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From Uptodate on Clinical Manifestations of Hypocalcemia: Acute hypocalcemia directly increases peripheral neuromuscular irritability [ 1 ]. As measured electromyographically, tetany consists of repetitive high-frequency discharges after a single stimulus. Hyperexcitability of peripheral neurons is probably the most important pathophysiologic effect of ...


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It is a question of transmembrane potential. Ca++ being a cation, means that if you decrease the amount of ionized calcium in the extra cellular fluid, it conceptually is nearly equivalent to having a more positively charged intracellular fluid. This in turn means that the cell will be closer to its threshold potential for depolarization, therefore ...


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Unfortunately at this time, there are no known glucosepane breakers which can feasibly be used in a living organism. There is a small (very small) amount of research being done on the topic by Yale university in cooperation with the SENS foundation, but the focus is extremely early stage - nothing more than synthesis and detection of artifical glucosepane ...


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I'll try a brief answer myself. No, the heart is not the only energy provider, as others have stated above. Does vasoconstriction inject energy into the system? Not really. Arteriolar constriction will increase the resistance of the system. Therefore, more energy will be required to keep flow at a constant level when vasocontriction occurs. Arteriolar ...


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Succinycholine, as its name might suggest, is a cholinergic agonist indeed. It acts on the neural plate of skeletal muscles, where it activates the muscle cholinergic receptors. Phase 1 block due to succinylcholine thus occurs by activating so many receptors at once, that the whole muscle gets desensitized and therefore paralyzed. A corollary of that is ...


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I just want to add a few points to the above answer: Heart is not the only organ which helps blood flow. The following structures also help: The action of muscles on deep veins acts as a pump - Soleus is called peripheral heart for that matter The compliance itself adds to the flow - Infact the compliance of the blood vessels is what makes the blood flow ...


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The circulatory system is a dynamic system which cannot be adequately explained by your example (at least not by me). You need to understand it, not seek to make it fit your (especially) electrical circuits with resistors. Blood isn't electricity. At least try a fluid dynamics model. Let's take this very simple model: Blow up a balloon four-fifths of the ...


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To put it in very simple words the reason for isovolumetric contaction and relaxation is to make the necessary pressure changes that is necessary to allow blood to flow into or flow out of the ventricles. The basic formula you need to remember to understand this is:- Fluids flow from high pressure area to low pressure area along the pressure gradient ...


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Period of Isovolumic (Isometric) Contraction:Immediately after ventricular contraction begins, the ventricular pressure rises abruptly, as shown in Figure causing the A-V valves to close. Then an additional 0.02 to 0.03 second is required for the ventricle to build up sufficient pressure to push the semilunar (aortic and pulmonary) valves open against the ...


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To measure cardiac output by the so-called “indicator dilution method,” a small amount of indicator, such as a dye, is injected into a large systemic vein or, preferably, into the right atrium. This passes rapidly through the right side of the heart, then through the blood vessels of the lungs, through the left side of the heart and, finally, into the ...


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Drs. Swan and Ganz developed a direct method of measuring cardiac output by thermodilution. They invented a multilumen catheter with a thermal resistor on the end (a Swan Ganz catheter) which could be advanced into the pulmonary artery. Through another lumen, a cold saline solution of known temperature and volume is injected into the right atrium. Using a ...


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An interesting question! I am attaching the picture from Boron & Boulpaep, Medical Physiology, 2nd Ed, p921 here to clarify the details left out in the hand drawn picture. The flow of the digestive pancreatic enzymes increase mainly during food consumption. This is brought about by a number of redundant systems. The fasting secretion of pancreatic ...


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To say that there is a cutoff of one minute at which time shocking becomes ineffective is incorrect. The best way to defibrillate a heart within one minute of VFib onset is with electric shock. In fact, short of certain drugs in certain instances, it's the only way to defibrillate Vfib, regardless of the amount of time that has passed. If the one minute ...


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Between at least the endocardial and epicardial regions, I believe the transient outward current is facilitated much more in epicardial cells. This article demonstrates the differences in Ito between the two cell types in dogs. I'm also recommending the following article about Ito phenotypes: "Transient outward potassium current, ‘Ito’, phenotypes in the ...


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Unless defibrillated within 1 minute after fibrillation begins, the heart is usually too weak to be revived by defibrillation because of the lack of nutrition from coronary blood flow. However, it is still possible to revive the heart by preliminarily pumping the heart by hand (intermittent hand squeezing) and then defibrillating the heart later. In this ...


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When haemoglobin takes on oxygen the colour will shift from blue to red. the reason for this is a change in orientation of the Nitrogen ligans of the haemoglobin molecule. The red cells pass through the veins in the lung(s) to the aevioli; the blue haem (pH~7.2) exchanges CO2 for O2 (now pH~7.4) 98% saturation and goes from blue to red. We see the ...


