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

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119 views

How is hibernation/aestivation different from anesthesia?

How do hibernation/aestivation happen? I read on wikipedia that a squirrel injected with the body fluids of a hibernating fellow is more prone to hibernation. If hibernation/aestivation are driven ...
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142 views

How long can a bee surive in a jar?

So, some people and I encountered an adventure game where you have a bee in a jar and need to move it from place to place before it suffocates, and someone tried to find out how long a bee would ...
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90 views

Dimensionless number for blood volume

Comments from the question How is the blood volume of a living organism measured without killing it? by @Nico discussed that the time of blood recirculation scales with the size of the organism. I was ...
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37 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 ...
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50 views

Counterintuitive action of Vitamin D?

Vitamin D acts in a way which to me is counterintuitive. It functionally supplemets Parathormone. It in the intestinal tract steps up calcium absorption by altering nuclear gene expression and also ...
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79 views

How is membrane capacitance related to the increased speed of saltatory conduction?

Here is the original question which inspired my question below. As explained by the answers there, the reason saltatory conduction in myelinated neurons is faster than non-myelinated conduction is ...
3
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46 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?
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24 views

How is olfactory acuity rated/measured?

Acuity of one's sight is rated on the 20/20 scale. An online search appeared to indicate there is no comparable 'standard' to rate olfactory acuity. How is acuity of the olfactory system rated?
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154 views

what are the mechanics of sweating?

The causes of sweating aside, i.e. I'm not interested in which and how nerve signals are transmitted to sweat glands. But I would like to read a detailed account on what a sweat gland consists of, ...
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41 views

Patch-Clamping Neurons Resources

Are there any lectures available on Patch-Clamping? Were can I find a mathematical model of Patch-Clamp? (that can be easily implemented in matlab). I have found some step-by-step protocols on ...
3
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42 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 ...
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43 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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73 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, ...
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54 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 ...
2
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40 views

How well do we notice asynchronicity?

I'm stopped at a stoplight and, with nothing to do, my thoughts wander to the timed don't-walk sign that governs any pedestrians who might wish to cross the street I'm driving along. I can see two ...
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44 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 ...
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50 views

Would my hands sweat this much if I wasn't wearing gloves?

I've wondered about this for a long time, and hopefully someone here has a reasonable answer. I'm a cell and molecular biologist, and much of my time at the bench is spent wearing (usually nitrile) ...
2
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71 views

Size of classical liver lobule across species

A classical liver lobule is made up of a central vein and the portal triads. A typical human liver weighs around 3 lbs. , while a typical bovine liver weighs around 12 lbs. I was wondering if anyone ...
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247 views

How is Hypertonic Urine Produced in a Mammalian Kidney?

I know that the ascending loop of Henle is impermeable to water and ions, and, by end of the ascending limb, the osmolarity of the tubular fluid is very low due to the active transport of ions out ...
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30 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 ...
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69 views

What are the physiological effects of wine?

I have read that alcohol in general and wine in particular can have advantageous as well as detrimental effects on human health. Is this true? What are the physiological effects of consuming wine in ...
2
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0answers
59 views

Are there any situations in which phenylephrine is preferred to pseudoephedrine?

In the mid 2000s in the US, due to issues of drug enforcement, pseudoephedrine containing medications were brought behind the pharmacy counter and in most cases require ID, and phenylephrine was ...
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20 views

Nearly Exhaustive List for Cholesterol Pathways

I have run across an interesting case that is similar to only two others I've encountered. What makes it interesting is the combination of undetectable (under normal testing conditions, can elaborate ...
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34 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 ...
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24 views

Voltage-gated Potassium channels in the action potential of cardiomyocyte?

There is one type of potassium voltage-gated channels open in Phase 1 too. Some call them early repolarization channels. I am not convinced that the channels are different in different phases: 0, 2, ...
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34 views

Calcium levels and nerve hyperexcitation

Why does lower blood calcium levels (or lower calcium levels in ECF) cause nervous hyperexcitaton? Why does it cause over stimulation of nerves and muscles and spasmic contractions of muscles? This is ...
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51 views

Sodium levels and blood pressure

Why does low $\ce{Na+}$ levels cause hypotension (low blood pressure). Alternatively, why does excessive intake of $\ce{Na+}$ cause hypertension or high blood pressure? From what I ...
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18 views

Amphibian blood circulation

In an amphibian blood entering the right atrium shows higher levels of oxygenation than that in left atrium when : A.It is hyperactivated B.it is hibernating C.it is submerged D.it is in the ...
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28 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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35 views

Why delayed Power nap might degrade our night sleep?

