When a muscle has used up its normal energy stores, but still needs energy, lactic acid is released into the muscles. Small amounts of lactic acid acts as temporary energy source, helping the body to avoid fatigue. A build-up of lactic acid in the muscles causes a burning sensation in the muscles that can slow down or halt activity.
The lactic acid is due to a lack of oxygen called oxygen debt in your muscles, which is what makes your muscles feel sore. The best way to maintain physical activity is to run and stretch because it allows the blood to get to your muscles which brings oxygen with it.
The only effect in the muscle is the decreasing of pH (increasing of acidity).
burning your skin havent you ever seen untracble
produce lactic acid
The liver will extract lactic acid from the blood stream and convert it into glycogen, a reserve fuel type of energy.
The increase in lactic acid concentration in the muscle fiber's site doesn't allow the calcium ions flow from the sarcoplasmic reticulum to bind with the troponin of the actin site.Therefore the tropomysin doesn't clear the way from myosin cross-bridges to bind with the troponin which leads to the further muscle contraction.So from that point the entire muscle action ceases, till the lactic acid drains itself to be converted into useful products to be used by the body.But this is only in the case of trained athletes and in case of untrained, sedentary human, the lactic acid concentration takes a leasure-long time to get removed from the site followed by long lasting DOMS (delayed onset of muscle soreness) after any exercise and the opposite action is true in case of trained athletes.
A single muscle cell is called a muscle fiber.
Myofibril
make more muscle fiber
The short answer is "concentrated lactic acid." Concentrated lactic acid can get trapped in the spindle in the muscle fiber and can not get out. When this lactic acid gets trapped in the muscle spindle the feedback nerves that are protected in the muscle spindle can only send a weak signal to the cerebellum. A weak signal from the feedback nerve to the cerebellum tells the cerebellum to contract a muscle. The feedback nerve is trying to send a strong signal which would tell the cerebellum to relax but because the concentrated lactic acid is trapped in the spindle and interfering with the feedback nerve the correct signal can not get to the brain. As a result the muscle keeps contracting and it never relaxes. The muscles gets stuck in this "bad signal loop" which causes many other problems in the body.
a muscle fiber
muscle fiber
The smaller fiber in a muscle fiber is called a myofibril. A band of tissue that connects bone to bone is called a ligament.
The amount of oxygen liver cells require to react lactic acid to produce glucose or the glycogen is the oxygen debt. Threshold stimulus is the minimal amount of energy required to contract a muscle fiber.
The sacromere with the proteins actin and myosin allow the muscle cell (fiber) to contract.