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

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Why is erythropoietin produced in the kidney?

Erythropoietin is a hormone produced in the kidney to stimulate the generation of more red blood cell. It is triggered by low oxygen via HIF transcription factors. Makes sense. Oops, oxygen is low, ...
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1answer
28 views

Could one hear without his ear?

Might be a stupid question, but I'm quite curious about finding out ^^ If someone looses his ear, or for example cuts it of, just as Van Gogh did. Would he still be able to hear, since the actual ...
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0answers
15 views

Could a baby heart be grown next to an old heart?

Could a small cloned heart (or any other vital organ) grown in a test tube be hooked up with the big heart and assist until it is large enough to remove the big heart? Could the replacement heart be ...
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1answer
48 views

Animals as organ donors and organ's life expectancy

Recent attempts to find reliable organ donors was using genetically-engineered (GE) pigs as heart donors. The pig's DNA is altered so that its tissues will appear identical to the patient's tissue and ...
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0answers
49 views

Why do we have a protruding nose?

What is the evolutionary reason behind a protruding nose ? And why don't monkeys and chimpanzees, for example, have it? Some say that the large brain in the skull kicks out the nose. But why do we ...
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0answers
18 views

Is there a organ or type of cell that makes Nagalase?

Schindler disease / Kanzaki disease is being described as alpha-N-acetylgalactosaminidase deficiency. So then, which organ or cell(s) produce this alpha-N-acetylgalactosaminidase (Nagalase) ?
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1answer
947 views

Why do eyes change colour after death?

Why exactly do eyes turn black when we die? (Or even change colour at all). The source of inspiration to this question is due to this video https://www.youtube.com/watch?v=6mNs_TcUyHc&t=627s (it's ...
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1answer
112 views

Why can't humans use dietary citric or acetic acid as a primary source of energy?

As the Krebs cycle is involved with the conversion of food in to citric acid, why can't eating citric acid be used as a temporary primary source of energy - in place of fat/carbohydrate/protein?? It ...
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1answer
389 views

Why do we need to close eyes to sleep?

Out of all our sensory organs, we need to stop taking signals explicitly only from eyes in order to sleep. Even interestingly, those who are not able to receive signals from eyes (i.e., the visually ...
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1answer
626 views

All somatic cells contain the same genome, then how does it knows that it should develop into a specific organ?

All somatic cells contain the same genome, then how it knows that it should develop into a specific organ. In https://www.youtube.com/watch?v=aeAL6xThfL8, Joe Hanson says that each cell has the same ...
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1answer
490 views

Can a hemorrhage occur after death?

Can a hemorrhage occur after death? Specifically lung hemorrhages. Can an organ hemorrhage after death and, if so, how long for?
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0answers
57 views

What structures (i.e. organs) are suspended by tensile forces?

In several areas of biomechanical literature I have read, the concept of "tensegrity" has arisen. Definitions are as follows: “The integrity of a stable structure balanced by continuous structural ...
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0answers
391 views

Do all body organs grow in proportion during the period of physical development?

It is obvious that during childhood and puberty, the human body grows uniformly or proportionally so that a child's arm length, for example, is shorter than an adult's arm length but is proportional ...
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0answers
65 views

Which organs can be donated after clinical death?

The information I found about organ donation does not address clinical death. For example: The process of donation takes place only after physicians declare a person brain dead [...] cessation of ...
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1answer
1k views

Medical term for “holding urine for a long time”

Sometimes I get/feel pain in my stomach because of holding urine for long time. Is there any medical terminology describing: "holding urine for a long time", or pain associated with this activity?
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0answers
15 views

In Vitro Meat Initial Production

I've gotten interested in the science behind in vitro meat, and I was wondering what would be necessary to create it. Would you initially need a primary culture, or an immortalized cell line? And how ...
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0answers
69 views

Changes in spongy urethra during tumescence

How does the columnar cells of spongy urethra expand during tumescence(erection of penis)? If we assume that the urethra has the length, long enough to sustain tumescence without expansion of cells, ...
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2answers
687 views

How does the bladder transition from releasing urine at night to being able to hold urine at night?

I wonder about this. What's the biology of the transition from wetting the bed at night to holding urine at night? Is there a chemical change with how the bladder muscles contract?
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0answers
75 views

Are sepals and petals analogous?

