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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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Why does sympathetic activity constrict pulmonary vessels?

I don't know understand why sympathetic stimulation constricts pulmonary vessels? I thought that the sympathetic nervous system activated the body for physical activity. Physical activity would need ...
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do platelets cytoplasm contains DNA?

I'm a 12th-grade student and I have an entrance exam this year. I have a question in biology. I would appreciate you if you help me <3 as we thoroughly know platelets are multiple pieces of a big ...
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1answer
17 views

Why is there a layer of moist lining the inner walls of alveoli?

I'm taught that the walls of the alveoli are moist, so gaseous oxygen molecules can dissolve into this water. This then allows the dissolved oxygen (liquid state) to diffuse faster from the alveoli ...
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879 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 ...
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Does low gravity exposure to early stages of human fetus have potential to unloc unused genetic information from earlier stages of evolution?

The title seems quite self explanatory but let me elaborate. New mutations do take a very long time and many generations to occure in the genetic code. But our genetic code already holds all the ...
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2answers
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Is it possible that by mutation a human could see infrared or other 'colours'?

Incoming light reacts with the several types of cone cells in the eye. In humans, there are three types of cones sensitive to three different spectra, resulting in trichromatic color vision. Each ...
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2answers
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How hot can a beverage get without burning the tongue?

What is the maximum temperature that a beverage can be without burning the tongue? I suspect there's a maximum temperature that the surface tissue of a tongue can withstand without being damaged (...
0
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1answer
48 views

Can diet, supplementation and/or drugs affect sexual dimorphism?

After puberty, can certain diets, exercise, and/or possible drugs affect masculine/feminine dimorphism in adults? We know dimorphism and/or morphology is a product of genes, but to what extent can ...
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Colour of our organs

Upon researching the organs of the body I have found that in every picture that I have seen the organs are of colour for example the kidneys are a light red colour. I understnad that our organs are ...
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What are the proportions of average human arms, legs and torso to each other that the population tends towards?

Normally when I draw or model something, I have a reference image. However, I want to draft a human-like creature for which there is no reference image, so I have to build it from scratch. For some ...
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22 views

Is male cosmetic surgery a viable mating strategy for choosy females?

Is a man in modern times "competing" with other men based on genetics for reproductive success? If so, would male cosmetic surgery of any degree be viable as a modern attempt at competing for female ...
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3answers
237 views

Why does an increased heart rate mean increased blood pressure?

Say a person starts exercising. If their cardiac volume remains the same but their heart rate increases so that the overall result is an increase in cardiac output, will their blood pressure increase ...
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2answers
33k views

Can nosebleeds cause death?

Can epistaxis or nosebleeds be a cause of death?
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3answers
222 views

How much energy we get from oxygen?

During a whole day breathing, how many kcal or watts do we get from the oxygen we breathe?
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1answer
120 views

Is there a specific suffix for “within a cell”? i.e. in a similar manner to how -aemia refers to within the blood

Words like hyperglycemia and hyponatremia refer to the relative level of each component in the blood, not in the cell. Is there a suffix for within the cell? For reference I would like one word as an ...
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2answers
716 views

Why do humans transport glucose but not sucrose like plants?

The reason why plants transport sucrose rather than glucose is due to the fact that it is more efficient and that nearby cells would not take up all the glucose too quickly. Hence the plant convert ...
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3answers
14k views

Supercomputer Vs Human Brain

With supercomputers doing calculation in petaflops ($10^{15}$ Calculations per Second), have we crossed the speed of Human Brain?
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2answers
73 views

Red neurons - Acute neuronal injury

“Red neurons” are evident by about 12 to 24 hours after an irreversible hypoxic/ ischemic insult. The morphologic features consist of shrinkage of the cell body, pyknosis of the nucleus, disappearance ...
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1answer
12 views

Why proximal muscle weakness is seen earlier than distal muscle weakness in Dermatomyositis?

It is said that in dermatomyositis(DM) , proximal muscle weakness is seen earlier than distal muscle weakness. It is also said that , DM is due to damage to small blood vessels contributing to muscle ...
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1answer
95 views

How can a child be blood type AB, if both of the parents are blood type A?

Basically, both of my parents are blood type A (both are confirmed and it's also certain both of them are my biological parents). I recently found out my blood type is AB. How is this possible? I ...
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0answers
11 views

What does ubiquitination between 2 genes mean?

I have come across the Hedgehog signaling pathway. In this pathway, the genes Cul3 and ptc have an interaction of ubiquitination (The information is available from the KGML file). What does this ...
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2answers
82 views

Infant immunization

I know that polio vaccine consists of small dose of polio virus itself, which activates body's immunity against the disease. An infant is given a no of vaccines including chickenpox, tetanus, ...
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0answers
5 views

Histology cheek swab

I recently did a cheek swab and I can recognize the cells the nucleus and cell membrane, but I noticed a section that had a cluster of nuclei resembling dots. I was wondering if it was just cells ...
5
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1answer
48 views

Do fat people have more chances of developing nitrogen bends?

I was reading some text on deep sea physiology. I got to know that solubility of nitrogen in fat is five times that in water. The exact text from the book animal physiology adaptation and environment ...
3
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1answer
408 views

How does hyperthyroidism cause diarrhea?

According to Robbin's Pathology, hyperthyroidism leads to an overactivity of the sympathetic system. It also goes on to mention that this sympathetic hyperstimulation in the gut leads to increased ...
0
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1answer
18 views

Is the lac operon repressed in the presence of both glucose and lactose?

