Embryology

Front 1

Aortic Arch 3

Back 1

common carotid

Front 2

Aortic Arch 4

Back 2

right subclavian

Front 3

Aortic Arch 6

Back 3

pulmonary trunk and pulmonary aa.

Front 4

Truncus Arteriosus

Back 4

ascending aorta and pulmonary trunk

Front 5

7th intersegmental a.

Back 5

left subclavian (and distal right subclavian)

Front 6

Dorsal Aorta

Back 6

descending aorta

Front 7

Aortic sac

Back 7

ascending aorta and brachiocephalic a.

Front 8

Longitudinal anastamoses between first 7 intersegmental aa.

Back 8

vertebral a.

Front 9

bulbis cordis

Back 9

smooth parts of right and left ventricles

Front 10

primitive ventricle

Back 10

trabeculated part of ventricles

Front 11

primative atrium

Back 11

trabeculated part of atria, auricles

Front 12

sinus venosus

Back 12

smooth walled part of right atrium

Front 13

embryonic umbilical artery

Back 13

adult umbilical artery

Front 14

Somites

Back 14

prochordal plate--> primitive streak-->paraxial mesoderm--> somites--> dermomyotomes--> skeletal muscles of body wall and striated muscle of abdominal wall

Front 15

Dermomyotomes

Back 15

source of connective tissue of anterior abdominal wall

Front 16

Intraembryonic Coelom

Back 16

lined by mesothelium
becomes pericardial, pleural and peritoneal

Front 17

Amniotic fluid

Back 17

from 2nd trimester on- fetal urine contributes significantly, removed by fetal swallowing

Front 18

oligohydramnios

Back 18

less than 1/2 normal volume
*caused by renal agenesis
causes joint problems, pulmonary hypoplasia, compression of umbilical cord

Front 19

polyhydramnios

Back 19

greater than 2x the normal volume of amniotic fluid
caused by anencephaly (which disrupts swallowing)
esophageal or duodenal atrisia- prevents fluid from being absorbed

Front 20

umbilical cord-

Back 20

houses vitelline duct and secretory yolk sac
-amnion forms outer layer

Front 21

7th week

Back 21

herniation of midgut into umbilical cord

Front 22

abdominal diaphragm formed from:

Back 22

septum transversum, pleuroperitoneal membranes, 3rd-5th cervical hypaxial dermomyotomes,
mesoderm

Front 23

Bochdalek foramen

Back 23

hole between pleural and peritoneal cavity through abdominal diaphragm, caused when pleuroperitoneal membrane fails to form on one side.
bowel herniates through occupying lung space = **pulmonary hypoplasia

Front 24

Chorion

Back 24

composed of trophoblast lined by connective tissue derived from extraembryonic mesoderm.

Villous Chorion has same DNA as fetus

Front 25

Twins

Back 25

dizygotic- 2 eggs
monozygotic- 1 egg:
either splits early
or
2 inner cell masses from w/in blastocyst (share placenta and chorion)= monochorionic diamnionic
- can have av anastomosis resulting in twin-twin transfusion syndrome
or
two primative streaks form w/in a single disc= monoamnionic twins- half are conjoined, high mortality due to twisted umbilical cord

Front 26

lungs

Back 26

function at 24-28 weeks

Front 27

notochord

Back 27

lies dorsal to aorta
persists as nucleus pulposus

Front 28

neural folds and neural tube

Back 28

begins to form during 3rd week
* closure 4th week
notochord induces neural folds
folds join to form tube-gives rise to brain and spinal cord

neural crest cells form: dorsal root ganglia, paravertebral ganglia, parasympathetic postganglionic neurons

Front 29

Spina Bifidas

Back 29

type of spinal dysraphisms (spinal cord malformations) in which vertebral arches are missing.
-due to improper fusion of neural folds

Front 30

Myelomeningocele

Back 30

Myelomeningocele and Myeloschisis
-most common
-causes paralysis caudal to involved segment
-hydrocephalus
-Arnold Chiari (cerebellum and medulla in cervical vertebral canal)
*-Alpha fetoprotein leaks into amniotic fluid

Front 31

Meningocele

Back 31

vertebral arch defect
-dura and arachnoid protrude through skin
-dorsal surface usually connected by fibrous cord

Front 32

Myelocystocele

Back 32

similar to meningocele except dorsal part of spinal cord doesn't form properly- treated surgically to avoid tethering.

