Untitled Quiz

Digestive System Overview

• The digestive system comprises the digestive tract and accessory organs.
• The digestive tract includes the mouth, pharynx, esophagus, stomach, small intestine, and large intestine.
• Accessory organs are the salivary glands, liver, gallbladder, and pancreas. These organs secrete fluids containing enzymes essential for digestion.

Mouth (Oral Cavity)

• The vestibule is the space between the cheeks (or lips) and the teeth.
• The oral cavity proper includes the palate and tongue.
• The palate has a hard palate (rigid surface) and soft palate (muscular structure).
• The tongue is a muscular organ that mixes food with saliva and compresses it into a bolus before swallowing.

Salivary Glands

• The salivary glands secrete saliva via ducts.
• The parotid gland is located in front of the ear, secreting serous fluids.
• The submandibular gland is located below the mandible and secretes mucous.
• The sublingual gland is located below the tongue and secretes mixed fluids.

Pharynx

• The pharynx comprises the oropharynx and laryngopharynx, and the muscular wall propels food to the esophagus.

Esophagus

• The esophagus is a 25 cm muscular tube that extends from the laryngopharynx to the stomach.
• It passes through the diaphragm.
• The gastroesophageal (cardiac) sphincter helps keep the esophagus closed when empty.

Stomach

• The stomach lies in the upper left part of the abdomen.
• It has two openings: the cardiac opening and the pyloric opening guarded by the pyloric sphincter.
• Parts of the stomach include the cardiac region, fundus, body, and pylorus.
• Borders of the stomach include the lesser curvature and greater curvature.

Small Intestine

• The small intestine is divided into three sections: duodenum (25 cm, "C-shaped"), jejunum (2.5 m), and ileum (3.5 m).
• It ends at the ileocecal valve.
• The liver and pancreas empty their contents into the duodenum.
• The greatest amount of digestion and absorption occurs in the small intestine.

Large Intestine

• The large intestine extends from the ileocecal junction to the anus (approximately 1.5 m).
• It comprises the cecum (blind pouch), appendix (attached to the cecum), colon (ascending, transverse, descending, and sigmoid), rectum, and anal canal.

Liver

• The liver is situated in the right upper abdominal quadrant, against the diaphragm's inferior surface.
• The liver is anatomically divided into four lobes: right, left, caudate, and quadrate.
• Liver functions include detoxification, storing glucose as glycogen and releasing it as needed, producing bile, synthesizing various proteins (e.g., blood clotting factors), and vitamin & mineral storage (e.g., vitamin A, B12, iron, and copper). It helps with cholesterol and triglyceride production and metabolism, fights infections by removing bacteria, and converts ammonia to urea for excretion.

Biliary System

• The biliary system includes the gall bladder (fundus, body, neck) and the cystic duct, hepatic ducts (right and left), and common hepatic duct.
• The bile duct (3 inches) is formed by the union of the common hepatic and cystic ducts, opening into the duodenum.
• The gall bladder stores bile.

Pancreas

• The pancreas is located within the concavity of the duodenum, with a head, neck, body, and tail extending to the spleen.
• It plays a crucial dual role:
  • Endocrine Function: secretes insulin
  • Exocrine Function: secretes digestive juices.