Embryo

Front 1

Embryo

What are the fetal landmarks:
Day 0
Within week 1
Within week 2
Within week 3

Back 1

Day 0: fertilization by sperm, initiating embryogenesis

Within week 1: implantation (as a blastocyst)

Within week 2: bilaminar disk (epiblast:hypblast), 2 cavities form (amniotic cavity, yolk sac), placenta is made of cytotrophoblasts and syncytiotrophoblast tissue

Within week 3: gastrulation, primitive streak, notochord, and neural plate begin to form,

Front 2

Embryo

Fetal landmarks for:
Weeks 3-8
Week 4 specifically
Week 8 specifically
Week 10

Back 2

Weeks 3-8: neural tube formed and organogenesis is occuring. Most suseptable to teratogens

Week 4: heart begins to beat: 4 chambers in week 4

Week 8: fetal movement; fetus looks like a baby

Week 10: genitalia have male/female characteristics

Front 3

Embryo

What is the alar plate and basal plate involve in fetal development?

Back 3

Alar: sensory
Basal: motor (MOW: think basal ganglion controls movement)

Front 4

Embryo

What is the rule of 2's for the 2nd week of fetal development?

Back 4

2 germ layers (bilaminar disk): epiblast, hypoblast
2 cavities: amniotic cavity, yolk sac
2 components to placenta: cytotrophoblast, syncytiotrophoblast

Front 5

Embryo

What is the rule of 3's for the 3rd week of fetal development?

Back 5

3 germ layers (gastrula): ectoderm, mesoderm, endoderm.

Front 6

Embryo

What is an epiblast and what does it ultimately result in forming?

Back 6

Epiblast: (precursor to ectoderm) it invaginates to form primitive streak.

Cells from the primitive streak give rise to both intraembryonic mesoderm and endoderm.

Front 7

Embryo

What does the surface ectoderm form?

Back 7

Surface ectoderm: adenohyophysis; lens of eye; eptithelial linings of skin, ear, eye, and nose; epidermis

Front 8

Embryo

What does the neuroectoderm derive into?

Back 8

Neurohypophysis, CNS neurons, oligodendrocytes, astrocytes, ependymal cells, pineal gland.

Front 9

Embryo

What does the neural crest derive into? What germ cell layer does it come from?

Back 9

Ectoderm --> neural crest

ANS, dorsal root ganglia, cranial nerves, melanocytes, chromaffin cells of adrenal medulla, enterochromaffin cells, pia and arachnoid, celiac ganglion, Schwann cells, odontoblasts, parafollicular (C) cells of thyroid, laryngeal cartilage, bones of the skull.

Front 10

Embryo

Endoderm forms:

Back 10

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

Front 11

Embryo

Notochord forms:

Back 11

Induces ectoderm to form neuroectoderm (neural plate).

Its postnatal derivative is the nucleus pulposus of the intervertebral disk.

Front 12

Embryo

Mesoderm forms:

Back 12

Mesoderm: dura mater, connective tissue, muscle, bone, cardiovascular structures, lymphatics, blood, urogenital structures, serous linings of body cavities (eg peritoneal), spleen, adrenal cortex, kidneys.

Front 13

Embryo

Mesoderm defects cause:

Back 13

VACTERL:
Vertebral defects
Anal atresia
Cardiac defects
Tracheo-esophageal fistula
Renal defects
Limb defects (bone and muscle)

Front 14

Embryo

Seven common congenital malformations?

Back 14

1. heart defects
2. hypospadias
3. cleft lip (with or without cleft palate)
4. congenital hip dislocation
5. spina bifida
6. ancephaly
7. pyloric stenosis

Front 15

Embryo

Infant with projectile vomiting Dx?

Back 15

Associated with projectile vomiting

Front 16

Embryo
Tetratogens

Alcohol

Back 16

Birth defects and mental retardation (leading cause); fetal alcohol syndrome

Front 17

Embryo

ACE inhibitors

Back 17

renal damage

Front 18

Embryo

Cocaine

Back 18

abnormal fetal development and fetal addiction

Front 19

Embryo

Diethystilbestrol (DES)

Back 19

Vaginal clear cells adenocarcinoma

Front 20

Embryo

Iodide

Back 20

Congenital goiter or hypothyroidism

Front 21

Embryo

13-cis-retinoic acid

Back 21

Extremely high risk for birth defects

Front 22

Embryo

Thalidomide

Back 22

Limb defects ("flipper" limbs)

Front 23

Embryo

Tobacco

Back 23

Preterm labor, placental problems, attention-deficit hyperactivity disorder (ADHD)

Front 24

Embryo

Warfarin, x-rays, anticonvulsants

Back 24

Multiple anomalies

Front 25

Embryo

Describe monozygotic twins

Back 25

1 zygote splits evenly to develop 2 amniotic sacs with a single common chorion and placenta.

