Blood supply, Development, and Innervation of the GI Tract

Question 1

Peritoneum

Answer 1

A serous membrane

Question 2

Parietal Peritoneum

Answer 2

Lines the body wall

Question 3

Visceral Peritoneum

Answer 3

Covers the external surfaces of most digestive organs

Question 4

Peritoneal Cavity

Answer 4

A slit-like space between the abdominal body wall and digestive organs (contains serous fluid)

Question 5

Mesentery

Answer 5

A double layer of peritoneum that extends from the body wall to the digestive organs

Question 6

What does the mesentery do?

Answer 6

• Holds the organs in place
• Provides a route for circulatory vessels and nerves
• Its length determines the motility of an organ

Question 7

Lesser Omentum

Answer 7

Runs from the liver to the stomach

Question 8

Greater Omentum

Answer 8

Links inferior surface of the stomach to adjacent organs

Question 9

Mesentery

Answer 9

A double layer of peritoneum that provides a neuromuscular communication between an organ and the body

Question 10

Omentum

Answer 10

A double-layered extension of peritoneum attaching the stomach and first part of the duodenum to adjacent organs

Question 11

Ligament

Answer 11

Two layers of peritoneum that connect two organs to each other or an organ to the abdominal wall; may transmit neuromuscular structures

Question 12

What does the falciform ligament connect?

Answer 12

The liver to the anterior abdominal wall

Question 13

What does the splenorenal ligament connect?

Answer 13

The spleen to the left kidney

Question 14

What happens in week 4 of development of the abdominal organs?

Answer 14

The embryo becomes a cylindrical shape with an enclosed inner tube that is composed of endoderm and splanchnic mesoderm

Question 15

Endoderm

Answer 15

Gives rise to the epithelium of the alimentary canal and gut-derived organs (liver, pancreas, gallbladder)

Question 16

Splanchnic Mesoderm

Answer 16

Gives rise to all outer layers in the wall of the alimentary canal and gut-derived organs

Question 17

The embryonic gut tube is divided into what three regions based on their relation to the vitelline duct in the yolk sac?

Answer 17

• Foregut
• Midgut
• Hindgut

Question 18

Foregut

Answer 18

Gives rise to the esophagus, stomach, pancreas, duodenum, liver, and bile ducts

Question 19

Midgut

Answer 19

Small intestine distal to the bile duct, cecum, appendix, ascending and most of transverse colon

Question 20

Hindgut

Answer 20

Remainder of the colon

Question 21

The midgut is supplied by the?

Answer 21

SMA

Question 22

For 4 weeks, the rapidly growing midgut…

Answer 22

• Herniates into the proximal part of the umbilical cord
• As it returns to the abdominal cavity, the midgut rotates 270 degrees around the axis of the SMA
• As the parts of the intestine reach their definitive positions, their mesenteries undergo modifications (some mesenteries shorten and some disappear)

Question 23

(Digestive Tract in the Oral Cavity) The branches of the external carotid artery supply… via what?

Answer 23

Oxygenated blood to the viscera, muscles and glands of the oral cavity via branches such as the lingual, facial, superior thyroid, and maxillary

Question 24

(Esophagus) The majority of the esophagus is supplied with…

Answer 24

Oxygenated blood from branches off the abdominal aorta
- Bronchial
- Esophageal
- Phrenic

Question 25

The cervical esophagus is supplied by blood from...

Answer 25

The inferior thyroid arteries

Question 26

Arterial supply to the abdominal part of the alimentary tract, spleen, liver, gallbladder, and pancreas is derived from...

Answer 26

The abdominal aorta

Question 27

The 3 major unpaired branches of the abdominal aorta are:

Answer 27

- Celiac Trunk - Superior Mesenteric Artery (SMA) - Inferior Mesenteric Artery (IMA)

Question 28

The stomach is

Answer 28

Heavily vascularized

Question 29

Gastric blood supply stems from...

Answer 29

The celiac trunk

Question 30

The lesser curvature receives blood from...

Answer 30

The right and left gastric arteries

Question 31

The greater curvature receives blood from...

Answer 31

The right and left gastro-omental arteries

Question 32

Jejunum

Answer 32

- Color is deeper red - Caliber is 2-4 cm - Wall is thick and heavy - Vascularity is greater - Vasa Recta is long - Few large loops - Less fat in mesentery - Circular folds (L. plicae circulares) are large, tall, and closely packed

Question 33

Ileum

Answer 33

- Color is paler pink - Caliber is 2-3 cm - Wall is thin and light - Vascularity is less - Vasa Recta is short - Many short loops - More fat in mesentery - Circular folds (L. plicae circulares) are low and sparse; absent in distal part

Question 34

The main channel of the portal venous system is? What is it formed by?

Answer 34

Hepatic portal vein, formed by the union of the superior mesenteric and splenic veins

Question 35

What does the portal venous system do?

Answer 35

Collects blood from the abdominal part of the alimentary tract, pancreas, spleen, and most of the gallbladder and carries it to the liver

Question 36

Effects of Sympathetic Stimulation in Thoraco-Lumbar Outflow

Answer 36

- Inhibits peristalsis and constricts blood vessels to digestive tract so blood is available to skeletal muscles - Contracts internal anal sphincter to aid fecal continence

Question 37

Effects of Parasympathetic Stimulation in Cranio-Sacral Outflow

Answer 37

- Stimulates peristalsis and secretion of digestive juices - Contracts rectum and inhibits internal anal sphincter to cause defecation

Question 38

The GI tract is mostly innervated by? What are they?

Answer 38

Branches of Cranial Nerves - CN 5: Trigeminal- Motor to muscles of mastication - CN 7: Facial- Parasympathetics to salivary glands, etc. - CN 9: Glossopharyngeal- Motor and sensory to oropharynx - CN 10: Vagus- Motor to muscles of the pharynx and sot palate/ Parasympathetic to viscera of the thorax and abdomen - CN 12: Hypoglossal- Motor to the tongue muscles

Question 39

Hiatal Hernia

Answer 39

Protrusion of a part of the stomach into the mediastinum through the esophageal hiatus of diaphragm - More frequent in patients of middle age due to potential weakening of muscular part of diaphragm

Question 40

Gastric Ulcers

Answer 40

Open lesions of the mucosa of the stomach

Question 41

Peptic Ulcers

Answer 41

Lesions of the mucosa of the pyloric canal or duodenum

Question 42

Ulcers

Answer 42

- Associated with Helicobacter pylori bacterium - Acidic environment of the stomach overwhelms the bicarbonate produced by the duodenum (leaves the mucosa vulnerable)

Question 43

Omphalocele

Answer 43

Congenital umbilical hernia of the midgut; the midgut naturally enters the umbilical cord during development, but may fail to return before birth - The momentum covering the GI tract is visible