Embryonic Development (Block 2 Week 5)

Front 1

What is omphalocoele?

Back 1

Intestines don't retract all of the way back into the body
Due to imperfect closure of the umbilical ring
Appears as skin
Usually small intestines covered by protrusion

Front 2

What is gastroschisis?

Back 2

Intestines break through the abdominal wall due to rupture

Front 3

Hirschspring disease?

Back 3

Lack of innervation of distal portions of colon and rectum due to lack of neural crest migration; no ganglia
Leads to megacolon because of no peristalsis

Front 4

Foregut derivatives and blood supply?

Back 4

Ceilac artery

Lung lining
Esophageus lining
Stomach
Pancreas
Liver
Gall bladder
Pharnyx -> thyroid
Branchial pouches
-Eustachian tubes (BP 1)
-Tonsils (BP 2)
-Thymus (BP 3)
-Parathyroids (BPs 3 and 4)

Front 5

What is the origin of the two layers of the amniotic sac?

Back 5

The ectoderm and somatic mesoderm (somatoplure)

Front 6

What is the origin of the two layers of the yolk sac?

Back 6

The endoderm (+hypoblast) and splanchnic mesoderm (splanchnoplure)

Front 7

What is the origin of the thyroid?

Back 7

Endodermal floor of the pharynx

Front 8

What abdominal organs are retroperitoneal?

Back 8

Pancreas
Duodenum
Kidneys

Front 9

What organs derived from the midgut and what is the blood supply?

Back 9

Superior mesenteric artery

Small intestine
Ascending colon
Proximal part of transverse colon

Front 10

What organ forms partially in the yolk sac and why?

Back 10

The small intestines
Because the embryonic liver is initially very large, the SIs are forced out into the yolk sac (herniation)

Front 11

What mesentary structure suspends the abdominal part of the gut tube and from what is it derived?

Back 11

The omentum, and it is from visceral mesoderm

Front 12

What structures derived from hindgut and what is its blood supply?

Back 12

Inferior mesenteric artery

Distal transverse colon
Descending colon
Rectum
Part of bladder and urethra

Front 13

How is the gut innervated?

Back 13

Primarily from neural crest cells migrating from anterior neural tube into walls of foregut, then down the gut

Front 14

What can be the result of a VSD?

Back 14

Congestive heart failure

Front 15

What is the Tetralogy of Fallot and in what condition is it common?

Back 15

1.) VSD
2.) Pulmonary stenosis
3.) Right ventricle hypertrophy
4.) Aorta placed over VSD

Often found in DiGeorge Syndrome (22q11 deletion)

Blue baby syndrome at birth

Front 16

When and where is blood made in utero?

Back 16

Week 3: Yolk sac blood islands
Week 5: Liver
End of term: Spleen and bone marrow (like adult)

Front 17

Name the major arterial tracts in the embryo and their locations

Back 17

1.) Dorsal aorta connects to the aortic arches and the vitelline artery (to the yolk sac)
2.) Umbilical artery attaches with the dorsal aorta (from the maternal circulation)
3.) Vitelline artery attaches to the dorsal aorta; takes old blood to yolk sac

Front 18

Name the major veins of the embryo

Back 18

1.) Anterior and posterior cardinal veins receive blood from the dorsal aorta and empty into the common cardinal vein, just posterior to the heart
2.) Vitelline vein provides the embryo with fresh blood from the yolk sac; connects to heart via common cardinal vein
3.) Umbilical vein connects to heart via common cardinal as well

Front 19

What are the four changes in fetal circulation that take place at birth?

Back 19

1.) Foramen ovale closes, which allowed communication between right and left atria
2.) Ductus venosis closes, which formerly was a shunt that bypassed the liver.
3.) The umbilical artery is no longer functional (the remaining is attached to the umbilicus and the superficial surface of the bladder)
4.) Ductus arterosis closes, which used to send blood from the pulmonary artery directly into the aorta instead of the lungs

Front 20

What is horseshoe kidney?

Back 20

Fusion of two kidneys across the midline at their posterior poles - mesodermal dysfunction

Front 21

Polycystic kidney disease?

Back 21

Either autosomal dominant or recessive, resulting in fluid filled cysts, leading to kidney failure

Front 22

What is hypospadias?

Back 22

Disorder characterized by a lack of midline closure of the urethra in boys; often due to androgen insuffiency

Front 23

Where does skeletal muscle come from?

Back 23

Paraxial mesoderm (except for a few muscles in the face from neural crest)

Front 24

Where does smooth and cardiac muscle come from?

Back 24

Splanchnic mesoderm of the lateral plate

Front 25

Bones from the paraxial mesoderm?

Back 25

Base and back of skull
Vert column
Ribs
Scapulae
Pelvis

Front 26

Into what three layers do somites differentiate?

Back 26

Sclerotome
Myotome
Dermomyotome

Caused by signals from adjacent tissues (ectoderm, notochord, neural tube)

Front 27

Name the three primitive kidney structures (from anterior to inferior)

Back 27

Pronephros
Mesonephros
Metanephros

Front 28

Describe the fate of:
Pronephros
Mesonephros
Metanephros

Back 28

Pronephros is lost

Mesonephros contains a duct (Wolffian duct) that persists in males but degenerates in females

Metanephros becomes the adult kidney (via branching of the uterine bud)

Front 29

Describe the path of germ cell migration from the yolk sac

Back 29

In week 4, from near the base of the allantois, the move along the dorsal mesentary of the hindgut until they reach the genital ridges

Front 30

what is the origin of the genital ridges and where do they form?

Back 30

Intermediate mesoderm on the medial side of the mesonephros

Front 31

What determines sexual genotype?

Back 31

Expression of SRY

SRY leads to Sertoli and Leydig development

Sertoli produces mullerian inhibiting substance, which leads down the path of male development

Front 32

What is derived from the mesonephric duct?

Back 32

Male spermatic ducts:
Seminal vesicles
Epididymus
Vas deferens

Front 33

What is the fate of the paramesonephric duct?

Back 33

Lining of the fallopian tubes