Introduction to GIT and Stomach

To BDS 2nd year

Dr. Laxman Khanal

Assistant professor, Department of Human Anatomy

BPKIHS, Dharan

21-01-2018

Introduction

• Gastrointestinal tract (GIT) performs digestion (mechanical and chemical), absorption and excretion of waste products.

• Consists of mouth, esophagus, stomach, intestines and accessory organs.

• Medical specialty to study GIT is called as Gastroenterology.

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Protein of foodwith variousamino acid

Digestion

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Absorption

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Human protein

• Basic chemical unit of food andour tissue is same.

• Food looks so different fromtissue because units arearranged so differently.

Utilization

Gastrointestinal system1. GI tract• A continuous tube extends from

oral cavity to the anal canal.• It passes through the thoracic

cavity, abdominal cavity andpelvic cavity.

• 5-7 meter long (longer incadavers).

2. Accessory organs Consist of teeth, tongue and

glands. They helps in mechanical

digestion, swallowing and digestion.

Foregut

Midgut

Hindgut

Derivatives of endodermal lined gut tube and blood vessels supplying them

Transpyloric plane

Intertubercular plane

Midclavicular planeHorizontal planesTranspyloric planePasses through lower border of L1 vertebra.Subcostal planePasses through upper border of L3 vertebra.Intertubercular planePasses through upper part of L5 vertebra.

Vertical planeMidclavicular planeMidpoint of clavicle to midinguinal point.

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9 regions division of abdominopelvic region

Diaphragm

Pelvic inlet

Vertebral column

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1. Skin2. Superficial fascia (camper’s fascia)3. Superficial fascia (scarpa’s fascia)4. Muscle layers5. Transversalis fascia6. Extraperitoneal CT7. Parietal peritoneum

7 Anteriolateralabdominal wall

Viscera of abdominal cavity

Intraperitoneal or peritoneal organ

Extra peritoneal organ

Mesentery During development1. Peritoneal organ2. Extraperitoneal organSecondary

Primary

Basic structure1. Lumen2. Mucosa3. Submucosa Meissner’s plexus4. Muscularis layer Outer longitudinal Myenteric plexus Inner circular5. Serosa

Regulation of GI functions

1. Neural regulation

a. Intrinsic neural regulation- enteric nervous system

b. Extrinsic neural regulation- autonomic nervous system

c. Reflex control (gastrointestinal reflexes)

2. Hormonal regulation

a. Intrinsic hormones- endocrine cells of GI tract

b. Extrinsic hormones- thyroxin & cortisol

Stomach

• Widest part of GIT• Most distensible part of GIT• Mostly J shaped• Developed from foregut• Position Epigastric region Umbilical region Left hypochondrium• Capacity At birth-30ml At puberty-1 liter In adults-1.5-2 liter

Greater omentum

Lesser omentum

Cardiac end

Cardiac notch(Below the nipple)

Pyloric end

Pyloric sphincter

Angular incisura

Fundus

Body Greater curvature

Lesser curvature

123Pyloric part1. Pyloric antrum2. Pyloric canal3. Pylorus (with orifice)

External features 2 ends 2 surfaces 2 curvatures

Location of stomach ?

Q. Which of the following is not true regarding position of stomach?a. Most of it lies in left hypochondrium regionb. It also occupies epigastric regionc. Most of it lies under left costal margin and left

lower ribs.d. Pylorus part almost always extends to hypogastric

region.

Peritoneal relationship of stomach

Gastric triangle: Gastrostomy is done in this area to feed the patient during complete esophageal obstruction.

Anterior relationship of stomach

Bed of stomach• Diaphragm• Left kidney• Left suprarenal gland• Pancreas• Splenic artery• Left colic flexure• Transverse mesocolon

Wall and interior of the stomach

Gastric canal

• Longitudinal furrow formedbetween the longitudinal fold ofmucosa at lesser curvature duringswallowing.

• Absence of oblique layer of muscle• Prone to gastric ulceration

Coeliac trunk1. Splenic artery2. Left gastric artery3. Common hepatic artery

Splenic artery• Short gastric arteries• Left gastroepiploic artery

Left gastric artery

Common hepatic artery

Right gastric artery

Gastroduodenal artery• Sup pancreaticoduodenal artery• Right gastroepiploic artery

Hepatic artery proper Arteries of stomach

Sup mesenteric vein

Splenic vein

Portal vein

Hemiazygous vein

Portosystemic anastomosis

Lymphatic drainage of stomach

Rt gastric

Lt gastric

Pyloric LN Rt gastroepiploic LN

Pancreaticosplenic LN

Hepatic LN

Coeliac Node

Rt & Lt Vagus nerve

Parasympathetic supply

Post & Ant Vagal trunk

Sympathetic supply: T6-T9 segment

Nerve supply of stomachT6T7T8T9

Coeliac plexus

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Peptic ulcer diseases (PUD)• Breach in the mucosal lining of stomach, first part of duodenum or

esophagus, commonly caused by H Pylori & NSAIDs.

• In stomach, often localized toward lesser curvature.

Types of PUDs by location1. Gastric ulcer2. Duodenal ulcer3. Esophageal ulcer4. Meckel’s diverticulum

Virchow’s LN (signal LN)• LN of the left supraclavicular fossa• Enlarged during gastric cancer

(Troisier’s sign)

Vagotomy:• Removal of part of Vagus nerve to

reduce its secretion in PUD.• Potential side effect: Vit B12

deficiency