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

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104 views

How do animals handle light refraction in different media?

For a human, when diving underwater, everything is blurry because of the water's different refractive index compared to that of air, which we are accustomed to. How do animals, like turtles, seals or ...
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0answers
12 views
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2answers
61 views

What is the effect of persistent hypothermia on cardiac performance?

I define persistent hypothermia in this thread about the mechanisms of persistent hypothermia. The Graph of Katzung et al. in Pharmacology about Heart Failure: I am thinking which parts here are ...
7
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1answer
71 views

Should we induce fever to assist healing?

I am currently reading "The Fundamentals of Anatomy Physiology" 10th edition, and have found it an incredibly interesting book. I have just been reading about the lymphatic system, and the various ...
18
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3answers
2k views

Is there any use of CO₂ in human body?

We all know CO₂ as a waste product of metabolism . Does CO₂ have any helpful role , apart from having a role in pH of blood ?
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2answers
106 views

What physiological processes within a muscle cause the latent period in a muscle fiber?

This is a lab question I cant find the answer in the lab manual or in the text book. What physiological processes in a muscle cause the latent period in a muscle fiber? Please help. Edit: The latent ...
7
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1answer
47 views

Why can good music raise goosebumps?

Listening to really good music right now, I was wondering why it raises goosebumps. Is there any physiological reason for this reaction to specific wavelengths or something? EDIT: Due sometimes ...
0
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1answer
42 views

Similarity between a heart attack and a spasm

When someone is having a heart attack, could it be considered , in some situations, a spasm? Below, I have written how I believe the process may work. The heart is basically a muscle working ...
5
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0answers
67 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 ...
6
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5answers
72 views

Is the amount of blood that flows through every vein and artery per minute really a constant?

I was listening lectures from Mark Saltzman via Open Yale Courses. Now, if I did not understand him wrong, he said that the amount of blood that travels through every vein and artery in our bodies per ...
5
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1answer
49 views

Is hands-only CPR as effective as traditional CPR?

Is hands-only CPR as effective as traditional CPR ? Wouldn't 30 chest compressions + 2 rescue breaths be more effective if the person doesn't have a pulse AND not breathing? From my understanding ...
4
votes
3answers
700 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 ...
2
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1answer
30 views

Is Norway spruce (Picea abies (L.) Karst.) isohydric or anisohydric species?

Question from a thesis defense list ask me this. But I can't find the exact answer on the internet or in books. In my thesis, I described isohydric plants, for example maize, lupin, pea, poplar. This ...
5
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1answer
68 views

Do people that don't feel pain shiver in the cold?

There are a few diseases that cause an insensitivity to pain. This question asks about the relationship between the cold and pain, which got me thinking: Is shivering a response driven by the ...
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4answers
1k views

Why are there no organisms with metal body parts, like weapons, bones, and armour? (Or are there?)

Reading this question, Why are there no wheeled animals?, I wondered why no organisms seem to make use of the tensile and other strengths of metal, as we do in metal tools and constructions. I am ...
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3answers
87 views

Does the necessary Carbon Dioxide need to be in the atmosphere for mammals?

In the answers to this question, we've learnt that carbon dioxide is necessary for mammalian life, but is it necessary in the atmosphere/to breathe it in? Or does the act of respiration give a ...
2
votes
1answer
37 views

Detailed mechanism of the cause of diabetes mellitus type 1?

I have read in some texts that diabetes mellitus type 1 is caused by degeneration of beta cells due to our body's own immune reaction.Is it true? Can you explain further how are such types of immune ...
3
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0answers
27 views

Normal ECG/EKG Measurement?

I'm getting started using ECG using a 3 lead system by iWorx. I have place the leads on my two wrists and the ground on my ankle and have recorded some data into the provided LabScribe 3 software ...
1
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0answers
26 views

how food moves in horizontal coils of small intestines [duplicate]

This is a very very basic question, and I am looking at it more from point of view of physics. The small intestine is a highly coiled structure, which means it has horizontal coils as well. I can ...
10
votes
2answers
143 views

Why do we urinate more when we are nervous?

This question is a result of my personal experience... But I guess that is common for many of us. My school timing is 8:00 am to 1:30 pm (usually). During normal school days I typically urinate one ...
1
vote
1answer
35 views

How does ANF increase GFR?

ANF as we know reduce the Na+ uptake and K+ removal in the distal tubules and it also functions as a Vasodialator (?) But again it says that ANF increases the Glomerular filtrate ? But if it is acting ...
4
votes
1answer
19k views

Why are (some) cats attracted by bleach?

(Sorry if this question is only partly biological) I have noticed that several cats (including the one that keeps sleeping in my house), are fond of the odor of bleach (eau de Javel) and chlorine. ...
2
votes
1answer
44 views

Genetic abscence of backpain among teen girls? [closed]

I heard a study somewhere (I can't remember where) that claimed that teenage girls are genetically absent to experience high degrees of backpain, specifically from rigorous exercise. Strangely, of ...
4
votes
1answer
116 views

How can we measure cardiac output?

I could find a way which could find it by body oxygen consumption and there is another way to measure it by injecting drugs — measuring cardiac output by the so-called “indicator dilution method,” a ...
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0answers
79 views

What's Incomplete atrioventricular heart block (AV)? [closed]

This is unclear for me and I can not understand differences between complete and incomplete atrioventricular heart block.also I want an electrocardiograph of incomplete atrioventricular heart block.
3
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1answer
91 views

What’s the reason for isovolumic contraction and isovolumic relaxation?

