Cell reproduction and the Continuity of Life: Membranes, Placenta, Umbilical cord, and Stem cells

Question 1

What are the 4 embryonic membranes?

Answer 1

• The Amnion
• The Chorion
• The Allantois
• The Yolk sac

Question 2

What is the Chorion and what does it do?

Answer 2

The membrane surrounding the amnion with many finger-like projections (chorionic villi). It secretes chemicals, disintegrating some of the endometrium to free up space for embryo growth, whilst also opening up some of its capillaries to allowing mother’s blood to circulate around the chorion. Chorionic villi eventually assist with forming the placenta.

Question 2

What is the amnion and what does it do?

Answer 2

The membrane surrounding developing embryos which becomes filled with fluids. It…
- Keeps embryos moist
- Protects embryos from shocks
- Prevents embryos from sticking to uterine walls
- Resists temperature fluctuations

Question 3

What is the Allantois and what does it do?

Answer 3

Membrane that disintegrates during month 2. Forms blood vessels of the umbilical cord and the bladder.

Question 4

What is the yolk sac and what does it do?

Answer 4

Membrane that disintegrates. small and insignificant for nourishment in humans. Blood cells form here first and helps form the umbilical cord, digestive tract and future eggs and sperm.

Question 5

What are the functions of the placenta?

Answer 5

• Serve as embryos lungs (Breathes O2/CO2 from/to the uterine blood)
• Serves as embryos digestive system (receives digested food molecules)
• Serves as embryos kidneys (Urea goes from placenta, to the uterine blood vessels, to the mother’s kidneys)
• Secretes progesterone and estrogen (Maintains uterine lining, prevent follicle growth)
• Passes antibodies from mother to fetus (Provides passive immunity)

Question 6

What does the umbilical cord do?

Answer 6

Joins embryos to placentas. It’s blood vessels carry O2 and digested food molecules to the embryo (Umbilical vein), and CO2 and urea away from the embryo to the placenta. (Umbilical artery). Two arteries, one vein. Also forms yolk sac and allantois.

Question 7

What are embryonic stem cells and what can they do?

Answer 7

Pluripotent stem cells that come from unused embryos. They can turn into all cell types and are a result of in vitro fertilization.

Question 8

What are the two types of adult stem cells?

Answer 8

• Stem cells donated from umbilical cords
• Induced pluripotent stem cells

Question 9

What are some details about donated umbilical cord adult stem cells.

Answer 9

They also may come from fully developed tissues (Brain, skin, bone marrow). They are multipotent with only a few stem cells in the tissues.

Question 10

What are some details about induced pluripotent adult stem cells?

Answer 10

They are adult stem cells modified in labs to resemble embryonic stem cells. They don’t seem different from embryonic, but none created yet can develop every kind of cell/tissue.

Question 11

What is the difference in pluripotent and multipotent stem cells?

Answer 11

Pluripotent: Capable of turning into all types of cells
Multipotent: Capable of turning into a specific type of cells (Eg; stem cells from livers only produce liver cells)