Pharmaceutical Studies Overview

Gastrointestinal Tract (GIT)

• The GIT is a complex system responsible for food digestion
• It comprises the mouth, pharynx, esophagus, stomach, small intestine, large intestine, and anus
• Food is broken down into absorbable parts and then waste is expelled
• The GIT includes accessory organs like the liver, gallbladder, and pancreas that support the digestive process

Introduction

• Digestion is the process of breaking down food into usable substances and waste
• Nutrients in food help with normal bodily functions and include proteins, carbohydrates, fats, vitamins, minerals, and water
• The body absorbs some nutrients, while others need to be broken down for use as energy

Mouth

• Food is crushed and ground into smaller pieces by the teeth, chewed, and made moist with saliva
• Saliva contains enzymes that break down carbohydrates into sugar
• The mouth is the initial site of digestion

Pharynx

• A cavity behind the mouth with muscles, connective tissue, and mucous membranes
• It acts as a passageway from the mouth to the esophagus
• The lining secretes mucus to lubricate and aid smooth food propulsion

Esophagus

• A muscular tube, also known as the gullet
• It carries food from the pharynx to the stomach
• Peristalsis, rhythmic waves of muscular contractions, propel food
• It prevents reflux of gastric contents

Stomach

• A sac-like organ where food is stored and partially digested
• The stomach wall muscles break down food further
• Stomach juices are released from the inner layer to continue digestion
• Water, salts, and some sugars are absorbed directly into the bloodstream
• Food is mixed with acid (HCl) and the enzyme pepsin creating chyme
• Chyme moves to the small intestine

Small Intestine

• The longest part of the digestive tract where digestion is completed
• Chyme mixes with liver and pancreatic juices
• Starches are broken into sugars, proteins into smaller particles, and fats into fatty acids
• Digested materials are absorbed into the bloodstream through intestinal cells
• Villi (tiny hair-like structures) on the walls absorb nourishment from the food

Large Intestine

• A long tube-like organ; part of the digestive system that connects the small intestine to the anus
• It comprises the cecum, rectum, ascending colon, transverse colon, and descending colon
• No more food digestion occurs in the large intestine
• Water, salts, and minerals are absorbed
• Undigested material is expelled as waste
• The rectum acts as a temporary storage site for feces

Accessory Organs

• (1) Liver*

• Controls and regulates most chemical levels in the blood

• Secretes bile to aid in fat breakdown and absorption

• Processes nutrients and metabolizes drugs

• (2) Pancreas*

• Part of the digestive and endocrine systems

• Secretes pancreatic juice containing bicarbonate (neutralizes stomach acid) and enzymes for carbohydrate, protein, and fat digestion

• (3) Gallbladder*

• Stores bile from the liver

• Releases bile into the small intestine to aid fat digestion

• (4) Salivary Glands*

• Produce saliva

• Protect the oral cavity with lubricating proteins

• Contains amylase for starting carbohydrate digestion

Common GIT Conditions

• Dyspepsia (Indigestion): A group of symptoms like belching, stomach pain, feeling full, early satiety, sour taste, and nausea. It's usually due to poor dietary habits

• Gastroesophageal Reflux Disease (GERD): Stomach acid reflux into the esophagus causing symptoms like acid regurgitation, heartburn, esophageal inflammation, and difficulty swallowing.

• Flatulence: Gas buildup in the digestive tract due to swallowed air, food, or bacteria usually causing fullness and discomfort.

• Ulcers: Sores in the stomach or duodenum. caused by an imbalance between factors that cause ulcers and mechanisms that protect the lining.

• Irritable Bowel Syndrome (IBS): A functional disorder involving abdominal pain, bloating. and diarrhea or constipation. It is often associated with stress, anxiety. and tension.

• Vomiting: Forcibly expelling stomach contents via the mouth. Caused by several factors including gastrointestinal infections, chemotherapy, early pregnancy, motion sickness, and medications.

• Diarrhea: Frequent, excessive passage of watery stools. Caused by food poisoning, allergies, infections, thyroid disorders, or digestive problems in the pancreas, liver, or colon.

• Constipation: Infrequent or difficult passage of hard stools. Common causes include lack of mobility or fiber intake, pregnancy, and intestinal blockage.

• Hemorrhoids: Inflammation and swelling of veins in the rectum and anus, frequently resulting from constipation, pregnancy, or prolonged sitting.

Drugs Acting on the GIT

• Antacids: Neutralize stomach acid to treat acid-related conditions like indigestion, heartburn, or ulcers.

• Anti-flatulents: Relieve gas buildup by dispersing and preventing gas pockets in the GI tract.

• H2 Receptor Antagonists: Reduce stomach acid production by blocking histamine receptors, used to treat ulcers and heartburn.

• Proton Pump Inhibitors (PPIs): Directly inhibit the production of stomach acid, particularly useful for duodenal ulcers and related conditions

• Cytoprotective Agents: Protect the stomach lining from damage by creating a protective barrier against acidity and its effects..

• Antispasmodics: Relax stomach and intestinal muscles to alleviate spasms or cramps.

• Anti-emetics: Reduce or stop nausea and vomiting.

• Anti-diarrheal: Reduce or stop diarrhea, usually by decreasing peristaltic movements.

• Laxatives: Promote bowel movements. They come in several types according to their mechanism of action.

IBS Treatment

• IBS treatment aims to manage symptoms (like stress and anxiety) and adjust diet to reduce triggers, and improve digestive health