52. GI anatomy part 2

Question 1

Discuss the layers of the abdomen (basic)

Answer 1

Skin
Connective tissue above the umbilicus
Camper’s fascia- superficial layer above umbilicus
Scarper’s fascia- deep layer underneath the fascia
Muscle
Viscera

Question 2

What are the flat muscles of the abdomen?

Answer 2

External oblique
Internal oblique
Transverses abdominis

Question 3

Where do the flat muscles of the abdomen meet?

Answer 3

Rectus sheath forms an aponeurosis around the vertical muscles of the abdomen. The middle of this structure is called the linea alba

Question 4

What are the vertical muscles of the abdomen?

Answer 4

Rectus abdominis and pyramidalis

Question 5

Give a brief overview of the flat muscles of the abdomen

Answer 5

External oblique- inferomedial (hands in pockets), ribs to pelvis

Internal oblique- infero lateral (hand in back pockets)

transversus abdominis- (transverse), pelvis to linea alba

Question 6

How are the tendons arranged in the rectus sheath?

Answer 6

Anterior wall- aponeurosis of external oblique and half of internal oblique

Posterior wall half of internal oblique and transverses abdominis.

Question 7

Give a brief overview of the Vertical Muscles in the abdominal region

Answer 7

Rectus abdominus, split by linea alba (vertically) and linea semilunaris (horizontally)

pyramidalis- small triangluar muscel that tenses linea alba. Pubic creast to linea alba

Question 8

Describe the innervation of the abdominal muscles

Answer 8

Ex. Oblique- (T7-11 and T12)

Int. Oblique-(T7-11 and T12)

Tr. Abdominus- (T7-11 and T12)

Rec. Abdominus- Thorocoabdominal nerves (T7-11)

Pyramidialis- subcostal nerve T12

Question 9

What are the nine plains of the abdomen (right to left, up to down)

Answer 9

1. Right hypochondriac
2. Epigastric
3. left hypochondriac
4. right lumbar
5. Umbilical
6. left lumbar
7. right iliac region
8. Hypogastric
9. left iliac region

Question 10

Which type of epithelium lines the oesophagus?

Answer 10

Stratified squamous non-keratinised

Question 11

Describe the course of the oesophagus

Answer 11

Starts at the cricoid cartilage (c6)
Descends through the diaphragm (t10)
Becomes the abdominal oesophagus for around 1.25cm and terminates at the cardiac orifice of the stomach

Question 12

What are the different layers of the oesophagus? (outer to inner)

Answer 12

Adventitia
Muscle
Submucosa
Mucosa

Question 13

Explain the composition of muscle in each thrid of the oesophagus?

Answer 13

Superior third- voluntary striated muscle

Middle third- voluntary striated and smooth muscle

Inferior third- smooth muscle

Question 14

What are the two sphincters of the oesophagus

Answer 14

Upper oesophageal sphincter- straited muscle sphicnter located at the cricopharyngeus muscle. Prevents air entering the oesophagus

Lower oesophageal sphincter- functional sphincter to prevent regurgitation

Question 15

How is the oesophagus drained?

Answer 15

Superior third- deep cervical nodes

Middle third- superior and posterior mediastinal nodes

Lower third- left gastric and celiac nodes

Question 16

How is the oeophagus arterially supplied?

Answer 16

thoracic- thoracic aorta and inferior thyroid artery

abdominal- left gastric artery

Question 17

How is the oesophagus venously drained?

Answer 17

venous drainage (thoracic)- azygous veins and inferior thyroid vein

abdominal- left gastric and azygous

Question 18

What are the four main anatomical divisions of the stomach?

Answer 18

Cardia- Where the oesophagu opens

Fundus- top, gas filled poriton

Body- main bit

Pylorus- Connects the stomach to the duodenum.

Question 19

Explain the arterial supply of the stomach

Answer 19

Top right- Right gastric artery- branch of common hepatic artery

Top left- left gastric artery- arises from coeliac trunk

Bottom right- gastro-omental artery- arises from common hepatic

Bottom left-left gastro-omental artery- arises from splenic artery

Question 20

How is the stomach venously drained?

Answer 20

Hepatic portal veins drain the right and left gastric veins

Short gastric vein, left and right gastro omental drain into superior mesenteric vein

Question 21

How is the stomach lymphatically drained

Answer 21

gastric and gastro-omental lymphs

coeliac lymph nodes

Question 22

How is the stomach innervated?

Answer 22

T6-T9 sympathetic

Question 23

What are the three parts of the small intestine?

Answer 23

Duodenum
Jejunum
Ileum

(in that order)

Question 24

What are the characteristic differences between the jejunum and the ileum (3)

Answer 24

Jejunum- Thick intestinal wall, longer vasa recta (straight arteries) less arcades

Ileum- Thin intestinal wall, shorter vasa recta, more arcades (arterial loops)

Question 25

What are the characteristic differences between the jejunum and the ileum (3)

Answer 25

Jejunum- Thick intestinal wall, longer vasa recta (straight arteries) less arcades Thin intestinal wall, shorter vasa recta, more arcades (arterial loops)

Question 26

What is the arterial supply of the duodenum? What is the venous drainage of the duodenum? What is the lymphatic drainage?

Answer 26

proximal to major duodenl papilla- gastroduodenal artery (this bit in between is the end of the foregut into hindgut) distal- inferior pancreaticoduodenal artery same venous drainage pancreatoduodenal and superior mesenteric nodes

Question 27

What is the arterial supply of the jejunum and ileum? what is the venous drainage lymphs?

Answer 27

Superior mesenteric artery drained via superior mesenteric Superior mesenteric nodes