I believe you're looking for "invasive species"
Answer:
After nutrients are absorbed during digestion, the excretory system removes solid waste products, or feces, through the rectum. The excretory system also works with the respiratory and circulatory systems and removes carbon dioxide (CO2) from the body. The excretory system also maintains fluid homeostasis.
Explanation:
Answer:The nuclear envelope reforms during the phase of mitosis called telophase. Telophase is the last phase of mitosis.
Explanation:
Answer:
The source of Calcium (Ca⁺⁺) for the skeletal muscle cells is the sarcoplasmic reticulum, the main store of intracellular Ca⁺⁺.
Explanation:
Calcium (Ca⁺⁺) is an ion that plays an important role in muscle contraction, a process that requires high cytoplasmic concentrations of this ion to promote myofibrillary activity.
The sarcoplasmic reticulum (SR) -equivalent to the endoplasmic smooth reticulum- is an organelle that regulates the contractile activity of skeletal muscle. The two terminal cisterns of the SR attach to the T-tube, forming a triad, which surrounds the myofibrilla.
Once the muscle cell receives the signal to contract, the Ca⁺⁺ channels are opened and allow Ca⁺⁺ to enter the cell, promoting the exit of this cation from the SR and increased its cytoplasmic levels. This stimulates muscle contraction.
