The study of the normal function of living organisms and the means by which it is achieved.

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1answer
47 views

How much is local blood non-Newtonian in Pathophysiology?

I am studying the Barus effect / Merrington effect / die swell / extrudate swell, which is a characteristic of non-Newtonian viscoelastic liquids (Introduction to the phenomenon in this video) i.e. ...
-5
votes
1answer
149 views

Why are plants classified in living things? [closed]

@Volunteers Beware that I am none of the biological magnates. Nor a philosopher. This is just a sign of curiosity. And, I want only an intuition that enables me to see the difference. As far as I ...
4
votes
1answer
55 views

Unable to identify a muscle of the anterior thorax

I was watching an YouTube Anatomy Video which goes over the major muscles of the anterior superficial thorax. There is a structure present throughout the video which goes unmentioned, and I can't seem ...
1
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1answer
92 views

What is enantiostasis?

I have searched around and read my textbook but I am failing to understand how enantiostasis is different to homeostasis. For reference, Wikipedia definition is as follows: Enantiostasis is the ...
0
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0answers
26 views

Why doesn't EMG data for triceps show a clear relationship?

In a surface electromyography (EMG) experiment of the triceps muscle where a person lifts weights, I found the value for maximum amplitude of EMG signal to be rather similar for all loads of 0-10kg. ...
1
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1answer
36 views

What is the role of gills in terrestrial Crustaceans?

Why do Crustaceans that live on land have maintained their gills? In aquatic species, the gills play a pivotal role in respiration, but terrestrial crustaceans have tracheal lungs. So why do they have ...
2
votes
1answer
310 views

Is it true that cats can drink sea (salted) water?

Found somewhere in the Net, that cats can drink sea (salted) water. This fact seems to me as being urban legend, not true (because the purpose of water in body apparently implies it should be clear). ...
2
votes
0answers
17 views

How to use the law of diffusion in the presence of electric forces?

Isn't the movement of ions affected by the electric field as well? For instance, when a sodium channel in a cell's membrane opens, the sodium ions are said to diffuse into the cell, from higher ...
3
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1answer
91 views

Loss of appetite during fever

It is a well-known phenomenon that sickness like the common flu is often accompanied by reduced appetite. Why do sick people stop eating?
2
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1answer
208 views

Why do mice have a higher metabolism?

Mice and other small animals have higher metabolic rate than humans. How does that happen on cellular level, if we look on one cell in the mouse body? What is it in this cell that will be ...
1
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1answer
50 views

Wheatgrass in thalassaemia

In local newspapers there was a not so recent story about wheatgrass juice being "curative" in thalassaemia. Although I do not take the article at face value, it would be enlightening to know if there ...
1
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1answer
163 views

Why do animal cells lack a contractile vacuole?

I was asked why animal cells do not have contractile vacuoles. Other than the lack of need, I don't know what else to say.
1
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1answer
45 views

Determining the osmolarity and tonicity of a cell

Consider a cell with urea concentration inside being 2mmol/L and outside being 2.5mmol/L. The cell itself is permeable to both urea and water. Ignoring the effect of other osmolytes, A) Urea flows ...
1
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0answers
26 views

What are the molecular/cellular basis of pruritus ?

Could someone please explain the cells and molecules involved in the clinical phenomenon of pruritus ? I'm interested in a general view about the subject, but detailed answers will be appreciated. ...
3
votes
1answer
69 views

What is the effect of reduced gravity on human height?

There has been talk recently of building a base on either the Moon or Mars. What I'm wondering is, if you are born and grow to adulthood on the Moon, where the gravity is a tenth of the Earth's, would ...
0
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0answers
68 views

Is there a lower temperature limit, below which we cannot sense a difference in temperature?

At work I have to handle samples stored at -20 and -70 degrees Celsius, and they don't feel that different to me.
1
vote
1answer
50 views

What differences in effect does fast repetitive exercise have compared to slower muscle-building exercise?