Front 33

Spinal dermal sinus

Back 33

midline dimple- if in intergluteal fold usually ends blindly and is harmless, if superior to intergluteal fold, tract can provide path for infection, depth must be investigated to see if it is tethered

Front 34

Spina Bifida Occulta

Back 34

failure of vertebral arches
no indication except by x-ray or tuft of hair.

Front 35

Anencephaly

Back 35

failure of neural tube closure in brain region
-fatal condition
-alpha fetoprotein

Front 36

Liver

Back 36

cystic diverticulum--> cystic duct hepatocystic diverticulum--> common bile duct

- usually supplied by Celiac artery, in some people arises more caudally= SMA

Front 37

Pancreas

Back 37

secretory cells from endoderm of foregut
-pancreatic secretory vol. enters duodenum at same site as bile b/c duct of ventral pancreas establishes connection w/duct of dorsal pancreas

Front 38

ventral pancreatic diverticulum

Back 38

part of hepatopancreatic diverticulum- contributes to pancreas, hugs septum transversum

outgrowth gives rise to liver and gallbladder

Front 39

Septum Transversum

Back 39

derived from mesoderm
gives rise to central tendon
gives rise to capsule and connective tissue of liver
gives rise to lesser omentum and falciform ligament

Front 40

Omphlocele

Back 40

intestine in umbilical cord at birth
alpha fetoprotein
associated with cardiac and renal abnormalities and therefore poor prognosis

Front 41

Gastroschisis

Back 41

umbilical cord ruptures- midgut exposed to amniotic flud
= alpha fetoprotein
-less serious because not associated with other anomalies
-bowel becomes inflamed

Front 42

Meckel's Diverticulum

Back 42

vitelline duct and yolk sac normally degenerate
-when vitelline duct persists= Meckel's diverticulum- at antimesenteric border of ileum.
can get infected

Front 43

Annular Pancreas

Back 43

ventral pancreatic diverticulum bifurcates.
one branch behind, one anterior to duodenum- causes duodenal obstruction which must be corrected

Front 44

Pancreatic Divisum

Back 44

failure of fusion of ventral and dorsal pancreatic duct

Front 45

Hirschspring's Disease

Back 45

Congenital Mesocolon
- neural crest cells don't invade and form parasympathetic postganglionic neurons
-causes that region to be aperistaltic- extend all the way to anus.
-causes abdominal distension (in normal part), delayed passage of meconium, constipation, and painful defacation

Front 46

Gut: secondarily retroperitoneal

Back 46

duodenum, ventral pancreas, most of dorsal pancreas, ascending colon, descending colon

Front 47

Arterial supply of gut

Back 47

foregut:celiac
midgut:SMA
hindgut: IMA

Front 48

Dorsal mesentery

Back 48

persists as sigmoid meso-colon

Front 49

Dorsal mesogastrium

Back 49

dorsal mesentery in greater curvature of stomach.
mesoduodenum- lesser curvature

lower mesogastrium=gastrocolic ligament, greater omentum, apron of greater omentum.
upper mesogastrium- lienorenal ligament, gastrosplenic ligament

Front 50

Ventral mesentery

Back 50

adult derivative= lesser omentum
-hepatogastric ligament
-hepatoduodenal ligament

Front 51

Cardiac mesoderm

Back 51

derived from primitive streak
-migrates cranial to oropharyngeal membrane
-ventral to bend in coelom
-first organ to become functional
*3rd week

Front 52

IV septum

Back 52

becomes thick walled septum,
bulbar ridges, truncal ridges, endocardial cushion= membranous portion in adult IV septum

Front 53

IA septum

Back 53

septum primum and septum secundum (secundum on right)

Front 54

Foramen Ovale

Back 54

septum primum more flexible, allows blood to flow right to left. lower part of septum primum is valve of foramen ovale. after birth, arterial pressure in l. atrium increases, causing septum to fuse. depression is fossa ovalis

Front 55

If aorticopulmonary septum fails to form in a spiral fashion?

Back 55

aorta and pulmonary trunk will be in switched position

Front 56

most common cardiac malformation?

Back 56

ventricular septal defect- in membranous portion

Front 57

unequal division of truncus arteriosus=

Back 57

ventricular septal defect

Front 58

probe patent foramen ovale

Back 58

leads to left to right shunting of blood

Front 59

Ventricular septal defect

Back 59

most common in males, causes blue babies

Front 60

Atrial septal defect

Back 60

more common in females, does not result in blue babies

Front 61

Tetrology of Fallot

Back 61

pulmonary stenosis
VSD
overriding aorta
hypertrophy of right ventricle
*defect of septation of truncus arteriosus

Front 62

Coarctation of the aorta

Back 62

preductal or postductal
more common in males
-preductal is associated with PDA and VSD, cyanosis to lower part of body.

post ductal- blood supply through anastamoses
-causes upper body hypertension and LV hypertrophy. Diagnosed in childhood by weak femoral pulse or hypertension in upper limbs

Front 63

AV septal defects

Back 63

failure of endocardial cushions to fuse, leaving hole in center of the heart.

