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

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174 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 blood?...
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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
431 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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1answer
292 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 ...
9
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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
81 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
216 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
61 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
373 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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422 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
1k 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
64 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
9k 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 ...
2
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1answer
48 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
105 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
139 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
331 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 different?...
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1answer
59 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
603 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
158 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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0answers
28 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. ...
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4answers
392 views

Resilience to the neurotoxins of Indian King Cobra

I read on Wikipedia about this: King Cobra - Wikipedia In Thailand, a concoction of alcohol and the ground root of turmeric is ingested, which has been clinically shown to create a strong ...
2
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1answer
539 views

Is it true that cats can drink sea (salted) water?

Found somewhere in the Net, that cats can drink sea (salted) water. This fact seems to me as being urban legend, not true (because the purpose of water in body apparently implies it should be clear). ...
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1answer
98 views

Loss of appetite during fever

It is a well-known phenomenon that sickness like the common flu is often accompanied by reduced appetite. Why do sick people stop eating?
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0answers
18 views

How to use the law of diffusion in the presence of electric forces?

Isn't the movement of ions affected by the electric field as well? For instance, when a sodium channel in a cell's membrane opens, the sodium ions are said to diffuse into the cell, from higher ...
3
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1answer
37 views

classical conditioning paradigm for hippocampal learning

I wanted to know what a suitable classical conditioning experiment would be to analyze learning and memory capabilities in rodent models with respect to hippocampal long-term potentiation. For ...
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0answers
69 views

Is there a lower temperature limit, below which we cannot sense a difference in temperature?

At work I have to handle samples stored at -20 and -70 degrees Celsius, and they don't feel that different to me.
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2answers
80 views

What causes goose bumps?

What is the actual process and reflexes that cause the goose bumps? Why is it an evolutionary advantage to have goose bumps in the first place?
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1answer
26k views

What is the normal duration of human sexual intercourse?

Wikipedia is saying: Men's typical ejaculatory latency is approximately 4–8 minutes How the researchers measured this? How did they know if the test subjects weren't suffering from premature ...
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1answer
58 views

Wheatgrass in thalassaemia

In local newspapers there was a not so recent story about wheatgrass juice being "curative" in thalassaemia. Although I do not take the article at face value, it would be enlightening to know if there ...
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1answer
227 views

Why do animal cells lack a contractile vacuole?

I was asked why animal cells do not have contractile vacuoles. Other than the lack of need, I don't know what else to say.
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1answer
48 views

Determining the osmolarity and tonicity of a cell

Consider a cell with urea concentration inside being 2mmol/L and outside being 2.5mmol/L. The cell itself is permeable to both urea and water. Ignoring the effect of other osmolytes, A) Urea flows ...
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0answers
27 views

What are the molecular/cellular basis of pruritus ?

Could someone please explain the cells and molecules involved in the clinical phenomenon of pruritus ? I'm interested in a general view about the subject, but detailed answers will be appreciated.
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1answer
76 views

What is the effect of reduced gravity on human height?

There has been talk recently of building a base on either the Moon or Mars. What I'm wondering is, if you are born and grow to adulthood on the Moon, where the gravity is a tenth of the Earth's, would ...
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1answer
52 views

What differences in effect does fast repetitive exercise have compared to slower muscle-building exercise?

As a drummer who likes to play high-energy music (fast, aggressive metal) it's safe to say I burn a fair amount of calories when doing so. But I've been drumming for over a decade and despite the ...
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0answers
48 views

Which Lactobacillales (Lactic acid bacteria — LAB) strains are capable of degrading starch?

I've been researching bacteria strains but am having trouble finding amylolytic LAB strains with amylolytic and lactic acid producing character. The only species I've found, that are capable of ...
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2answers
6k views

Can humans transdermally absorb minerals from ocean water, and if so how much?

According to several studies quoted here, chemicals can be absorbed by the skin transdermally, at least under certain conditions. When it comes to elements in seawater like sodium, magnesium, ...
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2answers
101 views

Why we have to damage our muscles to build them?

I know that new muscle cells are made when actin fibers are disrupted. My hypothesis is that muscle mass is limited, from birth, and that nutrients (protein) are only directed to grow muscle when ...
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0answers
33 views

Is lung size/shape a factor in long-continuous running of animals?

Apart from other factors, does lung shape/structure/size play any role in long-continuous running animals. Is there any similarity in lung structure between different long-continuous running species?
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2answers
8k views

Why there is a very high drop in pressure from arteries to arterioles?

Laplace law explains why the pressure is the same in aorta and arteries (100). I am thinking why there is so big drop in pressure when going from arteries to arterioles (40-60). Why there is a great ...
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1answer
128 views

Are there fishes with a double circulatory system?

Our courseware materials say there are such fishes, but my Internet searches suggests fishes only have a single circulatory system.
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1answer
73 views

which organelle produce glycogen phosphorylase and why

I know that Glycogen phosphorylase doesn't produce from rough endoplasmic reticulum in liver cell. But almost every proteins such as insulin receptor, serum albumin, and lysosomal enzyme have to ...
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0answers
62 views

What is a common body composition in mammals?

The Physiology Of The Racing Greyhound states that most species have about a 40% muscle mass to body mass ratio. Understanding Body Composition puts "optimal fitness" in humans at 16-25% body fat for ...
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2answers
308 views

What is the relationship between W, X, Y and P, M retinal ganglion cells?

In Guyton and Hall Textbook of Medical Physiology (12e) the retinal ganglion cells (RGCs) are classified into W, X, and Y types. However, in Gray's Anatomy (40th ed.), RGS are subdivided into midget ...
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1answer
83 views

Does exercise really reduce stress in the biological meaning?

It is a very widespread claim, that movement in general helps body to get out stress hormones. It is used as a warning for long sitting at the computer and I also heard it as a pro-vegan argument (We ...
13
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2answers
8k 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 ...
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1answer
133 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 ...