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Questions tagged [physiology]

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

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Muscular tetany and hypocalacemia

Decreased serum calcium level leads to increased excitability of neuron and at same time decreases the contractibilityof the muscle fibres.But still its causing tetany.Wouldn't these two counteract to ...
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2answers
73 views

Why did a lot of common insects evolve such a thin waist?

Something that doesn't quite make sense to me is why lots of insects like ants, bees and wasps have a such a small petiole when it connects many major organs to the rest of their body from a suddenly ...
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16 views

Why is the V/Q Ratio 0.8 not 1?

According to: https://en.wikipedia.org/wiki/Ventilation/perfusion_ratio the ideal V/Q Ratio would be 1.0 because 1 L of blood can hold about 200 mL of oxygen and 1L of humidified air has about 200 mL ...
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1answer
22 views

What is the difference between optokinetic and vestibular nystagmus?

Optokinetic nystagmus is for stabilising the pictures we see when we are observing moving objects for example if we are rotating on an office chair. If we wear a mask while rotating however, the ...
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1answer
26 views

Why does sympathetic activity constrict pulmonary vessels?

I don't know understand why sympathetic stimulation constricts pulmonary vessels? I thought that the sympathetic nervous system activated the body for physical activity. Physical activity would need ...
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1answer
16 views

Does focusing on a certain part of the body increase electrical activity in that region?

I am batting around ideas for master's thesis topics and was wondering whether or not just focusing on an area of the body would cause of boost of neuronic activity? Not sure whether this would fall ...
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1answer
25 views

Blood pressure in various blood vessels and heart

What are the typical systolic and diastolic blood pressure in arteries,capillaries, veins and the heart? I know it must be highest in the arteries. arteries>capillaries>veins Arteries: 120-80mmHg (...
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2answers
45 views

What causes “ear rumbling”?

The video Ear rumbling happens below the range of human hearing demonstrates that the "ear rumbling" sound is actual sound and can be recorded by a sensitive microphone near the ear. What is it ...
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1answer
30 views

How does vasoconstriction increase the pressure of blood?

Is the increase of pressure due to the decrease in volume? Wouldn't the decrease in volume push the components of blood closer to one another resulting in an increase of repulsive forces, thus ...
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20 views

Why doesn't action potential takes place in every cell?

I've read that Acetylcholine (ACh) released at synaptic terminal diffuses across synaptic cleft and binds to receptor proteins on muscle cell's plasma membrane, triggering an action potential. In this ...
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0answers
8 views

What is the optimal time to implant embryo in uterus for in vitro fertilization?

What is the best time to implant an embryo in the uterus. I was under the impression that the earlier the better and more natural, but also if you wait until the blastocyst age, it may be better to ...
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0answers
6 views

How do booklice avoid dessication?

I often find booklice (aka psocids) in old paper notes I have in semi-storage. These pages of paper are intentionally left in dry conditions on my desk to avoid damage. However, if the psocids live ...
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34 views

Why does water stress lead to alkalinity of xylem sap in plants?

I was reading this book: Plant Physiology and Development, Sixth Edition by Lincoln Taiz, Eduardo Zeiger, Ian M. Møller, and Angus Murphy when this doubt came to my mind. Abscisic acid, the stress ...
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11 views

Etymology of eccentric/concentric contractions

I was wondering if anyone knew why the terms eccentric and concentric were chosen to refer to lengthening and shortening muscle contractions? The basic etymology of the words are to do with ...
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31 views

Fight or flight

I have two questions: How do some bodily structures have only sympathetic nervous supply? For example, some structures like skin blood vessels have only sympathetic nerves which make these vessels to ...
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1answer
37 views

When muscles contract is the process similar to how non-newtonian fluids react?

I'm trying to understand how muscles contraction/tension works but getting loss in on the cellular level. From my understanding, when muscle tissue need to contract, the cells are flooded with calcium?...
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When we laugh or run for sport which autonomic system works?

