Final answer:
The increased muscle size in the body builder patient is the result of muscle hypertrophy, which is the enlargement of existing muscle fibers due to the increase in the number of myofibrils and sarcomeres within the muscle cells from resistance training.
Step-by-step explanation:
Muscle Hypertrophy in Body Builders
The increased size of the patient's muscle, who is a body builder, is documented by the nurse as resulting from muscle hypertrophy. This is the increase in the size of a structure, particularly an increase in the size of muscle due to exercise. When a person engages in resistance training, such as body building, the number of myofibrils and sarcomeres within the muscle fibers increases, leading to an increase in muscle mass and strength.
This hypertrophy is largely due to strain from increased muscle activity and weight-lifting exercises which build up the connective tissue and increase the number of contractile elements within the muscle fibers.
Hypertrophy is a normal response in skeletal muscles subjected to regular, intense exercise and is different from the pathological or compensatory growth that can occur in heart muscles or other organs. The process is different from hyperplasia where there is an increase in the number of cells. In hypertrophy, the existing cells simply get larger.
Moreover, hypertrophy contributes to increased muscle strength because muscle strength is directly related to the amount of myofibrils and sarcomeres present in the muscle fibers.