Stem cells Flashcards
Cell proliferation:
When cells replicate themselves
Cell differentiation:
When unspecialised cells develop characteristics and functions of particular cells
How many different cell types can the inner cell mass (stem cells) become?
200+, anything but embryonic cells
Totipotent:
Any cell in the human body (200) + embryonic membrane, placenta and umbilical cord
Pluripotent:
Can become any cell in the human body, but not the embryonic membrane
Multi potent:
Gives rise to types of cells with a specific function, found in adults
Eg, red bone marrow gives rise to RBC
What are the three primary germ layers? + examples
Endoderm- epithilium lining of alimentary canal, urinary and gall bladder
Mesoderm- bones, cartilage, blood
Ectoderm- nervous system, teeth enamel, epidermis of skin
5 key roles of the placenta:
Endocrine gland- secretes oestrogen + progesterone Gas exchange Waste removal Immunity Nutrition (glucose, lipids)
Foetal development- 3 months
Forelimbs well developed, eyelids closed, outer ear completed, bone marrow formed, blood cells formed in bone marrow, sex distinguishable
Foetal development- 4 months
Arms and hands fully shaped, skeleton completed, movement of muscles
Foetal development- 5 months
Fine hair covers body, gripping reflexes, more growth
Foetal development- 6 months
Respiratory movements, digestive glands begin to function, tooth buds formed, eyebrows/ eyelashes
Foetal development- 7 months
Period of greatest growth, all systems functional except respiratory system
Foetal development- 8 months
Accumulation of fat beneath skin, growth slows
Foetal development- 9 months
Eyes open, nose well for,ed, sucking and grasping reflexes, fine body hair is shed