When we laugh or run for sport which autonomic system takes place in this time? While I am not sure what happens in heart while laughing (tachycardia or bradycardia), but for sport running I'm sure ...
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1answer
68 views

Continuous (yeast) culture system satisfying multiple criteria

There are multiple ways yeast cells can be grown in liquid cultures. Batch cultures are easy to prepare but cell density, medium composition and physiology change over time Chemostats allow to ...
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3answers
1k views

Public database of animal specifications

I'm a math teacher looking for data to help my students interested in biology complete a quantitatively flavored study of animals. (As a math person, I apologize if I'm not using discipline-...
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1answer
57 views

Is there a name for the use of sunlight in metabolic processes?

"Photosynthesis" is what is used to describe how plants use sunlight to synthesize sugars, but, I also heard some animals like humans use sunlight in the process of creating vitamin D. Is there a ...
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1answer
81 views

Do sharks fart?

My son is 5 and I'm encouraging him to be curious and ask questions of the world around him. He asked if sharks fart and how does it smell? He feels that it would smell of fish and be disgusting. He ...
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0answers
20 views

Why is the glomerular filtrate isotonic to the blood in the capillaries?

How can the osmolarity of the filtrate be the same as the blood in the peritubular capillary when there is no red blood cells filtered?
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1answer
167 views

What are the limiting factors of human stamina?

What are the limiting factors of (human) stamina? Let's define stamina as the capacity to continue doing a physical activity. We clearly have our limits, so what aspects of physiology impose a limit ...
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1answer
54 views

Why do musk deer have the smallest red blood cells and amphibians have the largest?

What is the reason that musk deer have the smallest red blood cells and amphibians have the largest? Should they not be proportionate to the size of the organism?
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0answers
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What is the benefit of reducing inflammation when producing antibodies?

We just learned in lecture that IL-10 promotes the formation of plasma cells over memory cells. Which seemed strange to me as IL-10 also reduces inflammation, and I figure you would want inflammation ...
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2answers
5k views

Why is wombat excreta shaped like cubes?

I've heard that wombat excreta is cube shaped, but I don't understand how that can happen. Has anyone studied the phenomenon? What would the evolutionary pressure have been to cause this?
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1answer
47 views

How does vasodilation slow blood flow?

During inflammation, cytokines and histamine cause vasodilation to increase blood flow to the inflamed area. However, it is also said that vasodilation slows blood flow which facilitates the adhesion ...
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1answer
33 views

Common english name for tissues which are separated from the blood by blood-tissue barriers

Which general term is used to denote such organs/tissues as: brain, testis, thymus etc., which are separated from the blood by blood-tissue barriers?
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21 views

How the albumin regulates osmotic pressure

Do I understand correctly that: When albumin binds non-water molecules to itself, the concentration of non-water molecules decreases, thus the osmotic pressure decreases; When albumin carries water, ...
4
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1answer
71 views

What physiological processes give rise to a linear cell survival curve?

If we plot the number of surviving cells in a structure over time (assuming no replacement), the shape of that curve should imply something about the underlying process responsible for cell death. For ...
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2answers
36 views

Cross-species infections

I’ve heard that HIV developed from SIV, etc. I’ve also heard that most species (including most monkeys) can’t get a common cold like humans. So then what causes infections to be able to travel ...
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1answer
32 views

What is (are) the medium of conduction for an electrical current with an external source in the human body?

I am trying to get some background for some personal research I am doing into the effects of Electro Convulsive Therapy. I don't understand how electric current from an external household source, say, ...
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1answer
125 views

Why do crocodiles have a high concentration of lactic acid in their blood?

