Questions tagged [human-physiology]

For questions on the biochemical, physical, and mechanical functioning of humans in good health including their organs and cells.

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What is the evidence that “release of synovial fluid gases” is the cause of knuckle cracking?

It has been said that knuckle cracking is due to release of built-up gases in the synovial fluid of joints, and thus not harmful. What evidence supports this statement?
powerful_bob's user avatar
1 vote
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17 views

Neuronal reflex circuit

I am having trouble understanding an exam question. I am given a diagram which looks like this: I am having a lot of trouble understanding this diagram since it looks unlike the diagrams usually ...
Rosarosa's user avatar
2 votes
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Why do different people perceive the colors of the Northern Lights (Aurora Borealis) differently?

A few days ago, I was in Norway with a group of about 20 people. We were fortunate enough to witness an impressive display of the Northern Lights that lasted several hours. The next day, we discovered ...
Vorbis's user avatar
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Bile storage and secretion

I know that the liver has left and right hepatic ducts that unite forming the common hepatic duct that then unites with the cystic duct of the gall bladder forming the common bile duct which unites ...
user7777777's user avatar
1 vote
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Understanding certain limited biochemical impacts of egg yolk

I am researching the use of isolated egg yolk lecithin (EYL) in food preparation. I am interested in its ability to act as an emulsifier without having ancillary negative impacts. I am aware that some ...
BobF's user avatar
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1 answer
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Nernst Equation and Membrane Potential

I am a bit confused on how to use the Nernst equation to determine polarization. I saw in the textbook that if potassium channels were open in a neuron cell, there will be a net diffusion of $\ce{K+}$ ...
Jaehyun Ahn's user avatar
2 votes
1 answer
55 views

Chloride Clamp and Nernst potential

The Nernst potential for chloride is -70 mV. The neuronal Resting Membrane Potential (RMP) is -70 mV. Under this condition, if the chloride channels are open (as it happens in Inhibitory Post Synaptic ...
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Does Lymph Clot?

According to my professor, lymph has the ability to clot because it contains plasma which has dissolved fibrinogen. He says that as long fibrinogen is present in a bodily fluid, it should be able to ...
Schrödinger's Cat's user avatar
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What happens to the gamma motor neuron during too much contraction of a muscle?

Suppose a muscle is contracting too much, so we need a reflex to stop it from contracting too much. Contraction of a muscle causes the muscle spindle to go slack, hence the Ia axons and II-axons do ...
Maria's user avatar
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Working in heat

What does working in temperatures of 180 degree dry heat for long periods do to the body? Such as inside of a cooking cyclone scraping product out of it while it's still at 180 degrees.
Henry Dalton's user avatar
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What is the cost of increased neural adaption for strenght?

Axiom: Physical strength is a function of muscle mass and neural adaption. I understand that increases in muscle mass incur associated metabolic costs. What are the corresponding costs for neural ...
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What torque can the human wrist take?

Say you are holding a rod in one hand with your tumb on one side and the rest of your fingers on the other. What amount of torque could be exerted onto the rod (with the axis of rotation being around ...
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Minimum conditions for human life

I don't know so much about biology, my strengths it is in physical science and mathematics. Well i like rifle shooting, I don't hunt, i think that is cruelty and coward. In some conditions of temp,...
Synco's user avatar
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1 answer
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Is “random arousal” in humans still caused by/connected to “background” sex drive?

I’m not sure if the title is the best way to word the concept but I don’t know how else to put it briefly; though honestly this question itself might be a bit hard for me to communicate concisely in ...
pastina's user avatar
2 votes
1 answer
291 views

How does sperm gets oxygen in the female reproductive tract?

At the time of insemination, sperm along with seminal plasma enters in female reproductive tract and the plasma contains fructose for providing the energy to sperm If the fructose follows just EMP ...
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1 answer
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Can citrate in semen be utilized as a source of energy by the sperm?

Prostatic secretions of semen include citrate as one of the component. The role of citrate in motility has been suggested by some researches. (Kavanagh JP. Isocitric and citric acid in human prostatic ...
Mohit J's user avatar
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What is the mechanism behind antibiotic resistance and how can it be mitigated or prevented? [closed]

What causes antibiotic resistance, and how can we combat it? I am interested in the mechanisms behind antibiotic resistance and strategies to prevent it in bacteria.
nane albert's user avatar
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CSF types in humans

There are several blood types such as A, B and O. Crossing these blood types such as in a transfusion, the results can be fatal. Along these lines, issues can arise when an organ or bone marrow are ...
Narasimham's user avatar
12 votes
3 answers
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How deep under water can humans open their naked eyes without damaging them?

