Embryology Flashcards
What is the pharyngeal apparatus consist of?
Clefts = Pharyngeal groove = ectoderm Arches = mesoderm Pouches = endoderm
What is another name for the pharyngeal apparatus?
brachial
means gill
What does each arch have?
own nerve, vasuclar, muscular
Why is the 5th signicant?
rudimentary
disappears
no 5th arch, cleft, pouch
What happens with the 4th and 6th arch?
incorporated into 4th
What is the derivative of the arches and pouches?
Ear, tonsils, bottom to, top
1 = tympanic (middle ear cavity) + auditory (eustacian) tube
2= palatine tonsils + tonsilar fossa
3= inferior parathyroid gland + thymus
4= superior parathyroid gland + ultimobranchial body (parafollicular C cells of thyroid gland)
What is the fate of the clefts?
1st = external auditory meatus
2, 3, 4 = obliterated by overgrowth of the 2nd and 4th arch to form cervical sinus
How many arches are there at the 4th week?
4 arches
What happens if 2,3,4 clefts persist?
branchial cyst or fistula along anterior border of sternocleidomastoid
Fistual= has secretion inside and drains to outer border of SCM
What is the only membrane that persists?
1st = tympanic membrane
What do kids do at the golden arches?
Chew (1st) = 5 Smile (2nd) = 7 Stylish (3rd) = 9 Swallow (4th) Speak (6th) 10
What are the derivatives of the 1st arch?
Arch: mandibular
Nerve: V2 maxillary and V3 mandibular
Muscles: mstication (temp, mass, med lat ptery, mylohyoid, ant belly digastric, tensor palatine, tensory tympani
Sig skeletal: Meckel’s cartilae, malleus, incus
What are the derivatives of the 2nd arch?
Arch: hyoid
Nerve: VII facial
Muscles: facial expression (buccinator, auricularis, frontalis, playsma, orbicularis oris, orbicularis oculi), post belly digastric, stylohyoid, stapedius
Sig skeletal: stapes, styloid process, stylohyoid ligment
What are the dervicates of the 3rd arch?
Arch:
Nerve: IX glossopharyngeal
Muscles: stylopharyngeus
Sig skeletal: body of hyoid bone
What are the dervitives of the 4-6 arch?
Arch:
Nerve: X vagus = superior laryngeal and recurrent laryngeal
Muscles: cricothyroid, levator palatine, onstrictuors of pharynx, instrinsic mucles of larynx
Sig skeletal: thryoid
What is the path of IX glossopharyngeous?
1 innervates Stylopharngeous
2 goes into tonsilar fossa to supply palatine tonsil
3. taste of posterior 1/3 of tongue
What does all msucles of palate except one?
X
except tensor palatine = 5
What does superior parathyriod’s parafollicular c cells make?
calcitonin- role in calcium metabolism
Where does the thyroid develop from?
growth from floor of primordial pharynx between 1st and 2nd pouches
at foramen cecum of tongue
decends to larynx
What drags the thyroid down?
thryoglossal duct
Where does parathyroid gland relocate?
inferior down, superior up
thymus drags to center of chest
What are the parafollicular cells from?
mainly from 4th pair of pharyngeal pouches
What happens if the thyroid gland does not descend completely from tongue?
ectopic thyroid gland
What happens if thyroglossal duct persists?
thyroglossal duct cysts
located at midline of neck under mandible near hyoid bone
How does the oral part (anterior 2/3) of the tongue develop?
from fusion of 2 lateral lingual swellings and median tongue bud
sensory by V and taste by 7
How does the pharyneal part (post 1/3) of the tongue deveop?
from copula (hypobranchial eminence)
IX
Where do the muscles of the tongue arise?
from migration of occipital myotomes
What is anklyoglossia?
tongue tie
cant protrude tongue, cant articulate letters
What is lingual thyroid?
extopic thyroid
interrupted thyroid duct so extra tissue
What are the 3 prominences of the face development?
1 frontonasal
2 maxillary
3 mandibular
Which prominance is unpaired?
frontonasal
Which prominence forms the forehead and dorsum and apex of nose?
frontonasal
Which prominence forms the alae/side of the nose?
lateral nasal
what prominence forms the nasal septum, ethmoid boine, cribriform plate?
medial nasal
Which prominance forms the upper cheek regions and upper lip?
maxillary
Which prominence forms the chin, lower lip, lower cheek region?
mandibular
How does the palate form?
the fusion of an unpaired median process (1ry)
and
paired lateral palatine process (2ry palate)
How does cleft lip happen?
failure of mesenchymal masses i the medial nasal and maxillary prominences to merge
usually environmental and genetic factors
How does cleft palate happen?
failure of mesenchymal masses in palatal processes to meet and fuse
lateral palatine processes
What are babies with cleft palate/lip in danger of?
Babies aspirate a lot through the nose because no connection when suckling so fluid can be inhaled
What is treacher collins syndrome?
First arch syndrome
abnormal development of the first pharyngeal arch. It is due to failure of migration of the neural crest cells into arch 1.