Crocodilians have high concentration of lactic acid in their blood. This is the cause that prevents them from prolonged intense activity, since prolonged intense activity causes the muscles to secrete ...
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0answers
38 views

Acute calculous cholecystitis

The action of mucosal phospholipases hydrolyzes luminal lecithins to toxic lysolecithins. The normally protective glycoprotein mucus layer is disrupted, exposing the mucosal epithelium to the direct ...
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41 views

Hematuria due to Nitric Oxide

Drug interactions between properly dosed NO and other medications are not expected, but side effects may include noisy breathing, hematuria, or possibly atelectasis. (pg.no:577; Goodman and Gilman ...
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0answers
37 views

about the muscle's tension's variables

I'm reading the paper "THE PROBLEM OF THE INTERRELATION OF CO-ORDINATION AND LOCALIZATION", which is written by N. Bernstein. The paper said "The degree of tension of a muscle is a function, in the ...
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1answer
53 views

Is every neurotransmitter receptor an ion channel?

This is a rudimentary question--perhaps the answer is well known to biologists, but is every neurotransmitter receptor also an ion channel? For example, NMDAR is a glutamate receptor and cation ...
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1answer
90 views

Are we evolving as fast as the oxygen is depleting?

How much oxygen saturation have we lost in the last 100 years? As oxygen levels dwindle and industry, deforestation, and population increases, at what year and saturation will the low levels of ...
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52 views

Why do people have characteristic body odour?

I am informed that odour (specifically coming from armpits) is due to bacteria residing on the skin do the work of manufacturing the malodorous compounds. So why do people have characteristic body ...
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2answers
101 views

How does 2,3 biphosphoglycerate works to release oxygen bound to the hemoglobin?

I read on Wikipedia that 2,3 BPG binds with the deoxygenated state of hemoglobin and helps in stabilizing it. It was also written that it helps release remaining oxygen from the hemoglobin. How? ...
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1answer
277 views

Mechanism by which hypokalemia reduces insulin secretion

Is there any known mechanism by which hypokalemia reduces insulin secretion? This video explains a mechanism, but its inherently wrong because ATP dependent K+ channels will allow movement of K+ from ...
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15 views

CETP inhibitors and LDL levels

While CETP inhibitors effectively reduce LDL, they also paradoxically increase the frequency of adverse cardiovascular events (angina, revascularization, myocardial infarction, heart failure, and ...
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0answers
50 views

Is there a biological determinant for right- or left-handedness?

When I was very young, I was sent by parents to examination where I was told both my hands are dominant in the same way. My parents preferred to make my life easier and chose to focus on my right hand ...
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1answer
111 views

Why does applying pressure to a venipuncture site prevent haematoma?

From what understand, when drawing blood, a phlebotomist puts pressure on the venipuncture site while withdrawing the needle to prevent a haematoma. I'd like clarification; How does this prevent a ...
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49 views

Boron vs Costanzo for first year of medical school?

Which book for physiology out of Costanzo and Walter Boron would you recommend to a first year medical student who has read upto the level of Campbell’s Biology textbook in high school?
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1answer
154 views

Are all mammals capable of sneezing?

I only know dogs and humans sneeze... so do other mammals sneeze as well? Is it possibly an evolutionarily-determined immunological trigger?
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1answer
77 views

How increased potassium intake increases sodium excretion?

"K+ antagonises the biological effects of Na+". I have been reading the same many times without any explanation. How actually (mechanism) K+ helps excretion of Na+?, their interactions? And eventually ...
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1answer
57 views

Does estrogen increase muscular growth in females?

Regarding humans it is said that most psychological effects caused in men by testosterone are caused in women by estrogens. There are many studies on that, particularly regarding temporary shifts of ...
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1answer
29 views

Square-cubed law and health

Does the square-cubed law lead to possible health detriments for taller people? I'm not sure what the optimum height is for humans (e.g. due to their cross-sectional bone density constraints), but ...
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0answers
118 views

What do Caucasians see in their peripheral vision, and how is their visual field?

I am an Asian who has no idea how much of their nose Caucasians (especially for those with extremely deep-set eyes, very prominent and low brow ridges, and high noses like Brian Shimansky or Rishi ...