Questions tagged [human-biology]

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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7
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1answer
802 views

Why clotting does not occur during Menstruation

As we know when we get injured our body's clotting systems stop the bleeding. So why does it take days for menstruation to stop ?
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46 views

Sulforaphane vs. Hyperthermic conditioning (sauna use) which would induce a greater heat shock response in the human body?

I’m curious to know which would induce a greater upregulation of heat shock proteins, consuming sulforaphane or putting the body through heat stress such as using the sauna. Sulforaphane reference- ...
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33 views

How does the immune system recognize harmful proteins?

How does the human immune system detect whether a protein happens to be a protein found in the body that is supposed to be there, a bacterial toxin that should be inactivated, an already inactivated ...
2
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0answers
44 views

Is the tendon width determined by genetic predisposition, and if so, is genetics the sole factor?

Tendons' widths vary widely across humans. E.g.: {1}: "the mean patellar tendon width was 26.10mm (SD = 3.31; range 18.33mm-33.33mm)" {2}: "Size of the patellar tendon width, measured at the same ...
4
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1answer
125 views

When does the brain stem appear in humans?

This article states: Once the neural tube closes, at around week 6 or week 7 of pregnancy, it curves and bulges into three sections, commonly known as the forebrain, midbrain and hindbrain. ...
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1answer
50 views

Can anyone help me with these Biology evolutionary properties homework questions? [closed]

my teacher assigned these worksheet questions, they are ungraded, but he said something might come up on the test really similar to this so I really want to get all of them right. I am pretty ...
4
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0answers
31 views

Can sperm cells penetrate the cell membrane of non-ovum cells?

Sperm cells have tiny bags of enzymes on their tip (the acrosome) which allow them to penetrate the ovum. My question is whether or not the process that allows sperm cells to penetrate the cell ...
5
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0answers
61 views

The truth behind human urine and marking territory?

So some years ago, I remember watching a survival show in which the host said that human males produce a type of chemical in the urine that animals such as wolves can acknowledge as a territory marker....
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0answers
15 views

How do viable sperm persist for weeks?

Tests on men who have undergone vasectomies show viable sperm in their ejaculate weeks and dozens of ejaculations after ligation of their vas deferens. How is this possible? How long does a ...
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0answers
118 views

What is the tensile strength of muscle?

So I am looking at determining the pressure needed to impale a person with an object of a given size and shape. To figure this out, I believe I need to know the tensile strength of skin, bone, and ...
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0answers
38 views

How can I learn biology by myself? [duplicate]

I am only 15 years old,and my primary school education hasn't been that good,also I forgot a lot of things. I would like to start again,and I am asking for your advice. What are some of the good ...
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0answers
80 views

The space of all human DNAs [closed]

This is both a math and biology question but I think it makes more sense for a biologist to answer it. My question is: what can be said, if anything, about the space of all possible human DNAs (for a ...
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2answers
91 views

Force applied to the human body

This is the basic premise of a physics question I have been attempting to solve over on the Physics SE. (I'm working on solving the actual science behind an old movie myth). How hard a punch hits ...
2
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2answers
328 views

What is the difference between “hamstring tendon” and “common hamstring tendon”?

What is the difference between "hamstring tendon" and "common hamstring tendon"? I have seen both terms being used but I don't know whether they referred to the same tendon. For example, Johnson, ...
2
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0answers
20 views

What are all the elements affecting human reaction time?

I'm helpless at biology/science-y stuff in general. But, as a writer, for the sake of story research, I often have to delve into it. I make use of the Worldbuilding Stack Exchange, but this question ...
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24 views

Pulse Oximetry, what significance does a decimal place hold?

I work in a sleep research lab. We have a couple of Masimo pulse oximeters that report pulse oximetry values in terms of integers (e.g. 90, 91, 92, etc.). Now our principle investigators used to use ...
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0answers
23 views

what is the difference between a “subclonal expansion” and a “clonal sweep”

I am trying to understand the difference between a subclonal expansion, and a clonal sweep and therefore why this means that some subclonal mutations are important.
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0answers
89 views

Why do children not have the Acid Mantle?

