasmata regions consistent within a single organism?
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0answers
72 views

Is hypoxia/anoxia the ultimate cause of death?

I know there are different causes of death for humans like heart disease, cancer, stroke, injury and so on, but i was thinking if in every case in the last instance death is due to hypoxia/anoxia. ...
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1answer
146 views

Do human somatic cells have 46 chromosomes all the time?

As far as I know, a human somatic cell has the cell cycle: Interphase and Replication (mitosis). In interphase the cell has 2 growth phases (G1 + G2) and a synthesis one (S phase being in between G1 ...
2
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1answer
73 views

Is blood pressure in the aorta and brachial artery the same or different?

Does the blood pressure at the root of aorta equal the blood pressure in the brachial artery? I've heard it does, but it doesn't quite seem to make sense as I'd think the blood pressure would be ...
7
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1answer
347 views

What will happen if a foetus is Rh- and the mother is Rh+?

If a mother has Rh-negative blood and her foetus has Rh-positive blood it will result in rhesus incompatibility and lead to erythroblastosis fetalis. What will happen if the reverse occurs, when a ...
4
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1answer
134 views

Why do we sleep?

While we do know that the human body is regulated by a circadian clock that keeps humans on a sleep/wake cycle, we don’t really know why. Sleep is the time when our bodies repair tissues and perform ...
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2answers
6k views

Do identical twins have the same fingerprint?

When there is every thing same from their genes to their phenotype so then why they don't have same fingerprints?
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2answers
9k 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 ...
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1answer
3k views

Can swallowed fingermails, hair, or skin get caught in your appendix? [closed]

There is a common saying in my place: If you eat your skin, hair or nails, it will be deposited in the cecal (Vermiform) appendix, and can cause appendicitis. (This is mostly told to children to ...
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1answer
2k views

How long can human tissue last without blood?

I've heard it said various times that the body's tissues will begin to necrotize after being cut off from the blood supply for only a few minutes, but that can't be true. A few years ago, I woke up ...
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0answers
27 views

Is there any evidence to suggest that exercise reduces the side effects of caffeine?

I heard a friend say: I'm not drinking coffee this week. My body can only process the caffeine if I run at least 15km a week. I found this claim fascinating - that exercise temporarily ...
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0answers
17 views

Ions in different cell compartments

I would like to understand the distribution of metal ion concentrations (such as Mg2+) in the different cell compartments. I tried very hard but still couldn't find such information. Could anyone ...
4
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1answer
225 views

The arrangement of retinal cells?

The section of retina shows a layered arrangement of the various retinal cells. Starting from the inside (where the light strikes first) is the nerve fibre layer, ganglionic layer, amacrine cell ...
4
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1answer
54 views

Are there testosterone receptors in female mammary tissue?

Does female mammary tissue have receptors for testosterone hormones? Do male hormones influence female mammary glands, as female hormones influenced the male mammary tissue, such as in gynecomastia? ...
4
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1answer
220 views

Could a trans-female person ever become pregnant?

I was told that a transgender person, which I will define as anyone assigned male or female at birth that identifies opposite to that assignment, could never become pregnant conceptually, due to the ...
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1answer
575 views

How heavy are all foreign microorganisms in and on the human body?

I define "foreign microorganism" as a microorganism which is not produced by the human body (not antibodies or leukocytes) including bacteria, viruses, fungi, biofilm aggregates or small lifeforms ...
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1answer
1k 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 ...
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1answer
116 views

Why do we have two eyes? [duplicate]

Humans, animals and birds all have two eyes. Why? In addition to why two instead of one, why aren't there more than two?
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0answers
22 views

is there a difference in meaning between the terms “bone architecture” and “bone structure”?

I'm wondering whether "bone architecture" and "bone structure" mean the same thing, or whether they refer to two different concepts. In this article - ...
6
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1answer
76 views

Is eradication of the Common Cold possible?

This is a thought experiment, but everywhere I've read seems to say that colds ALWAYS come from someone else. There's no mention of a cold arising in someone without it coming from another infected ...
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0answers
39 views

Life after decapitation? [duplicate]

I saw a video where an ant lost its head and was still walking for some time. If this is possible for an arthropod, what keeps it from working with a vertebrate? (Humans, especially)
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1answer
21 views

Corneal transplant and HLA matching

Is HLA matching/ blood grouping required for corneal transplants ? I think,it shouldn't be, because cornea is avascular. I tried searching on the net but most of the references are old and ...
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1answer
58 views

Genotype of children conceived after stem cell transplant?

If you have sickle cell disease and have a succesful stem cell or bone marrow transplant, your blood type changes to AA. But what about your future children? Do your sperm or egg cells continue to ...
3
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1answer
72 views

Write the haplotypes of the family

I'm doing old exam assignments to prepare for my finals on Monday and I've stumbled on one assignment that I'm not sure how to tackle. A family with 2 children is examined for cataracts using PCR ...
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1answer
46 views

Can skin be removed and replaced so that it maintains its original cellular structure?

The cells in our body that form tissue, such as our skin, are interconnected. I would think that cutting out tissue or trying to repair/replace it, as is done in surgery, or after an injury, could not ...
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1answer
105 views

How many, and how severe, are known single gene polymorphisms for obesity?

A fairly recent meta-analysis of studies examining the association between adult obesity and polymorphisms of the FTO gene (Peng et al., 2011). The paper looked at 59 studies and concluded that, "FTO ...
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1answer
86 views

How much of the jejunum is bypassed during gastric bypass?

There is both long and short limb gastric bypass surgeries (along with several other variations on intestinal bypass procedures). How much of the jejunum is bypassed with a long-limb and short-limb ...
3
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1answer
1k views

How are non-glucose sugars metabolized in the body?

In my biology book's section on disaccharide metabolism and glycolysis, it states that sugars other than glucose must be acted upon to enter glycolysis. Let's take sucrose as an example. Sucrose is ...
29
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2answers
6k views

What do ants do with our finger nails?

There is place in my house where I cut my nails. Here, there is an ant hole where an ant colony is seen. Whenever I cut my nails from here, they take my nails inside their hole. I was wondering what ...
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3answers
12k views

Why do men have a higher hematocrit (red blood cell count) than women?

The hematocrit, also known as packed cell volume (PCV) or erythrocyte volume fraction (EVF), is the volume percentage (%) of red blood cells in blood. It is normally 45% for men and 40% for women. ...
2
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1answer
36 views

What is the mechanism of folic acid deficiency and neural tube defects?

I am having difficulty finding the mechanism by which folic acid reduces the risk of neural tube defects. I know that it does so, but what in particular actually occurs with folic acid deficiency to ...
5
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1answer
452 views

How does a fetus retain a blood group different from its mother?

It's a well-established fact that blood group is decided by genotype. But, when a new child starts its journey in the womb, the mother's blood (along with it's agglutinins and agglutinogens) flows ...
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0answers
52 views

Why can't men produce milk, just like women? [duplicate]

This might seem a bit weird, but why can only women produce milk? Wouldn't it be more beneficial to our species if all humans could produce it? I can't think of any reason only one gender would need ...