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

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3
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2answers
102 views

What are the factors that control the speed of propagation of neuronal signals?

If we consider an analogy between a wire and a neuron there may be some resemblance between the factors controlling the data flow rate. For example the increased width of wire leads to decreased ...
0
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1answer
15 views

What triggers the release of gonadotrophin-releasing hormone with the onset of puberty?

I am interested to know the process of development of puberty. During puberty, when boys/girls reache 12-14 (puberty) years of their age, their hypothalamus releases gonadotropin releasing hormone ...
2
votes
1answer
172 views

Why does caffeine consumption cause one to urinate more?

What is the physiological mechanism behind the diuretic effect of caffeine?
1
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1answer
68 views

Why do humans have only one liver? [closed]

Humans have two lungs, two kidneys... But only one liver. If the liver is vital to our survival, why do humans only have one?
2
votes
1answer
68 views

Why does the arch of aorta coils?

My study materials use the word vesselcompression chamber of aorta to emphasize aorta's elastic property. The arch of the aorta only coils, not its straight part. I think the reason why the arch ...
0
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1answer
22 views

Why is Aorta sometimes called Compression chamber?

I find this statement that Aorta is called Compression Chamber in my study materials. Aorta can it keeps blood flowing it can accumulate potential energy for bumping and compression However, why ...
2
votes
2answers
116 views

Why there is a very high drop in pressure from arteries to arterioles?

Laplace law explains why the pressure is the same in aorta and arteries (100). I am thinking why there is so big drop in pressure when going from arteries to arterioles (40-60). Why there is a great ...
4
votes
3answers
69 views

How does strength of a pulse related to EKG(ECG)?

There are variabilities in the heart rate as well as strength of heartbeats. I want to know if one can predict which heartbeat will be strong or weak based on the corresponding EKG/ECG signal. I am ...
7
votes
5answers
283 views

Why is the human body able to repair a broken bone and not a heart muscle?

The human body can repair skin/organ laceration, fractures, even repair nerves - albeit the duration and rate of recovery differ. For instance: The burn scar on my arm from the hot soldering iron ...
1
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1answer
29 views

Gastro-intestinal physiology reference

I am a physicist but I have always wanted to understand how my digestion takes place in as much detail as possible. I have no idea about books or reference on the subject of Gastro-intestinal and ...
12
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3answers
2k views

Why is high fructose corn syrup unhealthy?

I understand that high fructose corn syrup was found to have detrimental effects on peoples' health. Why is this so?
2
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3answers
832 views

What organs are absolutely needed by the human body?

The title is my question: what organs are absolutely needed (fatal if injured/removed) by the human body and perhaps animals in general? I'm not asking which organs are mechanically replaceable, but ...
2
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0answers
38 views

Relationship between mN and mg in vessel contraction studies?

What is the relationship between mN and mg as the units involved to measure the changes in contraction? A tool most widely used is an instrument called myograph. In these exoeriments, either units of ...
1
vote
1answer
23 views

What are the movement mechanisms of thrombus?

I am thinking how thrombus (veins, arteries and heart) can move. Secondary mechanisms come to my mind only: some enzyme which lyses it, probably adhesion mechanism. Blood circulation (flow rate) ...
3
votes
1answer
76 views

Where do the 31 spinal nerves start/meet?

Which part of the brain is the first place (from top to bottom) where all 31 pairs of spinal nerves (on each side) meet? Or if they all start at one place - where is that? Nominally, the beginning of ...
9
votes
3answers
761 views

Do men have more extreme variations than women?

This question was considered unsuitable for Skeptics and I think it is more suited to BIology than Cognitive Sciences I was reading this article which I found interesting. It is not supported with ...
2
votes
1answer
51 views

Inductance in cell

In an animal cell, especially neuron and in particular its axon, while there is electrical resistance and capacitance mechanism in the cell, which play essential roles in the cable theory model of ...
7
votes
3answers
104 views

Where does extra blood come from to fill your muscles during exercise?