During cardiac cycle, there are two periods in which the heart volume doesn’t change, but there is a change in tension/pressure. It takes about 0.25-0.35 second to achieve this change. I searched in ...
4
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1answer
161 views

Relationship between nerves and axons

I just wanted to get a realistic viewpoint of our nervous system. I understand arteries and veins, but I wanted to know how similar our nervous system is to that? I understand we have neurons ...
2
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1answer
57 views

Biphasic T wave caused by digitalis toxicity

Digitalis is a drug that can be used during coronary insufficiency to increase the strength of cardiac muscle contraction. But when overdosages of digitalis are given, depolarization duration ...
0
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1answer
71 views

Why is pericardium muscle repolarizated earlier than endocardium? [closed]

I was reading about heat muscle contraction and I read: The endocardium depolarization happens earlier than pericardium , but pericarduim repolarization happens earlier, therefore the T wave in ...
3
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1answer
2k views

What are the units of Q10 (temperature sensitivity)?

$Q_{10}$ is the increase in a rate (e.g. activity of an enzyme) observed with a 10° temperature increase. According to Wikipedia: ...
2
votes
1answer
65 views

What happens to our umbilical cord internally as we age?

I was always curious as to if or how much of the internal structure or workings of the umbilical cord are still in existence as we age. What happens to it over time? The wikipedia article naval ...
13
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0answers
2k views

Why do we experience temperatures below 37 degrees Celsius as 'hot'? [duplicate]

We always prefer to be in 20-25° C, although our core temperature is about 37°? Why is our skin temperature lower than our core temperature?
2
votes
1answer
33 views

Why is the resting potential of a neuron so close to the equilibrium potential of K⁺?

I know this has something to do with the K+ leak channel. I just don't understand how. I know that 3 Na+ are pumped out for every 2 K+ pumped in. This makes the cell interior net negative. I know ...
15
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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?
5
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3answers
116 views

Which fruit compounds affect the speed of fructose absorption?

Blood fructose levels are not regulated by insulin in the human body. This means that the body absorbs pure fructose very fast, and it raises the blood fructose levels rapidly. Do fruits/ vegetation ...
2
votes
2answers
118 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 ...
1
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1answer
48 views

What specific sensory nerves act as receptors for “pins and needles” (neuropathy)?

According to this excellent answer, the difference between "pain" and "pins and needles" (neuropathy) is that different receptors (sensory nerves) trigger in reaction to different stimuli. Different ...
4
votes
2answers
135 views

Why do skin and nail go blue in cyanosis?

I have learned that Cyanosis presents with blue skin and nails. What is the reason for the blue coloration of the skin and nails? Why wont the skin and nails turn another color in the visible spectrum ...
1
vote
1answer
86 views

Is there a known glucosepane cross-link breaker?

I read the following on wikipedia: There is, however, no agent known that can break down the most common AGE, glucosepane, which appears 10 to 1,000 times more common in human tissue than any ...
4
votes
3answers
133 views

How does vasoconstriction/vasodilation change blood pressure?

Background: I am coming at this question from an electrical engineering background, and I feel like I am missing certain assumptions that are going into the statement found in my physiology textbook, ...
0
votes
2answers
113 views

What is the name of the condition where no pacemaker cells are active in the heart for a short-time?

Assume that the heart is beating, but no pacemaker cells are working for at least 15 seconds. This would be a very long compensatory pause if extrasystole started it. There may be some low frequent ...
0
votes
1answer
41 views

How can succinylcholine cause myorelaxation?

I first thought that this is because of prolonged depolarisations. However, I am not sure anymore, because after reading PubChem, the only possible pathways are are Choline agonist. So I would say ...
3
votes
2answers
101 views

Why can't we defibrillate the heart within 1 minute after ventricular fibrillation by electroshock?

We mostly can defibrillate the heart before 1 min of ventricular fibrillation by electroshock.Then we often can't do defibrillate it with electroshock. What's the reason and What's the best way to ...
3
votes
1answer
45 views

Why do the size of the phase 1 notch vary among cardiac cells?

The size of the phase 1 notch varies among cardiac cells. It is prominent in myocytes in the epicardial and midmyocardial regions of the left ventricular wall and in ventricular Purkinje fibers. ...
2
votes
1answer
105 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? ...
9
votes
1answer
221 views

Why doesn't HDL cause diseases like LDL? [duplicate]

LDL particles pose a risk for cardiovascular disease when they invade the endothelium and become oxidized, since the oxidized forms are more easily retained by the proteoglycans. A complex set of ...
2
votes
1answer
252 views

Why do men have a higher hematocrit (red blood cell count) than women?

The hematocrit, also known as packed cell volume (PCV) or erythrocyte volume fraction (EVF), is the volume percentage (%) of red blood cells in blood. It is normally 45% for men and 40% for women. ...
8
votes
2answers
173 views

Why don't we see turbulence in the aorta even in normal situations?

I read about the Windkessel effect. Then I read about pulse pressure waves getting reflected from the periphery. If the pulse pressure wave is reflected during diastole and at the same time blood is ...
5
votes
1answer
177 views

Is a raised baseline between T and QRS normal in any ECG lead?

Here are excerpts from an unknown ECG lead. I find it weird that the "baseline" changes after the T wave and doesn't return until after the following QRS complex. Is that normal/expected for any lead? ...
0
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1answer
47 views

Does repolarization of muscle fibers mean that the muscle bundle is relaxed?

If I flex my bicep and continue to contract it does it mean that the muscle cells are in depolarizing state and not repolarizing?