EMBRYO

Question 1

Neural crest derivatives of Peripheral Nervous System

Answer 1

ANS
Vagus nerve
Sympathetic ganglia
Dorsal root ganglia
Sensory nerves
Schwann cells
CNS

Question 2

Neural crest derivatives of the ear

Answer 2

Bones of the ear

Question 3

Neural crest derivatives of the eye

Answer 3

Anterior chamber
Cornea
Sclera
Ciliary muscle
Iris pigment cells

Question 4

Neural crest derivative of adrenal gland

Answer 4

Chromaffin cells of medulla

Question 5

Neural crest derivative of mouth

Answer 5

Odontoblast

Question 6

Neural crest derivative of heart

Answer 6

Aorticopulmonary septum (Spiral septum)

Question 7

Neural crest derivatives of digestive system

Answer 7

Enteric nervous system
Celiac ganglion
Enterochromaffin cells

Question 8

Neural crest derivative of thyroid

Answer 8

Parafollicular cells

Question 9

Neural crest derivative of skin

Answer 9

Melanocytes

Question 10

During what weeks of fetal development does organogenesis take place?

Answer 10

3-8 weeks

Question 11

Embryo origin of anterior pituitary

Answer 11

Surface ectoderm

Question 12

Embryo origin of lens

Answer 12

Surface ectoderm

Question 13

Embryo origin of retina

Answer 13

Neuroectoderm

Question 14

Embryo origin of olfactory epithelium

Answer 14

Surface ectoderm

Question 15

Embryo origin of mammary glands

Answer 15

Surface ectoderm

Question 16

Embryo origin of salivary glands

Answer 16

Surface ectoderm

Question 17

Embryo origin of sweat glands

Answer 17

Surface ectoderm

Question 18

What adult structures are derived from 3rd aortic arch?

Answer 18

Common carotid, proximal internal carotid

Question 19

What adult structures are derived from the 4th aortic arch?

Answer 19

Left: aortic arch
R: proximal subclavian

Question 20

What adult structures are derived from the 6th aortic arch?

Answer 20

Proximal pulmonary arteries and ductus arteriosus

Question 21

Outline the pathway by which the heart tube forms the atria of the four chambered heart.

Answer 21

Tube grows, elongates, and folds into an S shape –> atrial chamber lays posteriorly in S, and ventricular chamber lays anteriorly in S –> atrial chamber grows and incorporates SVC and pulm vein – > septum primum forms – > septum secundum forms incompletely leaving foramen ovale and cell death in septum primum forms a hole called ostium secundum

Question 22

Outline the pathway by which the ventricles and their outflow tracts are separated.

Answer 22

Ventricular chamber lays anteriorly in the S shaped heart tube – > muscular ventricular septum forms which begins to divide the ventricles. Truncoconical swellings/ridges of the truncus arteriosus meet, fuse, and zip (both superiorly and inferiorly) in a 180 degree turn to form the spiral septum. Inferior portion of spiral septum meets with muscular ventricular septum to divide the ventricles and form the aorta and pulmonary arteries.

Question 23

Describe how the ventricles are remodeled in order to form the AV valves.

Answer 23

Myocardium erodes – > ventricles enlarge as a result – > residual mesodermal tissue becomes fibrous and forms chordae tendinae. Formation of papillary muscles and AV valves.

Question 24

Which embryologic structure gives rise to the ascending aorta and pulmonary trunk?

Answer 24

Truncus arteriosus

Question 25

Which embryologic structure gives rise to the coronary sinus?

Answer 25

Left horn of sinus venosus.

Question 26

Which embryologic structure gives rise to the SVC?

Answer 26

R common cardinal vein and R anterior cardinal vein

Question 27

Which embryologic structure gives rise to the smooth parts of the L and R ventricle?

Answer 27

Bulbous cordis

Question 28

Which embryologic structure gives rise to the smooth part of the R atrium?

Answer 28

R horn of sinus venosus

Question 29

Which embryologic structure gives rise to the trabeculated L and R atria?

Answer 29

Primitive atria

Question 30

Which embryologic structure gives rise to the trabeculated parts of the L and R ventricle?

Answer 30

Primitive ventricle

Question 31

What causes the ductus arteriosus to close?

Answer 31

Increase in O2 causes decreased prostaglandins. | Also pharm rx is indomethacin.

Question 32

What causes the foramen ovale to close?

Answer 32

When the infant breathes in, there is a decrease in pulmonary vascular resistance causing an abrupt increase in L atrial pressure relative to R atrial pressure.