Gastroenterology & Gastrointestinal (GI) System

Overview of Gastroenterology

Gastroenterology is the medical specialty focused on the anatomy, physiology, and diseases of the gastrointestinal system. Gastroenterologists use diagnostic tests, medical and surgical procedures, and pharmacological treatments to manage GI diseases.

• Gastroenterology: Study of the stomach and intestines.

• GI System: Composed of organs and glands forming a pathway for digestion, absorption, and elimination.

Word Breakdown: Gastroenterology

• Gastr/o-: Stomach

• Enter/o- / Intestin/o-: Intestine

• -logy: Study of

Upper GI System Anatomy

The upper GI system includes the oral cavity, pharynx, esophagus, and stomach. The oral cavity is the entry point for food and contains several important structures.

• Oral Cavity: Contains teeth, gums, tongue, hard palate, and soft palate.

• Pharynx: Common passageway for air and food.

• Esophagus: Muscular tube connecting pharynx to stomach.

• Peristalsis: Wave-like muscular contractions moving food through the digestive tract.

Salivary Glands

Salivary glands are triggered by sight, smell, and taste. They include:

• Parotid Glands: Located anterior to the ear.

• Sublingual Glands: Located under the tongue.

• Submandibular Glands: Located inferior to the mandible.

Stomach Anatomy

The stomach is an elongated sac with four main regions: cardia, fundus, body, and pylorus. It is lined by gastric mucosa and contains rugae for expansion.

• Cardia: Junction with esophagus

• Fundus: Rounded upper portion

• Body: Large curved region

• Pylorus: Narrow region joining duodenum

• Lower Esophageal Sphincter: Controls entry from esophagus

• Pyloric Sphincter: Controls exit to small intestine

Pancreatic Enzymes

• Amylase: Breaks down carbohydrates

• Lipase: Breaks down fats

• Protein-Digesting Enzymes: Break down proteins

Small and Large Intestines

The small intestine is divided into three segments: duodenum, jejunum, and ileum. The large intestine includes the cecum, colon (ascending, transverse, descending, sigmoid), rectum, and anus.

• Villi: Increase surface area for absorption in small intestine

• Haustra: Pouches in colon for expansion

• Ileocecal Valve: Prevents backflow from large to small intestine

Accessory Organs

The liver, gallbladder, and pancreas are accessory organs supporting digestion.

• Liver: Produces bile, processes nutrients

• Gallbladder: Stores and concentrates bile

• Pancreas: Secretes digestive enzymes and insulin

Digestion and Absorption

Digestion involves mechanical and chemical processes. Absorption occurs mainly in the ileum, with water absorption in the large intestine.

• Mechanical Digestion: Mastication, deglutition, peristalsis

• Chemical Digestion: Enzymatic breakdown of food

• Absorption: Nutrients and water absorbed into blood

Common GI Diseases and Terminology

Medical terminology for GI diseases is based on word roots, prefixes, and suffixes. Examples include:

• Anorexia: Decreased appetite

• Dysphagia: Difficulty swallowing

• Glossitis: Inflammation of the tongue

• Gastritis: Inflammation of the stomach

• GERD: Chronic reflux of stomach acid

• Appendicitis: Inflammation of the appendix

• Hepatitis: Inflammation of the liver

Laboratory and Diagnostic Procedures

• Albumin: Liver function test

• Cologuard: Stool DNA test for cancer

• Fecal Occult Blood Test: Detects hidden blood in stool

• Liver Function Tests (LFTs): Panel for liver health

• Barium Enema: Radiologic imaging of colon

• Gallbladder Ultrasound: Imaging for gallstones

Medical and Surgical Procedures

• Enema: Relieves constipation

• Appendectomy: Removal of appendix

• Bariatric Surgery: Treats obesity

• Colostomy: Creation of opening for fecal passage

• Liver Transplantation: Replacement of diseased liver

Pulmonology: Respiratory System

Overview of Pulmonology

Pulmonology is the medical specialty focused on the anatomy, physiology, and diseases of the respiratory system. Pulmonologists diagnose and treat respiratory diseases using various tests and procedures.

• Pulmon/o-: Lung

• -logy: Study of

Anatomy: Upper Respiratory System

The upper respiratory system includes the nose, nasal cavity, and pharynx. The nasal cavity is lined with mucosa and contains turbinates to warm and moisten air.

• Nose: Entry point for air, traps particles

• Nasal Cavity: Divided by septum, contains turbinates

• Nasal Mucosa: Produces mucus, humidifies air

Pharynx and Associated Structures

The pharynx is a common passage for air and food, divided into nasopharynx, oropharynx, and laryngopharynx.

• Nasopharynx: Superior part

• Oropharynx: Middle part

• Laryngopharynx: Inferior part

Anatomy: Lower Respiratory System

The lower respiratory system includes the larynx, trachea, bronchi, bronchioles, and lungs. The bronchial tree transports air to alveoli, where gas exchange occurs.

• Larynx: Voice box, contains vocal cords

• Trachea: Windpipe, supported by cartilage rings

• Bronchi: Main airways entering lungs

• Bronchioles: Smallest airways, end in alveoli

• Alveoli: Site of gas exchange, secrete surfactant

Lung Structure and Pleura

The lungs are divided into lobes and surrounded by pleura, a double-layered membrane that secretes pleural fluid for smooth movement.

• Right Lung: Three lobes (RUL, RML, RLL)

• Left Lung: Two lobes (LUL, LLL)

• Pleura: Visceral and parietal layers, pleural fluid

• Mediastinum: Central area containing heart, trachea, esophagus

• Diaphragm: Muscle separating thoracic and abdominal cavities

Summary Table: GI and Respiratory System Structures

Additional info: Academic context and expanded explanations were added to ensure completeness and clarity for medical terminology students.