Histology: Chapter 2:MITOSIS

MITOSIS

Mitosis can be viewed as the means whereby identical genetic material, contained in the chromosomes, is distributed to two daughter nuclei. It can be divided into four stages, each characterized by certain features of nuclear or chromosome morphology and chromosome movement. The stages are arbitrary in that mitosis is a continuous process from its inception at prophase through the stages of metaphase and anaphase to the final stage of telophase. The nucleus of a cell that is not dividing is in the interphase stage.

The number of mitotic figures in a tissue is an index of the rate of turnover of the component cells. In benign tumors, mitotic figures are few in numbers, whereas in malignant tumors, mitotic figures are more numerous and may include many bizarre forms. Hence, the recognition of mitotic figures is one criterion for the interpretation of various kinds of pathology of a tissue.  

Identify stages of mitosis on slide 34.

1. On slide 34, Mitosis (Iron H), are longitudinal sections of onion root tips in which cells have been fixed in various stages of mitosis. Learn to identify the characteristic arrangement of the chromatin in each state.