I. Muscles and movement, movement and brain, systems and unit of movement
The muscles (musculus) are bodily organs built of tissues with the ability to contract. During contraction they convert chemical energy (ATP, glycogen, glucose) into mechanical energy thus ensuring the active movements of the body, the visceral organs, blood circulation, and organization of the blood supply through regulation of the heart and the diameter of the blood vessels. During use they generate heat, so they have a significant role in the regulation of body heat.
The muscle cells contain fibers capable of contraction and relaxation. These fibers move, effectively changing the size and shape of the cells. The muscles are responsible for triggering the effort of movement of the body and the internal organs.
There are three types of muscle tissues: smooth, skeletal and heart.
The human heart and smooth muscle contractions cannot be controlled voluntarily, they function autonomously. These muscles control vital body functions like heart contractions and peristalsis which is a series of contractions that move food through the digestive tract.
The skeletal muscle, made up of elongated transversely striated muscle tissues, which can be voluntarily controlled and highly maneuverable. These striated muscle tissues are responsible for respiration, speech, swallowing bowel movements and urinary tract control. It should be noted that, in addition to muscle cells, almost all cells are capable of active movement.
Muscles & movement, movement & brain, and systems & units of movement:
- every movement, including human movement, is based on mechanical principles;
- the body is a system of levers which are moved by muscles;
- humans have over 600 muscles which are controlled by nerves;
- brain signal and spinal nerve network regulate the intensity of the muscle energy;
- the majority of muscle work is done subconsciously and is automatically organized by the nerve-muscle (neuromuscular) network.
Additional information sources, literature, recommendations:
http://hu.wikipedia.org/wiki/Izom
http://www.webbeteg.hu/cikkek/sport_egeszseg/8202/webbeteg---sport-es-az-izuletek-vedelme
filament
myosin and actin
creatin
glycogen
Other sites and reading materials:
Motor system, muscle system, musculoskeletal system function, muscle soreness, motor neurons, axons, nerve cells, skeletal muscles fibers, motor endplates, impulses, synaptic, acetylcholine, effector, receptor, intercalary.
We also differentiate between fast (white) and slow (red) fibers within the striated muscles. Each muscle fiber ends with nerves. The stimuli to the muscle fibers cause contraction. The stimulus from the nerve cell membrane enters the muscle cells by electrical activity. Muscle contraction is created by the increase in the concentration of calcium ions.
Reciprocal innervation describes skeletal muscles as existing in antagonistic pairs, with contraction of one muscle producing forces opposite to those generated by contraction of the other. For example, the muscles moving the limbs are known as flexor and extensor muscles. These two muscle groups are opposites. If the flexor muscle receives stimulus, it contracts while the flexor relaxes and vice versa. This is called reciprocal innervation.