Lec 17 - Embryonic Origins of Tissues

T/F? A zygote is a fertilized egg

True

Upon fertilization, _______ get sprevented

polyspermy (fertilization of an egg by more than one sperm cell)

After fertilization and cell division starts happening, what does the embryo become?

Blastocyst (hollow ball of cells)

What does the blastocyst contain?

inner cell mass (ICM - pluripotent stem cells)

trophoblast (future placenta)

Fertilization → _______ → compaction/adhesion → ________→ blastocysts → ________

cleavage, morula (totipotent), hatching

What does pluripotent means

stem cells that can make all types of embryonic cells except the placenta

The ICM is where the __________ stem cells originate

embryonic

Hatching is when the cell breaks out of the _______ _______

zona pellucida

Cell potency _____ over time as egg/embryo develops

decreases

Why does the cell potency decreases over time?

blastomeres → totipotent → pluripotent; over time differentiates

What are genetic comorbidities

presence of two or more disease/medical conditions in a patient

congenital birth defects: genetic v.s. environmental

genetic: BOAS

environmental: cyclopia (exposure to corn lily during pregnancy)

What happens after the blastocyst stage

gastrulation

What are the 3 germ layers of gastrualtion

1. ectoderm (outer) - neural, skin

2. endoderm (inner) - lung, gut, most internal organs

3. mesoderm (middle) - cardiac, bone, blood

Gastrulation happens during the _____ week of embryogenesis, once the cell has _______ into the uterine wall

2nd, implanted

Ectoderm → neural tube → ______ & ______

brain, spinal cord

Examples of Ectoderm (neural, skin)

epidermis

cloacal opening (rear hole)

mouth

brain

spinal cord

Examples of Mesoderm (blood, cardiac, bone)

Demis (inner layer of skin)

kidney

urogenital tract

kidney

muscle

vasculature

gonads

heart

Examples of Endoderm (lung, gut, most internal organs)

intestinal epithelium

stomach

liver

urinary bladder

thyroid glands

pulmonary tissues

pancreatic cells