Tagged Questions

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

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7
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2answers
1k views

Can human organs be transplanted indefinitely?

I watched this movie, where they rented hearts to people for a year. I wonder if it is possible to transplant a heart indefinitely from person to person, or does the heart have a lifetime? So, do ...
1
vote
1answer
31 views

Does pupil size affect image focus in persons with no lens?

If an individual has no lens like Claude Monet (who had them removed). They should be able to still focus the images they see in a well light area if they shrink their pupils to a very small size ...
0
votes
0answers
12 views

Where can I find the details of kinematics data, physical parameters, and anatomical data of the forelimbs and hindlimb of a kind of horse?

Now, I am doing a simulation of horses, and some basic data, such as weight, height, species should be obtained to model a virtual horse. I am a student of engineering, and want to find some ...
0
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1answer
23 views

Does vitamin D form crystals in the blood with calcium and magnesium?

I read on a vitamin-D product (2000NE) that I should not use calcium and magnesium with it, because it can result crystal formation in the blood. I googled, but find anything about this. Is it true? ...
1
vote
2answers
21 views

How does the cell regulate different metabolic pathways?

I heard somewhere that cells use different nucleosides bound to triphosphates e.g. ATP, GTP, CTP and other modified compounds: NADH, NADPH to distinguish between different metabolic pathways and so ...
1
vote
1answer
31 views

Does the cellular response to every receptor work the same way?

I heard somewhere that activating any receptor results in the same intracellular response (signaling) which involves NF-κB. If that is true, I hardly understand how the cells distinguish between ...
6
votes
2answers
96 views

Does muscle get bigger by increase in size of individual cells or increase in number?

Somewhere in the back of my mind, I have the claim that a muscle never increases its amount of cells but, if the muscle gets bigger, it's simply because individual cells get bigger. The book Anatomy ...
3
votes
1answer
57 views

Do human visual functions degenerate due to genetic factors or by external factors?

Does eyesight primarily deteriorate 'naturally' due to genetics (genomic/epigenomic factors), or due to external factors such as normal wear and tear, or disease? By normal wear and tear I include ...
1
vote
1answer
30 views

Why is LH level much higher than FSH level at ovulation?

My teacher showed us an elaborate collection of graphs with one of them showing FSH and LH plasma levels during the menstrual cycle. LH level was almost 3 times higher than FSH level. Why? Does this ...
4
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1answer
30 views

Examples of genes involved in plastic responses

Adaptive plasticity involves sensing the environment and responding adaptively to it. Intuitively, I would think that this process may ask for a more or less complex genetic machinery of regulation of ...
5
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2answers
71 views

How do diving marine mammals avoid decompression sickness?

How do marine mammals, whose very survival depends on regular diving, manage to avoid decompression sickness or "the bends?" Do they, indeed, avoid it?
3
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0answers
45 views

Does eating antacid (such as Magnesia) before meal have any impact on digestion?

During an anatomy lecture I heard of the importance of the acidity of gastric acid (e.g., killing microorganisms, dissolving food, being a factor for triggering further processes). If a healthy person ...
0
votes
1answer
24 views

Recovery from a more severe injury can be shorter than from a less severe one [closed]

I vaguely remember reading somewhere that in certain cases, recovery from a more severe injury can occur faster than from a less severe injury. This was motivated by claiming that the less severe ...
0
votes
2answers
79 views

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

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

Does re polarization 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 re polarizing?
0
votes
0answers
16 views

Physiology of benign eye twitching?

About four times in my life I have experienced the feeling of my eyelid fluttering for a few minutes by itself, and then it stops. I have talked to other people who have had the same experience so I ...
6
votes
3answers
89 views

Why do I feel funny in my tummy when riding a virtual roller coaster?

I've ridden a virtual roller coaster on an Oculus Rift. I felt tension as I went up to the top, but more interestingly I actually felt my stomach drop when I went down the steep drop on the other ...
3
votes
0answers
29 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 ...
0
votes
0answers
9 views

Does dendrite have Na/K electrical channels?

Does dendrite have Na/K electrical channels if not so how can we sense the touche/pain/scald in our skin because we learned that Na/K electrical channels are present only in nerve fibers (axon).In ...
2
votes
0answers
42 views

What is the difference between rheobase and threshold?

What is the difference between rheobase and threshold? In the definitions I've read it's described as almost the same thing like it says the threshold is Stimulus whose strength (or voltage) is ...
0
votes
1answer
17 views

What is the difference between the basal membrane and the basal lamina?

I'm researching about the basal lamina in lung tissue and I'm not sure if the basal membrane is the same. What is the difference between them?
2
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0answers
18 views

How many cells are there in an apical meristem?

How many cells are there in the apical meristematic tissue? Looking at this picture... I would tend to think that there are few hundreds (maybe only a hundred) cells in the meristem tissue. But I ...
1
vote
1answer
43 views

What are the risks of elevating the legs too regularly and when tired?

I started to to think the pathophysiology of elevating legs high next to the wall too often and when you are tired. I think possible manifestations some damage to valves of the veins (No!) because ...
0
votes
0answers
18 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 ...
0
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0answers
30 views

Why are there no animals with a length greater than 30-40 meters or with a mass greater than 200 tonnes?

