Final answer:
The network of channels within cells that assists in substance movement is the cytoskeleton, complemented by mechanisms like facilitated diffusion using channel and carrier proteins and gap junctions between cells.
Step-by-step explanation:
The fine network of channels within cells that aids in the movement of substances is known as the cytoskeleton. It is a protein fiber network that maintains the cell's shape, secures some organelles in specific positions, allows cytoplasm and vesicles to move within the cell, and enables unicellular organisms to move independently. In addition to the cytoskeleton, other mechanisms such as gap junctions connect the membranes of adjacent cells to facilitate movement of small molecules and ions between their cytoplasms, providing electrical and metabolic coupling.
Furthermore, to transport substances across the cell membrane, mechanisms like facilitated diffusion are utilized. This involves channel proteins and carrier proteins. Channel proteins allow the passive movement of substances down their concentration gradient, while carrier proteins are more selective and can facilitate the transport of specific molecules such as hormones and neurotransmitters through specific interactions.
The cytoskeleton also includes structures such as microtubules, which extend the cell's ability to conduct electrical signals, guide the movement of chromosomes during cell division, and assist in intracellular transport. Overall, the cytoskeleton and associated proteins provide the cell with a dynamic framework for transport and communication between and within cells.