This tag is for questions about the general biological features of human beings (as opposed to the biology of non-humans).

learn more… | top users | synonyms

0
votes
0answers
13 views

Regarding benzoic acid and its effects

One of the users on the chemistry s.e. mentioned that when benzoic acid forms in the body in response to other chemicals it might have a mutating effect on one's DNA. Is this true?
0
votes
1answer
10 views

What causes muscle spasms?

What causes muscle spasms with muscles that are not in the heart ? Could it be some sort of stimulus overload that causes a massive contraction?
1
vote
1answer
15 views

Human population growth - where can I find the data?

Out of curiosity, I'd like play around with data of human global demography. Where can I find data that describe the "per region (per continent for example) population size" versus time since the ...
0
votes
1answer
23 views

How does cancer of the larynx (laryngeal cancer) affect the respiratory system?

The larynx is part of the respiratory system and is responsible for producing sound (our voices). My question is how cancer in the larynx (voice box) affect the respiratory system overall? I ...
0
votes
1answer
30 views

Feeling of spicy

I have done a survey on my friend When everytime they eat something spicy, They will eat ice or drink icy water. First, Mostly they feel nothing but a cool sensation. However when they finished, they ...
2
votes
1answer
34 views

What happens when we stretch?

From the wikipedia page on stretching: Stretching is a form of physical exercise in which a specific muscle or tendon (or muscle group) is deliberately flexed or stretched in order to improve the ...
3
votes
1answer
46 views

Bayes theorem for mutations

MEN 2A is a dominant inherited disease caused by a mutation in the RET proto-oncogene. The probability of being sick when you have the mutation of the RET proto-oncogene varies with age and is assumed ...
4
votes
1answer
32 views

How can a heart of human work if one of its valve is not working?

Yesterday I went to a hospital and heard a doctor say that one of the heart valves of a patient is not working. However, the patient was still alive and was healthy; the patient could walk and talk ...
2
votes
1answer
73 views

Is homosexuality an adaptation in humans?

Homo sapiens have menopause - as some other mammals (e.g. some Cetacea) - a phenomenon where older females live for decades after the end of their own reproduction. Perhaps homosexuality, that looks ...
0
votes
2answers
30 views

Why is my peripheral vision better for seeing in the dark? [duplicate]

I often walk around my house at night with the lights turned off and one night I noticed that looking straight at an object with very little light available made the object disappear from sight but if ...
4
votes
1answer
69 views

Do human-ape hybrids exist?

Since humans and apes share up to 99% of their DNA, can they interbreed? For example, a horse and a donkey seem to be just as distantly related and produce offspring. Mules, however, are sterile. ...
3
votes
0answers
46 views

Is there any biological support for the concept of “chakras”? [closed]

Is there any support in modern biology for the ancient concept of "Chakras"? I've seen the concept of 7 chakras linked to the major endocrine glands in the human body (pineal,thyroid, adrenal, ...
-1
votes
1answer
74 views

Does the DNA of a tadpole change after it becomes a frog?

Does the DNA of a tadpole change after it becomes a frog? In other words what changes take place as a tadpole becomes a frog, and does this metamorphosis affect the DNA in any way? I would appreciate ...
1
vote
0answers
37 views

How many mitotic divisions do haploid cells undergo before fertilization?

Background This question is about human physiology and gametogenesis. A spermatozoid is not necessarily the direct "offspring" of diploid cell. Stated differently, a spermatozoid cell can be the ...
-2
votes
1answer
62 views

Our muscles give us the ability to move our arms but…? [closed]

I have a strange question, but let me tell you something first. If you think of this carefully, then you realize something, please try this right now: Contract your muscles only so that your arms ...
1
vote
1answer
15 views

Difference between pulse and blood pressure

I'm a very naive and biologically illiterate person, and from what I've read on the internet I'm not really sure I understand the difference between pulse and ...
-5
votes
1answer
45 views

Why do fingers swell during cold winters?

