Embryology

Question 1

Which of the three germ layers will give rise to connective tissue?

Answer 1

mesoderm

Question 2

Name the cell mass that form the floor of the amniotic cavity.

Answer 2

epiblast

Question 3

The neurohypophysis, CNS neurons, oligodendrocytes, astrocytes, and pineal are derived from which primitive layer?

Answer 3

neuroectoderm

Question 4

The ANS, chromaffin cells of adrenal medulla, parafollicular cells, and laryngeal cartilage are derived from which primitive layer?

Answer 4

neural crest

Question 5

Which of the three germ layers will give rise to the epithelial lining of the respiratory tract?

Answer 5

endoderm

Question 6

Trace the seven steps of spermiogenesis, from spermatogonia to spermatozoa.

Answer 6

spermatogonia (46xy), primary spermatocyte, first meiotic division, 2 secondary spermatocytes (one 23x, one 23y), second meiotic division, 4 spermatids (two 23x, two 23y), 4 spermatozoa (two 23x, two 23y)

Question 7

Which structure contains a fluid-filled cavity that separates the blastomere into two distinct parts?

Answer 7

blastula

Question 8

Which of the three germ layers will give rise to the nervous system?

Answer 8

ectoderm

Question 9

Name the precursor of the ectoderm.

Answer 9

epiblast

Question 10

Which structure contains 12-15 blastomeres?

Answer 10

morula

Question 11

What is the postnatal derivative of the notochord?

Answer 11

nucleus pulposus of the intervertebral disk

Question 12

Which germ layers arise from the primitive streak?

Answer 12

intra-embryonic mesoderm and endoderm

Question 13

Where does fetal erythropoiesis occur in the 3rd to 8th weeks?

Answer 13

yolk sac

Question 14

How many spermatids are produced from one spermatogonia?

Answer 14

4

Question 15

What is the genetic complement of a spermatogonia cell?

Answer 15

46 XY

Question 16

Which monosaccharide is the main energy supply for sperm?

Answer 16

fructose

Question 17

Which structure induces the ectoderm to form neuroectoderm (neural plate)?

Answer 17

notochord

Question 18

Muscles, bone, CV structures, lymphatics, blood, spleen, and adrenal cortex are derived from which primitive layer?

Answer 18

mesoderm

Question 19

The bilaminar disk is formed within which week?

Answer 19

week 2

Question 20

What is the function of ductus arteriosus in fetal circulation?

Answer 20

deoxygenated blood from SVC is expelled into the pulmonary artery and ductus arteriosus to the lower body of the fetus.

Question 21

What is the spermatic complement of a spermatocyte that has undergone the first meiotic division?

Answer 21

one 23x and one 23y (secondary spermatocytes)

Question 22

Branchial pouches are derived from which primitive layer?

Answer 22

endoderm

Question 23

Which structures does the truncus arteriosus gives rise to?

Answer 23

ascending aorta and pulmonary trunk

Question 24

What does the embryonic ductus venosus become after birth?

Answer 24

ligamentum venosum

Question 25

Branchial clefts are derived from which primitive layer?

Answer 25

ectoderm

Question 26

What is the function of foramen ovale in fetal circulation?

Answer 26

most oxygenated blood reaching the heart via the IVC is diverted through the foramen ovale and pumped out of the aorta to the head.

Question 27

What kind of blood (oxygenated/deoxygenated) do the umbilical arteries carry?

Answer 27

deoxygenated blood from fetus to the placenta

Question 28

The gut tube epithelium and derivatives (lungs, liver, pancreas, thymus, thyroid, parathyroid) are derived from which primitive layer?

Answer 28

endoderm

Question 29

Days 15-28 make up which phase of the menstrual cycle?

Answer 29

luteal (secretory) phase

Question 30

Which structure closes at birth after the infant takes its first breath?

