28. Human Development

Which of the following is a benefit of cells getting smaller as cleavage occurs?

A hollow ball of cells created by cleavage is called a(n)?

Indicate whether each of the following statements is describing (a) cleavage or (b) gastrulation.

_______ (1) period during which a morula forms

_______ (2) period when vast amounts of cell migration occur

_______ (3) period when the three embryonic germ layers appear

_______ (4) period during which the blastocyst is formed

The outer layer of the blastocyst, which later attaches to the uterus, is the

(a) decidua

(b) trophoblast

(c) amnion

(d) embryoblast

Match each adult structure in column B with the embryonic structure it derives from in column A.

Column A

_______ (1) notochord

_______ (2) ectoderm (not neural tube)

_______ (3) intermediate mesoderm

_______ (4) lateral plate mesoderm

_______ (5) sclerotome

_______ (6) coelom

_______ (7) neural tube

_______ (8) endoderm

Column B

(a) kidney

(b) peritoneal cavity

(c) pancreas, liver

(d) parietal serosa, most tissues of limbs

(e) nucleus pulposus

(f) hair and epidermis

(g) brain

(h) ribs and vertebrae

The germ layer from which the epidermis and brain are derived is the

(a) ectoderm

(b) endoderm

(c) mesoderm