Final answer:
Muscle paralysis and atrophy occur when a nerve supplying a muscle is cut, leading to a loss of muscle function, muscle fiber narrowing, or potentially transforming into fat cells. Tendons connect muscles to bones, and disorders can affect this relationship. Skeletal muscle enables voluntary movement, and both ALS and Myasthenia Gravis demonstrate how nervous system issues can lead to muscle dysfunction.
Step-by-step explanation:
When the nerve supplying a muscle is cut, muscle paralysis and atrophy occur. This means that the affected muscle is no longer able to contract because it no longer receives signals from the nervous system. Consequently, the muscle fibers will begin to atrophy, or become narrower, due to the lack of stimulation and use. Muscle atrophy can also lead to muscle fibers turning into fat cells over a prolonged period, and a significant decrease in muscle mass is often observed.
The relationship between muscles, muscle fibers, and fascicles is that muscles are composed of bundles of muscle fibers called fascicles. Each muscle fiber within the fascicle is an individual muscle cell capable of contracting and contributing to the overall movement of the muscle. Tendons are connective tissues that attach muscles to bones, and muscular system disorders involving tendons could include conditions such as tendinitis.
The main type of muscle tissue used when you make a voluntary movement of one of your limbs is skeletal muscle, while smooth muscle and cardiac muscle function independently of conscious control by the brain. Muscle contraction involves the shortening of muscle fibers and is facilitated by the release of the neurotransmitter acetylcholine from motor neurons that innervate muscle fibers.