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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Fish performing Backstroke

Can Fish perform Backstroke similar to Humans? Can Fish swim only in forward motion and not reverse? Can there be any fish species which can perform backstroke? If No, Why?
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1 vote
1 answer
29 views

Entry of particulate pollutants into the nasal cavity

NCERT Chemistry of Grade XII (India) writes Particulate pollutants bigger than 5 microns are likely to lodge into the nasal passage, whereas particles about 10 microns enter the lungs easily. I'm ...
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1 vote
3 answers
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How can you diagnose albinism in a naturally light-colored person? [closed]

Not all albinos have white hair. There is a type of albinism where the affected person has light yellow hair and the skin color can be the same as a normal North European person. How can you diagnose ...
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6 votes
1 answer
50 views

What Produces the Postive Potenial in the lumen of the thick ascending loop of Henle?

In the Thick Ascending Loop of Henle, Paracellular diffusion of certain Solutes like magnesium and calcium takes place. Such diffusion is a result of the positive lumen potential. Looking at the image ...
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4 votes
0 answers
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Which single substance among Potassium and Phosphate has the greatest osmotic activity in the Intracellular fluid?

My physiology textbook mentions that potassium has the greatest concentration ( 155 mEq/L ) in the Intracellular fluid and that I thought would make it the most osmotically active but the answer given ...
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4 votes
1 answer
89 views

How long does it take for a new muscle fiber to be connected to motor neuron?

When new muscle fibers are formed through hypertrophy, how long does it take for motor neurons to connect to the new muscle cells in order to be able to control them? After taking a break from ...
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3 votes
0 answers
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Hypothalamus and posterior pituitary gland in ADH production

Concerning the role of hypothalamus and the posterior pituitary gland in osmoregulation and especially when water potential of the blood is low, When the osmoreceptors in the hypothalamus detect the ...
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1 vote
0 answers
27 views

Phenotype of a possible gene mutation

I have noticed multiple cases where patients had similar body characteristics : decreased ability to gain weight (slim) they are capable of sleep only 6 hours or less with normal functioning (...
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At what cold temperature at thermoreceptors human feel pain (e.g. in fingers)?

I've tried web search but have not found that specific answer. As far as I know at least some people feel pain (e.g. in fingers) when exposed to cold for prolonged amounts of time. E.g. here ...
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Medical Physiology

I've come across the topic of the influence of inhaled ammonia (caustic ammonia) on breathing rate and some cardiovascular changes. All of this stuff is thought to be mediated through the fifth ...
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0 votes
0 answers
78 views

Why do people make "aaagh" noises when they make an effort (e.g. trying to hit a ball hard)?

I'm referring to, for instance, grunting in tennis. It refers to how many tennis players make loud "aaagh" noises when hitting a ball. In daily life, people often also do this when trying to ...
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1 vote
1 answer
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What are the roles of ATP and ADP in muscle contraction?

I've always known that the hydrolysis of ATP generates ADP, P, and energy, so I'd assume that if energy is necessary in a given process, ATP hydrolysis should occur (or another exothermic process). ...
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-3 votes
1 answer
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Why is it easier to spin in one direction than in the other?

When I use a rotating floor disk to spin fast (while standing), I notice that I can keep balance much easier and rotate much faster in clockwise direction rather than in counterclockwise direction. I ...
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6 votes
1 answer
194 views

How does increased resistance to flow decrease blood pressure?

I have recently encountered this question: Waldenström's macroglobulinemia is a condition which causes increased blood viscosity due to high protein content in the blood. How would Waldenström's ...
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1 vote
0 answers
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How does medicine work? [closed]

Take aromatase inhibitors for example. In order for a molecule to stop the enzyme aromatase from converting androgens into estrogens, it must meet 6 criteria: Not get broken down by the acidity or ...
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5 votes
2 answers
464 views

Pathogens vs Microbes and the Immune System

I hope my question isn't too basic or silly. I am currently learning about infectious diseases in Year 11 Biology right now, and I'm stuck at the concept of pathogens and micro-organisms. Whenever I ...
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2 votes
0 answers
25 views

Vitamin B12 deficiency Megaloblastic anemic

I have two doubts regarding Megaloblastic anemia which shakes my mind (1) first is- I know that vitamin B12 is required for thymidine synthesis which is further required for DNA synthesis and so if ...
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1 vote
0 answers
347 views

What causes metallic tastes when you receive electric shocks

Whenever I receive small electric charges (most often by, e.g. touching the jack of a plugged in charging cable, or the casing of a charging Apple device), I experience a very distinctive taste in my ...
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Is it true that the cells of large and small intestines cannot secrete digestive enzymes into the GI tract in the same way as the stomach does?