I came across a MCQ Question that asked sepals are analogous to petals or leaves?I think the answer is petals as both have same function of protection but different structures.Am I correct or the ...
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0answers
1k views

How to tell if something is an organ or apparatus?

An apparatus is defined as Physiology. a group of structurally different organs working together in the performance of a particular function. An organ is defined as: Biology. a grouping of ...
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1answer
132 views

Stem cell and organ growing genitals [closed]

I've been reading a lot about stem cell research and the work on growing artificial organs. I assume, with sufficient advance in the technology, there is no theoretical reason it would not be ...
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1answer
240 views

What technique biologists use in order to determine the function of organs? [closed]

How the biologists were able to determine the functions of body organs? Using a specific example organ for an answer would be ideal.
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1answer
91 views

Normal cell diffusion in normal organism?

We know, that cancer cell can travel across an organism. Is this ABSOLUTELY impossible for NORMAL cells? For example, is it EXACTLY ZERO probability to find some bone cells inside liver or some skin ...
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1answer
4k views

Is DNA replaced after organ donation?

If an organ from person A is transplanted to a new human body B, is it possible that we can detect A's DNA in B? How long until the organ's DNA is replaced by B's DNA so that we are no longer able to ...
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1answer
321 views

Lysosome function [closed]

Does any cell have lysosomes in it? Or maybe there are other organelles that do the same function. I read about it a lot and I can't find a good answer.
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1answer
152 views

Which organs need to have fluid compartments in order to develop properly?

I am a student, slightly struggling with the new concept of fluid compartments. I know that there are two main types of fluid compartment, extra and intracellular fluid. I also read that most organs ...
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0answers
63 views

Why are kidney discard rates so high?

A recent report from UNOS states: The kidney discard rate has returned to pre-KAS levels, dropping from 20.2 percent in the first six months to 18.4 percent in months 7-10. To me, this seems quite ...
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1answer
186 views

Please identify organ

This is the gut area of an Eastern Grey Kangaroo taken of a property in the Southern Highlands of NSW, Australia. The top red organ appears to be the spleen but what is the elongated tubular organ ...
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1answer
169 views

Is there a blood panel lab test that measures all the hormone-producing glands?

I understand that there are gland-specific hormone tests, such as: Secretin: for the pancreas; and Prolactin/ACTH: for the pituitary; and PTH: for the payathyroid, etc. However, are there any "...
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2answers
102 views

Organ donation compatibility based on DNA

As far as I know, multiple tests are made before organ transplant to determine matching. Would it be possible to do the matching based on the DNA of the patients, rather than the actual serum antigen/...
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1answer
46 views

What causes tissues manifest the various forms that they do? [closed]

A heart (or any other organ) is comprised of a group of cells. To the best of my knowledge, the growth of a heart depends on cell division. However, cell division by itself doesn't seem to explain why ...
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1answer
155 views

Why does organ transplant work although it seems organ's motor neuron isn't connected to recipient's CNS

Although it seems impossible with current technology to connect organ's capillaries to the recipient's capillaries and its motor neuron to the CNS, transplanted organ works for years. But why?
3
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1answer
138 views

Is MHC1 knockout sufficient to prevent transplant rejection?

A few days ago I read about MHC1 knockout pigs for organ transplantation research. I was just wondering, is it enough to knock out MHC1 in the donor (lets say from same species, pig to pig) for ...
3
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1answer
114 views

Does the palate truly house the sense of taste?

Source: Your “palate” is the roof of your mouth, and by extension, your sense of taste. I was reading Etymonline's entry for palatable {adj.}, which cites and derives from palate {noun}: ... ...
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2answers
20k views

Is blood regarded as an organ?

It consist approximately 7 percent of body weight. By definition organ is composed of multiple tissues. Blood is a fluid, a circulating tissue. Therefore can we call this fluid system a liquid organ?...
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2answers
2k 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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1answer
64 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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3answers
2k 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
3k 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
473 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
675 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
13k 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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2answers
4k 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
652 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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2answers
2k 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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4answers
6k 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, ...
7
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1answer
4k 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 ...
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2answers
509 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. ...
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2answers
15k 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 ...
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1answer
233 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 for ...