Front 26

Embryo

Describe dizygotic (fraternal) and monozygotic twins can both develop:

Back 26

Individual placentas, chorions, and amniotic sacs.

Front 27

Embryo

Describe the umbilical cord:

Back 27

Contains 2 umbilical arteries, which return deoxygenated blood from fetal internal iliac arteries, and 1 umbilical vein, which supplies oxygenated blood from the placenta to the fetus.
There is also an allantoic duct (fetal urethra), Wharton's jelly within the cord, and amniotic epithelium lining the cord.

Front 28

Embryo

What is the allantoic duct? Function?

Back 28

A duct within the umbilical cord that removes nitrogenous waste from fetal bladder (its like a urethra)

Front 29

Embryo
What does this embryonic structure give rise to:

Truncus arteriosus

Back 29

Ascending aorta and pulmonary trunk

Front 30

Embryo
What does this embryonic structure give rise to:

Bulbus cordis

Back 30

Smooth parts of the left and right ventricle

Front 31

Embryo
What does this embryonic structure give rise to:

Primitive ventricle

Back 31

trabeculated parts of the left and right ventricle

Front 32

Embryo
What does this embryonic structure give rise to:

Primitive atria

Back 32

Trabeculated left and right atrium

Front 33

Embryo
What does this embryonic structure give rise to:

Left horn of sinus venosus

Back 33

Coronary sinus

Front 34

Embryo
What does this embryonic structure give rise to:

Right horn of SV

Back 34

Smooth part of right atrium

Front 35

Embryo
What does this embryonic structure give rise to:

Right common cardinal vein and right anterior cardinal vein

Back 35

SVC

Front 36

Embryo

Describe the process of fetal erythropoiesis:

Back 36

Fetal erythropoiesis occurs in:
Young Liver Synthesizes Blood
1. Yolk sac (3-8wks)
2. Liver (6-30wks)
3. Spleen (9-28wks)
4. Bone marrow (28wk onward)

Front 37

Embryo

What percentage of blood in umbilical vein is saturated with O2?

Back 37

80%

Front 38

Embryo

Describe the three important shunts in fetal circulation:

Back 38

1. Foramen ovale: most oxygenated blood reaching the heart via the IVC is diverted through the foramen ovale and pumped out the aorta to the head
2. Ductus arteriosus: deoxygenated blood from the SVC is expelled into the pulmonary artery and ductus arteriosus

3. Ductus venosus: blood entering the fetus through the umbilical vein is conducted via the ductus venous into the IVC

Front 39

Embryo

What is indomethacin used for?

Back 39

close a PDA

Front 40

Embryo
Fetal-postnatal derivatives:

Umbilical vein

Back 40

ligamentum teres hepatis

Front 41

Embryo
Fetal-postnatal derivatives:

Umbilical arteries

Back 41

umbiLical arteries: mediaL umbilical ligaments

Front 42

Embryo
Fetal-postnatal derivatives:

Ductus arteriosus

Back 42

Ligamentum arteriosum

Front 43

Embryo
Fetal-postnatal derivatives:

Ductus venosus

Back 43

Ligamentum venosum

Front 44

Embryo
Fetal-postnatal derivatives:

Foramen ovale

Back 44

Fossa ovalis

Front 45

Embryo
Fetal-postnatal derivatives:

Allantois

Back 45

allaNtois: urachus - mediaN umbilical ligament

Front 46

Embryo
Fetal-postnatal derivatives:

Notochord

Back 46

Nucleus pulposus of intervertebral disk

Front 47

Embryo
Fetal-postnatal derivatives:

What is the urachus?

Back 47

The urachus is part of the allantoic duct (which becomes the mediaN umblical ligament) and is located between the bladder and the umbilicus

Front 48

Embryo
Aortic arch derivatives:

1st part?

Back 48

MAXillary a (1st is maximal)

Front 49

Embryo
Aortic arch derivatives:

2nd part?

Back 49

Stapedial artery and hyoid artery (Second=Stampedial)

Front 50

Embryo
Aortic arch derivatives:

3rd part?

