umbilical cord

Question 1

what does the outer layer of the umbilical cord consist of?

Answer 1

flattened squamous/ cuboidal amniotic epithelial cells

Question 2

what does the internal layer of the umbilical cord consist of?

Answer 2

the internal mass consists of mucous connective tissue (mesenchyme, wharton’s jelly)

Question 3

what is embedded in the umbilical blood vessels

Answer 3

• two umbilical arteries

- left umbilical vein

Question 4

what are the umbilical arteries?

Answer 4

muscular arteries in which the thickness of the tunica media and it’s elastic fiber content increases towards the umbilicus

Question 5

what is in the outer aspect of the tunica media of the umbilical artery?

Answer 5

smooth muscle cells, which display spiral courses

Question 6

what do the contraction of the spiral smooth muscle cells

Answer 6

results in shortneing of the vessels and inward bulgings of the intima that narrows the lumen

Question 7

why do the umbilical vessel contrict?

Answer 7

as a response to stretching, cooling during and after the birth

Question 8

what forms in the umbilical cord? and what happens when temperature decreases

Answer 8

• bradykinin forms in the umbilical cord

- when temp. decreases it induces a contraction of the umbilical a. & v. and the ductus arteriosus