In the presence of both sugars (glucose and lactose) will there be repression of the lac operon completely? I know that more glucose means less cAMP --> less CAP --> less positive regulation, and ...
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0answers
349 views

What is the weight of a single human sperm (spermatozoon) compared to a single human egg

While the difference in dimension is well covered, I have been unable to find the mass measurements of each.
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2answers
1k views

What causes skewed lanes in a DNA gel electrophoresis experiment?

In gel electrophoresis, what causes effects like these (see column 11 in the first one, and column 6 in the second)? (These images were samples that I took from an online activity we did for class)...
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3answers
8k views

Do we consume dna, proteins of other organisms?

When we eat raw meat, e.g. chicken or fish, we are actually consuming the DNA, proteins etc. which are present in their cells. Wouldn't this affect our cell functions as this DNA might enter our ...
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0answers
14 views

What is the max amount of photons per second of the rods and cones in our eyes?

The title says it all. I just cannot find any information about this - I have tried for so long now. Therefore, I figured that I could reach out to some clever guys in this forum for help instead:) ...
2
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1answer
43 views

What are the effects of oxygen toxicity in human blood?

I was reading some text on deep sea Physiology, and for to know that diving to do could cause oxygen toxicity in the blood. This was the exact text from the book Textbook of Medical Physiology by ...
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0answers
22 views

Why silver hair is starting to come in black [duplicate]

I am 68 years old and have been happily silver haired since my late 50s. What I'm noticing lately is that a lot of new hair that's coming in is either black or very dark brown (my original hair color.)...
0
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1answer
35 views

Can endemic diseases be acute?

Diseases can be classified as :endemic ,or pandemic,...etc. An endemic disease is an infectious disease which is generally or constantly found among people in a particular area. Disease conditions ...
0
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1answer
56 views

Does estrogen increase muscular growth in females?

Regarding humans it is said that most psychological effects caused in men by testosterone are caused in women by estrogens. There are many studies on that, particularly regarding temporary shifts of ...
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2answers
60 views

How does common cold START?

When I searched for the causes of common cold, I found out that it's only cause is the spreading of virus and that it's a myth that you get cold when you get wet. If that is true then how does the ...
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1answer
19 views

can magnesium bicarbonate be absorbed in the mouth?

Can Magnesium Bicarbonate be absorbed in the mouth?" Magnesium Bicarbonate occurs naturally in some mineral waters.
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1answer
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We know that the hepatitis C virus can live on surfaces for at least six weeks. Maybe longer. The infectivity study ended after just six weeks; why?

Background A paper has found that the hepatitis C virus (HCV) can remain infective for at least six weeks on ordinary household surfaces. You can see the free full text, or a summary for busy ...
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0answers
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Do all commercial ionizers produce harmful ozone?

I'm not a scientist. I have read that negative ions have health benefits. I am interested in increasing the ratio of negative to positive ions in the air in my home. I see that ionizer machines exist ...
0
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1answer
80 views

Self Grown Organs

Could a viable organ be partially grown in a test tube then be hooked up to the host in some way until it is large enough to swap it with the bad organ? For example: Could a smaller replacement heart ...
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3answers
5k views

Why do I want to urinate when I touch water?

I've noticed that whenever I come in contact with running water (especially when I do my dishes), I have a desire to urinate. A quick Google search (link,link) gave me few different hypotheses: Cold ...
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3answers
126 views

Serological assays measuring antibody response

Given that an appropriate immune response to a bacteria may be thwarted in an individual, including not producing all of the antibodies which are known to occur in people who have been infected, or ...
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0answers
18 views

Is genetically given percent of fat stored under the skin higher for colder regions?

Is there a study on the dependence of the natural amount of subcutaneous fat and environment temperature? Is there a genetic difference in fat storing across human populations?
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1answer
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A study found that the hepatitis C virus can live on surfaces for six weeks. Did they end the study before the seventh week began?

A study once found that the hepatitis C virus (HCV) can remain infective for six weeks on ordinary household surfaces. You can see the free full text, or a summary for busy clinicians. What happened ...
4
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1answer
365 views

Does a generator potential pass along a nerve the same way an action potential does?

I have read that a generator potential is a localized depolarization of a membrane. Does that mean that it does not pass along a neuron the same way an action potential does ? If not, then how do ...
0
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1answer
19 views

Effects of horizontal vs. vertical motion on human body

I want to know if moving along a vertical plane in a circle differs in its effects on the human body from moving horizontally in a circle. Imagine a ferris wheel with a diameter of 50 metres. If a ...
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1answer
50 views

Is it possible to grow brain tissue in vitro? Can we make a super-brain this way? [closed]

I wonder whether such experiments were conducted? Is it possible to create a "biological super-computer" this way?
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1answer
27 views

Height prediction based on genetics

My height, as predicted by my genetics, is 156 cm whereas my actual height is 172 cm. What could be the reasons for this substantial discrepancy? Does it just mean I had very good nutrition as a child?...
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1answer
37 views

When muscles contract is the process similar to how non-newtonian fluids react?

I'm trying to understand how muscles contraction/tension works but getting loss in on the cellular level. From my understanding, when muscle tissue need to contract, the cells are flooded with calcium?...
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0answers
45 views

When the present state of knowledge concerning central noradrenergic transmission was established?

Some time ago I began to search for descriptions of the mechanisms responsible for the regulation of noradrenergic transmission in the central nervous system of man and to my great surprise the most ...
3
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1answer
34 views

Osmotic Pressure Clarification

My textbook states that the higher concentration of solutes, the greater the osmotic pressure will be and the greater the pull of water in will be. However, osmotic pressure is defined "as the ...