Peds- abdomen embryology

Question 1

what 5 things are included in embryology?

Answer 1

1. fertilization
2. zygote
3. blastula
4. gastrula
5. organogenesis

Question 2

what is organogenesis?

Answer 2

cephalocaudal and lateral foldings lead to formation of primitive/primordial gut from endoderm

Question 3

what are the 3 primary germ layers?

Answer 3

1. endoderm (inner layer)
2. mesoderm (middle layer)
3. ectoderm (external layer)

Question 4

3 primordial gut parts?

Answer 4

1. foregut
2. midgut
3. hindgut

Question 5

What forms the foregut? (9)

Answer 5

• pharynx
• oral cavity
• upper/lower respiratory system
• esophagus
• stomach
• duodenum
• liver
• bile ducts
• pancreas

Question 6

during duodenal development what occurs?

Answer 6

• during duodenal development, the lumen becomes obliterated and recanalizes
• if this fails, duodenal atresia or stenosis occurs
• infants present with bile-stained vomiting

Question 7

what does the midgut form?

Answer 7

• part of duodenum
• jejunum
• ileum
• cecum
• appendix
• part of transverse colon

Question 8

when does physiological herniation occur?

Answer 8

9-11 weeks

Question 9

what is physiological herniation?

• when does midgut return into abdomen?
• what are the last structures to return?
• what becomes fixed to posterior of andominal cavity?

Answer 9

• rapidly enlarging liver and kidneys cause a shortage of room
• midgut forms a loop and elongates into the umbilicus (week 9)
• midgut returns to abdo. by the 12th week (anticlockwise rotation)
• cecum and appendix are the last structures to return
• large bowel becomes fixed to the posterior of abdo. cavity

Question 10

what does the hidgut form?

Answer 10

• left 3rd of transverse colon
• descending colon
• sigmoid
• rectum
• upper part of anal canal

Question 11

What is the rectum separated from the urogenital organs by?

Answer 11

a septum

Question 12

if there is abnomral seperation from rectum and urogenital organs what occurs?

Answer 12

• fistulas to the urethra, bladder, and vagina occur

Question 13

When does the liver, GB, and bild duct system form?

Answer 13

4-6th week of fetal development

Question 14

endodermal outgroth or hepatic diverticulum forms at what week?

Answer 14

4-6th week of fetal development

Question 15

How does the endodermal outgrowth or hepatic dicerticulum form?

• caudal portion?
• cephalic portion?

Answer 15

• caudal portion differentiates into cystic duct and bile duct
• cephalic portion 2 buds begin forming the right and left hepatic lobes

Question 16

cephalic portion of liver formation?

Answer 16

• The buds grow into columns that branch and form networks
• These eventually become the liver sinusoids.
• The columns of endodermal cells and the liver parenchyma grow into the surrounding mesoderm
• The mesoderm provides tissue for the portal tracts and the Glisson capsule

Question 17

When do the liver lobes become different sizes?

Answer 17

• In the beginning both lobes are equal in size
• The liver begins developing blood cells
• By end of 6th wk right lobe becomes larger, left lobe undergoes some degeneration
• Liver fills most of the abdominal cavity

Question 18

Liver, Gallbladder and Bile Duct System- oxygenated blood/ nutrients are delivered via?
- 2 branches?

Answer 18

• umbilical vein, which has two branches
• Intrahepatic part of umbilical vein joins left portal vein (ligamentum teres)
• Ductus venosus flows into IVC (ligamentum venosum)

Question 19

Ligamentum venosum and teres can become recanalized as?

Answer 19

collaterals in portal hypertension

Question 20

what is the spleen?

Answer 20

• intraperitoneal

- lymphatic organ

Question 21

what does the spleen form from?

Answer 21

• mesenchymal cells

- mesodermal

Question 22

How does the spleen develop?

Answer 22

cells differentiate to form the:

• splenic pulp
• supportive connective tissue
• capsule pulp

Question 23

spleen- what does while pulp consist of?

Answer 23

• lymphatic tissue (lymphocytes and macrophanges)

Question 24

spleen- what does red pulp consist of?

Answer 24

• vascular sinuses that are capable of storing morse than 300ml of blood

Question 25

What does the pancreas develop from?

Answer 25

- ventral and dorsal pancreatic buds | - mainly derived from the dorsal pancreatic bud

Question 26

What pancreatic bud appears first?

Answer 26

dorsal pancreatic bud

Question 27

where does the ventral pancreatic bud develop?

Answer 27

near the entry of the bile duct to the duodenum

Question 28

ventral bud forms? | dorsal bud forms?

Answer 28

ventral bud - uncinate process/head | dorsal bud- body/tail

Question 29

what forms the main panc. duct of wirsung?

Answer 29

- ventral and dorsal buds fuse, the duct system fuses

Question 30

Development of the renal tract?

Answer 30

- the development of the urinary and genital systems are intimately related - The ducts from the urinary system go on to be incorporated into the genital system - Occurs in 3rd week of fetal development

Question 31

kidneys begin to form from?

Answer 31

- mesoderm

Question 32

what three sets of excretory organs develop in an embryo in a cranial to caudal progression?

Answer 32

1. pronephros 2. medonephros 3. metanephros

Question 33

pronephros?

Answer 33

rudimentary non-functioning

Question 34

mesonephros?

Answer 34

well developed and functions briefly

Question 35

metanephros?

Answer 35

becomes permanent kidneys

Question 36

what becomes the permanent kidney?

Answer 36

metanephros

Question 37

Renal tract 4th week? - pronephros - mesonephros

Answer 37

The Pronephros: -degenerates rapidly, leaving a duct to be used by the next kidney The Mesonephros: - forms caudad to the pronephros - provides partial function while permanent kidneys continue to develop - by the end of the embryonic period, the mesonephros → the mesonephric ducts/ Wolffian ducts (male genital structures), disappear in females

Question 38

rental tract 5th week? - metanephros - nephrons

Answer 38

The Metanephros: - appears as ureteric buds - distal end forms the pelvis, calyces, collecting tubules - proximal portion forms the ureters Nephrons form from the mesoderm around the buds.

Question 39

at first how does the permanent kidney lie?

Answer 39

- close to each other in the pelvis | - as abdomen grows the kidneys move cranially until they come in contact with the adrenal glands

Question 40

What 2 parts do the adrenal glands consist of?

Answer 40

- medulla | - cortex

Question 41

adrenal gland- medulla?

Answer 41

- developed from neural crest cells (sympathetic) | - Adrenal medullary pathology may appear along the sympathetic neurons at the celiac axis

Question 42

Adrenal glands cortex?

Answer 42

- derived from gonadal mesoderm | - Ectopic adrenocortical tissue along the gonadal migration path

Question 43

adrenal gland develop from?

Answer 43

- different embryonic tissues | - form 2 different anatomical and functional structures within one endocrine gland