What are the clinical presentations of first arch syndrome?
Clinically presented by facial hypoplasia, microganthia, external ear abnormalities, lower eyelid abnormalities & tracheo- esophageal fistula.
Face eye ear mouth AIRWAY
What is the most common head and neck congenital malformation?
unilateral cleft lip
When does the heart start beating during development?
4th week
Where are the three layers of heart cells (endocardium, myocardium, epicaridum) derived from?
splanchnic mesoderm
Where do the atrium and ventricle move doing development?
Atrium- cranially
ventricle- caudally
where do the aortic arches come from?
trunchus arteriosus
What contributes to the aorta and pulmonary trunk?
truncus asteriosus
what contributes to the smooth part of right venticle (conus arteriosus) and smooth part of left ventricle (aortic vestibule)?
bulbus cordis
What contributes to the trabeculated part of right ventricle and trabeculated part of left ventricle?
primitive ventricle
What contributes to the trabeculated part of the right atrium and left atrium?
primitive atrium
what contributes to the smooth part of the right atrium, coronary sinus, and oblique vein of left atrium?
sinus venosus
What is the smooth part of the right atrium?
sinus venarum
How is the atrial septum formed?
Atrium not ventricular because artial forms shunts
Right shunts to left
During development no lungs functioning- placenta is lungs
No pressure in left atrium because no pulmonary veins pumping
Septum helps fetal cirulation
Right Atrial Blood shunted through foramen ovale to secondary foramen to left atrium
How does the atrial septum change from before birth to after birth?
Before birth = shunt
After birth = lungs work = pressure in left atrium
Pressure shuts down septum
foramen ovale becomes fossa ovalis
Look for fossa ovalis in septal wall between left and right atrium
What is the AP septum spiral?
Pulmonary trunk in front anterior of ascending arota posterior
Spiral because of septum
AP septum issue = transposition of the vessels
Abnormalities = aorta in front, pulmonary in back
Abnoramlties from failure of migration of neural crest cells and messed up spiral
What is PTA?
persistent truncus arteriosus
- partially development of the AP septum
problem in AP septum development, mixing blood between ascneding aorta and pulmonary trunk
usually because of ventricular septal defects VSD (shunt between atrium and ventricle)
What is marked cyanosis?
blue color baby
mixing oxygentated blood with deoxygated blood
What is transpotion of the great vessels>
abonormal division of the truncus arteriosus
nonspiral develppment of AP septum
aorta coming out of right ventricle, pulmonary trunk coming out of left ventricle.
uncompatible with life unless a shunt like VSD, patent foramen, or patent ductus arteriosus exists
cyanoic
What is the most common convenital heart defect>
Ventricular septal defects VSD
faulty fusino of rt bulbar ridge, lt bulbar ridge, and AV cushions
more membranous than muscular
What is tetralogy of Fallot?
PROVE
pulmonary stenosis
right ventricular hypertrophy
overriding aorta
ventricular septal defect (VSD)
PS= stenosis in pulmonary valve = extra pressure in right ventricle
Hypertrophy= because of increased pressure
Overiding aorta= receive blood from right and left ventricle instead of just from left
marked cyanosis
What is patent foramen ovale?
septal defect
atrial septal defect (ASD)
incomplete fusion of septum primum and septum secundum
What are the 2 ducts in fetal circulation?
Ductos venosus= shunt from left umbilical vein to IVC (drains in rigth atrium) over liver
Ductus arteriosus= becomes ligamentum arteriosum
How many umbilical arteries are there?
2- carry deoxygenated blood from iliac to placenta for gas exchange
How many umbilical veins are there?
1!
Just LEFT (no right)
carries oxygenated blood
What is the adult remnant of fetal right and left umbilical arteries>
medial umbilical ligaments
What is the adult remnant of fetal left umbilical vein>
ligamentum teres
What is the adult remnant of fetal ductus venosus
ligamentum venosum
What is the adult remnant of fetal foramen ovale?
fossa ovlale
What is the adult remnant of fetal ductus arteriosus
ligmaentum arteriosus
Which aortic arches disappear?
1 (except maxillary arteries)
2 ( except hyoid and stepedial arteries)
5 (totally)
What are two most common congenital heart defects from circulatory system error?
patent oval foramen
patent ductus arteriosus (PDA from rubella of mom)
What does the 3rd arch give>
common carotid artery on each side and part of internal and little bit of external
Are right and left 4 arch the same>?
NO!
right = right subclavian left = part of arch of aorta 6
What is difference between 6th proximal and 6 distal arch?
right proximal- near midling, right pulmonary artery
distal- disappears- right vagus recurrent at right subclavian because right distal and 5th arch gone
left proximal- left pulmonary artery
left distal- ductus arteriosus
Where is the coronary sinus derived from?
sinus venosus
Which division of truncus arteriosus has a problem if diagnosis is traspotiion of great vessels?
aorticopulmonary septum
what is a right sided heart?
dextrocardia
