Stem Cell Introduction





Humans have about 200 types of cells.

Examples? (Record a few…)

• Neurons (nervous system); adipocyte (fat cells), heart muscle cells; erythrocyte (red blood cells); helper T cells

(immune system); rod and cone cells (eyes)

MOST of these cells either:

• Only reproduce to form same type of cells (e.g. skin cells)


• Don’t reproduce to make new cells

• Ex) damaged neurons, damaged heart muscle

• Can’t easily be replaced (think spinal injuries)

Totipotent stem cells – first few cells in an embryo

• Can reproduce to become any cell type

• Can hypothetically form an entire new organism

• Human embryos only totipotent for first 3-4 days.

Pluripotent or “embryonic” stem cells

• Present in embryos after the first 3-4 days/week

• Can form any type of cell in the developing baby

• But not a complete organism

• Obtain most embryonic pluripotent stem cells from discarded embryos (e.g. fertility clinics)

• Controversy ?

Induced pluripotent stem cells

• Obtained from adults – “tricked” from specific cell type

(e.g. skin) back into pluripotent in the lab

• No controversy (video will explain more)

Multipotent or “adult” stem cells

• Can divide to become only a FEW cell types

• Present in children, adults

• NOT embryos

• Multipotent stems cells are found in most organ/tissue systems

• Ex) blood stem cells

• Can create RBCs, WBCs, platelets…

Research with stem cells – why could it be good?

• If we can force stem cells to create cells that can’t “naturally” be replaced (e.g. neurons), maybe we can cure/fix damage/problems.

• We could research how to create properly working cells to cure diseases (like diabetes) in which cells are not working properly.

• Stem cells could be used to regenerate tissue damaged, for example in cancer treatment.

• Stem cells let us learn how all types of cells develop and work

– and this provides information on how to potentially cure all sorts of problems.

• Most stem cell research uses pluripotent or induced pluripotent stem cells

Take notes

• Record 3 substantive facts/ideas you learn about induced pluripotent stem cells