Back 50

Common Carotid artery and proximal part of internal carotid a.

C = 3rd letter of the alphabet

Front 51

Embryo
Aortic arch derivatives:

4th part?

Back 51

On left: aortic arch
On right: proximal part of the subclavian artery

"4th arch = 4 limbs = systemic"

Front 52

Embryo
Aortic arch derivatives:

6th part? (note: no fifth)

Back 52

Proximal part of pulmonary arteries and (on left side only) ductus arteriosus

"6th arch = pulmonary and the pulmonary-to-systemic shunt"

Front 53

Embryo

What is the branchial apparatus composed of? Derivations?

Back 53

Branchial apparatus:

Composed of branchial clefts (ectoderm), arches (mesoderm and neural crests), and pouches (endoderm).

"CAP = covers outside --> inside = Clefts (ectoderm), Arches (mesoderm), Pouches (endoderm)

Front 54

Embryo

Branchial arch 1 derivatives:

Back 54

M's

Meckels cartilage
Mandible
Malleus
incus
sphenoMandibular ligament
Muscles of Mastication (temporalis, Masseter, lateral and Medial pterygoids)
Mylohyoid
anterior belly of digastric
tensor tympani
tensor veli palatini
anterior 2/3 tongue

Front 55

Embryo

Branchial arch 2 derivatives

Back 55

Reichert's cartilage: Stapes, Styloid process, lesser horn of the hyoid, Stylohyoid ligament

Muscles: muscles of facial expression, Stapedius, Stylohyoid, posterior belly of digastric

Nerve: VII

Front 56

Embryo

Branchial arch 3 derivatives

Back 56

Cartilage: greater horn of hyoid
Muscle: stylopharyngeus
Nerve: CN IX

Front 57

Embryo

Branchial arch 4-6 derivatives

Back 57

Cartilages: thyroid, cricoid, arytenoids, corniculate, cuneiform

Muscles (4th arch): most pharyngeal constrictors, cricothyroiid, levator veli palatini

Muscle (6th arch): all intrinsic muscles of larynx EXCEPT CRICOTHYROID.

Nerve:
4th arch - CN X (superior laryngeal branch)
6th arch - CN X (recurrent laryngeal branch)

Front 58

Embryo

Branchial arch (1-6) innervation

Back 58

Arch 1: derivatives supplied by CN V2 and V3

Arch 2: derivatives supplied by CN VII

Arch 3: derviatives supplied by CN IX

Arch 4 and 6 supplied by CN X

Front 59

Embryo

Tongue development

Back 59

1st brachial arch forms anterior 2/3 (thus sensation via CN V3, taste via CN VII)

3rd and 4th arches form posterior 1/3 (thus sensation and taste mainly via CN IX, extreme posterior via CN X)

Motor innervation is via CN XII

"Taste is CN 7, 9, 10 (solitary nucleus)
pain is CN V3, 9, 10
motor is CN 12"

Front 60

Embryo

Branchial cleft derivatives

Back 60

1st cleft develops into external auditory meatus.

2nd through 4th clefts form temporary cervical sinuses, which are obliterated by proliferation of 2nd arch mesenchyme.


Thyroglossal duct cyst in midline neck.

Front 61

Embryo

What forms a branchial cyst?

Back 61

Persistant cervical sinus can lead to a branchial cyst in the lateral neck.

Front 62

Embyro

What forms a midline cyst in neck?

Back 62

Thyroglossal duct cyst forms in the midline of the neck.

Front 63

Embyro

What ear components are formed from the first arch?
first cleft?

Back 63

First arch:
Malleus
Incus
tensor tyMpani (V3)

First cleft: external auditory meatus

Front 64

Embryo

What ear components are formed from the second arch?

Back 64

Stapes (bone)
Stapedius m. (VII)

Front 65

Embryo

Branchial membranes are located at the junctions of clefts with pouches --

What derives from the first branchial membrane? (2)

Back 65

Eardrum
Eustachian tube

Front 66

Embryo

Branchial (pharyngeal) pouch derivatives:

1st pouch

Back 66

1st pouch:
develops into middle ear cavity, eustachian tube, mastoid air cells

(contributes to endoderm-lined structures of ear)

Front 67

Embryo
Branchial (pharyngeal) pouch derivatives:

2nd pouch?

