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Questions tagged [human-physiology]

For questions on the biochemical, physical, and mechanical functioning of humans in good health including their organs and cells.

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What is the Speed limit of thinking or doing other things?

Is there something like speed limit of thinking or doing something physically? I mean when babies born, they learn everything with copying from other humans. Humans are live in some standard interval ...
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21 views

What is the significance of different types of papillae present on tongue?

Fungiform, Circumvallate, Filiform, Foliate Papillae are present on the surface of the tongue. They have a role in increasing surface area for taste buds that can be accommodated on the tongue. Each ...
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1answer
26 views

Why does histamine cause bronchoconstriction?

What purpose does histamine-caused constriction serve in lungs during allergies and such, since it's vasodilator in other parts of body. Wouldn't it be more practical to vasodilate lungs so that white ...
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1answer
52 views

How are testosterone levels distributed among men and women?

Wikipedia tells me that men have 7 to 8 time higher levels of testosterone than women, on average. Since the hormone is linked with performance in certain athletic events, my hypothesis, which I ...
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2answers
44 views

Is it impossible to increase skeletal bone mass, as opposed to just bone density? [closed]

I've heard exercise and resistance/strength training increases the density, but doesn't increase mass. So basically, experimentally or theoretically possible at least, can modern science do this/is it ...
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2answers
36 views

After how many hours water drunk is expelled from the body?

If one drinks a liter of water at 7 am when (in what span) will that water be eliminated through uresis? Is that process influenced by any factors such as empty stomach, sleep or other?
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1answer
41 views

Coronary circulation

It is said that the coronary artery that gives the posterior descending artery(PDA) determines if the heart is right dominant(most cases) or left dominant. Is there any reason to this? Why PDA?
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8 views

Can disorders involving involuntary muscle twitches and spasms have a hypertrophic and increased residual muscle tension effect?

Meaning disorders specifically like myokymia, myoclonus (positive and negative) and fasciculations. From the section of the literature I've seen, sometimes passing mentions are made when the disorder ...
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25 views

Why different people have different Sympathetic reaction

We all know that sympathetic mechanism is similiar in humans . Why people react differently for example one may ran after seeing a lion while other may keep standing or may shout without escaping ?
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1answer
53 views

Is it correct that the nicotinic acetylcholine receptor has nothing to do with Dopamin?

As I know Dopamine is almost exclusively produced via metabotropic receptors, is it possible for a nicotinic ACH receptor to influence a dopamineric neuron? Can a nicotinic ACH receptor cause a ...
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1answer
21 views

Can motor neurons in the brain stem start movements?

Supposedly (consciouss) movement is started in the cerebral cortex. But some time ago I've read a research which stated it might be possible some movements (not specified which ones, probably mean ...
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1answer
49 views

Does every protein starts with Methionine amino acid [duplicate]

During process of protein synthesis we need AUG Codon to start translation .As we know this codon codes for Methionine amino acid so can we say that every protein starts with Methionine amino acid ?
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547 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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In oscillometric blood pressure measurement, why do we assume that highest oscillations correspond with mean arterial pressure?

As far as I've seen, the point on the oscillometric curve where there are greatest oscillations represents the mean arterial pressure (MAP). My question is - why? What is the logic behind this ...
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30 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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1answer
68 views

Is it possible for human beings to feed through the nose?

There is a prediction on a futurology site that food can be eaten by inhalation https://2050.earth/predictions/smell-can-feed-you Although aerosol foods do exist they are still eaten by the mouth. ...
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1answer
54 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
35 views

How is fructose absorbed into the body

I’m finding contradicting methods of Fructose transfer to blood page no 264(10)One of which saYs fructose is absorbed by simple diffusion And another sources like this say that fructose is ...
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2answers
141 views

Why is urea not converted to ammonia in the body?

After the liver processes metabolites to produce urea and other by-products, these travel in the blood to the heart, then they are oxygenated, and some travel through the renal artery to the kidneys. ...
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15 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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73 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 ...
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1answer
45 views

human body in an environment where temperature is above body temperature

What would happen if humans were to live in an environment where the temperature is above the body temperature? Does the human body have a mechanism to cool the body? When the surrounding ...
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0answers
56 views

Does our brain use up more ATP after smoking cannabis?

kind of an amateur here. If the firing of the neurons' signals uses up some ATP, and smoking cannabis makes them fire off more quickly, do our brains use up more ATP to sustain that rapid firing?
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2answers
68 views

Reaction of the body to heat

In massage school we are being taught hydrotherapy -- applying cold and heat to specific areas. It says that when applying cold, first the body goes through vasoconstriction, and then later ...
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1answer
98 views

Is there any way bicondylar/bigonial, bizygomatic or bitemporal breadth can change in adults?

Without cosmetic surgery or etc., are there any cases/example wherein a human adult has had a change in significance regarding these regions of the face? I have seen many anecdotes where people have ...
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1answer
50 views

How deep could a human swim with SCUBA apparatus?