Recently in the research areas we come across the term "Power Nap" which says after a nice lunch it would be nice to get a nap for 20-30 minutes which will make the body relaxed and fresh afterwards. ...
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596 views

What are potential side effects of myostatin inhibitors?

Myostatin inhibitors, which are being developed to treat muscle wasting diseases like muscular dystrophy, are likely to be abused by athletes. What are the potential long-term side-effects of taking a ...
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64 views

Why do ion concentrations change with different secretion rates in pancreatic juice?

Why is it that when secretory rate increases in the pancreas the concentration of chloride ions decreases, and the concentration of bicarbonate increases in the production of isotonic NaCl secretion? ...
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36 views

Where can I find approximate rates of sequestration of CO2 for different species of algae?

For a study, I want to compare the rates of CO2 sequestration and fixation of a few different species of algae. I could not find any data on the sequestration rates. Any pointers to where I can find ...
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4 views

How does regurgitated food go to the 3rd stomach chamber instead of going to the 1st?

Ruminants are known for their regurgitation of food; the food goes through the 1st and 2nd stomach chambers, then returns to the oral cavity in cuds. The cuds then come back into the stomach, but this ...
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4 views

Effect of axillary stretching on prevention of congestion from hyperemia

In exercising not-opposing muscles of arms (biceps, not triceps), hyperemia of tissues occurs i.e. active process in arteries. I feel personally sour muscles many days afterwards if I do not stretch ...
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16 views

Are there naturally occurring Biological Pacemakers?

There are artificial biological pacemakers which express funny channels. I am thinking if it is possible to have also naturally occurring (only in recovery cases and in silent tissues) biological ...
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5 views

Mechanisms to start simultaneous depolarisation of two Pacemakers?

I am thinking the biochemical mechanisms of the simultaneous depolarisations of two pacemakers. My intuition Funny channels (but not alone) No autonomic nervous system (my conjencture) What are ...
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6 views

What are the mechanisms of disabling extrinsic control of heart?

I started this thread by thinking this question but I developed it further below What is the mechanism maintaining refractory period of pacemakers? My conjuncture is that the mechanism is the ...
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7 views

Which reflex arcs work in Heart with extrasystoles?

I am researching what is triggering the extrasystoles - initial idea from this thread about Which ionic channels of Pacemakers can work in very low frequencies in extrasystole? I am interested in the ...
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8 views

Calling for Pressure pictures about Right and Left atrium

I am trying to understand the partially patent foramen ovale in patients with right-side heart failure. I am interested how the pressure in right and left atrium change in normal case in abnormal ...
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0answers
7 views

Laser surgery to stop damaged Sinus node from beating

I am trying to find any publication about laser surgery to stop the damaged sinus node which cannot anymore beat. I could only find publications which modifies SA node function. I am not sure if it ...
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15 views

Normal Frequencies in Heart

I am trying to visualise possible ranges of frequencies from different structures of heart: different valves and their possible frequencies heart sounds I - IV and their normal frequencties what can ...
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10 views

How do the symptoms of Sepsis affect heart function?

I have intuition that Sepsis with infection can cause spastic functioning of heart during systole heart working spontaneously in snatches during systole atrial fibrillation first contraction of ...
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0answers
10 views

How does vasomotor and bronchomotor reactions equilibrate local blood flow to correspond local ventilation?

I am trying to find some figure(s) to explain this. There is probably better name for "bronchomotor" reaction. They seem to opposite terms and actually affecting same things (alveolar diameter/tone); ...
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0answers
7 views

To characterise diameter of capillaries in organs

I know that there exist Continuous capillaries (skeletal muscle, adipose tissue, connective tissue, pulmonary circulation), Fenestrated capillaries (small intestine, renal glomerulus, exocrine ...
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11 views

What is the quality rate of intrinsic autoregulation in the heart?

Autoregulation is the maintenance of constant blood flow to an organ in spite of fluctuations in Blood pressure. It involves the relaxation of myocardium and contraction. It is local. I know that ...
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17 views

Are there any forms of heart failure where cell size decreases?

I think hypertrophy happens in most of the cases. However, I am not sure if hypertrophy always happens. I started to think about wet lungs (pulmonary reason for the left-sided heart failure). Can the ...
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0answers
12 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) is ...
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0answers
12 views

What is a good ECG book on Schema level?

I need to know ECG on scheme level, not on Guyton level. The problem is that I have read it on Guyton level and now I should find some review book about this review level. For instance, the ...
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19 views

To define the total Resistance of Systemic Blood Circulation

Some systems are in parallel so let's just call those like $R_{\text{lungs}}$. I got this formula $$R_{\text{total}}=R_A+R_a+R_c+R_V+R_v$$ where $R_c$ capillaries, $R_a$ arterioles, $R_A$ Small ...