Final answer:
Sarcoplasm refers to the cytoplasm of a muscle cell, which is crucial for metabolic activities necessary for muscle contraction, and it hosts the sarcomere, the functional contractile unit of the muscle fiber.
Step-by-step explanation:
Sarcoplasm is another term for the cytoplasm of a muscle cell. It is the site of metabolic processes for muscle contraction and contains organelles, such as mitochondria, and the myofibrils responsible for the muscle's contractile properties.
The sarcoplasm is surrounded by the sarcolemma, which is the plasma membrane of the muscle cell. The sarcoplasmic reticulum (SR), a specialized form of smooth endoplasmic reticulum, plays a crucial role in the regulation of calcium ions (Ca++) that are essential for muscle fiber contraction. The functional unit of contraction in a skeletal muscle fiber is the sarcomere, which contains the arrangement of actin and myosin myofilaments necessary for muscle contraction.