Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

3 - GI > Development of the GI Tract > Flashcards

Development of the GI Tract Flashcards

1
Q

In what week is the primitive gut tube formed in embryo

A

4th-5th weeks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

State the derivatives of the foregut

A
  • Stomach
  • Liver
  • Pancreas
  • Oesophagus
  • Proximal duodenum (proximal to sphincter of oddi)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

State the derivatives of the midgut

A
  • Distal duodenum
  • Jejunum
  • Ileum
  • Caecum
  • Ascending colon
  • Proximal 2/3 of transverse colon
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

State the derivatives of the hindgut

A
  • Distal 1/3 of transverse colon
  • Descending colon
  • Sigmoid colon
  • Rectum
  • Upper anal cana
  • Lining of bladder and urethra
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

State the blood supply to the foregut, midgut and hindgut structures

A
  • Foregut - celiac trunk
  • Midgut - superior mesenteric artery
  • Hindgut - inferior mesenteric artery
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe how the coelomic cavity and peritoneal cavity develop

A
  • Intraembryonic coelom formed as the embryo folds
    • Begins as one large cavity – all cavity have same membrane
    • Later subdivided by the future diaphragm into abdominal and thoracic cavities
  • One membrane lining the whole intraembryonic cavity
    • Includes specialized pericardium and pleural membrane
  • Peritoneum and peritoneal cavity
    • Peritoneal membrane lines the abdominal cavity and invests the viscera
      • During development it grows, changes shape and specialises
    • Peritoneal cavity is a potential space only
      - Normally contains nothing other than serous fluid
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Define mesentery

A

Double layer of peritoneum suspending the gut tube from the abdominal wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe the regions of the gut tube where dorsal and ventral mesenteries are found

A
  • Dorsal mesentery suspends the entire gut tube from the dorsal body wall
  • Ventral mesentery only in the region of the foregut
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe how the greater and lesser sacs are formed

A
  • Dorsal and ventral mesenteries in the region of the foregut divide the cavity into left and right sacs only in the foregut
    • Left sac contributes to the greater sac
    • Right sac becomes the lesser sac - lies behind the stomach
  • Caudal to the foregut, only the greater sac present
  • Greater and lesser peritoneal sacs connected through epiploic foramen
  • Formed from the rotation of the stomach during development
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Define omentum

A

Double layer of peritoneum that connects the stomach with other abdominal organs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Describe how the greater and lesser omentum are formed

A
  • Greater omentum formed from the dorsal mesentery
    • First structure seen when abdominal cavity is opened anteriorly
  • Lesser omentum formed from the ventral mesentery
    • Free edge conducts the portal triad
      • Goes from liver to lesser curve of stomach to duodenum
  • Formed due to the rotation of the stomach during development
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

List the peirtoneal structures within the body

A
  • Possess mesenteries

- Stomach, jejunum, ileum, appendix, transverse colon, sigmoid colon, rectum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe retroperitoneal structures and give examples

A
  • Were never in the peritoneal cavity and never had a mesentery
  • Eg. Kidney, aorta, inferior vena cava
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Describe secondarily retroperitoneal structures

A
  • Had a mesentery but with successive growth and development, mesentery is lost through fusion at posterior abdominal wall
  • Eg. Pancreas, duodenum, descending colon, ascending colon
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is fusion fascia

A
  • Movement of structure causes it to lose mesentery and pushed against abdominal wall
  • Previous peritoneal space becomes fusion fascia (secondary retroperitoneal structures)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describe the basic development of the foregut structures (stomach, liver, pancreas, duodenum)

A
  • Liver and biliary system developed from ventral mesentery
  • Pancreas developed from both dorsal and ventral mesentery (has fusion fascia)
  • Duodenum
    • Shape determined by rotation of the stomach
    • Rotation of the stomach pushes duodenum to right, then against posterior abdominal wall
    • Becomes secondarily retroperitoneal (has fusion fascia)
  • Stomach
    • Mid week 4, slight dilation of distal foregut indicates position of stomach primordium
    • Faster growth of dorsal border creates the greater curvature
      • Rotates, changing the position of the dorsal and ventral mesenteries
17
Q

