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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21 views
A fictional species relying on Mechanoreception to hunt prey? [closed]
I'm a writer currently developing a military sci-fi concept and could use help working through some theoretical creature designs.
During early concepting, the actual specifics of the creature-threat ...
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0answers
30 views
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1answer
21 views
Is mucus significantly affected by the presence of ions?
In mucus, there is besides water and the mucins (Proteins for mucus), there are Ions like $Ca^{2+},Na^{+}$, etc. I have read that These Ions can Control the mucus swelling, i.e. the volume that the ...
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1answer
32 views
Why does higher venous volume increase atrial pressure?
If the cardiac output stays the same, then why does higher venous volume increase right atrial pressure? Shouldn't the flow rate be conserved (with a constant cardiac output) so that the venous return ...
29
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1answer
6k views
What is the human energy consumption by organ?
The human brain uses about 25% of the human body's metabolic energy. How are the other 75% spent, in terms of portioning to its various systems?
I thought this could be answered by a simple search, ...
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1answer
47 views
Mithradates - Developing immunity to poison?
According to legend, Mithridates studiously researched and examined all known toxins and experimented with potential remedies by using prisoners as his guinea pigs. Supposedly, Mithridates’ toils paid ...
3
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1answer
48 views
How does an electrical impulse spread in a muscle fiber spread from the motor end plate?
Does this impulse in skeletal muscle spread much in the same way it does in neurons, with an initial potential change that spreads to its immediate surroundings and is then re-amplified or is it the ...
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0answers
10 views
Does increasing contractility increase LV ESP?
I see many PV diagrams showing a negligible difference in the ESP when contractility increases. I'm wondering why this is the case, because if more blood is being pumped out into the aorta, the MAP ...
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1answer
74 views
Can all animals breathe manually?
Originally I was pondering about why we have the ability to breathe manually. I couldn't think of any tangible advantage, given that the body can develop mechanisms to regulate the rate of breathing ...
27
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3answers
6k views
Does animal blood, esp. human, really have similar salinity as ocean water, and does that prove anything about evolution?
It is an often-repeated claim that human, and in fact all animal blood is salty because we evolved from aquatic organisms, and that blood has a similar concentration of salts as ocean water, or at ...
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0answers
17 views
How much does Scolopendra gigantea weigh?
For somewhat understandable reasons, most references I've found related to "size" of Scolopendra gigantea, and centipedes in general, seem to focus on length. There are numerous sites, blogs, etc., ...
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0answers
21 views
How does the descending branch of the loop of Henle equilibrate concentration?
I'm learning physiology and I have a hard time figuring out how the cortico-papillary gradient is created.
Most explanations go as follow:
1) Sodium is pumped out the ascending branch into the ...
2
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0answers
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 ...
2
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1answer
53 views
Why is there a mass limit on biological powered flight?
So, this is one thing I never fully understood. There are a lot of reasons for a flying creature to be limited in mass, from energy consumption to material strength. However there seems to be a reason ...
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0answers
8 views
Is atrial natriuretic peptide relased when we drink water?
I know that osmolarity is controlled by the hypothalamus and recover by ADH which reabsorb water. It also can be released when ECV is very low.
ECV/salt is controlled by aldosterone/atrial ...
5
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1answer
62 views
Can stress and arousal be independent?
I'm trying to figure out if it's possible to have a stress response without being initially, or simultaneously aroused. I'm defining stress to be physiological stress (ie. release of cortisol) and ...
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0answers
22 views
Vasoconstriction and blood flow
The resistance in a blood vessel is equal to the pressure difference divided by the blood flow. Let us now say that a sympathomimetic causes vasoconstriction which increases the resistance. Does this ...
1
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1answer
138 views
What is the difference between transpiration and evapotranspiration?
According to my point of view transpiration and evapotranspiration are different things, but i am confused about this topic. After great effort, I found a major difference between it.
Transpiration: ...
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0answers
8 views
Using EMG to measure increases in strength
I have a DIY EMG kit and I know it can be used to measure muscle activation. I am wondering, is there a relationship between muscle strength and the value obtained from the EMG sensors measuring on ...
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0answers
29 views
What adaptations does the human body have to handle frequent and sustained changes in orientation?
Most animals are horizontal with the ground. When they lie down, they get closer to the ground, but their orientation does not change.
Humans, on the other hand, stand up straight and tall, ...
4
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0answers
55 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 ...
3
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1answer
56 views
What differentiates neurons in different parts of the brain?
For example: what makes a neuron in the hippocampus of the brain different from a neuron in, say, the amygdala, or the frontal lobe, or anywhere else in the brain? Do neurons in different parts of the ...
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0answers
29 views
How to troubleshoot in vitro formaldehyde fixation for nucleosomes?
For an experiment, I am trying to fix the mononucleosomes (100ng) using formaldehyde as crosslinking agent in HEPES buffer. I have been using 2% formaldehyde in a reaction buffer containing 1mM EDTA, ...
