Questions tagged [physiology]

The study of the normal function of living organisms and their anatomical parts and the means by which their normal functioning is achieved.

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89 views

How much do arteries expand during pulse?

Arteries expand during a pulse. The amount of expansion may differ from artery to artery. How much do arteries expand? I understand it might be a range. Inform the same. Even values specific to some ...
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How nasal hairs filter particles of micron size?

This book says: The larger particles (> 10 μm diameter) are filtered by hair in the nostrils If we see the anatomy of nasal hairs and its density in the nostrils then it seems that its impossible ...
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What is the lifespan of Skeletal Muscle Cells?

I have read that skeletal muscle cells cannot multiply and are generally not created after early development. However, I have also read that they have a "lifespan" of 10-15 years. Could this lifespan ...
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Does human skeletal muscle fascia grow new additional collagen in response to increases in skeletal muscle size?

For example, if a human skeletal muscle is growing repeatedly due to periodic weightlifting, does the fascia eventually respond to the increasing volume by growing more quantities of collagen or other ...
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221 views

What is the lifespan of a human skeletal muscle cell (such as in the biceps)?

I have read that most human skeletal muscles (such as those in the biceps) cannot multiply after development (except for exceptional situations of severe damage that involve satellite cells) and that ...
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Will you stop sweating if you exercise in a cold enough room?

It's common knowledge that you will sweat from being in a very warm room. And you will also sweat from exercise, presumably because it raises your body temperature. But if you exercise in a cold ...
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1answer
366 views

Why do we die of old age? [closed]

Not sure where to ask this question and thought this would the best place. I am not after any opinion or theological, philosophical answers. I am after the science or biology research, experiments or ...
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How do bile salts affect lipase activity?

BACKGROUND: It is well known that bile salts are needed for emulsification of fats. It is then said that this increases the surface area for activity of pancreatic lipase, implying that bile salts ...
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214 views

Why does fetal distress (hypoxia) cause bradycardia?

In a non stress test performed in the labor room, fetal bradycardia is a danger sign indicating fetal distress (hypoxia). Why does fetal hypoxia cause bradycardia while hypoxia in adults cause ...
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2answers
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Where do mushrooms get their energy from?

I'm wondering where field mushrooms get their energy from. I've heard that they can easily grow on soil in a dark room. So, it seems to me that there wouldn't be any photosynthesizing plants from ...
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Which organisms require the least fluctuation in ambient temperature?

Note that I am NOT asking "which organism can survive the most extreme temperatures." Many extremophiles like the tardigrade can survives extreme heat, but also extreme cold. Many heat adapted animals ...
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Do pregnancy and breast feeding increase basal metabolic rate?

Since pregnant or breastfeeding women have extra nutritional needs, does that mean they have a higher BMR? Why I thought the conclusion would be sensible: Since BMR is the energy needed to perform ...
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695 views

Why do cats' claws retract?

Humans have nails, horses have hooves - but they are always exposed. Why are cats' claws retractable rather than always exposed? Is it related to "Why are there nail growth differences between humans ...
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915 views

How lymphocytes in lymphatic system get oxygen?

We know that the gas-transporting protein hemoglobin is absent from the lymphatic system. So, how does gas transportation takes place in lymphatic system? Is mere diffusion from surrounding blood ...
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369 views

Why can't we half-close our eyes?

Can we half-close our eyes such that they don't vibrate? If not, then why we are unable to half-close our eyes properly? Alternatively, why isn't it possible to keep the upper eyelid close to the ...
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447 views

Pneumonia in children after abdominal operations

This textbook says: Consequently, young children are prone to suffer from pneumonia after abdominal operations, because they resist breathing (being abdominal) due to pain. As a result the ...
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613 views

Are there neuron mediated reactions faster than reflexes?

I'm interested in how fast the human body can respond to a stimulus. I know the fastest reflex, the blink reflex, operates around 100ms from stimulus to reaction. I also know that the blink reflex ...
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1answer
355 views

Can assimilated energy be simply lost from a trophic level?

