Questions tagged [physiology]
The study of the normal function of living organisms and the means by which it is achieved.
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1answer
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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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10 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.
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8 views
electrical excitation of a skeletal muscle
Does anyone have any idea why the mechanism of this coupling has been difficult to determine? It is an end of a chapter question in my human physiology textbook.
2
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0answers
51 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
23 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
65 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
20 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
36 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?
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1answer
161 views
Why does the peak magnitude of the cardiac pacemaker action potential not increase to levels closer to the Ca++ equilibrium potential? [closed]
it does for K+ and Na+ but not calcium? why?
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0answers
13 views
Muscular tetany and hypocalacemia
Decreased serum calcium level leads to increased excitability of neuron and at same time decreases the contractibilityof the muscle fibres.But still its causing tetany.Wouldn't these two counteract to ...
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3answers
166 views
Why did a lot of common insects evolve such a thin waist?
Something that doesn't quite make sense to me is why lots of insects like ants, bees and wasps have a such a small petiole when it connects many major organs to the rest of their body from a suddenly ...
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0answers
21 views
Why is the V/Q Ratio 0.8 not 1?
According to: https://en.wikipedia.org/wiki/Ventilation/perfusion_ratio the ideal V/Q Ratio would be 1.0 because 1 L of blood can hold about 200 mL of oxygen and 1L of humidified air has about 200 mL ...
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1answer
32 views
What is the difference between optokinetic and vestibular nystagmus?
Optokinetic nystagmus is for stabilising the pictures we see when we are observing moving objects for example if we are rotating on an office chair. If we wear a mask while rotating however, the ...
3
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1answer
43 views
Why does sympathetic activity constrict pulmonary vessels?
I don't know understand why sympathetic stimulation constricts pulmonary vessels?
I thought that the sympathetic nervous system activated the body for physical activity. Physical activity would need ...
2
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1answer
19 views
Does focusing on a certain part of the body increase electrical activity in that region?
I am batting around ideas for master's thesis topics and was wondering whether or not just focusing on an area of the body would cause of boost of neuronic activity? Not sure whether this would fall ...
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1answer
26 views
Blood pressure in various blood vessels and heart
What are the typical systolic and diastolic blood pressure in arteries,capillaries, veins and the heart?
I know it must be highest in the arteries. arteries>capillaries>veins
Arteries: 120-80mmHg (...
3
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2answers
86 views
What causes “ear rumbling”?
The video Ear rumbling happens below the range of human hearing demonstrates that the "ear rumbling" sound is actual sound and can be recorded by a sensitive microphone near the ear.
What is it ...
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1answer
32 views
How does vasoconstriction increase the pressure of blood?
Is the increase of pressure due to the decrease in volume? Wouldn't the decrease in volume push the components of blood closer to one another resulting in an increase of repulsive forces, thus ...
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0answers
10 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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0answers
12 views
How do booklice avoid dessication?
I often find booklice (aka psocids) in old paper notes I have in semi-storage. These pages of paper are intentionally left in dry conditions on my desk to avoid damage. However, if the psocids live ...
2
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0answers
51 views
Why does water stress lead to alkalinity of xylem sap in plants?
I was reading this book: Plant Physiology and Development, Sixth Edition by Lincoln Taiz, Eduardo Zeiger, Ian M. Møller, and Angus Murphy when this doubt came to my mind. Abscisic acid, the stress ...
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0answers
11 views
Etymology of eccentric/concentric contractions
I was wondering if anyone knew why the terms eccentric and concentric were chosen to refer to lengthening and shortening muscle contractions?
The basic etymology of the words are to do with ...
1
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1answer
38 views
When muscles contract is the process similar to how non-newtonian fluids react?
I'm trying to understand how muscles contraction/tension works but getting loss in on the cellular level. From my understanding, when muscle tissue need to contract, the cells are flooded with calcium?...
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0answers
18 views
When we laugh or run for sport which autonomic system works?
When we laugh or run for sport which autonomic system takes place in this time?
While I am not sure what happens in heart while laughing (tachycardia or bradycardia), but for sport running I'm sure ...
0
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1answer
82 views
Continuous (yeast) culture system satisfying multiple criteria
There are multiple ways yeast cells can be grown in liquid cultures.
Batch cultures are easy to prepare but cell density, medium composition and physiology change over time
Chemostats allow to ...
18
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3answers
1k views
Public database of animal specifications
I'm a math teacher looking for data to help my students interested in biology complete a quantitatively flavored study of animals. (As a math person, I apologize if I'm not using discipline-...
2
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1answer
59 views
Is there a name for the use of sunlight in metabolic processes?
"Photosynthesis" is what is used to describe how plants use sunlight to synthesize sugars, but, I also heard some animals like humans use sunlight in the process of creating vitamin D. Is there a ...