Post puberty humans begin to secrete a substance called Sebum which changes the neutral PH of our skin from ~7 to 4.5-5.5. This has that advantage of serving as a protective line against pathogens and ...
2
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0answers
37 views

Is there other unknown-compound in Blood?

Blood is made of red blood cells, platelets, plasma etc. Let's say, then, there are these $x$ known compounds in blood. But how can one be sure that there is no other compound other than those $x$ ...
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0answers
67 views
+50

The afflictions of Tarrare

Are there any conjectured mechanisms that cause Tarrare's extremely oversized stomach and abdominal cavity? Along with his superhuman appetite of course. Whether from a medical perspective or a ...
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0answers
21 views

What is the average eye sight for humans? How bad is one's eyesight if you are1 or 2 SD below average?

What is the average eye sight for humans? How bad is one's eyesight if you are 1, 2 or 3 SD below average? I googled but it was hard to find good search terms.
2
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0answers
40 views

How much oxygen does a human need to breathe?

So, I know that the title isn't very precise, but so is my current knowledge of the subject. It begs the question of what unit are we talking or maybe percentage? Let me explain the situation. Earth'...
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0answers
35 views

Why can we hear above 8 kHz

Why have humans developed ears capable of hearing sounds that are (never?) heard in nature. Is it known why humans developed the ability to hear up to 20 kHz when all the relevant noises are below 8 ...
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0answers
15 views

How do some deep sea creatures lower their metabolism to stay alive for a long time?

I was watching some bio related videos and saw in one that some deep sea creatures and other organisms purposefully limit their movement to decrease metabolism rates. Do they live longer? If we ...
2
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0answers
37 views

Can the human body survive in a zero sugar diet strictly through gluconeogenesis?

I read an article a while back about athletes (I believe cyclists) being exposed to a 0 sugar diet and their blood sugar levels stayed relatively constant, which prompted the question whether people ...
5
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1answer
222 views

What's a “constitutionally small penis”?

I'm reading some urology papers and came across one involving penis growth (Kim & Song, 2008); here's an intro passage that I'm confused about: A total of 58 patients with constitutionally ...
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1answer
54 views

How do astronauts eat in space?

If there is no gravity in space how does the food enter the stomach? My guess is that it is due to the movement of the esophagus.Am I correct?
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1answer
86 views

Can I train my non-dominant hand and make it dominant?

Are our dominant limbs decided on birth or is there some way in which I can train my non-dominant hand and make it as coordinated as my dominant?
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0answers
11 views

Reason for acephalgic migraines

I suffer from acephalgic migraines, known commonly as ocular migraines. I’d like to know the reason why such migraines occur. Moreover, I’d be interested in knowing why do the following occur in the ...
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0answers
28 views

Is it possible to determine if it is the 5’-a 3’ strand or the 3’-5’ strand?

DNA is constructed in an antiparallel manner. This means if you number each of the 5 carbons in the sugar deoxyribose the 3rd carbon will be connected to one phosphate group and the 5th carbon will ...
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1answer
41 views

Have there been new discoveries concerning the perception of taste for the last 10 years? [closed]

What are the last discoveries concerning the perception of taste for the last 10 years? We discovered the 5th flavour: umami. Also the 6th and 7th: oleogustus and starchy. Anything else? Maybe in ...
6
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1answer
135 views

Are all genetic disorders inherited?

I know that genetic diseases such as cystic fibrosis are often passed down through generations and are therefore classified as genetic disorders, but if a mutation occurs spontaneously, which for ...
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0answers
30 views

Is there any explaination to homeopathies in modern biology sciences? [duplicate]

I'd like to know if there is any sort of explaination from rigurous biological arguments which could potentially explain how homeopathies could work? I'm not talking about placebo effects (...
2
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1answer
69 views

Do mutated c-sis oncogenes only affect cell growth?