I was reading Environmental Studies By B. S. Chauhan and there a diagram of a model of transfer of energy. NU = Not used energy has been shown, energy that was neither stored or exported to the next ...
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2k views

Why do we feel cold in the lower part when we lie down? [closed]

This question is based on my personal experience. But I believe that this common for many of us. Let us say that I am sitting on a chair in normal indoor dress. Then, if I lie down on bed, I will ...
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2answers
68 views

Division of proteins

This textbook states Proteins determined by a single gene may divide to form different proteins with various physiological actions. First how do proteins divide? Second if it's just fragmentation ...
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1answer
120 views

Do mucous membranes surround visceral organs?

Wikipedia claims that: A mucous membrane or mucosa is a membrane that lines various cavities in the body and surrounds internal organs. The first part of that sentence is clearly accurate, but I ...
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1answer
492 views

Why does a stomach come before the gizzard in birds?

Since the gizzard is for mechanical digestion, shouldn't that happen before the stomach digests the food with acids? (to make the morsels smaller)
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1answer
8k views

Location of t tubule in muscle

Why do mammalian skeletal muscles have t-tubules at the junction of the anisotropic and isotropic band, whereas non-mammalian muscles and cardiac muscles have it at Z-line? What could have been the ...
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1answer
576 views

Movement in microvilli

My textbook( COMPREHENSIVE TEXTBOOK OF PHYSIOLOGY VOL-1 by GK PAL) says: Microfilaments project into microvilli present on the epithelial surface such as on the intestinal mucosa, and extend up to ...
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How well can humans detect vitamin-richness?

Humans do prefer fatty, sweet/starchy and salty. And fatty foods are rich in vitamins. How well can humans detect vitamin content apart from fattiness of food? Can humans choose the vitamin-richer of ...
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2k views

Common site for atherosclerosis

My book( textbook of anatomy abdomen and lower limb 2nd edition - by vishram Singh pg.no:286) says: Acute arterial occlusion: It is mostly caused by embolism or thrombosis. It usually occurs in the ...
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1answer
537 views

What is a centrosome?

I know that a centrosme is composed of two perpendicular centrioles, but the following sentences of Wikipedia confuse me: Interestingly, centrioles are not required for the progression of mitosis. ...
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1answer
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Quantity of hemoglobin in the cells [closed]

According to my book- red blood cells have the ability to concentrate hemoglobin in the cell fluid upto about 34g in each 100 ml of cells.The concentration does not rise above this value because this ...
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1answer
727 views

Has the concept of allostasis been adopted in biology, in place of homeostasis?

Peter Sterling, among others, has been a prominent critic of the concept of homeostasis. He instead proposes a process called allostasis. Homeostasis involves having fixed set points for ...
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108 views

Can we use cancer cells to generate blood vessels?

Is there any possibility to use cancer cells, which generate blood vessels, to generate our blood vessels when we are wounded or when we have varicose veins in our legs? Thanks for your answer in ...
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1answer
130 views

What do bloodsucking animals actually feed on?

A number of animals, including mosquitos, leeches, ticks and so on, feed on blood. And yet, at least in mammals, most stored nutrients can be found in body fat as fat, muscles and liver as glycogen ...
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1answer
901 views

when does an erythrocyte start carrying oxygen molecules and what is the binding capacity

As it is in the title, I am just wondering when does an erythrocyte (especially Reticulocyte) start carrying oxygen molecules and what is the binding capacity for oxygen. That is, Under normal ...
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510 views

What are the sites of nutrient digestion and absorption in the human GI tract? [closed]

Where does nutrient digestion and then absorption take place for different nutrients along the alimentary tract?
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106 views

How screeching affects the body?