When exercising, tissue in the hands may swell. This may be caused by the muscles generating heat, which leads to blood being pushed to the vessels closest to the surface of your body to dissipate the ...
3
votes
1answer
52 views

Human bone density and Brown Bear bone density?

It is stated on this website that the density of a Grizzly bear bone is ten times our own. And since I am not into biology at all, I am confused as I don't understand the meaning of bone density here. ...
1
vote
0answers
35 views

Why do fingers swell during winters? [closed]

Why do fingers swell during winters (of temperature 5-15 degree celsius)? During winters mine and many others's fingers swell. is it due to blood circulation or what?
2
votes
1answer
29 views

Help reading gene markers

I'm sorry if "gene markers" is not the correct word. An edit could be appreciated but I don't study in an English speaking country unfortunately. Question overview: In a family, there is a genetic, ...
2
votes
2answers
31 views

Help reading chromatogram

A genetic variation is found in this chromatogram: It says that the "reference sequence" is the top line and that I can use the general genetic code to find the reading frame. I can see that there ...
4
votes
0answers
43 views

Why do we get tired

At the end of a day full of work, it is general for people that their eyelids start to feel heavy. Laziness takes over and we begin to yawn. We all know that we're tired at that time, but why people ...
5
votes
1answer
53 views

What's a mouth ulcer/canker sore “made of”, and why do they develop?

Mouth ulcers are red/white rings with a crater. They are sore and last for 7-10 days. What I want to know is what they are 'made of' - i.e., what is the ring filled with, and why is the centre crater ...
2
votes
0answers
23 views

The ring formation of ringworm

I know ringworm is caused by a fungus on the skin, nails or scalp but what causes the rash to form as a ring instead of like a normal spread out rash?
4
votes
0answers
22 views

Do blood glucose “spikes” contribute to insulin resistance, or is prolonged elevation required?

There's increasing public discussion about the health risks of chronic insulin resistance* (IR). In many cases there's a focus on high glycemic index foods that "spike" your blood sugar, which implies ...
0
votes
1answer
90 views

Why should or shouldn't we allow the human body to take its natural course? [closed]

For example, when you are sick but don't feel thirsty, this could be due to baroreceptor reflex that is attempting to readjust salt and water balancing. Why shouldn't a patient be left thirsty and ...
7
votes
1answer
337 views

Why do people feel pleasure when using roller coasters / centrifuges?

The feeling when using an amusement park unit is usually a pleasure. Why is it not a pain instead? Are there advantages, from an evolutionary point of view, in loving this potentially dangerous ...
3
votes
1answer
103 views

Why do people in the scientific community use terminology such as renal, hepatic, cardiac instead of kidney, liver and heart? [closed]

Why is there the need to map these everyday words into another set of words, it seems to complicate matters. Is it done mostly out of tradition or is there some logical basis to it?
0
votes
1answer
36 views

Survival with only water but no food [duplicate]

How long can the average, healthy adult human survive with only water?
1
vote
2answers
33 views

Can leukopenia in a person with an otherwise normal immune system lead to non-infectious diseases in the long-term?

If a person has developed leukopenia as a side-effect of long-term use of anti-convulsant medications and his/her immune system appears normal otherwise (does not get infections any more often than a ...
4
votes
1answer
36 views

How can human infants express chymosin with only a pseudogene at their disposal?

I read on the Wikipedia article about Chymosin http://en.m.wikipedia.org/wiki/Chymosin It stated that chymosin is produced by gastric chief cell in human infants. But it also stated that human only ...
0
votes
1answer
17 views

Beta oxidation of saturated fats

In my text book there is an example of a 18 carbon long fat and it says that it can run 8 laps of oxidation. I don't understand why it doesn't run 9? 2 are removed each cycle? Thanks.
1
vote
1answer
38 views

Why use creatine phosphate?

We use creatine phosphate as an energy storage to resupply ADP with a phosphate group as our muscle cells only contain about 2-5 mM ATP. But why doesn't the muscle cells just keep 20-30 mM ATP instead ...
0
votes
0answers
25 views

Why doesn't the body optimize how many fatty acids it burns?

