Cell Death, Growth, and Aging

metaplasia

a change in tissue structure over time

example of metaplasia

• smoking over time causes ciliated epithelial tissue in upper respiratory system to become striated hysquamous

hyperplasia

• cell proliferation by mitosis (increased cell number), during development

• ex: hemihyperplasia

hypertrophy

• cell growth in the absence of cell division (increase in cell size)

• ex: cardiac hypertrophy in athletes

neoplasia

• uncontrolled, unchecked cell growth (overactive mitosis, typically)

• ex: cancer

atrophy

• loss of tissue function caused by loss of tissue mass, usually after full development

• decrease in cell size, cell loss or death

• ex: skeletal muscle atrophy

hypoplasia

• lack of development by cell division (reduced mitosis)

• ex: thumb hypoplasia

apoptosis

• programmed cell death

• “cell suicide”

• ex: hand development

necrosis

• unorganized cell death

• “cell murder”; stress induced swelling and lysis

• ex: frostbite

apoptosis vs. necrosis

• apoptosis:

  • typically normal part of development, growth, and regulation

• necrosis

  • typically in responce to damage

stem cells

• for regeneration

• retain multipotency

multipotency

the ability to become a variety of different cell types