Questions tagged [physiology]
The study of the normal function of living organisms and their anatomical parts and the means by which their normal functioning is achieved.
168
questions with no upvoted or accepted answers
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Do sharks fart?
My son is 5 and I'm encouraging him to be curious and ask questions of the world around him.
He asked if sharks fart and how does it smell? He feels that it would smell of fish and be disgusting.
He ...
5
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0answers
93 views
How is atrophied muscle different than normal muscle in a chemical or biological way?
I am a writer with a question for a story I'm working on. In it, the character suffers from muscle atrophy due to spinal damage. So that I can portray this accurately, what would cause this type of ...
4
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74 views
Optimal carbon dioxide concentration range for the human body
Previously I had thought the maximum concentration of CO2 for human health to be given by the ‘Pettenkofer CO2 level’ with a maximum of 1000 ppm.
But according to this post
a growing body of ...
4
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40 views
Are there specific theories as to what causes cold[-water] muscle cramps?
The field of what might cause cramps is quite contested with a lot of controversy around the heat/dehydration cramps, but I find it surprising that no specific theories appear to have been proposed (...
4
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67 views
Is there a biological determinant for right- or left-handedness?
When I was very young, I was sent by parents to examination where I was told both my hands are dominant in the same way. My parents preferred to make my life easier and chose to focus on my right hand ...
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119 views
Can you "fight" a coma or serious illness?
In an article about the latest earthquake to strike Mexico, I read that a rescuer said to someone in a gurney, "Fight for your life, please!"
I've seen similar things in TV shows and movies where a ...
4
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239 views
Are there predefined implantation sites in mammalian uterus?
I do surgical embryo transfer of genetically modified (microinjected) mouse embryos (at 1 or 2 cell stage). As most of the constructs are new, we expect that it may affect birth rate. In case there ...
4
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64 views
What could be the reason for the large difference between sodium and potassium blood concentrations?
Reference values for sodium and potassium concentrations in blood tests are usually in the range of 135-145 mEq/L and 3.5-5.1 mEq/L, respectively.
My question is what could be the reason for this (...
4
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253 views
What is the essence of difference of how different chemicals affect the same receptor?
It is known that various chemicals can bind to the same receptor type, producing different effects. Be these chemicals agonists or antagonists, there are more variations in how they influence the ...
4
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1answer
537 views
What is the mechanism behind ventilatory acclimatization?
In my respiratory physiology lectures, my professor explained that hypoxia-induced hyperventilation occurs in 2 stages when people try to acclimate at high altitudes. My question is about the long-...
4
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2answers
931 views
What is the effect of persistent hypothermia on cardiac performance?
I define persistent hypothermia in this thread about the mechanisms of persistent hypothermia.
The Graph of Katzung et al. in Pharmacology about Heart Failure:
I am thinking which parts here are ...
3
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0answers
78 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 ...
3
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23 views
Hodgkin-Huxley Model and Propagation of Action Potential
I'm studying Hodgkin-Huxley model of action potential, and I have some confusion.
In the well-stated HH model, we have time constants for each ion currents, described as the reciprocal of the sum of ...
3
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0answers
280 views
What is blood pH for different animals?
So we all know that humans average blood pH is 7.4. But is it the same for the animals?
I need examples of animals with the same blood pH as humans and the ones with different blood pH.
I guess dogs ...
3
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0answers
79 views
How does isometric contraction work?
What exactly happens to myosin during isometric contraction? I suspect that either myosin heads just "freeze" in the middle of crossbridge cycle, or go through full crossbridge cycles repeatedly at ...
3
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294 views
Which mammal produces the most milk?
I'm searching for the mammal species that can produce the most milk during lactation. I Googled it, but it says dairy cattle which biologically speaking is not right answer, because a baby whale can ...
3
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0answers
319 views
Affinity for oxygen and carbon dioxide in animals
I'm currently reading Treatise on Invertebrate Paleontology (A) and don't understand the following fragment:
The affinity for oxygen in lower animals is many times that in higher ones, whereas ...