Answer 30

ductus arteriosus

Question 31

What kind of blood (oxygenated/deoxygenated) is carried by the umbilical vein?

Answer 31

oxygenated blood from placenta to the fetus

Question 32

Name the two main components of the placenta in the second week.

Answer 32

cytotrophoblast and syncytiotrophoblast

Question 33

Name the stages of embryogenesis from day zero to implantation at the end of week one.

Answer 33

fertilization (day 0), zygote (day 2), morula (day 3), blastocyst (day 5), implantation (day 6)

Question 34

Days 1-4 in the menstrual cycle make up which phase?

Answer 34

menstrual phase

Question 35

Monozygotic twins share ___ amniotic sacs, ___ placentas, and ___ chorions.

Answer 35

2, 1, 1

Question 36

Which of the three germ layers will give rise to blood vessels?

Answer 36

mesoderm

Question 37

Which of the three germ layers will give rise to the CV system?

Answer 37

mesoderm

Question 38

How many cavities in the second week of fetal development and what are they?

Answer 38

amniotic cavity and yolk sac

Question 39

Dizygotic (fraternal) twins share ___ amniotic sacs, ___ placentas, and ___ chorions

Answer 39

2, 2, 2

Question 40

Name the process whereby immature spermatids become spermatozoa.

Answer 40

spermiogenesis

Question 41

The adenohypophysis, lens of eye, epithelial linings, and epidermis are derived from which primitive germ layer?

Answer 41

surface ectoderm

Question 42

When do primary oocytes begin and complete meiosis I?

Answer 42

being during fetal life, complete just prior to ovulation

Question 43

Which of the three germ layers will give rise to glands that open into the GI tract?

Answer 43

endoderm

Question 44

Branchial arches are derived from which primitive layer?

Answer 44

mesoderm and neural crests

Question 45

What does the embryonic foramen ovale become after birth?

Answer 45

fossa ovalis

Question 46

How many germ layers are present in the third week and what are they?

Answer 46

ectoderm, mesoderm, endoderm

Question 47

Trace the five steps of oogenesis from primary oocyte to mature oocyte.

Answer 47

primary oocyte in primary follicle, first meiotic division, secondary oocyte (23x) in mature follicle and first polar body, second meiotic division, mature oocyte (23x) and second polar body (23x)

Question 48

Which structure does the right common cardinal vein and right anterior cardinal vein gives rise to?

Answer 48

superior vena cava

Question 49

Name the cell mass that forms the roof of the exocoelemic cavity.

Answer 49

hypoblast

Question 50

Which of the three germ layers will give rise to glandular cells of the liver and pancreas?

Answer 50

endoderm

Question 51

Which of the three germ layers will give rise to the lining of the GI tract?

Answer 51

endoderm

Question 52

Days 4-14 make up which phase of the menstrual cycle?

Answer 52

follicular (proliferative) phase

Question 53

Where does fetal erythropoiesis occur during the 9th to 28th weeks?

Answer 53

spleen

Question 54

Which of the three germ layers will give rise to blood cells?

Answer 54

mesoderm

Question 55

Name the process that converts a bilaminar embryonic disc into a trilaminar embryonic disc.

Answer 55

gastrulation

Question 56

Where does fetal erythropoiesis occur during the 6th to 30th weeks?

Answer 56

liver

Question 57

Where specifically does spermatogenesis occur?

Answer 57

seminiferous tubules

Question 58

When does the heart begin to beat and upper and lower limb buds begin to form?

Answer 58

week 4

Question 59

What does the embryonic ductus arteriosus become after birth?

Answer 59

ligamentum arteriosum

Question 60

What is the ploidy of a zygote?

Answer 60

diploid

Question 61

Implantation of blastocyst is present in which week?

Answer 61

1

Question 62

How many umbilical veins are there?

Answer 62

1

Question 63

What phase is meiosis II arrested in during oogenesis?

Answer 63

meiosis II is arrested in metaphase until fertilization