As a drummer who likes to play high-energy music (fast, aggressive metal) it's safe to say I burn a fair amount of calories when doing so. But I've been drumming for over a decade and despite the ...
3
votes
1answer
78 views

Which is more susceptible to dehydration — extracellular and intracellular fluid?

I want to ask in human body, there is intracellular and extracellular fluid that makes up the total body water of our body, which is drained first when we do activities? extra or intra? if I want to ...
1
vote
0answers
45 views

Which Lactobacillales (Lactic acid bacteria — LAB) strains are capable of degrading starch?

I've been researching bacteria strains but am having trouble finding amylolytic LAB strains with amylolytic and lactic acid producing character. The only species I've found, that are capable of ...
1
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0answers
33 views

Is lung size/shape a factor in long-continuous running of animals?

Apart from other factors, does lung shape/structure/size play any role in long-continuous running animals. Is there any similarity in lung structure between different long-continuous running species? ...
3
votes
2answers
96 views

Why we have to damage our muscles to build them?

I know that new muscle cells are made when actin fibers are disrupted. My hypothesis is that muscle mass is limited, from birth, and that nutrients (protein) are only directed to grow muscle when ...
0
votes
1answer
68 views

which organelle produce glycogen phosphorylase and why

I know that Glycogen phosphorylase doesn't produce from rough endoplasmic reticulum in liver cell. But almost every proteins such as insulin receptor, serum albumin, and lysosomal enzyme have to ...
3
votes
0answers
52 views

What is a common body composition in mammals?

The Physiology Of The Racing Greyhound states that most species have about a 40% muscle mass to body mass ratio. Understanding Body Composition puts "optimal fitness" in humans at 16-25% body fat for ...
34
votes
2answers
5k views

Are there any non-mammalian species known that lactate?

Are there any non-mammalian animals that produce milk to feed their young, or are mammals the only milk-producing animals?
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2answers
79 views

What causes goose bumps?

What is the actual process and reflexes that cause the goose bumps? Why is it an evolutionary advantage to have goose bumps in the first place?
1
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1answer
236 views

Is there nutrient absorption in the large intestine of hindgut fermenters?

In hindgut fermenters, plants are digested in the caecum by microbes. I want to know whether hindgut fermenters can absorb the nutrients obtained from the digestion in the large intestine because the ...
-1
votes
1answer
78 views

Does exercise really reduce stress in the biological meaning?

It is a very widespread claim, that movement in general helps body to get out stress hormones. It is used as a warning for long sitting at the computer and I also heard it as a pro-vegan argument (We ...
4
votes
1answer
107 views

What causes inhalation during breathing?

I have read here that the two major inhalation muscles are the (1) diaphragm and the (2) external intercostals. Additionally, inhalation can also be caused by (1) expansion of the abdominal cavity, ...
4
votes
0answers
74 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 ...
2
votes
1answer
73 views

Is blood pressure in the aorta and brachial artery the same or different?

Does the blood pressure at the root of aorta equal the blood pressure in the brachial artery? I've heard it does, but it doesn't quite seem to make sense as I'd think the blood pressure would be ...
0
votes
1answer
388 views

If a human is stranded with beer but no water, should they drink it? [duplicate]

TL;DR: At what percent (if any) will alcohol dehydrate you more/faster than drinking nothing? Let's contrive a situation for dramatic effect... A human goes out on a boat for a nice sail in the sea. ...
0
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0answers
77 views

Root etiology of non-pituitary low T4 and low TSH

Please note: I'd like to preface this question by stating that this is neither homework nor me seeking medical advice. I am simply trying to understand the biological, physiological root etiology ...
13
votes
1answer
855 views

Can an organism exist as a single cell but come together as multi-cellular during certain times?

I am trying to remember a particular segment from a BBC special, in which there was single cellular species. However, at certain times all the individual cells came together to form a structure, not ...
1
vote
1answer
55 views

does phagocytosis dependent on opsonization?

does phagocytotic activity of macrophages and neutrophils depends on opsonization by IGg (antibody) and C3 complex,if it does, so then why macrophages and neutrophils are categorized in Innate immune ...
3
votes
1answer
533 views

Is the swimming pool water harmful to frogs who jump in? If so, how?

