Amoeboid movement Amoeboid movement, which involves extending
pseudopodia, relies on both ectoplasm and endoplasm. A change in
pH stimulates the ectoplasm to change the direction of pseudopodia in the amoeba. Ionic changes and
osmotic pressure cause the amoeba to undergo a gel-sol (gel-like to liquid) conversion in the ectoplasm. Actin
depolymerization causes this transition to liquid, and the sol ectoplasm streams forward, extending the pseudopodium. Osmotic pressure then pushes the sol endoplasmic fluid into the extended pseudopodium. The endoplasm converts from sol to gel as the actin and myosin complex reforms, solidifying the pseudopodium. On the other end of the cell, the ectoplasm transitions from a gel to a sol, forcing cellular components toward the extension. Throughout this process, ectoplasm and endoplasm are repeatedly converted into one another. Cyclic movement occurs as endoplasm becomes ectoplasm at the tip of the pseudopodium, while ectoplasm becomes endoplasm at the posterior of the pseudopodium. Ectoplasm also forms an ectoplasmic tube when food is present, allowing the amoeba to consume the food and convert the tube to a
food vacuole.
Macrophages in the human
immune system also utilize ectoplasm to move by amoeboid movement.
Flow network in slime molds Slime molds utilize a flow network composed of ectoplasm tubes (gel) that transport endoplasm (sol). Ectoplasm forms these tubules with actomyosin interactions. These fibers undergo peristaltic contractions, pushing the endoplasm throughout the flow network. Changes in the diameter of the tubules determine the slime mold's behavior, allowing it to change direction. This network also channels nutrients and signals throughout the slime mold, making it adaptable to the environment. This adaptability allows slime molds to solve mazes and optimize networks throughout their surroundings.
Sertoli cells and reproduction Sertoli cells, located in the
mammalian
testes, form junctions called
ectoplasmic specializations with
sperm cells to facilitate sperm development. Ectoplasmic specializations are
Tight junctions composed of actin situated between the plasma membrane and the
endoplasmic reticulum. The proper formation of the
blood–testis barrier relies on this ectoplasm, and these ectoplasmic specializations facilitate the movement of spermatogenic cells through the seminiferous epithelium during
spermatogenesis.
Toxins such as
cadmium damage the ectoplasmic specializations, inhibiting proper sperm development and disrupting the blood-testis barrier. == Evolutionary significance ==