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2

Well, the answer which explains the difference between calcium and potassium is quite simple. Do we agree that charge separation (between the two sides of the membrane) is the thing which creates the potential? meaning, if the charge concentrations at the two sides were the same, then the membrane potential was zero. right? So here is the thing. You have ...


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GnRH-secreting neurons are not fully independent. To date, their most studied regulators are kisspeptin-secreting neurons. During childhood, kisspeptin-secreting neurons are off, due to GABAergic higher level structures and to lack of free leptin. So both brain and body fat have a word on it. Caveat: most of the evidence is circumstantial (for example, ...


3

It's just how we evolved. At some point in the past, a distant ancestor of ours had two lungs, two kidneys, one liver etc.( maybe then there was a pretty good reason for this). We evolved following that pattern and now we ourselves have two lungs, two kidneys, one liver etc. Snakes, for example, have just one functional lung because their elongated form ...


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The aorta is a compression chamber because it is an important drive for diastolic perfusion. To keep the blood flowing constantly, and not only during systole (as would be the case with a rigid aorta), the high elasticity of the aortic walls allows it to dilate as a consequence of the high systolic pressure. This allows the aorta to accumulate blood in its ...


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While correct, @AndroidPenguin 's answer is only part of the explanation. By far the main reason of the pressure difference is that the peripheral circulatory system has two main compartments: a resistive compartment, represented by arterioles a capacitance compartment, represented by capillaries The reason for the abrupt pressure fall from arterioles ...


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The main question can be answered in a very dumb way: because the lower part of the body also needs blood... and this configuration is the surest way of doing that because of reasons given below (among many others, I am sure). If you want an anatomical reason, well the most pertinent one would be that embryologically, the heart and vascular system are ...


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If you want a likely predictor candidate for the pulse wave amplitude (which seems to be what you are looking for), you will need to take into account some factors: is the heart normal or pathologic? are the vessels normal or pathologic? Now from your question, I assume that you want your model to represent a sane vascular system. In this case, the best ...


1

In simple terms, heart injury, most likely to be myocardial infarction (heart attack) involves death of the vascular heart tissue. Thus the word infarction. Death of a tissue just simply leads to the production of a fibrous scar. Therefore the heart muscle cannot repair that area of injury to 100% as before.


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If you have no medical background at all, you will need a general text that teaches more than just digestive physiology. That is because you need to understand the function of other systems that have an influence over the digestive system (for example, the peripheral nervous system). Here are a few good general references to get you started: Physiology by ...


2

Part of the answer is in fact extremely simple: coronary arteries (irrigating the heart muscle) are terminal vessels. This means that when a coronary artery sustains damage, the area it was irrigating becomes biologically dead with a very limited potential for recovery. The affected area turns to fibrous tissue produced by cells with much lower oxygen ...


3

Fructose has a special characteristic that other sugars do not have: its absorption in the human intestine is not regulated, as opposed to glucose, for example. The important implication is that all the fructose you consume will end inside your organism, either used immediately or stored as fat. Other sugars will only be partly assimilated, or will require ...


2

Ignoring the actual physiological mechanism(s) for why, consider that from a natural selection point of view, there probably isn't as much incentive for a body to heal itself of a condition that largely affects post-reproduction age individuals. While healing a broken bone would likely allow a young person to further reproduce, healing a heart ailment would ...


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It is unclear from your question what exactly "beat-to-beat variability" means from a physiological perspective. It would help if you could provide more information on the application you are working on and what kind of sensors you have access to. If you wanted to measure the force of the arterial pulse, you would need to measure pulse pressure (which is ...


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The following study abstract of "Consumption of high-fructose corn syrup in beverages may play a role in the epidemic of obesity" copied from http://www.ncbi.nlm.nih.gov/pubmed/15051594 seems to address your question. I added a paragraph break; the second paragraph seems most relevant to me: Obesity is a major epidemic, but its causes are still unclear. ...


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Besides a lot of propaganda there is not much evidence that high fructose corn syrup (HFCS) is more dangerous than normal sugar. Lets have a look at the sugar in detail: HFCS is produced from corn and is originally a glucose syrup. Since fructose is obviously much sweeter, the glucose is converted enzymatically into fructose (see here for more details). ...


3

Higher QRS complexes particularly in the lateral leads would suggest hypertrophy of the left ventricle. This in turn would suggest a stronger pressure is in place, although it is not known whether this is because it is required (incompetent valves) or a physiological response to exercise (where the volume is likely to actually be bigger). Alternatively, if ...


2

I'm not a medical professional, so this isn't exhaustive or guaranteed 100% accurate: You can live a (*mostly) normal life without your: appendix tonsils spleen gallbladder pancreas portions of your liver (pieces can be removed and it will regenerate) portions of your small or large intestines both lungs (one is needed) both kidneys (one is needed) ...


1

This answer aims to list existing models and do meta-analysis about them. This answer is a draft. There are many models made based on the thrombus movement. One of them is proposed by DevashishDas' answer but it seems to focus only on the first stage of hemostasis: The model assumes thrombin is generated on the surface of activated platelets in the ...


1

I am not sure whether I grasped the gist of your question appropriately, but let me provide some clarifications. $\text{Nerve}$ is simply a collection of axons. Therefore, all the spinal nerves are just bundles of assorted nerve axons. Now, the origin of nerve is slightly ambiguous as far as its meaning is considered. It can mean the physical origin, ...


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What one thinks, no matter how intuitive it may appear is not particularly relevant in science. The inductance associated with a neural axon has been well documented since Cole (1966). Its role in the propagation of neural signals is developed extensively in http://neuronresearch.net/hearing/pdf/7Projection.pdf#page=39 . The actual development begins ...


2

The answer provided by @MCM contains an important chunk of information (Bioluminescence!) but it does not answer the question entirely. First, let's correct a misunderstanding in the question. Sunlight does penetrate beyond 200m in the ocean. The intensity is not enough for photosynthesis to occur (and thus no phytoplankton below 200m) but depths between ...


6

The blood comes from the body's reservoirs: spleen (mostly erythrocytes) [1] liver [2] veins (probably the most important blood resevoir as they contain 50-60 % of the volume) [3] In pathological situations, if hypovolemia occurs, blood can also come from: splachnic vascular bed [5] But what attracts the blood into the muscle? The phenomenon is ...


3

How does extra blood come from to fill your muscles during exercise? Blood pumps (blood) and sucks (lymph). There are many pumps in our body thoracic pump smooth musculature respiratory pump which work together to provide the blood to the peripheral circulation. These pumps provide us Pulse, Vasomotor tone and Respiratory waves which when act together ...


1

If you stand up too quickly, you get a head rush. One way to counteract the symptoms of the head rush is to contract your leg muscles really intensely. This forces blood out of your legs and into the rest of your circulation, including your head. This is actually a tip my family doctor told me that I've always remembered. As mentioned in the links below ...


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Second paper is an article in science Daily and have a pretty decent source from Texas A&M University. It's much better than the first as it is un-sourced post on yahoo answers. Source: "Male Seahorses Are Nature's Mr. Mom, Researchers Say." ScienceDaily. ScienceDaily, 2 May 2008. Why male seahorses gets pregnant? Genetic answer: May be because only ...


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Here (mic.sgmjournals.org/content/127/1/121.full.pdf) is a link to a paper in which P. shermanii is grown in flask culture. Although the conditions are clearly designed to achieve low oxygen concentrations in the culture (the flask is almost full and is only shaken occasionally), they also indicate that oxygen is not toxic for this organism. Also, this is ...



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