Ketone bodies are produced due to an excess of fatty acids being burned (accumulation of acetyl-CoA) so my question is: Why doesn't the body simply regulate how many fats it burns so it doesn't have ...
2
votes
1answer
30 views

How are ketone bodies used?

While searching for literature on ketone bodies, I can only seem to find how they are synthesized, but not how they are broken down. I'm looking for the series of events with enzyme names and ...
9
votes
1answer
279 views

Why gluconeogenesis?

It seems quite pointless to me. Why would I want to use energy to create a molecule that I can then use again for less energy? It seems only to serve as a complete waste of energy to me? Can someone ...
2
votes
1answer
26 views

NADH shuttles - Why cytosol?

Why is the malate-aspartate and the glycerol-3-phosphate shuttles located in the cytosol and intermembrane space? The krebs cycle happens in the matrix so why wouldn't they push electrons from the ...
2
votes
0answers
20 views

Cholesterol's role in lipid uptake

I'm studying the digestion of fats and I understand that our dietary fats mostly consist of triglycerides. We absorb the fats and eventually they end up in a muscle/adipose cell for storage (as ...
13
votes
1answer
61 views

Why does mint oil feel cold on the skin?

When putting (japanese) mintoil on the skin it produces a cool feeling. You can experience this, when adding it to your bath or using a spray with mint oil on your skin. The cool feeling occures ...
5
votes
1answer
144 views

What is the maximum number of babies a human woman can have?

I know you could divide the female fertility period (~40 years, right?) by 9 months which would give something like ~50 kids (with no multiple kids per pregnancy). The limiting factor in this ...
1
vote
1answer
36 views

Myopia as a microscopic superpower?

A few years back my Physics professor made a joke that his Myopia/Nearsightedness gave him a "superpower" that allowed him to see close objects much more clearly than someone with typical eyesight. ...
9
votes
1answer
119 views

Circadian Clock During a Flight

I am interested to know how does our Circadian Clock respond (and its resultant changes if any) when we are traveling across Time Zones? UPDATE 24th April I am reopening this question as the ...
3
votes
1answer
103 views

Can Leptospirosis be spread through human urine

I am wondering if Leptospirosis can be spread via the urine of an infected human individual. All of the sources I have been able to find on the web have stated that the disease is primarily spread ...
0
votes
2answers
74 views

Difficulties understanding a pathway [closed]

I am not a biologist and I would love to understand what is going on with this pathway. I went to the description but it's still complicated, and I couldn't follow. Can someone please help me with it? ...
1
vote
1answer
24 views

Pasteurization and Bioavailability of Antioxidants in Beet Juice

What are the effects of pasteurization on the antioxidants found in beet juice ? Does the process render most of the beneficial nutrients (betaine) useless and make them unable for the body to process ...
3
votes
1answer
60 views

What is the impact of stress on the human body?

Can stress trigger any changes in the human body? I'd like to know more about things less commonly known than, for example: sweating and tiredness. What are the long term risks of chronic stress? Do ...
7
votes
2answers
119 views

Is it possible for a human to wake up in a wrong way?

There's an old folk saying that goes like "He got out of bed on a wrong foot" - to indicate that the person's day is going poorly because of the way that person woke up. Is it is possible for a human ...
0
votes
1answer
29 views

What would happen if we had a device that produced oxygen inside of our lungs? [closed]

Hypothetically speaking, suppose there is a device that produces a limitless supply of oxygen. The device is inhaled by a human and is resting inside the (a) lung. What would hypothetically happen if ...
8
votes
2answers
126 views

Should we induce fever to assist healing?

I am currently reading "The Fundamentals of Anatomy Physiology" 10th edition, and have found it an incredibly interesting book. I have just been reading about the lymphatic system, and the various ...
1
vote
2answers
67 views

How does the body respond to blood donation; are there any possible risks?

Can blood donation cause any harm to the donor? I have been told so, but cannot find any references supporting this claim. I have also learned that our body will replace the lost fluids within 24 ...