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Flashcards in Embryology Deck (107)
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1
Q

What does the truncus arteriosus (TA) form

A

Ascending aorta and pulmonary trunk

2
Q

What does bulbus cordi form?

A

Smooth par t(outflow tract) of left and right ventricles

3
Q

What do primitive atria form

A

Tracebulated part of lef tand right atria

4
Q

What do primitive ventricle form

A

Trabeculated part of L and R ventricles

5
Q

What does primitive pulm. vein form

A

Smooth part of L atrium

6
Q

L horn of sinus venosus (SV)

A

coronary sinus

7
Q

R horn of sinus venosus

A

Coronary sinus

8
Q

Right common cardinal vein and R anterior cardinal vein

A

SVC

9
Q

What is the first functional organ in vertebrate embryos

A

The heart, beats spontaneously by week 4 of development.

10
Q

When does heart tube loops gain polarity

A

Week 4 of gestation, establishing L-R polarity

11
Q

What can cause dextrocardia

A

Kartagener syndrome, defect in Left-Right dynein

12
Q

Primary ciliary dyskinesia

A

Kartageners

13
Q

Septation of the atria

A

Know the steps.

14
Q

What forms the atrial septum?

A

The fusing of the septum secundum and the remnant of the septum primum.

15
Q

What are the steps of ventricular septum formation?

A

First the muscular interventricular septum forms. Leaving a interventricular foramen. The aorticopulmonary septum rotates then fuses with muscular interventricular septum to form the membranous interventricular septum. The endocardial cushions separate the atria and ventricles.

16
Q

Where do you most commonly see VSD?

A

In the membranous interventricular septum. This is where the remnant of the interventricular foramen was.

17
Q

Where do the valves come from

A

They come from the endocardial cushions, all of them.

18
Q

Know the order in which fetal hematopoesis takes place

A
Young Liver Synthesizes Blood
Yolk Sac (3-8 Weeks)
Liver (6 weeks-birth)
Spleen (10-28 weeks)
Bone marrow (18 weeks to adult)
19
Q

What makes up fetal hemoglobin

A

HbF, alpha2gamma2

20
Q

What makes up adult hemoglobin

A

HbA, alpha2beta2

21
Q

Why does HbF more avidly bind O2 than HbA

A

it doesn’t bind 2,3-BPG as well

22
Q

What is delta hemoglobin

A

Starts around week 30 and very slowly increases through all of adult life???????

23
Q

When does HbF switch to HbA

A

Immediately after birth is the crossing point.

24
Q

Know fetal circulation.

A

…………..

25
Q

Why does ductus arteriosus close?

A

Placental separation leads to decreased prostaglandins which makes it close.

26
Q

What affects ductus arteriosus opening/closure

A
Indomethacin closes (prostaglandin inhibitor)
Prostaglanin E1 and E2 keep it open.
27
Q

PO2 of blood in umbilical vein

A

30 mmHg and is 80% saturated with O2

28
Q

What remnant does the umbilical vein form?

A

Ligamentum teres herpatis (contained in falciform ligament)

29
Q

What do umbilical arteries form remnant

A

MediaL umbilical ligaments

30
Q

What remnant does Foramen ovale form?

A

Fossa ovalis

31
Q

What remnant does AllaNtois form

A

Urcahus-mediaN umbilical ligamenet

32
Q

What is the allantois?

A

The allantois becomes the urachus.

33
Q

What is the urachus

A

The urachus is the part of the allantoic duct between the bladder and umbilicus. Urachal cyst or sinus is a remnant. The urachus removes urine from the fetal bladder.

34
Q

What does notochord leave as a remnant

A

Nucleus pulposus

35
Q

Thyroid development

A

Thyroid diverticulum arises from floor of primitive pharynx, descends into neck. Connected to tongue by thyroglossal duct, which normally disappears but may persist as pyramidal lobe of thyroid. Foramen cecum is normal remnant of thyroglossal duct.

36
Q

Most common ectopic thyroid tissue site?

A

The tongue

37
Q

Thyroglossal duct cyst presentation

A

Anterior midline neck mass that moves with swallowing or protrusion of the tongue (vs. persistent cervical sinus leading to branchial cleft cyst in the lateral neck)

38
Q

Foregut forms what

A

Pharynx to duodenum

39
Q

Midgut forms what

A

Duodenum to proximal 2/3 of transverse colon

40
Q

Hindgut forms what

A

Distal 1/3 of transverse colon to anal canal above pectinate line.

