Most of the muscles of the forearms are named based on their function because they are located in the same region and have similar shapes and sizes. It allows the teeth to close with a force of up to 55 pounds on the incisors or pounds on the molars.
Heart muscles are controlled by the sinus node influenced by the autonomic nervous system.
October Learn how and when to remove this template message Neuromuscular junctions are the focal point where a motor neuron attaches to a muscle. In the abdominal region, there are several sets of wide, flat muscles.
You can learn about musculoskeletal health problems in our section devoted to diseases and conditions. When we exert ourselves more than normal, the extra muscle contractions lead to a rise in body temperature and eventually to sweating. October Learn how and when to remove this template message Neuromuscular junctions are the focal point where a motor neuron attaches to a muscle. Recovery is very quick, with full creatine stores regenerated within five minutes. The cells of cardiac muscle are branched X or Y shaped cells tightly connected together by special junctions called intercalated disks. In addition, the axial skeleton that runs vertically through the back protects the spinal cord , which innervates almost all the muscles in the body. Muscles have long, thin cells that are grouped into bundles. Posture, such as sitting and standing, is maintained as a result of muscle contraction. Nearly 85 percent of the heat produced in the body is the result of muscle contraction. Connected to the sarcolemma are transverse tubules T-tubules that help carry these electrochemical signals into the middle of the muscle fiber. In addition to movement, muscle contraction also fulfills some other important functions in the body, such as posture, joint stability, and heat production. As a result of the high metabolic rate of contracting muscle, our muscular system produces a great deal of waste heat. Intercalated disks are made up of fingerlike projections from two neighboring cells that interlock and provide a strong bond between the cells.
The posterior scalene muscles, located on the lower sides of the neck, ipsilaterally bend the neck to the side and elevate the second rib. Aerobic training allows the oxygen delivery system to be more efficient, allowing aerobic metabolism to begin quicker.
Muscular system facts
Skeletal muscles also produce more subtle movements that result in various facial expressions, eye movements, and respiration. This is particularly evident in the knee and shoulder joints, where muscle tendons are a major factor in stabilizing the joint. Tendons are tough bands of dense regular connective tissue whose strong collagen fibers firmly attach muscles to bones. The place on the moving bone that is connected to the muscle via tendons is called the insertion. This small contraction is known as a twitch contraction. Muscle tissue also contains a stored supply of a fast acting recharge chemical, creatine phosphate , which when necessary can assist with the rapid regeneration of ADP into ATP. While individual muscle units contract as a unit, the entire muscle can contract on a predetermined basis due to the structure of the motor unit. When a motor neuron stops the release of the neurotransmitter, the process of contraction reverses itself. Tropomyosin is moved away from myosin binding sites on actin molecules, allowing actin and myosin to bind together.
The motor end plate contains many ion channels that open in response to neurotransmitters and allow positive ions to enter the muscle fiber.
Some muscles connect to more than one bone or to more than one place on a bone, and therefore have more than one origin.
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