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Thank you for the fascinating question! It was tough to research but very worthwhile. LDL is actually not such a bad molecule. It is formed from VLDL/IDL after VLDL/IDL distribute triglycerides, phospholipids, cholesterol and cholesterol esters to peripheral cells. With less to give, LDL subsequently tries to be helpful by providing any needy peripheral ...


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Two main types of action potentials occur in the heart . One type, the fast response, occurs in normal atrial and ventricular myocytes and in the specialized conducting fibers (Purkinje fibers of the heart)and is divided into five phases. The rapid upstroke of the action potential is designated phase 0.The upstroke is followed by a brief period of partial, ...


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Remember that except for the concluding pathway through the A-V bundle, the atrial muscle mass is separated from the ventricular muscle mass by fibrous tissue. Therefore, ventricular fibrillation. The mechanism of atrial fibrillation, except that the process occurs only in atrial muscle mass instead of the ventricular mass. A frequent cause of atrial ...


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This is an interesting theoretical question, but several things would need to be clarified: Does removing the R atrium relocate the SA node to the R ventricle or remove it completely from the picture? Does the remaining R ventricle have a tricuspid valve? Technically, the R atrium is the home of the sino-atrial node, which provides natural pacing of ...


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The skin appears blue due to the diffraction of light through the skin. Blood is either bright red (sufficiently oxygenated) or dark red. "The blue appearance of surface veins is caused mostly by the scattering of blue light away from the outside of venous tissue if the vein is at 0.5 mm deep or more. Veins and arteries appear similar when skin is removed ...


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Reference values for hematocrit are identical in male and female children and as well in elderly men and women. Differences in hematocrit between fertile women and men are caused by repetitive loss of blood - and therefore iron - in menstruating women.


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Under conditions of high CO2 (in tissues such as muscle) and hence high acidity hemoglobin binds preferentially CO2, thereby mediating CO2 removal. Under conditions of low CO2 (high pH) and high O2 (conditions met in the lungs), it preferably binds O2, thereby releasing CO2. Hence, the specific characteristics of hemoglobin allow for CO2 uptake in the body, ...


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This is due to the fact that skin is the interface where heat is lost. Our body due to constant functioning, produces heat constantly as a by-product (due to exothermic reaction of ATP break mainly). The excess heat needs to be conducted away from the body, or it will cause a decrease in the body metabolism to prevent temperature rise. Heat is lost mainly ...


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There will be few rapidly-dividing cells in a fresh wound (which is the wound to which H2O2 is applied). In general, it is a good idea to avoid applying irritants to rapidly dividing tissue. Hydrogen peroxide is a weak mutagen. It is produced in many body tissues, ingested in drinks, produced by mouth bacteria, etc. It may well cause some cancers. Some ...


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Both pictures you posted show that increased peripheral vascular resistance decrease cardiac output. If you are talking about someone outdoors not properly dressed in a Scandinavian winter, then their cutaneous vasculature would constrict and Also their extremities would get less blood flow. That would increase peripheral vascular resistance and thus ...


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It's a complicated answer. More than 200 cell types, each type of cell inherits a unique expression of receptors, internal and external. Diffusion of signals through the plasma membrane and/or nuclear compartment may act directly as cofactors, activators, etc. The specific sequestration, and pattern of expression of external receptors also influence what ...


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I'm unsure currently about the empirical data surrounding inhibition of GLUT5, but with regards to GLUT2, some data exists to point out flavonoids and phloretin as potential inhibitors found in diet. The following articles should provide some sort of starting point to dig a little deeper on the matter. http://www.ncbi.nlm.nih.gov/pubmed/17699876 ...


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The parasympathetic supply to the heart is by nerves and that is truncated during surgery as pointed out. The sympathetic supply to the heart is by two means: Through sympathetic nerves from the sympathetic trunk From the adrenal medulla which secretes both adrenaline and nor-adrenaline directly into the blood stream The heart contains the beta ...


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It is impossible to objectively answer this question, as there is no defined method to objectively tell if the animal is dizzy. All that is known is the existence of vestibular system. Vestibular system helps to define ones orientation with respect to gravity. The response of a reptile to such a stimuli would most probably be freezing as opposed to a ...


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Yes they do. The answer is glucose. Let's begin at the beginning: you eat a piece of fruit. The fruit contains many different kinds of sugars, including fructose and glucose. One of the immediate effects your digestion of this fruit has is to raise the levels in your blood of every type of sugar that was present, and the blood levels of many other types of ...


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Rhinorrhea, or runny nose is a response used by our nasal membrane to get rid of foreign particles including pollen dust and infection. As such we get runny noses when we have a cold, allergy or are exposed to high densities of air-born particles. Cold air may irritate our nasal membranes, both because of temperature differences relative to our body and due ...


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The short answer is: Yes. Fatal familial insomnia is a genetically passed down disease that at some random point in a carriers life will suddenly stop them from sleeping, ever, they die within 7 to 18 months I know you did not ask about the disease, but it shows (even without illegal war tests) that it will kill you eventually, even in humans. I believe ...



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