Since c-sis regulates only cell growth, a mutation there should only lead to an out of control growth of the cell, but the cells would still be mature, since c-sis does not regulate the function or ...
0
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1answer
118 views

Is it possible for human body to convert carbohydrates to protein? [closed]

Is it possible for human body to convert carbohydrates to protein to build muscle for example? EDIT: I read in many articles that you should eat more than 1.5 gram protein for each 1 kg weight of ...
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0answers
77 views

True or False: Endocytosis delivers vesicles directly to the cis face of the Golgi complex

Does anyone know the answer to this question, and also the explanation of to why this is True or False? I know that Endocytosis is the process of uptake of materials into cells including ...
2
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1answer
161 views

Why is exclusive breastfeeding recommended for 6 months only?

The WHO recommends exclusive breastfeeding for the first 6 months of a child's life. Review of evidence has shown that, on a population basis, exclusive breastfeeding for 6 months is the optimal ...
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2answers
1k views

Where did Neanderthals and Denisovan Man come from?

Neanderthals, Denisovans and our species (Homo sapiens) are commonly cited as closely related subspecies, even interbreeding with each other. Yet our species theoretically didn't migrate out of Africa ...
4
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1answer
115 views

Can the heart generate its own rhythm independent to the SAN?

My textbook and a revision guide, which I believe is a reinterpretation of the textbook, state that: The SAN initiates waves of excitation that usually override the myogenic action of the cardiac ...
0
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1answer
226 views

What are the brain structures directly on top of the brain stem?

I have been trying to learn the anatomy of the brain, and some information on their functions, through an iPad app called 3D Brain. Whilst going through the different parts, I have noticed that one ...
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0answers
21 views

What is the name of the wrinkles occurring in people's lips? [closed]

I was wondering if there is a name for the wrinkles occurring in people's lips. Just curious.
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1answer
63 views

Would our body adapt to changes that are not in our DNA?

If a person was to undergo a treatment or surgery at a very young age, that significantly reduced their final height, would the rest of their body adjust to the sudden change? If not; because our arms’...
0
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1answer
54 views

Where does the energy required to turn ADP into ATP come from? [closed]

My teacher states that in order to convert ADP into ATP, energy from respiration is required. However, I watched a video which states that energy from the son is used to turn ADP into ATP. Which is ...
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0answers
48 views

What is the role of plasminogen used in the preparation of APSAC? (Anisoylated Plasminogen Streptokinase Activator Complex)

What is the role of plasminogen in APSAC, and how is there indirect activation of plasmin through APSAC? Reference https://www.sciencedirect.com/topics/chemistry/fibrinolytic-agent
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2answers
149 views

Is reverse senescence/“anti-aging” actually scientifically possible among humans yet?

I have been very interested in this since I myself am interested in reversing my skin's aging/genes/damage/etc. I also am interested in volunteering any future genetic altering of skin quality. ...
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0answers
34 views

Is there a chemical compound, element or something else that could color the eye lens in purple?

I hope this is a right place to ask this question. I'm writing scifi book, and looking for information whether it is possible for any element, chemical compound, radiation or something else to color ...
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2answers
144 views

Are spinal nerves myelinated and unmyelinated at the same time?

I was trying to answer this question when I remembered that the somatic axon is myelinated, while both sympathetic and parasympathetic preganglionic axons are also myelinated. Are they only myelinated ...
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1answer
144 views

Lobed Nuclei still count as One nucleus?

Do the Lobed Nuclei of immune cells (such as Megakaryocytes) still count as one nucleus?
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0answers
7 views

Colour of Vein surface(tunica externa)

If vein from hand is isolated out and blood from within flushed then what will be the colour of vein surface.
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0answers
78 views

What are the (statistically) normal pH levels in the most-outer part of human sexual organs?

What are the (statistically) normal pH values of the outer skin/epidermis of human sex organs (groin/crotch) in the male and female? e.g male testes, female vulva, male glans, the enveloping epiderm, ...