Whats the process of muscle wasting (atrophy)?

Question

I am not quite sure on what happens during muscle atrophy. I saw this one person who was nothing but skin and bones and looked anorexic. So what happens to the muscles, and tissues and such. Does it just go away? Why are the people weaker? Does it have to do with cells? What about HIV wasting? Any answers would be appreciated.

Answer 1

damage, lack of blood flow. atrophy . its like taking a plant away from light and water, the muscles need proper blood flow

Answer 2

There are many diseases and conditions which cause a decrease in muscle mass, known as atrophy. For example diseases such as cancer and AIDS induce a body wasting syndrome called "cachexia", which is notable for the severe muscle atrophy seen. Other syndromes or conditions which can induce skeletal muscle atrophy are congestive heart disease and liver disease. Also simple inactivity, as when a limb is put in a cast, or when a patient undergoes prolonged bed-rest, can induce significant loss of muscle tissue.
Muscle atrophy occurs by a change in the normal balance between protein synthesis and protein degradation. During atrophy, there is a down-regulation of protein synthesis pathways, and an activation of protein breakdown pathways. The particular protein degradation pathway which seems to be responsible for much of the muscle loss seen in a muscle undergoing atrophy is the "ATP-dependent, ubiquitin/proteasome pathway. In this system, particular proteins are targeted for destruction by the ligation of at least four copies of a small peptide called ubiquitin onto a substrate protein. When a substrate is thus "poly-ubiquitinated", it is targeted for destruction by the proteasome. Particular enzymes in the ubiquitin/proteasome pathway allow ubiquitination to be directed to some proteins but not others - specificity is gained by coupling targeted proteins to an "E3 ubiquitin ligase". Each E3 ubiquitin ligase binds to a particular set of substrates, causing their ubiquitination.

Answer 3

This is a condition of motor unit dysfunction usually the result of a loss of efferent innervation,which means the is no proper muscle tone to cause contraction therefore the muscles loose their bulky shape and the extrimities maybe cylindrical,sometime is due to lack of motions or depleting diseases due to loss of important chemical components like calcium,vitamin D .etc that is people also who are beddriden or is a disease process condition

Answer 4

basically what happends after all the fatty tissue is literally eaten up by the body it starts working on the muscle tissue in order to maintain life.