Let's say I go to the gym and lift some weights an hour. During this time my arms will grow due to the "pump" -- the extra blood rushing in to feed the muscles. For example, I've measured about 2-3 ...
3
votes
2answers
65 views

Is vision a vestigial sense for deep ocean species?

Sunlight doesn't penetrate beyond a couple of hundred feet from the surface of the ocean. Species that exist at greater depth probably live in a state of perpetual night; yet from a quick google image ...
5
votes
1answer
67 views

Competition for mates in sea horses

This source here ...research has shown that it is STILL the males that compete for females. says that male sea horses compete for mates but this source here Females exhibit a ...
2
votes
1answer
31 views

What makes certain obligate anaerobes viable in fermentation starter cultures?

If Propionibacterium are obligate anaerobes (to wit, poisoned by oxygen), what makes 'Dairy' or classical propionibacteria (e.g. P. shermanii, P. jensenii, P. acidicpropionici, et al) viable in ...
2
votes
1answer
2k views

How does extracellular potassium ion concentration and calcium ion concentration affect the excitability of a cell?

When extracellular $K^+$ concentration increase by a certain amount, excitability of cells is higher because the resting potential shifts toward a higher equilibrium potential of $K^+$, therefore ...
-1
votes
1answer
57 views

What organism most efficiently converts a given quantity of mass into heat?

Question I am trying to answer: In the popular film The Matrix, heat given off by humans is harvested as an energy source. I wondered, if this were possible, would humans be a good organism to ...
7
votes
1answer
64 views

Excretion of monovalent and divalent ions in sharks

I have heard that sharks excrete $\ce{Na+}$ and $\ce{Cl-}$ by their gill surfaces but divalent ions like magnesium are excreted through feces. What could be the reason behind this?
2
votes
0answers
21 views

What does salt do to styes?

Styes formed in the eyes are cured by dabbing at them with lukewarm water(I saw this being done many a times as a home remedy.) At times, common salt is added to the water before dabbing. My mother ...
5
votes
1answer
43 views

How does a Na+/H+ antiporter drive osmosis in this “osmotic motor”?

This recent paper in Cell describes a cancer cell using osmotic pressure to move in confined spaces. The cell preferentially inserts Na+/H+ antiporters in the leading membrane. I want someone to ...
3
votes
2answers
108 views

Do women experience more bonding hormones than men after sex?

Does Oxytocin (or any other bonding hormone) increase more so for women than for men after sex? Someone told me that it increases 4-fold for men and 12-fold for women (unconfirmed). Is there any ...
4
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1answer
83 views

The mechanism of mechanoreception?

I am interested in knowing the molecular mechanism behind mechanoreception/mechanotransduction (i.e. mechanism behind receptor potential generation on mechanical stimulation). I know that most ...
3
votes
1answer
36 views

Hypersensitivity Simultaneously in Ear canals

I got experimental data where hypersensitivity (i.e. tonic pain when touching ear canal) was recognised for about 100 minutes. I do not know which type of hypersensitivity is this one. IgM can ...
6
votes
2answers
252 views

Can humans transdermally absorb minerals from ocean water, and if so how much?

According to several studies quoted here, chemicals can be absorbed by the skin transdermally, at least under certain conditions. When it comes to elements in seawater like sodium, magnesium, ...
2
votes
1answer
63 views

What happens during a Raynauds episode?

Raynaud's phenomenon can be a serious health issue, as the blood flow to the extremities, mainly the fingers is compromised, causing fingers to blanche, and then turn blue. Severe Raynaud's can cause ...
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0answers
21 views

Can non-carbonated energy drinks boost alcohol intoxication?

I just read news article about banning caffeine in alcohol drinks and about that energy drinks increase the urge to drink alcohol. Energy drinks cause sugar intoxication - answer about it here ...
2
votes
1answer
27 views

Why does crying lead to a running nose and reddened nose tip?

Why do we have a running nose for quite some time after crying? It persists even after we stop crying. Why is it so? I have faced this always. Also, why does our nose redden on crying for long?
5
votes
1answer
77 views

By what mechanism can hypoglycemia induce fainting?

