Figure 2Mitochondria
The mitochondria are located all along the myofibrils. They provide the energy a cell needs
to move, divide, secrete and contract. They are commonly known as the “powerhouses,” or
power centers of the cell. They are about the size of bacteria, but may have different shapes
depending on the cell type. The mitochondria produce energy in the form of ATP, which is used
during contractions, for daily activity, and recovery energy needs. Through regular and intense
high repetition resistance training, the cell must adapt by building more mitochondria. This will
boost cellular energy storage and ATP production capacity.
Other Cellular Components
Unlike most other cells in the body, there are several nuclei in the muscle tissue cells.
They are positioned all along the entire length of the muscle fiber and are embedded in the cell
membrane, or Sarcolemma. The nuclei contain DNA. This DNA controls all cellular functions,
and responds to various hormonal stimulations from the Pituitary, Adrenal, and Thyroid glands.
The absence of this hormone stimulation would result in the inactivity and degeneration of the
muscle tissue cell. The DNA transfers information from the nucleus to the mRNA housed in the
nucleolus. The mRNA’s function is to take instructions from the DNA to the ribosomes. The
ribosomes are the elements that actually manufacture protein. These ribosomes occur in the
Rough Sarcoplasmic Reticulum. The Rough Sarcoplasmic Reticulum is located all along the
length of the myofibril components. The ribosomes are the “assembly line” that actually builds
and repairs the contractile proteins, actin and myosin, in the damaged myofibrils using available
intracellular amino acids.