FAQ - Rigor Mortis
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From the time of death, how long does it take for rigor mortis to set in?

After a muscle contracts, ATP expenditure is required to release the myosin head of a thick filament from its binding site on the thin filament. Since all metabolic processes have come to a halt in a dead body, no ATP is being produced. Therefore, because of a lack of ATP, the myosin head cannot be released from the actin filament, and the sarcomere cannot relax. Because this happens in muscles all over the body, they become "stiff" and "locked" into place.

ATP is required to reuptake calcium into the sarcomere's sarcoplasmic reticulum (SR). Additionally, when a muscle is relaxed, the myosin heads are returned to their "high energy" position, ready and waiting for a binding site on the actin filament to become available. Because there is no ATP available, previously released calcium ions cannot return to the SR. These leftover calcium ions move around inside the sarcomere and may eventually find their way to a binding site on the thin filament's regulatory protein. Since the myosin head is already ready to bind, no additional ATP expenditure is required and the sarcomere contracts. When this process occurs on a larger scale, the disturbing twitches and gruesome postures associated with rigor mortis can occur. This happens after about 3 hours.

After about 72 hours, the body relaxes again, this time as a result of decomposition. This is known as resolution of rigor.  (+ info)

Dead weight. Does a body actually get heavier when rigor mortis sets in, where does the extra weight come from?

1. They call it dead weight because it is a hinderance. (something that is dead can't move itself or help in anyway) 2. Rigor mortis has nothing to do with weight, when the body starts to decay, lactic acid builds up in the muscle fibers, making the body stiff.

Wiki version: (In simpler terms, this means that the muscles become stiff because there is a build up of the waste of the energy producing process of the body. This buildup is because the chained tissues of muscles hook together and stick until the body starts to decompose. During decomposition, this buildup is broken down over time.)  (+ info)

If you observe a ded body with stiffened jaw and neck muscles but no further progression of rigor mortis,you?

can assume the victim has been dead for about.

A-two or three hours
B-six or twelve hours
C-twenty-four hours
D-two or three days

A  (+ info)

Rigor mortis/rotting in severed body parts?

My mom found the tail of a chipmunk that a stray cat killed. At the time we could move it and everything. Now after a few days its gone stiff.
My mom says that the skin in the tail isn't going to rot, and we don't have to skin the tail and let it dry in the sun in order to have it stay preserved. Is this true?

Pretty much. After a few days the tissue has dried out, which is why it's now stiff. It's going to stay this way.

BTW, rigor mortis starts about an hour after death, and eases a few hours after that (shorter in small animals, longer in bigger critters).

Oh, and kudos to your mom for letting you explore this instead of the knee-jerk "ew, ew."  (+ info)

Rigor mortis : how soon after death does it set in and how long does it last?

Rigor mortis begins within two to six hours of death. Over the next four to six hours, rigor mortis spreads throughout the body. Over the next twenty-four to eighty-four hours, the muscles relax once more. These times vary with age, temperature and the amount of physical activity the person was doing before death.  (+ info)

How are Rigor Mortis and Twitch the same? and How are they Different?

  (+ info)

what causes rigor mortis to go away?

I know that it is when your dead. I needed to know what causes the stiffness to go away. What is the chemical process........

  (+ info)

What is rigor mortis ?

What is " RIGOR MORTIS " ? after a death of any person
Please reply +vely ..

it is due to loss of adenosine triphosphate in the muscle fibbers after death.
it is noticeced very fast to occur i n animals which are fast runnig . and shout dead during running.
it has got forensic medicine importance.
it set in late 10 to 15 hours in winter season
3 to 5 hours in summer.
the time will be more if the body is in water.

it does not set in all parts of body a t a time. it sets down first in upper and lower limbs last in abdominal muscles.
it disappear when decomposition, starts .
the forensic importance is some time at the site of crime if the article like human hair or some materials hold in hand before death are not drooped out because of rig or mortise it is hold tightly.  (+ info)

how long does rigor mortis last fr the time it set in how long does it last?

Rigor mortis is one of the recognizable signs of death (Latin mors, mortis) that is caused by a chemical change in the muscles after death, causing the limbs of the corpse to become stiff (Latin rigor) and difficult to move or manipulate[1]. Eerily, during rigor mortis, muscles may contract in seemingly random and bizarre ways even though the body is dead.

After about 72 hours, the body relaxes again, this time as a result of decomposition. This is known as resolution of rigor.

Source: Neuroscience, Exploring the Brain 3rd ed. Bear, Connors and Paradiso

http://en.wikipedia.org/wiki/Rigor_mortis  (+ info)

what causes Rigor mortis when a person dies?

A few hours after a person or animal dies, the joints of the body stiffen and become locked in place. This stiffening is called rigor mortis. Depending on temperature and other conditions, rigor mortis lasts approximately 72 hours. The phenomenon is caused by the skeletal muscles partially contracting. The muscles are unable to relax, so the joints become fixed in place.

More specifically, what happens is that the membranes of muscle cells become more permeable to calcium ions. Living muscle cells expend energy to transport calcium ions to the outside of the cells. The calcium ions that flow into the muscle cells promote the cross-bridge attachment between actin and myosin, two types of fibers that work together in muscle contraction. The muscle fibers ratchet shorter and shorter until they are fully contracted or as long as the neurotransmitter acetylcholine and the energy molecule adenosine triphosphate (ATP) are present. However, muscles need ATP in order to release from a contracted state (it is used to pump the calcium out of the cells so the fibers can unlatch from each other). ATP reserves are quickly exhausted from the muscle contraction and other cellular processes. This means that the actin and myosin fibers will remain linked until the muscles themselves start to decompose.

Rigor mortis can be used to help estimate time of death. The onset of rigor mortis may range from 10 minutes to several hours, depending on factors including temperature (rapid cooling of a body can inhibit rigor mortis, but it occurs upon thawing). Maximum stiffness is reached around 12-24 hours post mortem. Facial muscles are affected first, with the rigor then spreading to other parts of the body. The joints are stiff for 1-3 days, but after this time general tissue decay and leaking of lysosomal intracellular digestive enzymes will cause the muscles to relax. It is interesting to note that meat is generally considered to be more tender if it is eaten after rigor mortis has passed.

Rigor mortis is caused by a chemical change in the muscles after death, causing the limbs of the corpse to become stiff and difficult to move or manipulate.
After death, respiration in organisms ceases to occur, depleting the corpse of oxygen used in the making of ATP, that forms your metabolism.

Hope this helps!  (+ info)

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