A collection of tissues which work together to accomplish a function. The organisational unit above tissues and below systems.

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107 views

Why do we have to exhale (or inhale) in order to speak?

Every time we speak, sing, or make any other kind of advanced noise with our throats, we exhale, or to put it that way, blow air through our throats. Why is this required? After all, speakers do not ...
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0answers
18 views

What do you NEED for a 100 meter sprint? [closed]

I was discussing with my friends the 100 meter sprint. Somehow, the topic changed to decreasing the time that the sprint would require: What parts of the human body could you feasibly remove to set a ...
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1answer
12 views

allogeneic organ transplant and the immune response

What happens when an allogeneic organ transplant is performed on an immunocompetent recipient vs. when it is performed on an immunosuppresed recipient using a donated organ with immunocompetent cells? ...
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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 ...
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1answer
348 views

Identifying internal structure of dissected prawn

Note: Some of the images might be disturbing. I have dissected prawn for the first time. Would like your help in identifying some structures . This is the dissection of the posterior part of the ...
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2answers
241 views

Does Science Say That We Should Die? [duplicate]

Excluding situations where you die from accidents, the main reason for death is -generaly- diseases. And usually it is about an organ which becomes "tired" after many years. These results are all ...
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1answer
55 views

Organs lifespan out of the body [closed]

What organ can be conserved outside of the body for the longest time and still function when reimplanted?
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2answers
771 views

The number of nipples (breasts) a species has?

Only mammals have mammaries and mammary glands. What evolutionary factors determines the number of mammaries (nipples/teats/breasts) a species has? Is it always an even number?
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1answer
249 views

Why is the liver the only internal organ of the human body to regrow?

Related to my earlier question, "How does the human liver regrow?", am curious as to why the liver is the only major organ that has this capability? Why is it that other major organs, such as the ...
3
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1answer
140 views

Why Is The Toughness Of Skin Different On Different Parts Of The Body?

My cat was licking my arm with his sandpaper like tongue. It hurt and the area he was licking was slightly smarting afterwards. However, when he licks the palm of my hand the feeling is rather ...
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0answers
86 views

Is there a biological process which causes organs to atrophy in response to enivronmental stressors? [closed]

I am aware of what happens when the body experiences starvation and breaksdown the muscles in the body for protein sources and the other processes that happen in such a scenario. However, i wondered ...
5
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2answers
463 views

What metabolic activities are performed by a developing human fetus's liver?

I understand that organ function varies with the stages of development. Does a fetal liver EVER perform lipogenesis, gluconeogenesis, make bile, etc? Or does it only begin performing these actions ...
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2answers
1k views

Why Is Most Life Symmetrical Externally But Not Internally?

Mammals, reptiles, arachnids, insects, etc are all as far as I am aware symmetrical in appearance. Take a human for instance, make a line from the top of our head right down the middle. However, ...
6
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1answer
751 views

What is the life-span of the various organs in the human body?

It is possible for a person to donate the harvestable organs (kidneys, eyes, and such) posthumously. Let's assume for a moment that the technology exists to kill rejection, and maintain the organ in ...
3
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2answers
173 views

Why is most tissue cellular?

Most tissue is comprised of cells. Why? It would seem inefficient to have so many individual nucleus, membranes, etc.? Specifically: Not all tissue is cellular. Much tissue is extracellular matrix. ...
7
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2answers
5k views

What are the consequences of voluntary total celibacy?

Psychologically this might be a tough question, but in means of biology, what are the effects of total celibacy on the gonads and the nervous system concerning both man and woman in short and long ...
9
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1answer
122 views

Organ cloning - possible to make a non-antigenic organ?

From a J. Neil Schulman article on Organ Cloning: Cannibalizing organs from other people also entails the risk of rejection because of incompatibilities, not only for tissue-typing but also ...
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3answers
681 views

Is the appendix a vestigial structure in all vertebrates?

In humans the Appendix is a vestigial organ. Does it serve no apparent purpose in all the vertebrates that have one?
7
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1answer
175 views

Can oxygen diffuse out through the lungs?

Let's say you accidentally walk into a room pressurized with pure nitrogen (or you're jettisoned into space). Within a couple of seconds, the partial pressure of oxygen within your lungs drops to 0. ...
8
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1answer
87 views

Which aspects of renal physiology are standing in the way of an artificial (mechanical) kidney?

Scientists have been able to create artificial organs with varying degrees of success. The mechanical heart (in its various forms, e.g. ventricular assist) is able to sustain life for some period of ...