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0answers
15 views
Is chlorine a good activator of osteoblasts?
I have read on the internet that Fluorine, which is a group 17 element is a good activator of osteoblasts. Since elements down the same group has similar properties, I’m wondering if Chlorine is a ...
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1answer
22 views
Does the frequency discrimination of the outer hair cells of the ear increase with sound pressure?
I'm wondering whether the frequency resolution of the inner ear increases/decreases with the volume level (caused by sound pressure $(N/m^2)$.
My assumption would be that as long as the pressure ...
2
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1answer
82 views
How does a nerve cell adjust if O2 diffusion is interrupted?
What effects would it have on a nerve if the oxygen supply is cut off? Is there any data on this?
Does the nerve conductance velocity increase? What about the Amplitude and receptor-channels on/in ...
2
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0answers
116 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 ...
3
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0answers
56 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 ...
1
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1answer
74 views
Why didn't these scientists restore electrical activity in this pig's brain?
This experiment was published in Nature Magazine: Pig brains kept alive outside body for hours after death. The researchers used a system called BrainEx to revive certain metabolic and physiological ...
1
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1answer
320 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 ...
2
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1answer
74 views
Why does muscle blood flow decrease during exercise?
My questions semi-relates to these two items: Where does extra blood come from to fill your muscles during exercise? , and Blood pressure during exercise .
While reading Exercise Physiology by Dr. ...
0
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1answer
133 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?
0
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1answer
70 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 ...
2
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0answers
123 views
Living potato clock? [duplicate]
Could a potato stay alive and power a clock while growing in the ground?
I know how a potato clock works as a electrochemical cell and involves chemistry, but I am only interested in a growing ...
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0answers
20 views
Is it possible for a human being to live on a different day cycle?
I am considering writing a story where a character lives on a 30-hour day cycle.
That is, this person sleeps for 9.5 hours and is awake for 20.5 hours. Then this person repeats the schedule.
I'd ...
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0answers
34 views
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 ...
4
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4answers
169 views
What's the benefit of the average human body temperature?
Why would the body choose a resting temperature of 36.1c to 37.2c? It seems a very inefficient mechanism of survival considering the typical ambient temperatures on Earth. If there is a benefit to ...
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0answers
24 views
What is the net effect of pancreatic somatostatin and how is it regulated?
I've read the following facts about pancreatic somatostatin released from delta cells of the islets of Langerhans:
Blood glucose, fatty acids, and plasma amino acids stimulate somatostatin
...
0
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0answers
11 views
What's the significance of independent control of glomerular capillary pressure and plasma flow, via efferent arteriole?
As I understand, the renal efferent arteriole, when constricted, allows an increase in glomerular capillary pressure, but a decrease in blood flow. This allows an independent control of renal plasma ...
4
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0answers
30 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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1answer
460 views
Why is the ingestion of salt and water beneficial to muscle cramp
According to Wikipedia, muscle cramps are caused by the inability of myosin fibers to break free from the actin filaments during contraction, resulting in a prolonged contraction.
A lack of ATP would ...
6
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2answers
168 views
Why do fruit flies go so close to large reservoirs of liquid when they are likely to fall in due to surface tension?
I had accidentally left out half a glass of red wine by the windowsill when I went to sleep. As anyone knows, if you do this with a window cracked you will get quite a few fruit flies near it in that ...
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0answers
213 views
How can we smell odor direction if we breathe through one nostril at a time?
It's known that humans breathe mostly through one nostril at a time. How can we then perceive the direction the smell is coming from? Some articles claim similarity between olfactory and auditory ...
8
votes
1answer
156 views
Do animals with their eyes ~180 degrees apart have depth perception?
Lots of animals have their eyes more on the side of their head, like an octopus or a parrot. Are animals with eyes more on the side able to tell the depth of objects at different distances? It seems ...
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0answers
11 views
Is creb level linked to cancer
I am just wondering if there is any evidence the overall proteome CREB transcript level is linked to cancer. Most likely since it is so Central to the underlying pH driven process.
4
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2answers
309 views
Why does the seed of the coconut tree have a liquid in it?
What is the purpose of water in the coconut seed? The reason I ask this is that I was reading about coconut water and all the benefits it has for us Humans. But why does the tree put a liquid in the ...
2
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1answer
33 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
199 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? ...
0
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1answer
40 views
Why does carbon dioxide diffuse easier through the bilipid layer than oxygen?
When gas exchange occurs during respiration, the pressure of oxygen in alveoli is around 105 mmHg, whereas in the blood vessels in close contact with alveoli is 40 mmHg. For carbon dioxide the values ...
2
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1answer
47 views
How does a decrease in free Ca2+ result in nerve/muscle overexcitability?
I have in my notes that a decrease in free Ca2+ increases membrane permeability to Na+ so that it is brought closer to threshold, but no further details. So how does this work?
