Which of the following element's ions are necessary for proper conduction of nerve impuises?

A. Transport proteins: Transport proteins are essential for moving ions, nutrients, and other molecules across the plasma membrane. While they play an important role in cardiac muscle function, they do not address mechanical stress caused by repeated contractions.

B. Glycolipids: Glycolipids contribute to cell recognition, signaling, and stability of the cell membrane. However, they are not structural elements that resist the pulling forces and stress cardiac muscle cells experience during contraction.

C. Tight junctions: Tight junctions create a seal between adjacent cells to prevent leakage of extracellular fluid. In cardiac muscle, their role is less about mechanical strength and more about maintaining selective permeability, so they do not counteract contractile stress effectively.

D. Desmosomes: Desmosomes are strong anchoring junctions that mechanically bind cardiac muscle cells together. They provide structural integrity and prevent separation during forceful contractions, making them the key feature that resists mechanical stress in the myocardium.

A. Organ systems operate independently of each other to maintain life: Organ systems work interdependently, with each system contributing to the overall homeostasis and function of the body rather than functioning in isolation.

B. The endocrine system is not a true structural organ system: The endocrine system is a recognized organ system consisting of glands that secrete hormones, which regulate various physiological processes, making it a true structural and functional system.

C. The immune system is closely associated with the lymphatic system: The lymphatic system provides structures such as lymph nodes, spleen, and lymph vessels that support immune responses. Lymphocytes and other immune cells travel through these pathways, linking immunity and lymphatic function.

D. Organ systems can be composed of cells or tissues, but not both: Organ systems are made up of multiple tissues, which in turn are composed of cells. Both levels are essential for the structure and function of organ systems.