***common in Down's syndrome

Front 64

Fetal circulation

Back 64

oxygenation higher in left, ascending.

-posthepatic portion of IVC carries well oxygenated blood.

Front 65

Cloaca

Back 65

urinary bladder

Front 66

mesonephric duct

Back 66

uteric bud
ureter, calyces, pyramids

Front 67

metanephric blastema

Back 67

nephrons

Front 68

ureteric bud + metanephric blastema=

Back 68

kidney

Front 69

mesonephros

Back 69

true kidney

Front 70

Suprarenal gland develops dependently or independently from the kidney?

Back 70

independently

Front 71

Syncytiotrophoblast

Back 71

secrets chorionic gonadotropin

Front 72

Placenta

Back 72

it is comprised of villous chorion and deciduas basalis

Front 73

Primitive Streak

Back 73

is the source of striated muscles of the abdominal wall
is the source of most of the cells in the body wall
is derived from epiblast cells

Front 74

patent allantois results in:

Back 74

urachal fistula between bladder and umbilicus

a patent urachus will result in leakage of urine from the belly button

Front 75

horseshoe kidney

Back 75

is trapped during ascent by IMA

Front 76

Ureteric duplication

Back 76

associated with urinary incontinence, especially in females

Front 77

partitioning of the cloaca

Back 77

creates perineal body between anal and urogenital membranes.
Tourneux's fold and paired Rathke folds lead to the partitioning of the cloaca.
Fistulas may develop if the Tourneux or Rathke folds fail t develop= rectovesical fistula

Front 78

Supernumary renal arteries

Back 78

are common and may compress ureter

Front 79

mesonephric duct

Back 79

ureter, ejaculatory duct, seminal vesicle, epididymis, vas deferens

Front 80

paramesonephric duct

Back 80

uterus, uterine tube, vagina (upper portion)

Front 81

Urogenital Sinus

Back 81

vagina (lower portion), greater vestibular glands, urinary bladder, penile urethra, bulbourethral glands, prostate

Front 82

homologous structures in male and females:
a)round ligament of uterus
b)bulb of vestibule
c)labia majora
d)vestibule of vagina
e)mesonephric tubules
f)labia minora

Back 82

a)gubernaculum of testes
b)corpus spongiosum of penis
c)scrotom
d)penile urethra
e)efferent ductules of testis
f)ventral penis

Front 83

Gartner's Ducts

Back 83

remnant of mesonephric duct in females

Front 84

anomalies of urogenital system

Back 84

hypospadias(on ventral side) of penis more common than epispadias

malformations of the uterus are due to faulty canalization of the uterovaginal primordium

Front 85

testicular feminization

Back 85

aka adrogen insensitivity syndrome
-have XY but no androgen receptors so develop as female, have no uterus and only a blind vaginal pouch. testes must be removed surgically (trapped in inguinal canal)=cryptorchidism

Front 86

Agenesis of the vagina

Back 86

results from failure of sinovaginal bulbs to develop and form vaginal plate

Front 87

adrenogenital syndrome

Back 87

(in females) vagina opens into the urinary bladder= persistent urogenital sinus
-can result in clitoral hypertrophy and labial fusion if untreated

Front 88

branchial arches

Back 88

filled with ectomesenchyme derived from neural crest

Front 89

neural crest

Back 89

gives rise to branchial arches

Front 90

striated skeletal muscle of the head is derived from?

