Re: How does the color and texture of an organ relate to its function?

This is a great question.

However, the color of an organ does not really tell what it does. For 
example, the liver and kidneys are both red. One filters the blood, the 
other is sort of a metabolic engine for the body. The spleen is also red, 
but is an immune system organ. These organs are all red because they have 
a lot of blood flowing through them. However, the brain has a lot of blood 
flowing through it, but it is greyish. They eyes, teeth and bones are all 
white, but that says nothing about their function.

The texture of organs does not tell you what they do either. Most organs 
have a similar texture. Bones, teeth and fingernails have a similar 
texture, but don't tell you what they do. Skin and liver have a similar 
texture too, but they have very different functions.

However, the color and texture of organs in a particular person do tell 
you a lot about how they are working. For example, this what happens when 
a person drinks too much:  http://www.pds.med.umich.edu/users/greenson/AUGUSTLIVER. The liver is 
yellowish-white. Like fat. Because it is full of fat (compare to this 
normal liver in surgery: http://vrai-
group.epfl.ch/projects/nccr/images/liver.jpg). This tells us that the 
liver was not processing fat properly. Patients who have metastatic cancer 
(cancer that has spread) often have hundreds of little nodules spread 
through the liver (many one the surface). But even then, you have to 
understand the function of the liver to understand the significance of the 
color changes.

More visiable, the texture of skin tells you a lot about the history of a 
person. For example, in middle-aged and older people, if the skin is dried 
up and wrinkled (compared to other people of the same age), the person may 
have been overexposed to the sun or smoked (both of which are bad for 
skin). If the skin is yellow, it might be because the person has liver 
failure (which cause jaundice).

There is one type of organ were the color tells you something about the 
function. Muscles are red because they have mitochondria and myoglobin 
(which is a protein that is similar to hemoglobin). In chicken, white meat 
is white because these muscles don't have a lot of mitochondria (they use 
anaerobic metabolism). These muscles tend to contract very rapidly. On the 
other hand, dark meat is dark because it has a lot of mitochondria (these 
muscles tend to contract more slowly). Humans have similar differences in 
muscles, but it is not as easy to see the difference by looking at the 
muscles. (See:  http://www.clubs.psu.edu/up/sciencelions/AskSL/Fall2002/white_meat.htm and  http://www.ifafitness.com/stretch/stretch2.htm).

But, for the most part, you really can't tell what an organ does by it 
color and texture. In the old days (say 1000 years ago), they did not even 
know that the brain is what we use to think and the heart pumps blood or 
what the liver or spleen really do.

The reason why is that looking with the naked eye a different parts of a 
body doesn't give the detail that is needed. It is sort of like looking at 
a city from the air. You can tell where the buildings are, but you can't 
really tell if a big building is an apartment building or a office 
building (or both).

Thanks for this excellent, thought-provoking question.