Humans can tolerate a maximum pressure of 100atm, but it becomes uncomfortable above 30 atms. Deep divers usually wear protective equipment like goggles among other things and our eyes seem to be more ...
Aditya Kumar Panda's user avatar
2 votes
0 answers
32 views

What proportion of lung compliance is attributable to alveolar surface tension?

I am reading Guyton and Hall, chapter 38, Pulmonary Ventilation. It states that the two main factors influencing lung compliance are 1) tissue elasticity 2) surface tension elastic force. An ...
Roby Vicary's user avatar
2 votes
2 answers
182 views

Do afterload and stroke volume form part of a negative feedback loop in blood pressure regulation?

Blood pressure is the product of cardiac output and total peripheral resistance: $\text{BP} = \text{CO} \times \text{TPR}$ Since cardiac output is the product of heart rate and stroke volume, we have: ...
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Human Fat Adipose Tissue: Maximum Energy Transferred out per Day?

The article "A limit on the energy transfer rate from the human fat store in hypophagia" states that subjects with moderate activity levels are found to have a limit on maximum energy ...
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Estimating Weight of Human Skeletal Muscle?

Is there a way to measure the weight of skeletal muscle? I understand body fat and lean body mass can be measured by: skin fold calipers, electrical impedance, table lookup based on formula of weight,...
Nick's user avatar
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2 votes
0 answers
191 views

Does all CO2 from the blood leave the body through the respiratory system?

I know that the primary way that CO2 leaves a healthy human’s body from the blood is by diffusing into the lungs during gas exchange and then being exhaled. Is there any other way in which CO2 from ...
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Why’s brush bordered columnar epithelium found in intestine and not brush bordered cuboidal when I’ve been explained that they have the same function?

I searched for differences between their functions which would result in their positioning but none of it satisfied the answer to my above question.
mehroop 's user avatar
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Has electrical activation, rather than mechanical tension been investigated as a direct trigger for hypertrophy?

Three of the most common theories for what induces hypertrophy are mechanical tension, muscle damage and metabolic fatigue. The prevailing theory at the moment is that mechanical tension is the main ...
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How can children scream so loud and so long?

Recently I saw a small baby shrieking extremely loudly (my ears hurt) for at least 4 minutes . How is it possible? If I yelled so loudly, I would be defeated by throat ache after less than a minute. I ...
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Is it better for a person's stomach to have 1 big meal or 2 small meals? Does this change as a person gets older?

Is it better for a person's stomach to have 1 big meal or 2 small meals? Does this change as a person gets older. Also what about water? Is it the same way or different and why?
Guest's user avatar
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Why does oogenesis have to begin in foetal stage itself?

In males, spermatogenesis begins after puberty and they retain this ability throughout their life time. However, in females, oogenesis begins and ends in the foetal stage itself and the female is ...
Muralidhar Rao's user avatar
-2 votes
1 answer
315 views

What are the mechanical properties of human skeletal muscle?

TL;DR: I need more information on the mechanical properties of human skeletal muscle; if you have such information, please give it to me. I'm writing something on how much more effective (or otherwise)...
KEY_ABRADE's user avatar
1 vote
1 answer
227 views

Entry of particulate pollutants into the nasal cavity

NCERT Chemistry of Grade XII (India) writes Particulate pollutants bigger than 5 microns are likely to lodge into the nasal passage, whereas particles about 10 microns enter the lungs easily. I'm ...
Ansh's user avatar
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1 vote
3 answers
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How can you diagnose albinism in a naturally light-colored person? [closed]

Not all albinos have white hair. There is a type of albinism where the affected person has light yellow hair and the skin color can be the same as a normal North European person. How can you diagnose ...
Icecre4m's user avatar
6 votes
1 answer
409 views

What Produces the Postive Potenial in the lumen of the thick ascending loop of Henle?

In the Thick Ascending Loop of Henle, Paracellular diffusion of certain Solutes like magnesium and calcium takes place. Such diffusion is a result of the positive lumen potential. Looking at the image ...
Omar Shahaltough's user avatar
4 votes
0 answers
137 views

Which single substance among Potassium and Phosphate has the greatest osmotic activity in the Intracellular fluid?

My physiology textbook mentions that potassium has the greatest concentration ( 155 mEq/L ) in the Intracellular fluid and that I thought would make it the most osmotically active but the answer given ...
Sayak Roy's user avatar
4 votes
1 answer
130 views

How long does it take for a new muscle fiber to be connected to motor neuron?