Back 67

2nd pouch
Develops in to epithelial lining of palatine tonsil

Front 68

Embryo

Branchial (pharyngeal) pouch derivatives:

3rd pouch?

Back 68

3rd pouch (dorsal wings) develops into INFERIOR parathyroids, (ventral wings) develops into THYMUS

Front 69

Embryo
Branchial (pharyngeal) pouch derivatives:

4th pouch?

Back 69

Develops into superior parathyroids

Front 70

Embyro

What can aberrant development of 3rd and 4th pouches cause:

Back 70

DiGeorge's syndrome --> leads to t-cell deficiency (thymic aplasia) and hypocalcemia (failure of parathyroid to develop)

Front 71

Embryo:

Explain the thyroid development?

Back 71

Thryoid diverticulum arises from floor of primitive pharynx, descends into neck. Connected to tongue by thyroglossal duct, which normally disappears by may persist as a pyramidal lobe of thyroid.

Front 72

Embryo

What is a foramen cecum

Back 72

Foramen cecum is a normal remnant of thyroglossal duct.

Front 73

Embryo

Cleft lip

Back 73

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

Front 74

Embryo

Cleft palate

Back 74

Failure of fusion of the lateral palatine processes, the nasal septum, and/or the median palatine process (formation of secondary palate)

Front 75

Embryo

What are the four things that the diaphragm is derived from?

Back 75

Several Parts Build Diaphragm

1. Septum transversum
2. Pleuroperitoneal folds
3. Body wall
4. Dorsal mesentery of esophagus

Front 76

Embryo

Explain why the diaphragm is innervated by C3, 4, 5?

Back 76

The diaphragm descends during development but maintains innervation from above C3-5.

Front 77

Embryo

What is a hiatal hernia?

Back 77

When there is incomplete development of the thorax that causes abdominal contents to herniate into the thorax

Front 78

Embryo

Explain the derivation of the pancreas

Back 78

Pancreas is derived from the foregut.

The ventral pancreatic bud becomes pancreatic head, uncinate process (lower half of head), and main pancreatic duct.

Dorsal pancreatic duct becomes everything else (body, tail, isthmus, and accessory pancreatic duct)

Front 79

Embryo

Explain the derivation of the spleen:

Back 79

Spleen: arises from the dorsal mesentery but is supplied by artery of the foregut.

Front 80

Embryo

What is annular pancreas?

Back 80

Ventral and dorsal pancreatic buds that abnormally encircle the duodenum; forming a ring of pancreatic tissue that may cause duodenal narrowing.

Front 81

Embryo

Describe the embryologic derivation of the GI tract:

Back 81

1. Foregut: pharynx to duodenum
2. Midgut: duodenum to transverse colon
3. Hindgut: distal transverse colon to rectum

Front 82

Embryo

The kidney progresses during development until it reaches its permanent form.

What are the names of the three embryologic derivations and when in development do they appear?

Back 82

1. Pronephros: week 4
2. Mesonephros: first trimester
3. Metanephros: permanent

Front 83

Embryo

What does the Mesonephric (wolffian) duct develop into?

Back 83

Seminal vesicles
Epididymis
Ejaculatory duct
Ductus deferens

(SEED)

Front 84

Embryo

What does the Paramesonephric (mullerian) duct develop into?

Back 84

Develops into fallopian tube, uterus, and part of vagina.

Front 85

Embryo

What is the function of the Mullerian inhibiting substance?

Back 85

Mullerian inhibiting substance secreted by testes suppresses development of paramesonephric duct in males.

Front 86

Embyro

What causes the development of the mesonephritic ducts?

Back 86

High androgen production

Front 87

Embryo
Male vs Female development
What does each grow into?

Genital tubercle

Back 87

Genital tubercle

DHT: glans penis
Estrogen: glans clitoris

Front 88

Embryo
Male vs Female development
What does each grow into?

Urogenital sinus

Back 88

Urogenital sinus:

DHT:
corpus spongiosum
bulbourethral glands (of Cowper)
Prostate gland

Estrogen:
vestibular bulbs
greater vestibular glands (of Bartholin)
Urethral and paraurethral glands (of Skene)

Front 89

Embryo
Male vs Female development
What does each grow into?

Urogenital folds

Back 89

DHT: ventral shaft of the penis (penile urethra)

Female:
Labia minora

Front 90

Embryo
Male vs Female development
What does each grow into?

Labioscrotal swelling

Back 90

DHT: scrotum

Estrogen: labia majora