When I read about the intestines, I usually see the word 'release' instead of 'secretion'. Secretions of the small intestine, for example, occur from two types of histological structures: Brunners ...
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3 votes
0 answers
119 views

Why does (insulin induced) hypoglycemia stimulate ADH secretion?

Intuitively, I understand that ADH (Anti Diuretic Hormone) is responsible for maintaining osmolarity, and increased serum osmolarity is a stimulatory factor for its release-- ADH increases water ...
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0 answers
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Is it correct that Afterload=Preload+Active tension?

Preload causes development of equal amount of passive tension which leads to distension of heart muscle. Further, afterload causes development of active tension or cross bridge formation which ...
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-2 votes
1 answer
34 views

why are dizygotic twins genetically dissimilar

I am a high school student and I am a little confused in a topic related to dizygotic twins, I get to know that dizygotic twins are genetically dissimilar because they are formed as a result of two ...
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1 vote
1 answer
110 views

Why is only the donor's antigen seen during a blood transfusion?

I am a high school student and I am a little confused that why only donor's antigen matters during blood transfusion? for e.g if the donor's blood is O- so it means that it will antibodies against all ...
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-3 votes
1 answer
40 views

Why do nerve impulses utilize potassium and sodium instead of other Group 1 metals?

Rubidium and potassium are very similar, yet the body utilizes sodium and potassium for nerve impulses. Why is this the case? Why not any other element? Likewise, why not Lithium? I've read a research ...
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0 votes
0 answers
46 views

Why does bicep activate during dead hang?

Hanging from a bar causes my bicep to feel much harder than when simply holding my arm straight above my head relaxed, without a bar. This was slightly surprising to me: I used to assume that since ...
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2 votes
0 answers
93 views

Type B Nerve fibres cause exactly what kind of autonomic sensation to the preganglionic neurons?

Ganong's Review of Medical Physiology (25th ed) presents the Erlanger and Gasser classification of mammalian Nerve Fibres as such: Type B Fibres are concerned with Preganglionic autonomic sensations, ...
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4 votes
1 answer
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How is the renal osmotic gradient maintained even though the blood osmolarity changes?

I am a high school student and I am a little confused in 2 things related to our urinary system: We know in our kidneys a countercurrent mechanism exists due to which there is a steep gradient of ...
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0 votes
2 answers
161 views

How do physics notions of fluid dynamics relate to pressure gradients in circulation?

I'm having a hard time comprehending why sometimes physiology notions seem to contradict each other and contradict physics teachings. More specifically I don't understand why aortic coarctation causes ...
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1 vote
1 answer
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How deep underwater could you breathe using a tube which breaks the surface until the water pressure makes it impossible to inhale air?

I'm struggling with a question asking how deep you can breathe underwater using a hollow reed before the water pressure makes it impossible to inhale. The question asked to use this data of maximal ...
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0 votes
1 answer
48 views

External "lungs" that process your blood the same as your real lungs do - would that stop your need for breathing?

So say your blood goes with a tube out of your body. In an external device all the chemical/biological magic would happen and it would be fed back to your body. Of course this doesn't exist (yet), but ...
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1 vote
1 answer
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Why can we eat salty food, but can't stomach salty water?

I know that too much sodium is bad for our health. However, it struck me as odd that we like to add salt to pasta sauce or other foods we eat, yet trying to drink salt water can bring on the gag ...
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0 votes
1 answer
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Which landmark paper first described the differentiation of T-cells?

T-cells are distinguished from B cells in part by their locus of differentiation/maturation (thymus). This is textbook knowledge, but I was wondering which particular person or people were responsible ...
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-3 votes
1 answer
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If you only ate fruits, vegetables or smoothies would you be able to skip drinking water?

If you only ate fruits, vegetables or smoothies would you be able to skip drinking water? I do not see some animals (like squirrels) drinking water daily (doesn't mean they don't have a water source) ...
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0 votes
1 answer
59 views

How do prodrugs exactly work? Are there multiple varieties of prodrugs?