Here is an odd question: Frogs have permeable skin. Indeed, via capillary action, frogs absorb water through their skin. Chlorine is in principle a harmful substance. I am sure what percentage of ...
1
vote
1answer
157 views

Drinking soda triggers tingling on a tiny spot on my upper back… but how? [closed]

The title pretty much says it all. Yes, I know it doesn't make sense. That's why I'm baffled. For the past week or two, I've noticed that drinking soda seems to cause a tingling/stinging sensation ...
6
votes
1answer
82 views

What is the top speed of muscle contraction?

Currently I am looking into what muscles groups are most used during a football kick. I have a hypothesis that the quadriceps are not as used as most people think because the momentum the swing ...
3
votes
1answer
60 views

Possible calculations with temperature, humidity, images and VIS spectrum of a plant in an Integrating sphere

I am currently working on a project which involves growing some plants in a integrating sphere made of foam. I have added temperature, humidity and soil moisture sensors as well as a Spectrometer (350 ...
3
votes
2answers
965 views

How does Bernoulli’s Principle apply to the cardiovascular system?

Below are graphs which illustrate the cross-sectional area, velocity, and fluid pressure through each vascular segment of the cardiovascular system. It makes sense that velocity and cross-sectional ...
0
votes
1answer
91 views

Would a human survive eating only living ants?

After reading an admittedly foolish question about 1 googol ants vs. 1000 humans, I had a question. Could a human survive solely on eating ants (common ants, not the stinging kind, or leafcutters ...
2
votes
2answers
80 views

How do t-lymphocytes become mature if thymus has lost its function?

The development of t-lymphocytes are done by thymus and we also know that the thymus degenerates before puberty and we also know the maximum lifespan of WBC's is 15 days. So, how do t-lymphocytes ...
2
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0answers
17 views

Peculiarity of chemo senses [closed]

We can easily recall our visual stimulus and auditory stimulus but why can't we recall chemical stimulus like smell and pain? We can recall a song or picture but we can't exactly recall smell and ...
5
votes
1answer
352 views

Where do most mutations come from, mitosis or meiosis?

According to this (old) paper there are 10 times more mutations during meiosis than during mitosis. One reason for that is that recombination often causes replication error and therefore mutations. ...
2
votes
1answer
94 views

How does Celiac's Disease cause people to stop growing?

In all of the sites I've looked on, one of the symptoms of Celiac's Disease is the failure to grow in children. Why would an immune attack against gluten cause stunted growth? Celiac.org states: ...
2
votes
1answer
44 views

Physiology of tricuspid and bicuspid(mitral) valves

The tricuspid and bicuspid valves are atrioventricular valves. Both are valves that prevent backflow of blood pumped from the atria to the ventricles. However, the former has 3 "flaps" while the ...
2
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0answers
169 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 ...
17
votes
3answers
2k views

Why does the face turn pale in dangerous situations?

I know what the effects are of a dangerous situation on the brain, i.e., an activation of the hypothalamic-pituitary-adrenal (HPA) axis which eventually results in an increased heart rate and elevated ...
4
votes
2answers
215 views

What is the relationship between W, X, Y and P, M retinal ganglion cells?

In Guyton and Hall Textbook of Medical Physiology (12e) the retinal ganglion cells (RGCs) are classified into W, X, and Y types. However, in Gray's Anatomy (40th ed.), RGS are subdivided into midget ...
3
votes
1answer
39 views

How do cold conditions help organ transplants?

Body organs are kept cold in-between explanting them from the donor and implanting them in the new host. How do these cold conditions help organs to stay viable while they haven't fresh blood, energy ...
1
vote
1answer
246 views

How much heat can a human sustain? [closed]

For how long can a human sustain a temperature of 180 degrees Fahrenheit (82oC) without damage in a confined place? For instance, suppose a person is sitting in a steam-filled room, without external ...