PATHOLOGY

Detailed explanation-1: -A ring of protein filaments called the contractile ring forms around the equator of the cell just beneath the plasma membrane. The contractile ring shrinks at the equator of the cell, pinching the plasma membrane inward, and forming what is called a cleavage furrow.

Detailed explanation-2: -Cytokinesis in Animal Cells Because of this, animal cells can bend their cell membrane inward and perform cytokinesis “from the outside in” by forming a cleavage furrow. A cleavage furrow is an indentation on the cell surface that continuously deepens until the animal cell is “pinched” into two separate halves.

Detailed explanation-3: -In animal cells, cytokinesis begins in anaphase, with the mitotic spindle determining the starting position of the contractile ring to form. In telophase, this ring becomes active, and the cleavage furrow forms and deepens until only a thin attachment, the midbody, remains.

Detailed explanation-4: -In fungal, amoeboid and animal cells, during the cytokinesis at the end of cell division, a cleavage furrow forms in the plasma membrane. A contractile ring containing actin and myosin is assembled at the selected site of the future cleavage furrow.