Most times when I hear a screech (such as moving a sharp object on a chalkboard thereby causing such unpleasant noise), my body twitches. There are also other unpleasant sounds that causes the ...
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1answer
628 views

Vo2 of the brain is 21% of Q=13% or of the entire blood?

I am reading now the book which states that the Q (blood flow per unit of time) of the brain is 13% while the Vo2 (relative Oxygen used per unit of time) is 21%. Now my question is if the Vo2 of the ...
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1answer
2k views

Why is contractile vacuole absent in parasitic protozoans but present in free living protozoans?

I know that contractile vacuole helps in osmoregulation of protozoans and some nitrogenous wastes are also excreted through it. Since contractile vacuole plays an important role in protozoans, why is ...
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40 views

State of voltage gated sodium channels in depolarised potentials

Case 1 We learn in Physiology that during the depolarization phase in the membrane, more sodium channels tend to open as the membrane potential increases i.e., less negative. This is a kind of ...
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Iron deficiency anemia [duplicate]

It is said that iron deficiency anemia is characterised by microcytic-hypochromic RBCs. I would like to ask how iron deficiency causes decrease in the volume of RBCs? If the volume is decreasing ...
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3answers
2k views

How can an animal live without a head / brain?

The human body is unable to do anything if it loses its head - as the brain is separated from the body, the body immediately dies. But why does the same not happen to other species or animals? (As ...
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1answer
65 views

Interleukin 6 class cytokines

Wikipedia says: Leukemia inhibitory factor, or LIF, is an interleukin 6 class cytokine that affects cell growth by inhibiting differentiation. So does this means that il6=LIF ? or does it implies ...
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2answers
695 views

Feeling warm and cool breezes - how does it work?

As you travel with your hand sticking out of a car the sensation you have is one of cooling: even though molecules are transferring energy to your hand, you interpret it as being colder. Now, at a ...
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227 views

Can human eys/the brain be trained to see with bidirectional monocular vision?

Most people have a dominant eye, and while it uses its non-dominant eye in tandem with the dominant eye most of the time, the brain, being an expert in eliminating redunant information, ignores the ...
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1answer
226 views

Why pain caused by blunt objects vanish after some time and return at the event of touching?

Background When any bone/muscle of body is hit badly by a blunt object, it hurts pretty bad of course for some time. But, after some time the pain goes off completely or to some extent. Then, if we ...
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1answer
55 views

Understanding of the saturation function in the Monod-Wyman-Changeux Model

I am reading Mathematical Physiology, Sneyd. I am a undergraduate mathematician interested in pursuing the field, so forgive me if my terminology is off. In this example, the writer considers a ...
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2answers
534 views

Should heart-to-body energy consumption ratio equal oxygen consumption ratio?

The human heart pumps oxygen to the body, and the heart itself requires oxygen. Both the body and the heart use energy, usually expressed in calories or ergs. If we look at the energy consumption (...
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How do nasal and aural passages connect?

I have had a bad flu with a lot of congestion. My husband suggests a way to clear my stuffed ears is to pinch my nose shut then blow air through. Sometimes that helps, sometimes there's just too ...
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How do bats manage lymph fluids?

We all know that bats hang upside down to sleep. I was watching some sleep for a while, and they don't move much while asleep. If I fall asleep sitting in a chair my lower legs will swell. Lymph ...
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1answer
812 views

Do organs or any structure in the human body shrink/shorten if it's function is no longer useful?

Charles Darwin was one of the first scientists to theorize on the function of the appendix, which in his day had been identified only in humans and other great apes. He hypothesized that the distant ...
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Is there an ideal evolutionary body?

I am a science fiction fan, and when I watch movies with aliens, I get annoyed at the fact that they're all humanoid. I think, "What are the chances that it will look that similar to humans?" But I ...
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33 views

Correlation between threat and odour, taste

Is there any sort of correlation between threat and taste/smell? Are we evolved such that things which are harmful to life taste and /or smell bad and things(food) which are useful to us taste, smell ...

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