Around what point is the axis for the midgut loop rotation

A

Superior mesenteric artery

18
Q

Describe the physiological herniation that occurs in GI development

A
  • During the 6th week, growth of the primary intestinal loop is very rapid
  • Liver is also growing rapidly - abdominal cavity is too small to accommodate both
  • Intestine herniate into the umbilical cord during first rotation
19
Q

State the direction and number of rotations of the GI tract

A
  • Rotation involves 3 counter clockwise 90˚ turns

- Cranial derivatives end up on the left and caudal derivatives end up on the right

20
Q

State the importance of the pectinate line in development

A
  • Anal canal is divided by the pectinate line into superior and inferior parts
    • Differences in arterial supply, venous and lymph drainage, and innervation
  • Proctodeum - junction between two embryonic germ layers
21
Q

Describe the differences in blood supply, lymph drainage, embryonic germ layer and innervation above and below the pectinate line

A
  • Above pectinate line
    • Blood supply from inferior mesenteric artery
    • S2-S4 pelvic parasympathetics
    • Columnar epithelium
    • Lymph drainage to internal iliac nodes
    • Made from endoderm - visceral
      • Can only sense stretch
  • Below pectinate line
    • Blood supply from pudendal artery
    • S2-S4 pudendal nerve
    • Stratified epithelium
    • Lymph drainage to superficial inguinal nodes
    • Made from ectoderm - somatic
      • Can feel pain, temperature, touch
22
Q

Describe the appearance of GI tract due to malrotation

A
  • Incomplete rotation
    • Midgut loop makes only one 90˚ rotation
    • Left-sided colon
  • Reserved rotation
    • Midgut loop makes one 90˚ rotation clockwise
    • Transverse colon passes posterior to the duodenum
23
Q

Describe the consequences of a volvulus in the GI tract

A
  • Obstruction in the intestines due to twisting or knotting of the GI tract
  • Structures that should not be mobile become mobile
  • Leads to strangulation and ischaemia
  • In adulthood, presents with bloated abdomen, constipation
24
Q

Describe the abnormalities that can happen due to vitelline duct remnants

A
  • Vitelline cyst - vitelline duct forms fibrous strands
    • Connect stomach to anterior abdominal wall
  • Vitelline fistula
    • Direct communication between umbilicus and intestinal tract
  • Meckel’s diverticulum
    • Bulge in the small intestine due to remnant of vitelline duct which can cause volvulus
25
Q

Outline the effects of recanlisation in the GI tract

A
  • Happens in oesophagus, bile duct, small intestine
  • In some gut structures, cell growth becomes so rapid that the lumen is partially or completely obliterated
  • Recanalisation acts to restore the lumen
  • If recanalisation is wholly or partially unsuccessful, atresia or stenosis of the structure can occur
  • Most occur in duodenum
26
Q

Describe the characteristics of pyloric stenosis

A
  • Hypertrophy of the circular muscle in the region of the pyloric sphincter
  • Not a recanalistion failure
  • In infants, narrowing of the exit from the stomach causes characteristic projectile vomiting
  • Vomit does not contain bile (not bilious)
27
Q

Differentiate between gastroschisis and omphalacoele

A
  • Gastroschisis
    • Failure of closure of the abdominal wall during folding of the embryo
    • Leaves gut tube and derivatives outside the body cavity
  • Omphalacoele
    • Persistence of physiological herniation
    • Differs from umbilical hernia because hernias have covering of skin and subcut tissue
    • Associated with other defects, including chromosomal defects
    • Less serious than gastroschisis as peritoneum present over gut
28
Q

What hindgut abnormalities can occur

A
  • Imperforate anus
    • Failure of anal membrane (cloacal membrane) to rupture
  • Anal/anorectal agenesis
  • Hindgut fistulae

3 - GI (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions