Topic 2 Human Reproductive Anatomy: Extra Information about Human Reproduction

Question 1

• Series of strong uterine contractions
  i. Cervix thins out and dilates, amniotic sac ruptures and releases fluids
  ii. Rapid contractions followed by birth
  iii. Uterus contracts and expels umbilical cord and placenta

Answer 1

1. Labor (three stages)

Question 2

i. Fraternal/dizygotic twins - two separate eggs are fertilized by two different sperm, so the eggs are not genetically identical, and are no more related than ordinary siblings
ii. Identical/monozygotic twins - result from indeterminate cleavage; a single fertilized egg splits into two, forming two genetically identical offspring

Answer 2

2. Twins

Question 3

• This section is complex, and can be difficult to understand at first. I personally find visualization helpful in general, but especially so with embryology. The DAT Booster Developmental Biology videos explain early human development, and are very helpful in understanding how each event takes place, and is connected to other events.
• Because this is a common area of confusion, remember that the notochord is derived from the mesoderm. The mesoderm tissue initially forms a notochordal process that fuses with the underlying endoderm to form the notochordal plate, and this plate is what rolls upward to form the notochord. The developing notochord induces neural tube formation. On either side of the neural tube, blocks of tissue called somites form that go on to produce vertebrae of the backbone and muscles of the axial skeleton. The somites are also derived from the mesoderm.

Answer 3

Note

Question 4

i. Totipotent stem cells - can give rise to any and all human cells, and even an entire functional organism (morula stage)
ii. Pluripotent - can give rise to all tissue types, but not an entire organism (blastula stage)
iii. Multipotent - can give rise to limited range of cells within a tissue type
iv. Unipotent - just one single cell type

Answer 4

3. Stem Cell Types

Question 5

• Embryonic stem cells are pluripotent (isolated from blastula/blastocyst), and have more therapeutic value. Adult stem cells (and umbilical cord blood cells) are multipotent. Induced pluripotent stem cells are formed by ‘deprogramming’ a fully differentiated cell

Answer 5

Note