5
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1answer
88 views
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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0answers
28 views
Why is the glomerular filtrate isotonic to the blood in the capillaries?
How can the osmolarity of the filtrate be the same as the blood in the peritubular capillary when there is no red blood cells filtered?
4
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1answer
170 views
What are the limiting factors of human stamina?
What are the limiting factors of (human) stamina? Let's define stamina as the capacity to continue doing a physical activity. We clearly have our limits, so what aspects of physiology impose a limit ...
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1answer
70 views
Why do musk deer have the smallest red blood cells and amphibians have the largest?
What is the reason that musk deer have the smallest red blood cells and amphibians have the largest? Should they not be proportionate to the size of the organism?
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0answers
23 views
What is the benefit of reducing inflammation when producing antibodies?
We just learned in lecture that IL-10 promotes the formation of plasma cells over memory cells. Which seemed strange to me as IL-10 also reduces inflammation, and I figure you would want inflammation ...
19
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2answers
5k views
Why is wombat excreta shaped like cubes?
I've heard that wombat excreta is cube shaped, but I don't understand how that can happen. Has anyone studied the phenomenon? What would the evolutionary pressure have been to cause this?
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1answer
49 views
How does vasodilation slow blood flow?
During inflammation, cytokines and histamine cause vasodilation to increase blood flow to the inflamed area. However, it is also said that vasodilation slows blood flow which facilitates the adhesion ...
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1answer
34 views
Common english name for tissues which are separated from the blood by blood-tissue barriers
Which general term is used to denote such organs/tissues as: brain, testis, thymus etc., which are separated from the blood by blood-tissue barriers?
4
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1answer
72 views
What physiological processes give rise to a linear cell survival curve?
If we plot the number of surviving cells in a structure over time (assuming no replacement), the shape of that curve should imply something about the underlying process responsible for cell death. For ...
2
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2answers
36 views
Cross-species infections
I’ve heard that HIV developed from SIV, etc.
I’ve also heard that most species (including most monkeys) can’t get a common cold like humans.
So then what causes infections to be able to travel ...
0
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1answer
33 views
What is (are) the medium of conduction for an electrical current with an external source in the human body?
I am trying to get some background for some personal research I am doing into the effects of Electro Convulsive Therapy. I don't understand how electric current from an external household source, say, ...
3
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1answer
168 views
Why do crocodiles have a high concentration of lactic acid in their blood?
Crocodilians have high concentration of lactic acid in their blood. This is the cause that prevents them from prolonged intense activity, since prolonged intense activity causes the muscles to secrete ...
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0answers
39 views
Acute calculous cholecystitis
The action of mucosal phospholipases hydrolyzes luminal lecithins to toxic lysolecithins. The normally protective glycoprotein mucus layer is disrupted, exposing the mucosal epithelium to the direct ...
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0answers
41 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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37 views
about the muscle's tension's variables
I'm reading the paper "THE PROBLEM OF THE INTERRELATION OF CO-ORDINATION AND LOCALIZATION", which is written by N. Bernstein.
The paper said
"The degree of tension of a muscle is a function, in the ...
2
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1answer
55 views
Is every neurotransmitter receptor an ion channel?
This is a rudimentary question--perhaps the answer is well known to biologists, but is every neurotransmitter receptor also an ion channel?
For example, NMDAR is a glutamate receptor and cation ...
2
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1answer
90 views
Are we evolving as fast as the oxygen is depleting?
How much oxygen saturation have we lost in the last 100 years? As oxygen levels dwindle and industry, deforestation, and population increases, at what year and saturation will the low levels of ...
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2answers
128 views
How does 2,3 biphosphoglycerate works to release oxygen bound to the hemoglobin?
I read on Wikipedia that 2,3 BPG binds with the deoxygenated state of hemoglobin and helps in stabilizing it. It was also written that it helps release remaining oxygen from the hemoglobin. How?
...
2
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1answer
337 views
Mechanism by which hypokalemia reduces insulin secretion
Is there any known mechanism by which hypokalemia reduces insulin secretion?
This video explains a mechanism, but its inherently wrong because ATP dependent K+ channels will allow movement of K+ from ...
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0answers
16 views
CETP inhibitors and LDL levels
While CETP inhibitors effectively reduce LDL, they also paradoxically increase the frequency of adverse cardiovascular events (angina, revascularization, myocardial infarction, heart failure, and ...
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0answers
51 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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1answer
142 views
Why does applying pressure to a venipuncture site prevent haematoma?
From what understand, when drawing blood, a phlebotomist puts pressure on the venipuncture site while withdrawing the needle to prevent a haematoma.
I'd like clarification;
How does this prevent a ...
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56 views
Boron vs Costanzo for first year of medical school?
Which book for physiology out of Costanzo and Walter Boron would you recommend to a first year medical student who has read upto the level of Campbell’s Biology textbook in high school?
