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

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69 views

What stops the coagulation process?

Whenever there are minor/major injury to blood vessels, the platelets, fibrin, thrombin, etc. are recruited. They then seal the wound and block bleeding. What tells them that their job is done?
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171 views

What use a pair of lips?

Pardon my ignorance ... A lip is apparently a very sensitive tactile device - as it at-least serves to warn it's owner they may just be about to consume something that could cause injury. Primates ...
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58 views

Is stereo olfactory ability restricted to humans?

Most animals I see around seem to have two nostrils - humans, snakes, birds, fish .. and so on. From reading online I see that 2 nostrils provide a stereo olfactory effect. This stereo effect is ...
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12 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 ...
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17 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 ...
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21 views

Is it okay to do carotid sinus massages during palpitations? [closed]

Is it okay to do carotid sinus massages during a palpitation to slow the heart down?
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38 views

Vitamin D oral intake, transportation and absorption

Several factors affecting vitamin D and its active form absorption and storage acidity of stomach (not significant effect) cytopathic effects of viruses cytopathic effects of bacteria where the ...
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25 views

What is the nature of action potentials in autonomic nervous system?

My conjuncture is that the natures of sympathetic and parasympathetic action potentials are different. My findings propose me that sympathetic action potential is little longer lasting than ...
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28 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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28 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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43 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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29 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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1answer
61 views

Is end-systolic volume (ESV) the same as residual volume?

I am reading this site and my study materials. The end-systolic volume (ESV), 50-60 ml, is the volume of blood found in ventricles after systole and contraction of ventricles. I think ESV is the same ...
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42 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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65 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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20 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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1answer
53 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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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 ...
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51 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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62 views

Harmful effects of radiation from cell phone towers? [closed]

As per this article - http://www.thehindu.com/news/national/mumbai-citizens-link-cancer-to-cell-phone-towers/article5139166.ece , people living adjacent to cell phone towers claim to have developed ...
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948 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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77 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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0answers
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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1answer
85 views

Body size, what are the evolutionary trade-offs?

Background Considering just the "Kingdom Animalia" branch of organisms. It is clear that bigger does not necessarily mean better - there is large variation in body size... From the 94 µm long ...
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3answers
180 views

Why do we exhale after we hold our breath?

I tested this out with my friends, and I find that after they hold their breath and can't hold it anymore, they exhale air, instead of inhaling air. Interestingly, they all try to inhale in as much ...
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2answers
39 views

Is there any format for official Physiological/Medicine answers? [closed]

Assume you have an exam which has 5 extensive questions and 60 minutes. You do not have time to cover most if you write everything in essay format. If you start to write essays, you do not really have ...
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51 views

Which fish will have more developed gills?

A fish lives at the depth of 1000-2000m and another at the depth of 200-700m. Which of them would have a more developed gill system ?
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90 views

Is there any evolutionary/physiological advantage to multi-lateral symmetry?

Just wondering ; I get the impression a large number of multicellular organisms are multi-lateral in their physical structure. Why would evolution/mutation have retained multi-lateral symmetry in an ...
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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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2answers
33 views

Is Sinus node conduction necessary for heart beating?

Assume a patient with previous cardial infaction which SA node not possible to activate action potential anymore. However, SA trying to beat unsuccessfully repeatedly waisting energy. Therefore, I ...
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1answer
70 views

Can too low oncotic pressure lead to Third spacing and Edema?

I know that low oncotic pressure is associated with many pathologies. I am interested how it is associated with Third spacing. My professor says that it can permit edema formation. The opposing ...
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1answer
50 views

Regional circulation and Cardiac output? [closed]

I am reading my study materials and think what is the systemic POV here Regional circulation Blood flow within the tissue/organs based on the functional demands of the tissue. E.g. The ...
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2answers
23 views

To understand Second messenger signalling in I/c and E/c

I found this picture in my study materials. I think it is too schematic and ignores the big pictures. I think the thing connected to the hormone is receptor. The second messanger is then connected ...
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1answer
35 views

Can you approximate Cardiac Output by Ohm's law?

I found this sentence from my notes which I cannot understand PR < CO, CO $\uparrow$, PR > CO $\downarrow$ where ...
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1answer
67 views

Death because of no radio waves

I read somewhere that a man dies if he is isolated from natural electromagnetic fields and waves. (I imply fields of radio frequencies and below.) Is it true?
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105 views

Is the resting state of the forearm in the pronated or supinated position?

It seems to me that my forearm is naturally in a more pronated position than the anatomic (supinated) position and that it actually takes work to make it hold the supinated position. Anyone an expert ...
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1answer
90 views

Why do bats huddle during late fall?

In the late fall, bats hibernate in clusters with many bats pressed together and holding on to one another. Which of the following supposed advantages of huddling behavior is, in reality, not true? ...
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1answer
34 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 ...
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1answer
67 views

What is atrial fibrillation?

I am wondering exactly what a-fib is (causes and symptoms). I would really appreciate having a sample of an EKG with it (because in my limited research, I have found it nearly impossible to find just ...
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1answer
28 views

Does Sympaticus and lymphatic circulation cause feeling of thirsty after short shower?

I have been reading blogs, Guyton and Pocock about what triggers the feeling of thirsty. I am not convinced that is the fact of warm water time is short so not much water lost Assume that the ...
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1answer
97 views

Are females more flexible than males in all mammals?

It's common that human females have a more flexible body than males, (but I don't know why, so it'd be helpful if someone answers why so as well!) but does this apply to all mammals?
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1answer
28 views

What is the function of clot retraction?

I am thinking how clot retraction and fibrinolysis work together. I think that clot retraction is a process that gets clot towards fibrinolysis process. Fibrinolysis process then lyses the clot. ...
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1answer
46 views

What is the difference between intracardiac and extracardiac reflexes in cardiac regulation?

The primary parameters of heart pumping are strength of contractility (inotropic positive; Frank-Starling relationship) rate of relaxation (lusitropic positive) heart rate (chronotropic positive) ...
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22 views

How many systemic reactions in inflammation?

I have this sentence in my notes Inflammation consists of two local reactions and one systemic reactions. which is difficult for me to accept. Two local reactions are vascular and cellular. I ...
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2answers
258 views

Converting unit/mg or unit/ml into ng/ml, or vice-versa

I am working with the enzyme Cu/Zn Superoxide (SOD1) and i am quantifying them in ng/ml. However, most past studies has SOD1 quantified in unit/mg or unit/ml, and i need to compare the SOD1 level of ...
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1answer
31 views

Late control mechanisms of blood pressure (arterial) level?

I first covered the fast and moderate control mechanisms which I think are Fast control: Baroreceptive reflex (tonus), Chemoreceptive reflex (CO$_2$). Moderate control: Bicarbonate (ECF), ...
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1answer
40 views

Which processes are included in the process called cells eating themselves?

I am reading about atrophy and I am thinking to which processes the phrase cells eating themselves refer to. Cells need something to survive these difficult times. To decrease protein synthesis ...
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19 views

Order of events in hibernation

Arrange this in sequence : i. Heat loss exceeds heat production. ii.As body temperature falls, heat loss decreases. iii.Body temperature equals environmental temperature. ...
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1answer
108 views

Why can CO2 be transported dissolved in plasma?

Is it because CO2 is more soluble in water or has it got to do with the alkaline pH of plasma ?I here mean only aqueous CO2 transport from body cells to lungs.
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1answer
98 views

All or none phenomenon

Let's say that the threshold potential of a neuron is +40 mV to make a muscle twitch. Now suppose we have two signals of +20 mV. So, this signal will cause the twitch in muscle because it has reached ...