Digestive System

Peritoneal Cavity and Extensions

• The peritoneal cavity is a fibrous covering in the abdomen with extensions that cover organs.
• Major extensions include the greater omentum and mesentery.

Anatomy of the Abdomen

• Imagining an anterior view of the abdomen:
  • Diaphragm is present with a central tendon where three major structures pass through.
  • Major organs include:
  • Right lobe of the liver (large)
  • Left lobe of the liver
  • Stomach (with greater curvature)
  • Falciform ligament (extends from liver)

Stomach Structure

• Transitioning to the inspection of the stomach:
  • The greater omentum extends from the greater curvature of the stomach, serving as a protective covering over the intestines.
  • The stomach is divided into clear segments:
  • Cardia (entrance point for esophagus)
  • Fundus (top section)
  • Body (main section)
  • Pylorus (leads to the small intestine)
  • Pyloric sphincter (controls passage into the duodenum)

Mesenteric Attachment

• The mesentery is an extension holding the small intestine against the posterior abdominal wall, allowing movement while keeping it attached.
  • Blood supply includes:
  • Superior mesenteric artery (supplies small and large intestines)
  • Inferior mesenteric artery (supplying lower portions of the large intestine)

Aortic Branches and Arteries

• Important arteries involved in abdominal blood supply:
  • Celiac trunk (first branch off the abdominal aorta):
  • Splenic artery (to spleen)
  • Common hepatic artery (to liver)
    • Branches into proper hepatic artery (to liver) and gastroduodenal artery (to stomach and duodenum).
  • Superior mesenteric artery (next branch, supplying almost entire small intestine and parts of the large intestine).
  • Inferior mesenteric artery (last branch, serves large intestine).

Renal and Gonadal Arteries

• Paired arteries from the abdominal aorta include:
  • Left and right renal arteries (to kidneys)
  • Left and right gonadal arteries (to reproductive organs).

Iliac Arteries

• Common iliac arteries split into:
  • Internal iliac arteries (supply pelvic floor)
  • External iliac arteries (continue to legs, becoming femoral arteries).

Venous System Overview

• Major veins draining into the inferior vena cava include:
  • Inferior vena cava (returns blood from lower body)
  • Portal vein (transports nutrient-rich blood from the digestive tract to the liver).

Blood Flow and Nutrient Processing

• Nutrient rich, oxygen poor blood travels from the digestive tract to the liver via the portal vein after digestion.
  • Liver functions:
  • Detoxifying toxins
  • Processing nutrients for body's use.

Division of the Gastrointestinal Tract

• Accessory organs aiding in digestion include:
  • Mouth (prepares food for swallowing)
  • Stomach (breaks down food into chyme)

Small Intestine Structure

• The small intestine consists of three parts:
  • Duodenum (first C-shaped section)
  • Jejunum (middle section)
  • Ileum (final section that leads to large intestine).

Large Intestine Functionality

• Begins at cecum (junction with small intestine) and includes:
  • Ascending colon
  • Transverse colon
  • Descending colon
  • Sigmoid colon
  • Rectum.

The Liver and Biliary System

• Features of the liver include:
  • Right lobe, left lobe, falciform ligament, round ligament.
• Gallbladder stores bile produced by the liver:
  • Bile aids in fat digestion.
• Bile travels through:
  • Cystic duct (from gallbladder)
  • Common bile duct (unites bile from liver and gallbladder).