Test2Embryo

Question 1

4 Regions of Gut

Answer 1

Pharynx/Foregut/Midgut/Hindgut

Question 2

6 Foregut Structures

Answer 2

Esophagus, stomach, proximal duodenum, liver, gall bladder, pancreas

Question 3

4 Midgut Structures

Answer 3

Distal duodenum, jejunum, ileum, proximal colon

Question 4

2 Hindgut Structures

Answer 4

Distal colon, anorectal canal

Question 5

Initial Gut Tube Structural Differentiation Mech

Answer 5

Gradient of retinoic acid (low to high) activates TFs specific for each region

Question 6

Initial Regional Specificiation Stabilization Mech

Answer 6

Epithelial-mesenchymal interactions as SHH from gut endoderm induces segmental expression of HOX genes in surrounding mesoderm, which induce endoderm to form specific regions

Question 7

Liver Formation

Answer 7

Entire gut has ability to form it, but pathway blocked unless factors from adjacent cardiac mesoderm release inhibition

Question 8

Ventral pancreas bud

Answer 8

Forms ventral head and uncinate process

Question 9

Dorsal Pancreas bud

Answer 9

forms all parts of pancreas except ventral head and uncinate process

Question 10

Pancreatic duct formation

Answer 10

Main pancreatic duct (Wirsung) formed by fusion of dorsal and ventral pancreatic ducts, while an accessory minor duct (Sartorini) is common

Question 11

Annular Pancreas

Answer 11

Ventral pancreas can form a ring around duodenum, potentially resulting in duodenal stenosis

Question 12

Formation of Omental Bursa

Answer 12

Stomach carries dorsal mesogastrium with it as it rotates in later development

Question 13

2 Stomach Rotations (in order)

Answer 13

Vertical around longitudinal rotation axis, and then clockwise around anteroposterior axis

Question 14

Positioning of Pancreas and Spleen

Answer 14

Rotation of dorsal mesogastrium pushes them to the left side, pressing pancreas into posterior abdominal wall making it secondary retroperitoneal

Question 15

Formation of Greater Omentum

Answer 15

Two omental bursa walls hanging down anteriorly fuse

Question 16

Positioning of Proximal Duodenum

Answer 16

Initially in middle, gut rotation swings it to left and retroperitoneally

Question 17

Midgut Rotation

Answer 17

270 degrees counterclockwise, with 90 deg occurring during umbilical herniation and remaining 180 during return to abdomen. Places transverse colon in front of duodenum

Question 18

2 Abormal Rotations of Primitive Intestinal Loop

Answer 18

Incomplete CCW Rotation - SI entirely on right and LI entirely on left, transverse colon forms “U”
Incorrect CW Rotation - Duodenum passes over transverse colon

Question 19

Omphalocele

Answer 19

Failure of intestinal loops to return to abdominal cavity

Question 20

Gastroschisis

Answer 20

Protrusion of abdominal contents through body wall directly into amniotic cavity

Question 21

Two Bowel Defects

Answer 21

Atresias (absence) and stenosis (narrowing)

Question 22

Vitelline Duct

Answer 22

Persistent connection b/w intestinal loop and yolk sac

Question 23

3 Aberrant Remnants of Vitelline Duct

Answer 23

Meckel’s diverticulum (1 vitelline ligament), vitelline cyst (2), and vitelline fistula (0)

Question 24

Formation of Urorectal Septum and Hindgut

Answer 24

5 weeks: Urinary tract drains into hindgut drains into cloacal membrane
7 weeks: Primitive urogenital sinus and hindgut drain into common proctoderm
8 weeks: Urogenital and anal membranes separately drain, separated by perineal body

Question 25

4 Hindgut Abnormalities

Answer 25

Urorectal fistula, rectovaginal fistula, rectal atresia, and imperforate anus

Question 26

Specification of Intermediate Mesoderm

Answer 26

Paraxial mesoderm stimulates TF expression in intermediate mesoderm which is essential for further kidney development

Question 27

3 Structures which Develop in Intermediate Mesoderm at closing of Internal Coelomic Cavity

Answer 27

Mesonephric duct, nephric tubules, and glomeruli

Question 28

3 Sequential Urinary Systems

Answer 28

Pronephros - never functional Mesonephros - functional during 2nd month Metanephros - produce urine by 12th week

Question 29

Primitive Nephron Formation

Answer 29

Mesonephric mesenchyme forms segmental tubules that connect serially with adjacent mesonephric duct

Question 30

Mesonephros

Answer 30

Transiently functional nephrons with glomeruli but no loops of Henle, can't so can't concentrate urine (or make a lot of urine)

Question 31

Metanephric Kidney Formation

Answer 31

Sequential factors released from tips of collecting tubules/tissue caps/metanephric blastema interact to produce ureteric bud outgrowth, which form tubules

Question 32

Tubule Formation Tissue Conversion

Answer 32

Continuous, sequential conversion of mesenchyme into epithelium

Question 33

Ureteric Bud Subdivision

Answer 33

Forms many collecting tubules draining developing nephrons in cortex

Question 34

Ascent of the Kidney

Answer 34

Originally in pelvis, ascends to higher position as caudal end of embryo grows and ureters elongate

Question 35

2 Abnormalities in Kidney Ascension

Answer 35

``` Pelvic Kidney (1 or 2) Horseshoe kidney prevents rising about IMA ```

Question 36

3 Ureter Abnormalities

Answer 36

Double and Partial-Double Ureters | Ectopic openings of ureters

Question 37

Autosomal recessive polycystic kidney disease

Answer 37

Progressive; cysts form in collecting ducts. Kidneys become large and fail in infancy/childhood

Question 38

Autosomal dominant polycystic kidney disease

Answer 38

Cysts form in all segments of nephrons, renal failure in adulthood

Question 39

Urorectal Septum

Answer 39

Intrudes into cloaca and divides it into urogenital sinus and anorectal canal

Question 40

Ureter/Mesonephric Duct Migration

Answer 40

Ureters to top of trigone and mesonephric ducts to bottom, which will eventually become prostate

Question 41

Urogenital development in males

Answer 41

Prostate buds from urethra and caudal mesonephric duct persists to form seminal vesicles and ductus deferens

Question 42

Allantois Persistence

Answer 42

Can form either urachal fistula, cyst, or sinus

Question 43

Bladder Exstrophy

Answer 43

Part of bladder exists outside body

Question 44

Sex Determination

Answer 44

SRY gene on Y chromosome, produces testis determining factor in which male development occurs, on in absence female development occurs

Question 45

Genital/Gonadal Ridges

Answer 45

Form along mesonephric ridges on both sides of dorsal mesentery and primordial germ cells migrate from yolk sacs to them

Question 46

Primitive Sex Cords

Answer 46

In ridge and penetrate into surface, allowing migration of primordial germ cells. While retaining connection with surface, male/female gonads can't be distinguished

Question 47

3 SRY Gene Influences on Gonadal Development

Answer 47

Testis: Medullary cords develop, no cortical cords, thick tunica albuginea Ovary: Medullary cords degenerate, cortical cords develop, no tunica albuginea

Question 48

Interstitial Cells of Leydig

Answer 48

Line testis cords and produce testosterone, influencing sexual differentiation of genital ducts and external genitalia

Question 49

Testes Duct System Derivation

Answer 49

Mesonephric duct

Question 50

Uterine Tube Derivation

Answer 50

Paramesonephric ducts