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Under the influence of the trophoblast, maternal blood vessels in the endometriu

ID: 79838 • Letter: U

Question

Under the influence of the trophoblast, maternal blood vessels in the endometrium A) disappear. B) attach to the inner cell mass. C) break down and form lacunae. D) form a capillary network in the trophoblast. E) increase in size and penetrate the blastocyst. A space opens within the inner cell mass that will form the A) blastocoele B) lacunae. C) amniotic cavity. D) chorion. E) allantois Attachment to and penetration of the endometrium by the blastocyst is referred to as a) cleavage. B) implantation C) placentation. D) embryogenesis E) fertilization. The ectoderm forms A) muscle. B) blood C) neural tissues. D) the lining of the stomach and small intestine. E) the urinary system. The mesoderm forms A) muscle. B) epidermis. C) the brain. D) the lining of the digestive tract. E) respiratory epithelium.

Explanation / Answer

29. Answer : C : break down and form lacunae

30. Answer : C : amniotic cavity : The amniotic cavity is the closed sac between the embryo and the amnion, containing the amniotic fluid.

The mesoderm and trophoblast combine to form the chorion.

The extraembryonic membrane that gives rise to the urinary bladder is the allantois

31. Answer : B : Implantation

The process of cell division that divides the cytoplasm of the zygote among blastomeres is called cleavage.

Placentation is the formation or arrangement of a placenta

The body and organs of the embryo begin to form is called embryogenesis.

32. Answer : C : Neural tissues

33. Answer : A : Muscle

Ectoderm (Outer layer) : Epidermis of skin, epithelial lining of mouth and rectum, nervous system.

Mesoderm (Middle layer): Skeletal system, muscular system, excretory, circulatory and lymphatic system, reproductive system, dermis of skin.

Endoderm (Inner layer) : epithelial lining of respiratory and digestive tract.