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) OR 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 theoretically form an entire new organism Human embryos only totipotent for first few days/week.

Pluripotent or “embryonic” stem cells Present in embryos after the first 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 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 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