Embryology

Front 1

How long after fertilization will the blastocyst implant into the uterine wall?

Back 1

~ day 6, definitely within first week

Front 2

How many, and which, germ layers are present in week 2?

Back 2

2 germ layers - Epiblast (recall: will invaginate to become primitive streak), and Hypoblast

Front 3

How many cavities are present in week 2?

Back 3

2 cavities - Amniotic cavity, and Yolk Sac

Front 4

What happens within week 3?

Back 4

Start forming primitive streak, notochord, neural plate

Front 5

When does organogenesis take place?

Back 5

Between weeks 3 and 8

Front 6

When is am embryo particularly susceptible to teratogens?

Back 6

Between weeks 3 and 8 - organogenesis and neural tube formation take place then!

Front 7

When is the neural tube formed?

Back 7

Day 18 - 21

Front 8

When does the embryo heart begin to beat?

Back 8

Week 4

Front 9

When do the embryo's limbs start to form?

Back 9

Week 4

Front 10

When can you start to tell if the baby will be a boy or girl?

Back 10

Week 10 - genitalia have male or female characteristics

Front 11

How many germ layers are present in the 3rd week?

Back 11

3 germ layers - ectoderm, mesoderm, endoderm

Front 12

What is the primitive streak?

Back 12

Primitive streak came from epiblast (bilaminar disc) and will eventually give rise to intraembryonic mesoderm and endoderm.

Front 13

The anterior pituitary, lens of eye, epithelial linings, and epidermis all come from:

Back 13

surface ectoderm

Front 14

The posterior pituitary, CNS neurons, oligodendrocytes, astrocytes, ependymal cells, and pineal gland come from:

Back 14

NEUROectoderm

Front 15

The bones of the skull, layngeal cartilage, and odontoblasts are derived from:

Back 15

NEURAL crest (ectoderm)

Front 16

The autonomic nervous system, dorsal root ganglia, cranial nerves, celiac ganglion, Schwann cells are derived from:

Back 16

NEURAL crest (ectoderm)

Front 17

The parafollicular cells of thyroid, chromaffin cells of adrenal medulla, enterochromaffin cells, pia, and arachnoid mater are derived from:

Back 17

NEURAL crest (ectoderm)

Front 18

Dura mater is derived from:

Back 18

MESOderm

Front 19

Connective tissue, bone, muscle, cardiovascular structures, lymphatics, blood, and spleen are derived from:

Back 19

MESOderm

Front 20

GU structures, serous linings of body cavities, adrenal cortex, and kidneys are derived from:

Back 20

MESOderm

Front 21

What structures are derived from endoderm?

Back 21

Gut tube epithelium and derivatives (lungs, liver, pancreas, thymus, parathyroid, thyroid follicular cells)

Front 22

What does the notochord do?

Back 22

Induces ectoderm to form neuroectoderm (neural plate). Later becomes nucleus pulposus of intervertebral disc.

Front 23

What is the leading cause of mental retardation in children?

Back 23

fetal alcohol syndrome

Front 24

How do ACE inhibitors affect fetal development?

Back 24

renal damage

Front 25

Is cocaine bad for pregnant women?

Back 25

Yes, get abnormal fetal development and fetal addiction.

Front 26

A young girl develops vaginal clear cell adenocarcinoma. Her mother most likely took what during pregnancy?

Back 26

dietheylstilbestrol (DES)

Front 27

A baby is born with flipper limbs. His mother was given what during pregnancy?

Back 27

thalidomide

Front 28

How does tobacco affect a fetus?

Back 28

Preterm delivery, placental problems, ADHD

Front 29

1 placenta, 1 chorion, and 2 amniotic sacs =

Back 29

monozygotic twins

Front 30

2 placentas, 2 chorions, 2 amniotic sacs =

Back 30

either dizygotic or monozygotic twins

Front 31

What structures are found inside the umbilical cord? (4)

Back 31

- 2 arteries carrying deoxygenated blood from fetus back to mom
- 1 vein carrying 80% saturated O2 blood to baby
- allantoic duct removes nitrogenous waste from baby, like a urethra

Front 32

What is a single umbilical artery associated with?