The biggest and heaviest aquatic animal is the blue whale: 30 meters long and a mass of 200 tonnes. The biggest and heaviest terrestrial animal was a Sauropod (plant-eating, long-necked dinosaur): 40 ...
3
votes
1answer
47 views

NADH inhibits gluconeogenesis?

I was told in a physiology lecture that alcohol inhibits gluconeogenesis because 'NADH produced from ethanol catabolism leads to product inhibition'. But is NADH not a reactant coenzyme of ...
5
votes
2answers
73 views

Why do small organisms make faster movements than big organisms?

I hesitated to ask this question because it seems so obvious and intuitive. However, I am not able to explain this tendency. Background It seems to me that small organisms make faster movements than ...
1
vote
1answer
42 views

All or nothing phenomena

We know that an action potential is produced by an active cell membrane when the stimulus reaches a certain threshold. When it does, an action potential fires, and when it doesn't, nothing happens. ...
2
votes
1answer
59 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 ...
12
votes
1answer
74 views

What is the mechanism responsible for the periodicity of hiccups?

Hiccups (singultus) are caused by involuntary spasm of the intercostal muscles and diaphragm, producing a sudden inspiration with associated glottic closure. It seems the neurobiology of the reflex ...
0
votes
2answers
49 views

Can you disconnect sensation from the brain without destroying muscle functions?

I want to know if it would be possible for a surgeon to "shut off" a person's senses without causing paralysis of any kind. The person would have to maintain their ability to speak and move, but not ...
2
votes
0answers
28 views

Biology Experiment Data (Hodgkin-Huxley)

I'm doing research into the Hodgkin-Huxley Model from an electronics/mathematics perspective and I'm looking to find actual numerical results from experiments on squid axons. I want to compare the ...
2
votes
1answer
71 views

How are arms different than legs?

Ok, this is a bit of a tangent question, but it came up yesterday and I didn't know the answer: How are arms and legs defined physiologically? For example, we say humans have two arms and two legs, ...
3
votes
1answer
40 views

Mechanisms of bone growth

The length of a bone is caused by growth of hyaline cartilage which is then replaced by bone tissue. How do cells know whether they should grow the hyaline cartilage? What are the key molecules that ...
3
votes
1answer
74 views

Mechanism of Muscle Growth

According to this video (sorry for the poor reference but it represents my level of understanding in physiology), muscle grow as a consequence of repairing micro-lesions. How are these micro-lesions ...
2
votes
1answer
48 views

What is the physiological difference between cortisone and cortisol?

There is only hydrogen bond different. Cortisol is synthesized by our body, while cortisone is given to the patient. Why you cannot give cortisol directly to the patient? I think the reason is ...
2
votes
1answer
35 views

Kinesiology Tape Benefits

Recently, kinesiology tape has become popular, especially in CrossFit. I have also noted its' use in the NFL, and I want to say Tennis as well. What beneficial effects does this tape offer our bodies ...
3
votes
1answer
188 views

Why do I breathe out of BOTH nostrils?

After reading the question why do I only breathe out of one nostril I realized that breathing out of both isn't common. I have always breathed out of both, and when I get a stuffy nose, or a runny ...
1
vote
1answer
46 views

brain activity responsible for imagination

Which part of brain is responsible for advance or unseen imagination For example:ones brain can make a situation in mind which is impossible to happen ...which part of brain is hyper active?
5
votes
1answer
32 views

Components of the concept of Developmental Noise?

Developmental noise is a concept that correspond to the amount of possible phenotypic variance of a given genotype in a given environment. Intrinsic noise (aka Cellular noise) is a component of ...
1
vote
0answers
34 views

Why is an inflammation in eye and brain more devastating and can lead to loss of organ function compared to other organ like liver etc.?

Recently I have learnt something about immunoprivileged site and I wonder why these sites like eye would prefer tolerating these antigens that sabotages the normal function of these to having ...
4
votes
1answer
70 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 ...
2
votes
2answers
213 views

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?
2
votes
1answer
31 views

What's the mechanism behind 'losing heat through your extremities'?

I can understand how if you are not circulating enough (warm) blood, by not moving much while in a cold environment, your extremities themselves lose heat, and become cold - but I don't understand how ...
0
votes
2answers
244 views

Negative role of Placenta

How can a placenta turn hostile to the mother or fetus ? What are the abnormalities found during placental delivery ?
0
votes
0answers
12 views

What biological processes are affected by dietary fiber besides peristalsis?

Dietary fiber affects the rate of peristalsis, but what other effects does it have? Does fiber affect signal transduction, hydration, the autonomic nervous system, organ function, other biological ...
1
vote
1answer
23 views

What triggers the release of gonadotrophin-releasing hormone with the onset of puberty?

I am interested to know the process of development of puberty. During puberty, when boys/girls reache 12-14 (puberty) years of their age, their hypothalamus releases gonadotropin releasing hormone ...
1
vote
1answer
89 views

Why do humans have only one liver? [closed]

Humans have two lungs, two kidneys... But only one liver. If the liver is vital to our survival, why do humans only have one?
1
vote
1answer
39 views

Gastro-intestinal physiology reference

I am a physicist but I have always wanted to understand how my digestion takes place in as much detail as possible. I have no idea about books or reference on the subject of Gastro-intestinal and ...
12
votes
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?