Chapter 12 Cell Differentiation 1 Cell differentiation 2
- Slides: 58
Chapter 12 Cell Differentiation
§ 1、 Cell differentiation § 2、 Cancer cell
Patterns of stem-cell division (a) Division of a stem cell produces two cells, one of which is a stem cell like the mother cell. In this way the population of stem cells is maintained. (b) The other daughter cell—a stem cell of more restricted potential—starts on a pathway toward producing more differentiated cells. When it divides, one of the daughters will be the same sort of restricted-potential stem cell as the mother and the other will be a progenitor cell for a certain type of differentiated cell. ©Progenitor cells can divide to reproduce themselves and, in response to appropriate signals, can differentiate into a terminally differentiated, nondividing cell.
癌症是一种严重威胁人类生命安全的疾病。动物体 内细胞分裂调节失控而无限增殖的细胞称为肿瘤细 胞(tumor cell)。具有转移能力的肿瘤称为恶性肿 瘤(malignancy）。 The term “cancer”, which means “crab” in Latin, was coined by Hippocrates in the 5 th century B. C. to describe diseases in which tissue grow and spread unrestrained throughout the body, eventually choking off life.
Depending on the cell type involved, they are grouped into three main categories. Carcinomas(癌), which are the most common types of cancer, arise from the epithelial cells that cover externaland internal body surfaces. Sarcomas(肉瘤) originate in supporting tissues of mesodermal origin. Lymphomas(淋巴瘤) and leukemias(白血病) arise from cells or blood and lymphatic origin.
Tumors arise when the rate of cell division exceeds the rate of cell differentiation and loss chemicals can cause cancer Radiation cause cancer Virus cause a variety of different animal cancer
Cancer is a genetic disease because it can be traced to alteration within specific genes, but in most cases , it is not an inherited disease. In an inherited disease, the genetic defect is present in the chromosome of a parent and is transmitted to the zygote. The genetic alteration that lead to most cancers arise in the DNA of a somatic cell during the lifetime of the affected individual.
The genes that hace been implicated in carcinogenesis are divided into two broad categories Oncogene and proto-oncogenes tumor-suppressor gene