5.2 Apoptosis

• What is the term for programmed cell death?

  Apoptosis
• How is the total number of cells in the body regulated?

  By controlling cell division and cell death
• What happens to cells that are no longer needed?

  They undergo apoptosis
• What is the role of phagocytic cells in apoptosis?

  They digest the remains of dead cells
• What is the difference between apoptosis and necrosis?

  Apoptosis is orderly; necrosis is chaotic
• What triggers apoptosis in cells?

  Activation of caspases
• What are caspases?

  Enzymes that initiate apoptosis
• How are procaspases related to caspases?

  Procaspases are inactive precursors of caspases
• What is the consequence of necrosis on neighboring cells?

  It can cause inflammation and injury
• What happens to the cell during apoptosis?

  The cell shrinks, condenses, and dismantles
• In which tissues does a significant amount of apoptosis occur during development?

  In tissues being remodeled
• How many cells die each hour in adult humans?

  Billions of cells
• What is the balance that maintains healthy tissues in adults?

  Apoptosis balanced by new cell formation
• What can abnormalities in apoptosis lead to?

  Neurodegenerative diseases and cancer
• How do some chemotherapy drugs affect cancer cells?

  They induce apoptosis in cancer cells