Hypoglycemia (Low blood sugar) is said to be among the potential causes of human-faintings. I was wondering by which mechanism this happens. Google search results are abundant; there are lists of ...
7
votes
1answer
558 views

Does the human ear adapt to noise levels?

I have noticed lately that if I go to sleep, when I have my radio running, it is on lowest volume, I still consider it kind of loud. In the morning, when being on the edge of waking up, I hear the ...
2
votes
0answers
27 views

Why does skin sometimes suddenly itch when you stretch it? [closed]

Sometimes, when I bend over, areas of my skin like my back can suddenly itch quite intensely. Sometimes it may be another part of my body and the pattern seems to be a part of the skin organ that is ...
1
vote
1answer
42 views

How Ants know about Earthquake?

How does an ant know about Earthquake is it because of an organ or due to other factors?
2
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1answer
33 views

Do Ants have a sense of Direction?

Do ants understand which way is up or down? Could they differentiate between uphill and downhill?
0
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0answers
53 views

Why the scent of mouth gets dirty after not eating for a long time?

After a long time of hard workout,not eating and nervousness makes your taste and scent of mouth very uncomfortable and bad why this happens and is there any way to prevent it?
6
votes
1answer
92 views

Disproportion in cranial nerve innervation?

The cranial nerve innervation is highly disproportionate, as far as humans are concerned. I am not sure of the advantage of being innervated by cranial nerve versus being innervated by a normal ...
0
votes
1answer
34 views

Can lymph be in peripheral blood?

I read an argument that 1-3% of lymph is in peripheral blood. However, I am not sure if this lymph is about lymphocytes in peripheral blood; not lymph itself. Lymph gets exchanged between capillaries ...
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vote
0answers
15 views

Effect of lower back on Lymphatic drainage in Posterior Lumbalis

I am studying how the muscle spasm of lower back can affect the anterior lymphatic drainage in a male obese situation (supine position) and quality of sleep. There seems to be very little lymphatic ...
0
votes
0answers
12 views

How Calcium regulated in myocardic AP and plateau phase?

The plateau phase is maintained by influx of calcium and outflux of potassium in the second stage: My conjuncture is that calcium transforms between two phases ionated phase (free calcium from ...
7
votes
2answers
1k views

How do we know the presence of light when our eyes are closed?

Last night I laid on my bed and tried to go to sleep with the light off. I closed my eyes (but hadn't gone to sleep). My younger brother touched the wireless mouse (which had laser) for the laptop. ...
1
vote
0answers
20 views

Fast standing and the heart's insufficient accommodation of the increased venous return

Assume you are 45 minutes on the supine position. Furthermore: you stand all of a sudden and fast and without sympaticus activity. The venous return (smooth musculature of vessels) accommodates ...
6
votes
4answers
280 views

Do tall people have more cells?

Within a single species, how does the relative number of cells in the body relate to the relative size of the organism? Let's say we take two humans, one of them is 6 feet tall and the other one is 5 ...
1
vote
2answers
88 views

Hypovolemia and orthostatic hypertension

What is the physiological mechanism behind the occurrence of orthostatic hypertension in the presence of hypovolemia?
4
votes
1answer
73 views

Enlargement of thyroid gland

Why does thyroid gland enlarge both in hypothyroidism and hyperthyroidism? Hypothyroid goitre is due to lack of iodine in diet and hyperthyroid goitre (Exopthalmic goitre, Grave's disease) is due to ...
1
vote
1answer
46 views

Can tubular secretion regarded as local hormone?

Tubular secretion is : The process in which ions and other waste products are transported into the distal tubules of the nephron. can it be regarded as local hormone??
0
votes
1answer
38 views

Mechanism of antiperistalsis

What is the mechanism of antiperistalsis that occurs during vomiting? Why the peristaltic waves normally don't propagate in anal to oral direction? Please give logical explanation with authentic ...