That one thing that I don’t know.
Primary germ layers are the three layers of cells that are established during gastrulation. (There’s a whole other part on embryonic development and how we go from a fertilized egg to a person but I’ll save that for a different time.)
http://forums.studentdoctor.net/proxy.php?image=http%3A%2F%2Fsnag.gy%2FiMuUm.jpg&hash=43474dd5b0a6c0360cdb95677c2b19de
Gives rise to:Ectoderm: outermost layer
Integument: epidermis, hair, nails
Epithelia of the nose, mouth, and lower anal canal
Most of the excretory system (kidneys)
Muscular and connective tissue layers of the digestive and respiratory systems
Endoderm: innermost layer
Epithelial linings of the digestive and respiratory tracts (lungs)
Now, how do you memorize this aside from staring at it hopelessly at 10:00PM at night and wondering why this has become your life?
Ectoderm- “attracto”derm (things that attract us to others, such as cosmetic features and “smarts”)
Mesoderm- “means”oderm (means of getting around as an organism, such as muscles and bone, and means of getting around in the body, such as the circulatory system, and means of getting around, such as the gonads)
Endoderm- linings of the “endernal” organs (digestive and respiratory tract, and their accessory organs attached to these systems)
ECtoderm- Epithelial and Communication systems (nervous system)
Mesoderm- Moving structures (muscle, bone, ligament, cartilage, blood)
Endoderm- Excretory structures (gastrointestinal, respiratory, urinary)
These are by no means comprehensive and if you’ve noticed, doesn’t account for everything in the body. So, good luck with that. The germ layers are complicated so don’t worry if you don’t get it right away!
-MCAT fact of the day (50/65)
