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

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Why does a blood test show ethanol when no alcohol was consumed?

Why would ethanol show up in a blood test if a person had not been drinking alcohol in many years. What are other reasons for showing ethanol?
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1answer
855 views

Can an organism exist as a single cell but come together as multi-cellular during certain times?

I am trying to remember a particular segment from a BBC special, in which there was single cellular species. However, at certain times all the individual cells came together to form a structure, not ...
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2answers
971 views

How does Bernoulli’s Principle apply to the cardiovascular system?

Below are graphs which illustrate the cross-sectional area, velocity, and fluid pressure through each vascular segment of the cardiovascular system. It makes sense that velocity and cross-sectional ...
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0answers
50 views

What causes anorexia nervorsa?

I've heard of anorexia nervosa being a severe loss of appetite. I'm wondering what causes such disease in humans?
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2answers
150 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 ...
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0answers
29 views

How hydrophilic is human mucus?

I am interested in the stability of virus particles in human mucus, and how this may bias the evolution of surface amino acids in respiratory viruses. For instance if the mucus environment were more ...
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0answers
22 views

Why do the vines change their spinning direction?

Look at the vines holding onto the lattice. The "vine springs" change their spinning direction in the middle. Why? And how do they achieve this? (By the way, what's the name for this plant? Is is ...
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2answers
157 views

Do people with gout live longer?

Antioxidants reduce damage to tissue (by scavenging the free radicals) and thus may reduce ageing.It is known that Uric acid is a very good antioxidant. People with gout have excess accumulation of ...
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1answer
4k views

How does a pine cone open?

When a pine cone is wet, it remains closed. However, when it's dry it opens again. From the perspective of physics or biomechanics, what is the mechanism that allows a pine cone to open and close as ...
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1answer
83 views

Are the cells (structures) of deep sea fish different? And can they survive in shallow water?

In the deep oceans the pressure is enormous. But still there are fish living. But are the cells of them different from fish who just live at the surface of waters? For example, are the cells smaller ...
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1answer
82 views

What causes swelling after impact?

Why does the head swell after getting hit by something hard? What is the liquid that forms after impact?
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0answers
18 views

Glycoprotein hormones metabolism

Why do the carbohydrate groups in glycoprotein hormones decrease the rate of metabolism? And increase the half-life?
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2answers
30 views

How does hypocalcaemia have an effect on the excitability of cell [closed]

Hypocalcemia increases sodium influx by leak channels. Why does this elevate the resting membrane potential and increase excitability?
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1answer
54 views

Does food continue to stay sequential once it is inside my body?

I may be very off on many scientific details here, but I'm always all ears. As far as I understand, any food that is eaten goes to the stomach, gets broke down even further into smaller food ...
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0answers
66 views

Can one eye affect the other eye's low-light adaption?

This previous question addresses how long eyes need to adapt to darkness and reach full contrast. My question is how does one eye affect the "transition" and/or efficacy of this "night vision" of the ...
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2answers
327 views

How efficient is the human body at metabolizing food?

My friend and I were having a discussion over how "efficient" human digestion is. If a human ate a 1000 calorie hamburger, how many of those calories (how much energy) does the body process into ...
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3answers
2k views

Why does the face turn pale in dangerous situations?

I know what the effects are of a dangerous situation on the brain, i.e., an activation of the hypothalamic-pituitary-adrenal (HPA) axis which eventually results in an increased heart rate and elevated ...
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0answers
24 views

Determination of Ageing by ECG inclusions/exclusions?

I am studying ageing and considering ECG signal because of its high sensitivity in theory (escardio). Some factors Sensitivity Gender Medical treatment ... Benchmark: RTG dental + wrist ...
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1answer
250 views

What is the maximum altitude where humans can survive?

What is the highest altitude that a human can survive without being pressurized? Let's assume that oxygen and heat/insulation are not the limiting factors? Why I asked.
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1answer
73 views

Is blood pressure in the aorta and brachial artery the same or different?

Does the blood pressure at the root of aorta equal the blood pressure in the brachial artery? I've heard it does, but it doesn't quite seem to make sense as I'd think the blood pressure would be ...
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1answer
60 views

Does our nose detect only if there is change in odor?

If I enter a room with certain odor, I can sense the odor. However, if I stay there for some time I cannot sense it anymore. A new entrant to the room can still smell it or I have to leave the room ...
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1answer
160 views

How does 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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3answers
1k views

Why Doesn’t Hypercalcemia Cause Muscle Spasms?

If you have more calcium in the cell, wouldn’t more attach to troponin and initiate muscle contraction? Why does hypercalcemia cause muscle weakness instead of spasms?
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1answer
101 views

When was the last common ancestor of pig and human?

Some religions regard pigs as unclean on the grounds that pig flesh is closest in composition to human flesh. I don't believe this for one instant, but it got me thinking, just how close is pig and ...
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1answer
125 views

How do cellular waste products enter arterial blood?

I recently learned that blood in renal arteries contains waste materials, which is filtered via nephrons in the kidneys. My question is, how are these waste materials getting into the arterial ...
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1answer
5k views

How do inward rectifier potassium channels work in the heart?

Apparently in cardiomyocytes, there is an inward rectifying potassium channel that operates during phase 4 of the cardiomyocyte action potential. I have heard that despite this potassium channel ...
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1answer
355 views

How is ammonia removed from the colon?

