Embryology of the GI Flashcards Preview

07. Year 2: Alimentary System > Embryology of the GI > Flashcards

Flashcards in Embryology of the GI Deck (81)
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1

When does fertilisation to implantation occur?

Week 1

2

When does the bilaminar germ disk form?

Week 2

3

When does the trilaminar germ disk form?

Week 3

4

When does organogenesis occur?

Week 3 to 8

5

What is organogenesis?

The production and development of the organs of an animal or plant

6

What is responsible for establishing the left sideness of an organ or body body?

Genes such as the PTX2 gene

7

What does mutations in the PTX2 gene result in?

Dextrocardio because it is responsible for establishing the left sideness of an organ

8

What are the general 3 phases of embryological development?

1) Growth/proliferation (cell division and elaboration of products)

2) Morphogenesis (development of shape, size of a particular organ or part of the body)

3) Differentiation (maturation of physiological processes)

9

What does exposure to teratogens during weeks 4 to 8 lead to?

Major congenital conditions

10

What is gastrulation?

Process of bilaminar embryonic disc being converted into trilaminar disc

11

What are the 3 layers of the trilaminar disc?

Ectoderm

Mesoderm

Endoderm

12

What does the ectoderm go onto form?

Skin (epidermis, hair, nails)

CNS

PNS

Sensory epithelia of the eye

Ear

Nose

Liver (except parenchyma)

Urinary bladder

13

What does the endoderm go onto form?

Epithelial lining of renal system

GI tract

Liver

Pancreas

Thyroid

Parathyroid parenchyma

Urinary bladder

14

What does the mesoderm go onto form?

Muscle

Bones

Cartilage

Dermis

Vascular system

Most of the CVS connective tissue

Blood cells

Bone marrow

Urogenital system except bladder

Spleen

Suprarenal gland cortex

15

What are the 3 parts of the digestive system?

Foregut

Midgut

Hindgut

16

What gives rise to the parietal and visceral mesoderm?

Lateral plate mesoderm

17

When does the gut tube form?

During the 3rd and 4th week from the endoderm lining the yolk sac

18

What is the gut tube closed by at the cranial end?

Oropharyngeal membrane

19

What is the gut tube closed by at the caudal end?

Cloacal membrane

20

What does the foregut form?

Oesophagus

Stomach

Omental bursa (lesser sac)

Duodenum

Liver and bilary apparatus

Spleen

Pancreas

21

Explain the development of the oesophagus?

1) Develops from cranial part of primitive gut tube

2) Laryngo-tracheal diverticulum (lung bud) develops from the ventral wall of the foregut

3)Tracheo-oesophageal septum divides the foregut tube into the trachea and oesophagus

22

What is the lung bud also known as?

Laryngo-tracheal diverticulum

23

What divides the foregut tube into the trachea and oesophagus?

Tracheo-oesophageal septum

24

When does the stomach develop?

4th week

25

Explain the development of the stomach?

1) Foregut dilates to form the stomach

2) Differential growth of the stomach wall creates the greater and lesser curvatures

3) Stomach rotates and adapts its shape to fit in with the other developing organs

4) Undergoes a 90o rotation around its own longitudinal axis

5) Undergoes an anterio-posterior roation to create final adult position

26

What is the stomach attached to the dorsal and ventral wall by?

Mesogastrium (a mesentery)

27

Explain the development of the omental bursa (lesser sac)?

1) Stomach is attached to dorsal and ventral wall by mesogastrium

2) Rotation along its longitudinal axis pulls the dorsal mesentery to the left creating the omental bursa (lesser sac)

28

When the stomach rotates on its longitudinal axis, what direction is the ventral mesogastrium pulled in?

Right

29

What is the duodenum formed from?

Caudal part of the foregut and cranial part of the midgut

30

Explain the development of the duodenum?

1) Formed from the caudal part of the foregut and the cranial part of the midgut

2) As the stomach rotates the duodenum becomes c-shaped and also rotates

3) Duodenal cap retains its dorsal mesentery but the rest of it is retroperitoneal following the fusion of the dorsal mesentery with the peritoneum of the posterior abdominal wall