41
Q

Rostral fold closure of anterior abd. wall results in

A

Sternal defects

42
Q

Lateral fold closure of ant. abd. wall results in

A

Omphalocele, gastroschisis

43
Q

Caudal fold closure of ant. abd. wall results in

A

Bladder exstrophy

44
Q

What causes duodenal atresia

A

Trisomy 21

45
Q

What causes jejunal, ileal, and colonic atresia

A

Vascular accident (apple peel atresia)

46
Q

Apple peel atresia????

A

?????????????

47
Q

Midgut development: 6th and 10th weeks

A

6th week: midgut herniates through umbilical ring

10th week: returns to abd. cavity + rotates around SMA

48
Q

What are the different types of tracheoesophageal fistula

A

Most common 85%: EA with distal TEF: Proximal esophagus atresia and distal esophagus connecting to trachea.

H-type: pure TEF
Pure EA: atresia or stenosis of esophagus

49
Q

What does TEF present with

A

Drooling, choking, and vomiting with first feeding.

50
Q

What causes cyanosis with TEF

A

secondary to laryngospasm to avoid reflux-related aspiration

51
Q

Which TEF has a gasless abdomen

A

Pure esophageal atresia

52
Q

Describe congenital pyloric stenosis

A

Olive mass in epigrastric region with nonbilious projectile vomiting at around 2-6 weeks old. Occurs in 1/600 live births, more often in firstborn males.

53
Q

Pancreas derived from what

A

Foregut

54
Q

What does ventral pancreatic bud form

A

Pancreatic head and main pancreatic duct.

55
Q

What does dorsal pancreatic bud form

A

Body, tail, isthmus, and accessory pancreatic duct.

56
Q

Annular pancreas path

A

Ventral pancreatic bud abnormally encircles 2nd part of duodenum forming ring of pancreatic tissue causing duodenal narrowing

57
Q

Pancreas divisum path

A

ventral and dorsal parts fail to fuse at 8 weeks

58
Q

Spleen origin

A

Arises in mesentery of stomach (hence mesodermal) but is supplied by foregut (celiac artery)

59
Q

What are the three embroylogical kidneys

A

Pronephros
Mesonephros
Metanephros

60
Q

Pronephros

A

Week 4; then degenerates

61
Q

Mesonephros

A

Functions as interim kidney for 1st trimester; later contributes to male genital system

62
Q

Metanephros

A

Permanent kidney; first appears in 5th week of gestation; nephrogenesis continues through 32-36 weeks of gestation

63
Q

Urteric bud

A

Derived from caudal end of mesoneprhic duct; gives rise to ureter, pelvises, calyces, and collecting ducts; fully canalized by 10th week

64
Q

Metanephric mesenchyme

A

Ureteric bud interacts with this tissue; interaction induces differentiation and formation of glomerulus through to distal convuluted tubule

65
Q

What is the last thing to canalize in the renal system

A

The Ureteropelvic junction, most common site of obstrution (hydronephrosis in fetus)

66
Q

Potter syndrome mnemonic

A

POTTER syndrome: Pulm. hypoplasia, Oligohydramnios (trigger), Twisted face, Twisted Skin, Extremity defects, Renal failure (in utero)

67
Q

Facial anomalies of oligohydramnios (potter’s)

A

low-set ears and retrognathia

68
Q

Causes of Potter’s

A

ARPKD, posterior urethral valves, bilateral renal agenesis

69
Q

Where are the horseshoe kidneys

A

Lower set because the inferior poles hit the IMA while migrating up.

70
Q

Horseshoe kidney sequelae

A

Increased risk for ureteropelvic junction obstruction, hydronephrosis, renal stones, and rarely renal cancer (Wilms tumor).

71
Q

Horseshoe kidney associated with….

A

Turner syndrome

72
Q

Multicystic dysplastic kidney cause

A

Abnormal interaction between ureteric bud and metanephric mesenchyme.

73
Q

Multicystic dysplastic kidney path

A

Nonfunctional kidney consisting of cysts and connective tissue. if unilateral (most common), generally asx with compensatory hypertophy of contralateral kidney. Often diagnosed prenatally via u/s.

