stem cells

the basic unit of life; they make up everything in our body
%%cell structure is related to its function%%
- cells have a nucleus full of DNA protein that supports its function
can be used to regenerate dead/damaged cells
%%different cells have different functions%%
- neurons (brain cells) = transmit information throughout the brain
- keratinocytes (skin cells) = protect the skin against foreign particles
in-vitro fertilization: the process of fertilization where an egg is combined with sperm in vitro (an artificial lab environment)

%%the process that cells undergo to gain their specific function + shape%%
when cells specialize:
- they have a new exact structure/function/shape
- have a unique set of active genes & a unique organelle makeup/location
during embryonic development:
- initially, genes for cell division are the only ones turned on to increase the number of cells
- after the embryo reaches the “magic number of cells,” different genes are turned on in groups of cells (one set becomes the placenta + amniotic sac; one sec becomes the baby)
- genes are turned off after in a specific order to create hundreds of other cells
when cells are fully differentiated, only the needed genes are turned on in each particular cell type
- ex: in brain cells, only brain-related / general maintenance cells are turned on
- turned on means to actively make protein for that specific cell type
humans start as a zygote / fertilized egg (single cell) that divides/differentiates
- %%specialization = division of labor; have tissues/organs working for a specific function to make things more efficient%%
after puberty, most cells stop differentiating
- neurons & cardiac cells do not divide (which is why Alzheimer’s & Parkinson’s are so terrible; once the cells are gone, they cannot regenerate)
- but some cells maintain the ability to divide (ex: RBC, WBC; in liver, skin, stomach lining, lung lining)

personalized medicine = an emerging medical practice that uses an individual's genetic profile to guide decisions made regarding the prevention, diagnosis, and treatment of disease
cell-based regenerative therapy = promotes the repair response of diseased, dysfunctional, or injured tissue using stem cells
have the potential to differentiate into many/any different types of cells in the body
%%pluripotent = can become%% %%any%% %%cell in the body, beginning of development%%
%%multipotent = limited to what kind of cell it can become (partly differentiated), usually becomes the cell type of the same family%%
signaling by cells directs differentiation
%%importance:%%
- can be used for drug development, personalized medication, or new pharmaceutical drugs
- can treat areas where the body cannot heal itself
3 stem cell types:
- %%embryonic%%
- after 5 days post-fertilization, are pluripotent
- %%adult/somatic%%
- multipotent, the “adult” part doesn’t mean it has to come from adults
- %%induced pluripotent (iPS)%%
- takes a fully differentiated stem cell and treats it with chemicals to reprogram it to act like an embryotic cell
- essentially an artificial cell