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.

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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 ...
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97 views

Do brain consume more energy when stressed or Anxious

When a person is anxious or stressed or suffering from chronic depression, it is observed that the person is usually tired. Is there there a connection between fatigue and racing thoughts/obsessions. ...
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91 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 ...
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64 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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34 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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63 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 ...
4
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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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1answer
1k views

What's so special about Chassaignac tubercle?

1-How does massaging of carotid artery at chassaignac tubercle( anterior tubercle of transverse process of C6 vertebra ) can relieve the symptoms of Supraventricular Tachycardia? My attempt: I think ...
4
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63 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 (...
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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
522 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-...
3
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200 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 ...
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75 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 ...
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236 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 ...
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317 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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702 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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314 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 ...
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78 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 ...
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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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313 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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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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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 ...
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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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124 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 ...
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76 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 ...
3
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2answers
919 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 ...
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32 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 ...
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35 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 ...
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30 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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38 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 ...
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31 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 / ...
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34 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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20 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 ...
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230 views

Why does K+ going out of the cell cause hyperpolarization?

I'm really confused by how the terms Hyperpolarization and Depolarization are used in Cell biology and hope somebody can enlighten me hopefully. Here's what they mean for me so far: Depolarization ...
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55 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 ...
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247 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 ...
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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 ...
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177 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 ...
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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 ...
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37 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 ...
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296 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 ...
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0answers
127 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 ...
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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 ...
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39 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 ...
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0answers
206 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 ...
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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 ...
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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 ...
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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
381 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 ...