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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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 ...
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0answers
7 views

Why do pupils dilate in response to emotional state? [migrated]

I just came across an article on the internet stating that, Pupils dilate when we find someone or something attractive. So, as far as I know, this kind of dilation doesn't seem to have any ...
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1answer
20 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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59 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
63 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 ...
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1answer
68 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 ...
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1answer
295 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 ...
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1answer
28 views

Does exercising increase the rate at which UV rays are absorbed and cause affects?

Does exercising while in sunlight affect the rate at which the human body absorbs and reacts to UV rays? As sunburn is the secretion of fluids, increased dilation of blood vessels and inflammation of ...
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1answer
84 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
5k 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
8k 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
47 views

Which part of the reflex arc takes the longest time?

If the reflex arc is composed of 4 parts: Activation of sensory receptors, Conduction to and from the CNS, Transmission across the neuromuscular junction & Activation of the muscular contractile ...
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1answer
2k 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
567 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
14 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 ...
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1answer
168 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 ...
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1answer
49 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? ...
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1answer
162 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
546 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
69 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
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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 - ...
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1answer
73 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
36 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
19 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
44 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 ...
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1answer
62 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
34 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
84 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 ...
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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 ...
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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
8k 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. ...
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1answer
33 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 ...
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1answer
271 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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2answers
355 views

During famine, does the human body do anything to prioritize which organs receive nutrients?

When food is scarce, the body slows its metabolic rate to conserve energy. Are there any other systems or processes that encourage prioritization of organs?
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0answers
46 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 ...
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0answers
27 views

Why is alcohol purged from the body more slowly when we sleep?

It is a popular belief that when you get asleep after drinking alcohol, in the morning you have higher level in your blood than if you stayed awake the whole night. Is this true? If so, why? Is it ...
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1answer
56 views

Over what range do Thyroid Stimulating Hormone (TSH) levels tend to fluctuate over the course of a day?

I understand that the majority of doctors consider the TSH test "the gold standard" for measuring thyroid function (examples stating that literally are here and here). The reference range for what is ...
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1answer
29 views

Who and when was the first human diagnosed with hemophilia, or considered a carrier?

The earliest case I can find is Queen Victoria of England, who ruled from 1837-1901. Is this the first hemophilia case on record?
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1answer
132 views

Is there a difference between drinking water straight from the tap compared to leaving it to sit?

An idle question - if a glass if filled from the tap and consumed immediately, it contains some dissolved oxygen from the physical process of moving through the pipes & tap. If left out ...
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1answer
34 views

Are all tastes just a combination of sour, sweet, bitter, etc.?

For example, can the taste of pineapple be isolated to just a certain amount of "salty-taste-triggering-molecules" and "sweet-taste-triggering-molecules" etc.? Can our current understanding of the ...
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1answer
5k views

Do human anal glands have any function?

Anal glands in all kinds of animals play a range of diverse functions - providing fat for preening feathers or waterproofing fur, generating distinct scent, even repelling predators. None of the ...
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4answers
1k views

Why do obese people tire quickly?

Fat people have a large amount of calories (energy) stored, but I have noticed all time when they do physical activities they get tired fast in comparison to fit people - why does this happen?
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1answer
11k views

What is the female equivalent of the morning erection that some men experience?

There was question about what causes "morning wood." It was answered that the erection in the morning is caused by decline of norepinephrine during REM sleep. Which in part allows to prevent ...
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1answer
331 views

How to identify the age of a “living” person?

An Indian old man claims he is 180 years old now. 180 years old We are not able to tell he is 180 or 181 probably. But can we tell he is 90, 120, 100 or 150? Different people may age differently. ...
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2answers
110 views

What are possible health risks to women having large numbers of children?

What is the possible health issue the women would face in this record? The record for most children born to a single couple belongs to the first wife of Feodor Vassilyev of Russia. In 27 ...
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1answer
170 views

Can androgen-insensitive genetic-males get pregnant?

According to the linked report, people with androgen insensitivity syndrome appear as male, but have both feminine and masculine outer genitalia. However, I was not able to find out whether their ...
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2answers
2k views

Can Biologists identify all viruses?

I went to the doctor today with my girlfriend, and the doctor said that she had a virus but doesn't know which one and she should let the infection heal with some rest. The fact that the doctor ...