Back 90

somitomere tissue or from dermomyotome tissue of the 4 occipital somites

Front 91

1st Branchial Arch

Back 91

malleus and incus of middle ear/ sphenomandibular ligament

Front 92

2nd Branchial Arch

Back 92

stapes
styloid process of temporal bone
lesser horn of hyoid bone
superior portion of body of hyoid bone/stylohyoid ligament

Front 93

3rd Branchial Arch

Back 93

greater horn of hyoid bone, most of body of hyoid bone

Front 94

4th and 6th Branchial Arch

Back 94

degenerate

Front 95

1st cleft/ectoderm

Back 95

external auditory meatus/epidermis of external auditory meatus

Front 96

1st pharyngeal pouch/endoderm

Back 96

eustachian tube and middle ear cavity/ lining epithelium of eustachian tube and middle ear cavity

Front 97

2nd pharyngeal pouch

Back 97

epithelial lining of palatine tonsil

Front 98

3rd pharyngeal pouch

Back 98

inferior parathyroid gland, nonlymphoid part of the thymus

Front 99

4th pharyngeal pouch

Back 99

superior parathyroid gland
C cells (calcitonin-secreting) of the thyroid

Front 100

ectomesenchyme ventral to the pharynx

Back 100

connective tissue of tongue
epiglottis

Front 101

what happens to external surfaces of 3rd-6th arches?

Back 101

they become buried beneath the skin of the neck

Front 102

innervates muscles derived from 1st branchial arch

Back 102

Trigeminal n.

Front 103

innervates muscles derived from 2nd branchial arch

Back 103

facial n.

Front 104

the muscles of facial expression are derived from?

Back 104

occipital dermomyotomes and somitomeres of the second branchial arch

Front 105

anomaly of parathyroid development

Back 105

inferior parathyroids can be found in mediastinum near the thymus

Front 106

lingual thyroid

Back 106

thyroid tissue is left embedded in tongue- can cause dysphagia, dysphonia, dyspnea

identify by uptake of I123

Front 107

most common anomaly of the head and neck

Back 107

thyroglossal cyst
-usually beneath the skin of the anterior midline of the neck just below the hyoid bone

-thyroglossal cysts move superiorly when child protrudes his/her tongue

Front 108

Opercular process

Back 108

forms lateral aspect of the neck, grows out of the 2nd branchial arch

smaller version from 6th branchial arch is called epipericardial ridge

Front 109

lateral cervical cysts, sinuses and fistulae

Back 109

caused when cervical sinus fails to obliterate.

Front 110

internal branchial sinus

Back 110

if sac opends into the pharyngeal cavity because one of the branchial septa ruptured, the resulting condtion is internal branchial sinus

Front 111

internal branchial sinus

Back 111

if because of 2nd branchial septum rupture, opens through palatine tonsil.

if it was from 3rd, then opens through thyrohyoid membrane

if continuous channel from skin through remnant of the cervical sinus and a ruptured branchial septum into the pharynx, the result is a branchial fistula

Front 112

Thyroid Diverticulum

Back 112

pyramidal lobe of the thyroid

a ligament thyroglossal extends from the pyramidal lobe or thyroid isthmus up to the hyoid

Front 113

failure of proper neural crest migration into branchial arches

Back 113

1st arch syndromes: when neural crest cells destined to populate the first branchial arch do not do so.= major deformations of maxilla, mandible, and ears

Front 114

DiGeorge's syndrome

Back 114

minor deformations in lower face combined with thymic and parathyroid aplasia and aoritcopulmonary septation. absence of thymus has deleterious effect on the development of the immune system. Absence of parathyroids leads to hypocalcemia

Front 115

Cleft lip

Back 115

occurs in 1:1000 births, w/ or w/o cleft palate. more common in males

Front 116

unilateral cleft lip

Back 116

maxillary prominence fails to fuse completely with one medial nasal prominence

Front 117

bilateral cleft lip

Back 117

occurs when the maxillary prominences fail to fuse completely with both medial nasal prominences

Front 118

median cleft lip

Back 118

occurs when the medial nasal prominences fail to fuse

Front 119

median cleft lower lip and/or cleft mandible

Back 119

occur when the mandibular prominences fail to fuse

Front 120

oblique facial clefts

Back 120

from upper lip to medial angle of the eye. occurs when maxillary prominence fails to fuse with both medial nasal prominence and a lateral nasal prominence.

preclude existence of nasolacrimal duct on the involved side

Front 121

cleft palate

Back 121

1:2500 births, w/ or w/out cleft lip. more common in females than males

(less common than cleft lip)

Front 122

unilateral secondary palate clefts

Back 122

occur when one of the lateral palatine processes fails to meet and fuse with the other and the nasal septum

Front 123

bilateral secondary palate clefts

Back 123

occur when both lateral palatine process fail to meet and fuse with the other and the nasal septum

Front 124

unilateral primary palate clefts

Back 124

occur when one medial nasal prominence fials to fuse with the lateral palatine process or maxillary promience

Front 125

bilateral primary palate clefts

Back 125

occur when both medial nasal prominences fail to fuse with the lateral palatine processes and/or maxillary prominences