I have been reading about a (new?) prodrug of LSD, 1CP-LSD, which is being synthesized in the body to LSD. However, I don't know how exactly. I read somewhere, that another prodrug of LSD, 1P-LSD was ...
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2 votes
1 answer
302 views

Does LSD "stay" in your fat storage and then "returns" back?

This rumor was told me by a very anti-drug person. A stance I agree with only lightly. The rumor was that when you take LSD, it stores itself in your fat storage, and then returns back in 3-6 months, ...
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0 votes
3 answers
96 views

Why aren't the twin organs like both the eyes, ears, hands and legs lying both sides of a human body identical?

Both the eyes are not identical in geometrical shape and size i.e. physical appearances of both the eyes of a person are different from each other. The same difference is observable in both the hands, ...
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4 votes
0 answers
35 views

How long does it take to reset sense of smell?

I have noticed that when I go on vacation for several days and then come back home, there is a distinctive, relatively mild paint smell in my apartment complex. However, under normal circumstances, ...
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0 votes
2 answers
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Why did the indigenous peoples of northern Asia and America not evolve the same physical characteristics as people of Nordic ancestry?

I was watching DW's documentary on the Arctic the other day, and I was struck by how the indigenous peoples of the far north seemed - visually speaking - to fit into two categories. On the one hand, ...
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1 vote
0 answers
31 views

Why do animals yawn? What is the biology behind it? [duplicate]

We yawn whenever we are tired and body needs rest. Why does the mouth open wide and a large volume of oxygen is inhaled?
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-3 votes
1 answer
55 views

What is the duration between: the moment we stop breathing and to body's and involuntary mucle movement? [closed]

I studied that if someone stops breathing by pressing their nostrils with fingers and start to starve without oxygen, the body will automatically cause the hands to leave the nostrils in a certain ...
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-1 votes
1 answer
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Plasmolysis and turgor pressures

I am a high school student and I am a little confused in plasmolysis, when we study plasmolysis, we say that at limiting plasmolysis, the turgor pressure OR pressure potential reduces to 0 what do we ...
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2 votes
0 answers
46 views

How would our vision be improved if our photoreceptors were not backwards?

I'm curious to how much better human eyesight would be if the nerves from our rods and cones were correctly placed behind the receptors? Are there any Animal Models with correctly placed ...
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0 answers
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Quantitative Physiology Textbooks Recommendations?

I am currently completing a 2nd year (UK) Mamamilian Physiology Module and a Neuroscience Module. However, my degree is also 40% Maths and Statistics. So in order to learn the content better, I am ...
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1 vote
1 answer
117 views

Why don't sodium Voltage Gated Channels open during Repolarization?

During Depolarization the Sodium VGC open when they receive the Threshold Stimulus. But when Repolarization occurs there comes a point when the cell interior has exactly the the same potential that it ...
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2 votes
1 answer
124 views

Is Pars intermedia functional in humans?

My textbook says, "Pars intermedia secretes only one hormone called melanocyte stimulating hormone (MSH)." My teacher says that in humans MSH is secreted by the anterior lobe because the ...
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2 votes
0 answers
33 views

How to estimate oxygen consumption of an average human during different activities?

I've tried to find some resource on the internet but had little luck. I'm looking to see if there's any data on average oxygen consumption of average to well trained humans during different activities....
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3 votes
1 answer
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Concept of mean systemic filling pressure

Mean circulatory filling pressure (MCFP) in humans was defined by Guyton as "the pressure that would be measured at all points in the entiere circulatory system if the heart were stopped suddenly ...
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0 votes
0 answers
102 views

What is "KK1 enzyme"?

In the book "The Kaizen Way" by Robert Maurer, I've read the following: When we’re sitting, our muscles go into a form of hibernation, causing our bodies to shut down the enzyme (called KK1)...
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2 votes
2 answers
182 views

Is water movement across cell membrane purely diffusive or it always requires channels?

If we see nephrons, in the descending part of Loop of Henle (LoH), water movement is allowed but solute movement is not. On the contrary, in ascending LoH, solute movement is allowed but not water. ...
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2 votes
0 answers
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What is the function of human Trypsin Inhibitor if trypsin is secreted in the inactive form of Trypsinogen? [closed]

I was reading about pancreatic digestive enzymes in a Textbook of Medical Physiology and I came across Trypsin Inhibitor. The text stated that: It is important that the proteolytic enzymes of the ...
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