74
Q

What are the stages of development of nervous system

A

Notochord signals for overlying ectoderm to differentiate into neruoectoderm and form the neural place. Neural plate gives rise to the neural tube and neural crest cells.

75
Q

What components make up the spinal cord

A
Alar plate (dorsal): sensory
Basal plate (ventral): motor
76
Q

How long does it take for neural plate to form neural tube

A

Between Day 18-21

77
Q

What are the three primary vesicles of the brain

A

Prosencephalon, Mesencephalon, and Rhombencephalon

78
Q

What does prosencephalon form

A

Telencephalon and diencephalon

79
Q

What does mesencephalon form

A

Mesencephalon

80
Q

What does rhombencephalon form

A

Metencephalon and myelencephalon

81
Q

What does telencephalon and diencephalon form

A

Tel: is cerebral cortex and lateral ventricles
Di: is Thalamus and the third ventricle

82
Q

What does mesencephalon form

A

Midbrain and aqueduct

83
Q

What does metencephalon and myelencephalon form

A

Met: Pons and cerebellum and upper part of fourth ventricle
Myel: Medulla nad lower part of fourth ventricle

84
Q

What forms PNS neurons and Schwann cells

A

Neural crest cells

85
Q

What forms ependymal cells, oligodendroglia, and astrocytes

A

Neuroectoderm, along with the CNS neurons

86
Q

What forms microglia

A

Mesoderm (like macrophages, which originate from Mesoderm)

87
Q

What increases risk of Neural tube defects?

A

Low folate intake before conception and during pregnancy

88
Q

Tests for NTDs

A

elevated alpha-fetoprotein in amniotic fluid and maternal serum. Increased AChE in amniotic fluid is a helpful confirmatory test (fetal AChE transudates across defect into amniotic fluid

89
Q

What is the path of NTDs

A

Neuropores fail to fuse (4th week) leading to persistent connection between amniotic cavity and spinal canal

90
Q

What are the three types of NTDs

A

Spina bifida occulta, meningocele, meningomyelocele

91
Q

What is AFP in meningocele

A

Normal

92
Q

What is AFP in meningomyelocele

A

??????????

93
Q

Anencephaly presentation

A

Malformation of anterior neural tube resulting in no forebrain, open calvarium (“frog-like appearance”). Inc. AFP, polyhydramnios from absent swallowing center in brain.

94
Q

Anencephaly associated with

A

Maternal diabetes Type I

95
Q

What decreases risk for anencephaly

A

Maternal folate supplementation

96
Q

Holoprosencephaly path

A

Failure of left and right hemispheres to separate, during weeks 5-6. Multifactorial that may be related to sonic hedgehog sinaling pathway.

97
Q

Holoprosencephaly presentation

A

Moderate form has cleft lip/palate, most severe form results in cyclopia

98
Q

What are the posterior fossa malformations

A

Chiari II (Arnold-Chiari malformation) and Dandy-Walker

99
Q

Chiari II

A

Significant herniation of cerebellar tonsils and vermis through foramen magnum with aqueductal stenosis and hydrocephalus. Often presents with lumbosacral myelomeningocele and paralysis below the defect.

100
Q

Dandy-Walker

A

Agenesis of cerebellar vermis with cystic enlargement of 4th ventricle (fills the enlarged posterior fossa). Associated with hydrocephalus and spina bifida

101
Q

What is syringomyelia

A

Cystic cavity within the spinal cord which leads to damage to crossing anterior spinal commissural fibers that leads to cape like distribution of bilaterall loss of pain and temp sensation in upper extremities with fine touch sensation preserved.

102
Q

What levels affected by syrinx

A

C8-T1

103
Q

What is syringomyelia associated with

A

Chiari I malformation (>3-5 mm cerebellar tonsillar ectopia; congenital, usually asx in childhood, manifests with HA and cerebellar sxs)

104
Q

What is hydromyelia

A

Cystic cavity in the central canal.

105
Q

Tongue development

A

1st and 2nd branchial arches form anterior 2/3 (thus sensation via CN V3, taste via CN VII)
3rd and 4th branchial arches form posterior 1/3 (thus sensation and taste mainly via CN IX, extreme posterior via CN X)
Motor innervation is via CN XII
Muscles of tongue from occipital myotomes

106
Q

What detects taste (neuro)

A

CN VII, IX, X (solitary nucleus)

107
Q

What detects pain

A

CN V3, IX, X