Back 32

chromosomal and congenital anomalies

Front 33

Truncus arteriosis -->

Back 33

ascending AO and pulmonary trunk

Front 34

Bulbus cordis -->

Back 34

smooth parts of L and R ventricles

Front 35

Primitive ventricle -->

Back 35

trabeculated parts of L and R ventricles

Front 36

Primitive atria -->

Back 36

trabeculated L and R atria

Front 37

Left horn of sinus venosus -->

Back 37

coronary sinus

Front 38

Right horn of sinus venosus -->

Back 38

smooth part of R atrium

Front 39

Right common cardinal vein and right anterior cardinal vein -->

Back 39

SVC

Front 40

During the period of organogenesis in fetal development, where does fetal erythropoiesis take place?

Back 40

3-8 weeks: yolk sac

Front 41

Between 6-30 weeks of development, where does fetal erythropoisis take place?

Back 41

liver

Front 42

During which time of fetal development does erythropoiesis take place in the spleen?

Back 42

9-28 weeks

Front 43

When does the fetus start making red blood cells from its bone marrow?

Back 43

28 weeks and onward

Front 44

Fetal Hb has 2 alpha chains and:

Back 44

2 gamma chains

Front 45

Adult Hb has 2 alpha chains and:

Back 45

1 beta chains

Front 46

Umbilical vein -->

Back 46

ligamentum teres

Front 47

umbilical arteries -->

Back 47

MEDIAL umbilical ligaments

Front 48

ductus arteriosus -->

Back 48

ligamentum arteriosum

Front 49

ductus venosus -->

Back 49

ligamentum venosum

Front 50

foramen ovale -->

Back 50

fossa ovalis

Front 51

allantois - urachus -->

Back 51

MEDIAN umbilical ligament

Front 52

Urachus =

Back 52

part of the allantoic duct between the bladder and the umbilicus

Front 53

Baby takes first breath -->

Back 53

lower pulmonary vasculature R --> raise LA P --> close foramen ovale
******************************
raise in O2 --> drop in prostaglandins --> close ductus arteriosus

Front 54

Purpose of ductus venosus =

Back 54

shunt O2-rich blood from umbilical vein to IVC, bypassing liver circulation

Front 55

Purpose of foramen ovale =

Back 55

shunt O2-rich blood arrived from IVC to left side of heart to be pumped out the AO and to the head

Front 56

1st AO arch -->

Back 56

part of maxillary artery

Front 57

2nd AO arch -->

Back 57

stapedial artery and hyoid artery

Front 58

3rd AO arch -->

Back 58

common carotid artery, proximal internal carotid artery

Front 59

4th AO arch (left and right) -->

Back 59

(left) AO arch
(right) proximal subclavian a.

Front 60

6th AO arch -->

Back 60

pulmonary arteries, ductus arteriosus (left side)

Front 61

branchial clefts came from ecto/meso/endoderm?

Back 61

ectoderm

Front 62

branchial arches came from ecto/meso/endoderm?

Back 62

mesoderm and neural crest (which is ectoderm)

Front 63

branchial pouches came from ecto/meso/endoderm?

Back 63

endoderm

Front 64

mandible, malleus, incus, sphenomandibular ligament came from:

Back 64

branchial arch 1

Front 65

muscles of mastication (temporalis, masseter, pterygoids) came from:

Back 65

branchial arch 1

Front 66

mylohyoid, anterior belly of digastric, tensor tympani, tensor veli palatini, anterior 2/3 of tongue came from:

Back 66

branchial arch 1

Front 67

CN V2 and V3 came from:

Back 67

branchial arch 1

Front 68

stapes, styloid process, lesser horn of hyoid, stylohyoid ligament came from:

Back 68

branchial arch 2

Front 69

muscles of facial expression came from:

Back 69

branchial arch 2

Front 70

stapedius, stylohyoid, posterior belly of digastric came from:

Back 70

branchial arch 2

Front 71

CN VII came from:

Back 71

branchial arch 2

Front 72

CN IX came from:

Back 72

branchial arch 3

Front 73

greater horn of hyoid, stylopharyngeus muscle came from:

Back 73

branchial arch 3

Front 74

posterior 1/3 of tongue from:

Back 74

branchial arches 3 + 4

Front 75

4th branchial arch -->

Back 75

most pharyngeal constrictors, cricothyroid, levator veli palatini, CN X superior laryngeal branch

Front 76

branchial arch 6 -->

Back 76

all intrinsic muscles of larynx, CN X recurrent laryngeal branch

Front 77

sensation of anterior 2/3 of tongue provided by:

Back 77

CN V3

Front 78

taste of anterior 2/3 of tongue provided by:

Back 78

CN VII

Front 79

sensation and taste of posterior 1/3 of tongue provided by:

Back 79

CN IX, extreme posterior CN X (branchial arche 3 & 4)

Front 80

motor innervation of tongue:

Back 80

CN XII

Front 81

taste is cranial nerves ??? which go to the ___ nucleus

Back 81

CN VII, IX, X; solitary nucleus

Front 82

tongue pain is sensed by cranial nerves ???

Back 82

CN V3, IX, X

Front 83

1 branchial cleft -->

Back 83

external auditory meatus

Front 84

eardrum, eustachian tube came from:

Back 84

1st branchial membrane

Front 85

branchial cyst in the neck is due to:

Back 85

persistent cervical sinus, which are 2nd - 4th branchial clefts

Front 86

1st branchial pouch -->

Back 86

middle ear cavity, eustachian tube, mastoid air cells

Front 87

2nd branchial pouch -->

Back 87

epithelial lining of palatine tonsil

Front 88

3rd branchial pouch -->

Back 88

(doral wings) inferior parathyroid glands, (ventral wings) thymus!!!

Front 89

4th branchial pouch -->

Back 89

superior parathyroid glands

Front 90

DiGeorge's syndrome...again:

Back 90

abnormal development of 3rd and 4th branchial pouches --> T-cell deficiency and thymic aplasia and hypocalcemia

Front 91

most common site of ectopic thyroid tissue:

Back 91

tongue

Front 92

foramen cecum =

Back 92

normal remnant of thyroglossal duct

Front 93

cleft lip due to:

Back 93

failure of fusion of maxillary and medial nasal processes (formation of primary palate)

Front 94

cleft palate due to:

Back 94

failure of fusion of lateral palatine processes, nasal septum, and/or median palatine process (formation of 2ndary palate)

Front 95

Diaphragm is derived from: (4)

Back 95

1) septum transversum
2) pleuroperitoneal folds
3) body wall
4) dorsal mesentery of esophagus

Front 96

diaphragm innervated by:

Back 96

phrenic nerves (C3,4,5)

Front 97

ventral pancreatic bud -->

Back 97

1) pancreatic head
2) uncinate process
3) main pancreatic duct

Front 98

pancreas is derived from:

Back 98

foregut - supplied by celiac trunk

Front 99

spleen is derived from:

Back 99

mesoderm - arises from dorsal mesentery, but supplied by celiac trunk (via splenic artery)

Front 100

annular pancreas is due to:

Back 100

ventral and dorsal pancreatic buds abnormally encircle 2nd portion of duodenum

Front 101

mesonephric/wolffian ducts -->

Back 101

seminal vesicles, epididymis, ejactulatory duct, vas deferens

Front 102

paramesonephric/mullerian ducts -->

Back 102

fallopian tubes, uterus, part of vagina

Front 103

What suppresses development of the mullerian duct system in males?

Back 103

mullerian inhibiting substance

Front 104

Increased androgen exposure to fetus may cause development of:

Back 104

mesonephric ducts