Using normal SCUBA apparatus and wet suit, how much pressure can the human body withstand? This is assuming that they descend as gradually as necessary for their body to make adjustments. What would ...
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Contracting mouth muscles as reaction to taking in specific food items

When eating very specific food items, especially confectionery like (salty) liquorice, (it feels as if) the muscles of my mouth contract, right when it hits my tongue. Does anyone know why this ...
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1answer
106 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 ...
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0answers
33 views

human sight at 1000x while looking into the mirror [closed]

I noticed that my eyeballs have the ability to see in what appears to be 1000x. Setting the conditions: Look into a mirror while in a well lit room. (for me the lighting in my living room as opposed ...
2
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1answer
29 views

Effect of the same caloric intake of different macronutrients on body weight

To gain weight, caloric intake > caloric expenditure. To lose weight, caloric intake < caloric expenditure. But what is the effect of the type of macronutrient ? That is to say : does the same ...
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3answers
117 views

Why do our bodies maintain blood pressure but not the flow rate?

This might be a silly question but i'm not not clear I'm always told that blood pressure is homeostatic parameter and can't not be changed but isn't what important is the flow rate to the organs? ...
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1answer
105 views

Where would vegetarians/vegans get a substitute of hemo/myoglobin from?

As far as I understand, there is a difference in the iron absorbed from meat than from other sources like grains and vegetables. If this is the case, is it possible that not ingesting the hemoglobin ...
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22 views

Do the normal in vivo spatial growth controls, not apply to hair follicles?

The common changes in hair growth are linked to changes in the size enlarging anagen follicles achieve. According to the accepted science in tissue physiology, the in vivo growth of the anagen ...
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65 views

Which major salivary gland secretes maximum amount of salivary amylase and which one secretes maximum amount of Saliva

Actually I was studying about digestion and got this confusion about which gland(Parotid or Sub-mandibulary) secretes maximum amount of saliva and which one maximum amount of Salivary Amylase. Also,...
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56 views

Is there any evidence that Vitamin K-2 megadoses increase bicondylar, bizygomatic or bitemporal breadth in humans?

Can megadosing or supraphysiological dosing of Vitamin K2 (MK4; Menatetrenone) over prolonged periods of time cause an adult's bicondylar breadth, bizygomatic breadth or bitemporal breadth to grow ...
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How is the “sampling time” of the human visual system influenced by things like hormones, metabolism, or our circadian rhythm?

For example people experience time passing slower when they are in a adrenalin rush. What is the mechanism behind it, and where can I read more about it ?
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Plasmatic anion gap or chloremia?

Since high anion gap metabolic acidosis is characterized by normal blood chloride levels and normal anion gap metabolic acidosis is characterized by elevated blood chloride levels, why it is necessary ...
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36 views

High altitude rail travel

This question is primarily about human performance. I do know about hypoxia, hence this question. I'm busy designing a fictional region, currently in the 1930's. I have a railway line that climbs to ...
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26 views

What is the optimal time to implant embryo in uterus for in vitro fertilization?

What is the best time to implant an embryo in the uterus. I was under the impression that the earlier the better and more natural, but also if you wait until the blastocyst age, it may be better to ...
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1answer
60 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 ...
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1answer
50 views

Actual definition of cardiac output

Is cardiac output the amount of blood pumped by both ventricles in 1 minute or only by the left ventricle in 1 minute?
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1answer
62 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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2answers
557 views

Wim Hof Method claims Alkaline Blood is Good. Contradictions? Counterproof?

The Wim Hof Method claims, that it is beneficial to have alkaline blood. On the other site there is the medical claim that if the pH-value is not within the range of 7.36 – 7.42, enzyms are ...
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1answer
62 views

What type of movement is “spontaneous movement” if it isnt reflex movement and it isnt purposive movement?

According to Spontaneous and induced fetal activity Spontaneous motor activity of the foetus depends significantly ot the foetal age; during the period between the 12th and 16th week it was ...
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1answer
106 views

What is meant with “the chest wall and lungs are coupled together”?

Since the lung and chest are elastic, we can represent them with springs. Under normal conditions, they are coupled together: the “lung” springs are stretched and the “chest” springs are compressed. ...
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2answers
95 views

Why is the resting membrane potential of excitable tissue not affected by the extracellular sodium concentration?

I know that the resting membrane potential for excitable tissue (eg, nerve) is primarily determined by the electronegative difference between the inside and the outside of the membrane for potassium ...
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1answer
43 views

How efficiently does the human body convert the energy stored in fat into kinetic energy?

I read that one gram fat contains 9 kcal energy. There are many tables around claiming that x type of exercise for t duration ...
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1answer
51 views

Is there any evidence of causation for breathing rate to affect blood pressure in a human?

I did some research and trials, and with 5 trials for a normal heart rate and 5 done 45 seconds into breath holding, the results came back showing that my heart rate of 116/65 mmHg increased to 138/90 ...
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1answer
45 views

Can some colours be processed faster/more accurately than others?

Is the human visual / motor system able to track, and move in response to, objects of certain colours more quickly and reliably than for others? By more reliably, I mean with greater accuracy in ...
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Why do I feel nauseous at the sight of blood, despite not being afraid of it?

Every time I ask google this question, all it spits at me is info on blood phobias ^-^; basically, I've always been hugely interested in morbid stuff, but I noticed that I always feel sick when ...