When new muscle fibers are formed through hypertrophy, how long does it take for motor neurons to connect to the new muscle cells in order to be able to control them? After taking a break from ...
timtam's user avatar
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3 votes
1 answer
65 views

Hypothalamus and posterior pituitary gland in ADH production

Concerning the role of hypothalamus and the posterior pituitary gland in osmoregulation and especially when water potential of the blood is low, When the osmoreceptors in the hypothalamus detect the ...
Donia Elwardany's user avatar
1 vote
0 answers
29 views

Phenotype of a possible gene mutation

I have noticed multiple cases where patients had similar body characteristics : decreased ability to gain weight (slim) they are capable of sleep only 6 hours or less with normal functioning (...
mohamed's user avatar
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0 answers
34 views

At what cold temperature at thermoreceptors human feel pain (e.g. in fingers)?

I've tried web search but have not found that specific answer. As far as I know at least some people feel pain (e.g. in fingers) when exposed to cold for prolonged amounts of time. E.g. here ...
Alex Martian's user avatar
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0 answers
32 views

Medical Physiology

I've come across the topic of the influence of inhaled ammonia (caustic ammonia) on breathing rate and some cardiovascular changes. All of this stuff is thought to be mediated through the fifth ...
Alexandr_Kabanets's user avatar
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0 answers
83 views

Why do people make "aaagh" noises when they make an effort (e.g. trying to hit a ball hard)?

I'm referring to, for instance, grunting in tennis. It refers to how many tennis players make loud "aaagh" noises when hitting a ball. In daily life, people often also do this when trying to ...
J Li's user avatar
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1 vote
1 answer
399 views

What are the roles of ATP and ADP in muscle contraction?

I've always known that the hydrolysis of ATP generates ADP, P, and energy, so I'd assume that if energy is necessary in a given process, ATP hydrolysis should occur (or another exothermic process). ...
Enlico's user avatar
  • 161
-3 votes
1 answer
425 views

Why is it easier to spin in one direction than in the other?

When I use a rotating floor disk to spin fast (while standing), I notice that I can keep balance much easier and rotate much faster in clockwise direction rather than in counterclockwise direction. I ...
Anonymous's user avatar
6 votes
1 answer
930 views

How does increased resistance to flow decrease blood pressure?

I have recently encountered this question: Waldenström's macroglobulinemia is a condition which causes increased blood viscosity due to high protein content in the blood. How would Waldenström's ...
LamGyro's user avatar
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1 vote
0 answers
39 views

How does medicine work? [closed]

Take aromatase inhibitors for example. In order for a molecule to stop the enzyme aromatase from converting androgens into estrogens, it must meet 6 criteria: Not get broken down by the acidity or ...
projective_line's user avatar
5 votes
2 answers
472 views

Pathogens vs Microbes and the Immune System

I hope my question isn't too basic or silly. I am currently learning about infectious diseases in Year 11 Biology right now, and I'm stuck at the concept of pathogens and micro-organisms. Whenever I ...
scratch342's user avatar
2 votes
0 answers
48 views

Vitamin B12 deficiency Megaloblastic anemic

I have two doubts regarding Megaloblastic anemia which shakes my mind (1) first is- I know that vitamin B12 is required for thymidine synthesis which is further required for DNA synthesis and so if ...
Rahul Dhillon's user avatar
1 vote
0 answers
2k views

What causes metallic tastes when you receive electric shocks

Whenever I receive small electric charges (most often by, e.g. touching the jack of a plugged in charging cable, or the casing of a charging Apple device), I experience a very distinctive taste in my ...
Brondahl's user avatar
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3 votes
0 answers
809 views

Why does (insulin induced) hypoglycemia stimulate ADH secretion?

Intuitively, I understand that ADH (Anti Diuretic Hormone) is responsible for maintaining osmolarity, and increased serum osmolarity is a stimulatory factor for its release-- ADH increases water ...
Bipasha's user avatar
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-2 votes
1 answer
43 views

why are dizygotic twins genetically dissimilar

I am a high school student and I am a little confused in a topic related to dizygotic twins, I get to know that dizygotic twins are genetically dissimilar because they are formed as a result of two ...
Arun Bhardwaj's user avatar
1 vote
1 answer
164 views

Why is only the donor's antigen seen during a blood transfusion?

I am a high school student and I am a little confused that why only donor's antigen matters during blood transfusion? for e.g if the donor's blood is O- so it means that it will antibodies against all ...
Arun Bhardwaj's user avatar

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