Cellular Differentiation
Elise Lambert
What is it?
Why is it Important?
- most cells start out as zygotes
- cells transform into different types of tissues
Plants and Animals
- happens in plants and animals
- meristematic cells in plants can differentiate into any type of plant cells
- stem cells can differentiate into any type of animal cells
- only the zygote and the first few divisions are totipotent (a cell that can differentiate into all types of cells)
- many cells can become totipotent in labs with plants
Stem Cells
- stem cells are totipotent
- can divide for indefinite periods
- three germ layers: mesoderm, endoderm, and ectoderm
Mesoderm
- middle layer
- building block to bone, muscle, and connective tissue
Endoderm
- lower layer
- later becomes lungs and digestive organs
Ectoderm
- outermost layer
- skin, nerves, and brain
Embryonic Germ Layer and Differentiated Tissue Diagram (from NIH.gov)
Endoderm
- Thymus
- Thyroid, parathyroid glands
- Larynx, trachea, lung
- Urinary bladder, vagina, urethra
- Gastrointestinal (GI) organs (liver, pancreas)
- Lining of the GI tract
- Lining of the respiratory tract
Mesoderm
- Bone marrow (blood)
- Adrenal cortex
- Lymphatic tissue
- Skeletal, smooth, and cardiac muscle
- Connective tissues (including bone, cartilage)
- Urogenital system
- Heart and blood vessels (vascular system)
Ectoderm
- Skin
- Neural tissue (neuroectoderm)
- Adrenal medulla
- Pituitary gland
- Connective tissue of the head and face
- Eyes, ears
Citations
"Differentiation and Development." Plant Sciences. Ed. Richard Robinson. New York: Macmillan Reference USA, 2001. Science in Context. Web. 20 Dec. 2015. (plants and animals section, what is it section)
Chandross, K.J. and Mezey, E. (2001). Plasticity of adult bone marrow stem cells. Mattson, M.P. and Van Zant, G. eds. (Greenwich, CT: JAI Press). (first picture)
The Stem Cell. In Stem Cell Information [World Wide Web site]. Bethesda, MD: National Institutes of Health, U.S. Department of Health and Human Services, 2009 [cited Sunday, December 20, 2015] Available at <http://stemcells.nih.gov/info/scireport/pages/chapter1.aspx> (stem cells, endoderm, ectoderm, and mesoderm sections)
Adult Tissue Stem Cell Production |. N.d. Web. 21 Dec. 2015. (second picture)
Digital image. Stem Cell Research. Brigham and Women's Hospital, 2015. Web. 21 Dec. 2015. (third picture)