3
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0answers
710 views
Physiological effects of electrical shocks on human body depending on the energy
When discussing safety of electricity, one usually considers a constant DC or AC current with constant amplitude over a longer time. It is easy to find tables in books or in the web which lists ...
3
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0answers
323 views
What is the lifespan of Skeletal Muscle Cells?
I have read that skeletal muscle cells cannot multiply and are generally not created after early development. However, I have also read that they have a "lifespan" of 10-15 years. Could this lifespan ...
3
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79 views
What is the evidence that mammals are unable to process excess sodium chloride?
I grew up hearing the mantra
excess salt causes heart disease
I had a vague understanding that it caused deposits in the body or something. Now that I give it more thought - I come up with three ...
3
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0answers
162 views
What happens to the cell during post-hypothermia?
A friend of mine said that the cell membrane somehow changes after rewarming from hypothermia and that the body does not recognize it's own cells, thus leads the immune system to attack it self. Is ...
3
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0answers
318 views
How does glucose delivered intraperitoneal (i.p.) get into the peripheral circulation?
Intraperitoneal delivery of drugs or fluids is something that occurs much more frequently in veterinary medicine than clinical medicine. In veterinary medicine or scientific studies using animals, ...
3
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0answers
1k views
Skin extra sensitive to heat after burn
I just got my finger burnt (first degree burn $\Rightarrow$ I didn't even bother to bear the wound). It didn't hurt much, even when I pressed the wound.
However, when exposed to heat (hot water, but ...
3
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0answers
1k views
Which types of blood vessels can regenerate in humans/mammals?
Which types of blood vessels can regenerate in humans/mammals?
From what I understand, arteries and arterioles can be created later in life, while this is not necessarily the case with veins. However ...
3
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76 views
Are small CO₂ concentrations devastating to certain cognitive tasks?
A new study shows strong effects of what should be a negligible CO2 concentration.
The paper "Is CO2 an Indoor Pollutant? Direct Effects of Low-to-Moderate CO2 Concentrations on Human Decision-Making ...
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125 views
A day in Beijing is like smoking Only one sixth of a cigarette
This is the title of this blog post followed by this other good post.
I'm particularly anti-tobacco-smoke, at the point of not always considering other pollution, and this article shows how this kind ...
3
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0answers
77 views
Physiological or molecular difference before and after sleep?
I know that the details of the process of sleep aren't entirely known, but have always wondered why I feel rested after sleep.
Biologically, what differences can be directly observed in the human ...
2
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0answers
43 views
Is it incorrect to assume alveoli as spherical and distinct, especially when analysing lung inflation/deflation?
I have recently read the paper "Laplace’s Law and the Alveolus: A Misconception of Anatomy and a Misapplication of Physics". To summarise it, here is a section from its abstract:
The ...
2
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0answers
44 views
Why doesn't the concentration of one ion affect the concentration gradient of another ion across a plasma membrane?
In the initial stages, some ion channels across the plasma membrane open to allow for ions to flow down their concentration gradient into or out of the cell. I understand that each ion's overall ...
2
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0answers
32 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....
2
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0answers
46 views
Does The Sympathetic Nervous System Increase or Decrease Urination?
According to my book:
Sympathetic nervous system stimulation, leads to the release of Norepinephrine(Noradrenaline), priming the body for the "Fight or Flight" response.
It is also stated ...
2
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0answers
34 views
Summation on muscles
I am learning myology and encountered 2 problems in tetanus and summation:
Unfused tetanus is just a continual summation of twitches if I am not mistaken. However, is it a MUST for summation / ...
2
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0answers
37 views
Why largest cats so much larger than canids?
It is striking to me that there is no dog-like creature larger than a wolf while there are at least two species, tigers and lions, many (at least twice and probably 3 or 4) times the size of the ...
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21 views
Can Chilopoda "vocalize" or produce sound for the express purpose of communication, as opposed to sound as a byproduct of other movements?