“Lactulose is also used to reduce the amount of ammonia in the blood of patients with liver disease. It works by drawing ammonia from the blood into the colon where it is removed from the body.” ...
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3answers
12k 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. ...
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1answer
237 views

Is there nutrient absorption in the large intestine of hindgut fermenters?

In hindgut fermenters, plants are digested in the caecum by microbes. I want to know whether hindgut fermenters can absorb the nutrients obtained from the digestion in the large intestine because the ...
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1answer
79 views

What is the effect of exendin on beta-cells?

Do you know if exendin, an analog of GLP-1 (glucagon like peptide-1), can be toxic for beta-cells? For example, what is the effect on INS1 or Min6 cells at a certain concentration or after 90 mins of ...
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1answer
78 views

Which is more susceptible to dehydration — extracellular and intracellular fluid?

I want to ask in human body, there is intracellular and extracellular fluid that makes up the total body water of our body, which is drained first when we do activities? extra or intra? if I want to ...
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1answer
135 views

Why are some human injections intraperitoneal?

In humans, what benefit do intraperitoneal (IP) injections(old/cheap rabies vaccines, or cancer related injections) offer versus traditional intramuscular injections? For example, where I live, the ...
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3answers
2k 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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1answer
56 views

How body loses more fat in CO2 form than in sweating form? [closed]

Yesterday, I saw TV Game Show. There is question like this: Body loses more fat in which form? It gave 4 options: 1) CO2 2) sweating 3) xxx 4) xyz sorry i didn't remember 3 & 4 options. ...
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2answers
371 views

How does the microbial environment in your gut initiate?

Clearly, a zygote does not harbor any microbes. As it develops, and the alimentary canal tissue is differentiated, I logically assume that there is still no microbial activity in the fetus's gut. I'm ...
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413 views

Where do the bacteria within the vagina originate from?

I understand that it's feasible the bacteria within the gastrointestinal tract originate from the food we eat and air we breath, but where does this population of microbes originate from?
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1answer
604 views

Why does a fetus drinks and urinates into the amniotic fluid?

I was reading this website saying that fetuses urinate into the amniotic fluid. It also mentioned that, because we drink the amniotic fluid, we’ve been drinking our urine for months. However, why do ...
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1answer
238 views

Are the byproducts of mammalian digestion simply depleted versions of the food or liquid consumed?

When mammals consume food and digest it or drink fluids that are then filtered by their kidneys, are the waste products generated simply depleted versions of what they consumed? Are there other ...
6
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1answer
63 views

How can hyperthyroidism induce osteoporosis?

It says in my physiology notes that hyperthyroidism can cause osteoporosis. I've been trying to figure out how this could be possible for a little more than an hour now. Every article that I look at ...
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3answers
7k views

Why is defibrillation in asystole (“flat line”) useless?

In most popular medical dramas, when a patient has a cardiac arrest and "flatlines" the doctors many times use a defibrillator to "shock the heart back into rhythm'. I know that actually, the proper ...
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1answer
47 views

How much is local blood non-Newtonian in Pathophysiology?

I am studying the Barus effect / Merrington effect / die swell / extrudate swell, which is a characteristic of non-Newtonian viscoelastic liquids (Introduction to the phenomenon in this video) i.e. ...
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1answer
92 views

What is enantiostasis?

I have searched around and read my textbook but I am failing to understand how enantiostasis is different to homeostasis. For reference, Wikipedia definition is as follows: Enantiostasis is the ...
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1answer
117 views

Which organs in the body are responsible for measuring temperature?

As an instrumentation engineer, I have designed temperature control systems capable of measuring and controlling temperature with a precision of 0.001K over a wide temperature range. I have always ...
2
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1answer
211 views

Why do mice have a higher metabolism?

Mice and other small animals have higher metabolic rate than humans. How does that happen on cellular level, if we look on one cell in the mouse body? What is it in this cell that will be ...
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1answer
55 views

Unable to identify a muscle of the anterior thorax

I was watching an YouTube Anatomy Video which goes over the major muscles of the anterior superficial thorax. There is a structure present throughout the video which goes unmentioned, and I can't seem ...
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2answers
4k views

Difference between facilitated diffusion and secondary active transport in cells

Specifically, what is the difference between facilitated diffusion carrier processes (passive transport) and secondary active transport co-transport processes (active transport)? They seem to be the ...
3
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2answers
518 views

When glucose production is low, the brain begins using ketoacids as energy… how does that work?

Can someone very generally describe how the brain consumes ketoacids/ketone bodies when blood glucose has been completely depleted?
4
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1answer
155 views

Why do people in the scientific community use terminology such as renal, hepatic, cardiac instead of kidney, liver and heart? [closed]

Are there differences between renal, hepatic, cardiac and kidney, liver and heart? Is the "jargon" used more commonly because of tradition, or is there some definitive biological basis to it?
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5answers
17k views

What is the cause of muscle cramps?

According to wikipedia, muscle cramps are caused by myosin fibers not being able to break free from the actin filaments during contraction, resulting in a prolonged contraction. Obviously a lack of ...
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0answers
26 views

Why doesn't EMG data for triceps show a clear relationship?

In a surface electromyography (EMG) experiment of the triceps muscle where a person lifts weights, I found the value for maximum amplitude of EMG signal to be rather similar for all loads of 0-10kg. ...