Is there any species of Chilopoda that can "vocalize" or or otherwise produce sound for the express purpose of communication, as opposed to sounds it might create as a byproduct of other movements ...
2
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0answers
60 views
Hematuria due to Nitric Oxide
Drug interactions between properly dosed NO and other medications are not expected, but side effects may include noisy breathing, hematuria, or possibly atelectasis. (pg.no:577; Goodman and Gilman ...
2
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0answers
284 views
What do Caucasians see in their peripheral vision, and how is their visual field?
I am an Asian who has no idea how much of their nose Caucasians (especially for those with extremely deep-set eyes, very prominent and low brow ridges, and high noses like Brian Shimansky or Rishi ...
2
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0answers
48 views
Does dreaming have any physiological impact on our body?
Personally speaking, when I wake up after a really good dream, I feel really happy, similar to how I would feel if something good has happened in reality. This makes me wonder if we are actually going ...
2
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0answers
184 views
Alpha-gamma co-activation
I am having trouble visualizing/grasping the necessity of alpha-gamma co-activation. My understanding is the following:
When an external load causes stretching of the sensory muscle spindles, the 1a ...
2
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0answers
50 views
What is the biggest structure in nature for structural coloration?
I'm interested in the actual sizes behind structural coloration: I find it fascinating and I think it may have a couple very nice applications.
The problem is I couldn't find anything but vague ...
2
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0answers
38 views
How urination prior to blood test may give error?
Source: Textbook of Practical Physiology, 4th Edition
according to it urination within 30 minutes is a precollection factor that may alter the results of blood test.
I am unable to comprehend how ...
2
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0answers
308 views
Why are many unable to defecate and urinate simultaneously?
Many people (including myself) do not defecate and urinate simultaneously, but rather in succession. Only after one is completed, the other commences. I have noticed this in myself, but the internet ...
2
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0answers
128 views
Origin of melatonin: oxidative stress defense OR circadian rhythm?
Question
Which functional role of melatonin came first?
Regulation of the circadian rhythm
Defense against oxidative stress
Other
Background
I was well aware of the important role melatonin plays ...
2
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0answers
89 views
How much do arteries expand during pulse?
Arteries expand during a pulse. The amount of expansion may differ from artery to artery. How much do arteries expand? I understand it might be a range. Inform the same. Even values specific to some ...
2
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0answers
42 views
Does human skeletal muscle fascia grow new additional collagen in response to increases in skeletal muscle size?
For example, if a human skeletal muscle is growing repeatedly due to periodic weightlifting, does the fascia eventually respond to the increasing volume by growing more quantities of collagen or other ...
2
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0answers
213 views
Why does fetal distress (hypoxia) cause bradycardia?
In a non stress test performed in the labor room, fetal bradycardia is a danger sign indicating fetal distress (hypoxia).
Why does fetal hypoxia cause bradycardia while hypoxia in adults cause ...
2
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0answers
63 views
Which organisms require the least fluctuation in ambient temperature?
Note that I am NOT asking "which organism can survive the most extreme temperatures." Many extremophiles like the tardigrade can survives extreme heat, but also extreme cold. Many heat adapted animals ...
2
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0answers
2k views
How to tell if something is an organ or apparatus?
An apparatus is defined as
Physiology. a group of structurally different organs working together in the performance of a particular function.
An organ is defined as:
Biology. a grouping of ...
2
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0answers
3k views
How long can an infant human hold his/her breath as part of the "dive reflex"?
Various other questions on the site have talked about the Diving Reflex, which is also known as the Mammalian Diving Reflex. This reflex is observed in mammals of various species, but also in human ...
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0answers
399 views
Would a transparent iris serve its purpose?
The function of the iris is to regulate the aperture of the pupil. How does the iris obstruct light? Is it due to the pigment present in it? Or is it just due to the sheer presence of it?
I am doing ...
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0answers
42 views
How do organoarsenics improve digestion efficiency in poultry?
It struck me as very surprising that these organoarsenic compound with structure looking not very compatible with living system is widely used as food additive to increase weight gain and improve food ...
