Interactive image digestive system

STOMACH

Structure

The stomach has four main anatomical divisions; the cardia, fundus, body and pylorus.

Functions

• Mechanical and Chemical Digestion
• Storage
• Killing Harmful Microorganisms

Diseases or disorders

• Gastritis: Inflammation of the stomach lining, often caused by irritation from excessive alcohol consumption
• Peptic Ulcers: Open sores that develop on the lining of the stomach (gastric ulcers) or the upper part of the small intestine (duodenal ulcers).
• Gastroesophageal Reflux Disease (GERD): Chronic condition where stomach acid frequently backs up into the esophagus.

Salivary Glands

Structure

Despite their different locations, each of these glands shares the same fundamental structure, branched ducts that open into the oral cavity and glandular secretory end pieces, called acini.

Functions

• facilitating mastication.
• swallowing, and speech.
• lubricating the oral mucosa.

Disorders or diseases

Sialadenitis: This is an infection of the salivary glands, usually caused by bacteria. It can lead to pain, swelling, and tenderness in the affected gland. Sialolithiasis: These stones can block the flow of saliva, leading to pain, swelling, and infection. Mucocele: It occurs when a salivary gland duct is injured or blocked, causing saliva to accumulate and form a cyst.

ESOPHAGUS

Structure

Approximately the proximal third of the esophagus is primarily composed of skeletal muscle while the distal two-thirds are smooth muscle.

Functions

• Transportation of Food
• Protection Against Acid Reflux
• Initiation of Digestion

Diseases or disorders

• Gastroesophageal Reflux Disease (GERD): Chronic acid reflux, causing heartburn and potential damage to the esophagus.
• Esophagitis: Inflammation of the esophageal lining, often due to GERD, infections, or other irritants.
• Esophageal Cancer: Malignant tumors that develop in the esophagus, often linked to factors like smoking and heavy alcohol consumption.

RECTUM

Structure

The rectum is the final portion of the large intestine, located just above the anus. It is approximately 6-8 inches in length and serves as a temporary storage site for feces before they are eliminated from the body.

Functions

• Fecal Storage
• Rectal Sensation regulate bowel movements.
• Initiation of Defecation Reflex

Diseases or disorders

Hemorrhoids: Swollen blood vessels in the rectal area or around the anus, which can cause discomfort, bleeding, and itching. Rectal Prolapse: The rectum protrudes from the anus due to weakened or damaged rectal muscles and tissues.

GALLBLADDER

Structure

The gallbladder sits in an indenture underneath the right lobe of the liver. It is about one inch wide and three inches long, and tapered at one end where it connects to the cystic duct.

Functions

• To store and concentrate bile.
• To respond to intestinal hormones (such as cholecystokinin) to empty and refill its bile stores.
• To contribute to regulating the composition of bile.

Diseases or disorders

• Gallstones (Cholelithiasis): Hardened deposits of digestive fluid components (cholesterol, bile salts, and calcium) that form in the gallbladder. They can cause pain and blockage of bile ducts.
• Cholecystitis: Inflammation of the gallbladder, often caused by gallstones blocking the flow of bile or due to infection.
• Choledocholithiasis: Gallstones that have moved from the gallbladder into the bile ducts, potentially causing blockage and complications.

PANCREAS

Structure

The right side of the organ—called the head—is the widest part of the organ and lies in the curve of the duodenum, the first division of the small intestine

Functions

• Endocrine Function
• Exocrine Function
• Bicarbonate Production

Diseases or disorders

• Pancreatitis: Inflammation of the pancreas, often caused by gallstones or excessive alcohol consumption.
• Pancreatic Cancer: Malignant tumors that develop in the pancreas, often detected at advanced stages.
• Diabetes Mellitus: A chronic condition where the pancreas doesn't produce enough insulin or the body can't effectively use it, leading to high blood sugar levels.

ANUS

Structure

The anus is the external opening at the end of the digestive tract, located at the end of the rectum. It is composed of muscular tissues and is surrounded by the anal sphincters, which are rings of muscles that help control the passage of feces.

Functions

• Elimination of Feces
• Sphincter Control
• Keeps infections out

Diseases and disorders

• Hemorrhoids: Swollen blood vessels in the anal area, which can cause discomfort, bleeding, and itching.
• Anal Fissures: Small tears in the lining of the anus or lower rectum, typically caused by straining during bowel movements or by passing hard stools.

MOUTH

Structure

The mouth consists of the oral cavity, which includes the lips, cheeks, tongue, and palate. It also contains the teeth and salivary glands, which produce saliva to aid in digestion.

Functions

• Ingestion
• Mastication
• Initiation of Digestion

Diseases or disorders

Cavities (Dental Caries): Tooth decay caused by bacteria that erode tooth enamel. Gingivitis: Inflammation of the gums, often caused by plaque buildup. Periodontitis: Advanced gum disease characterized by infection and damage to the tissues supporting

LIVER

Structure

The liver consists of 2 main lobes. Both are made up of 8 segments that consist of 1,000 lobules (small lobes). These lobules are connected to small ducts (tubes) that connect with larger ducts to form the common hepatic duct.

Functions

• Metabolic Regulation
• Detoxification
• Production of Biochemicals

Diseases or disorders

• Hemochromatosis: A genetic disorder leading to excessive iron absorption and accumulation in the liver, potentially causing damage.
• Wilson's Disease: An inherited disorder that leads to copper buildup in the liver and other organs.
• Autoimmune Hepatitis: A condition where the immune system mistakenly attacks the liver, causing inflammation and potential damage.

LARGE INTESTINE

Structure

The large intestine consists of the colon, rectum, and anal canal.

Functions

• reabsorption of water and mineral ions such as sodium and chloride.
• formation and temporary storage of faeces.
• maintaining a resident population of over 500 species of bacteria.

Diseases or disorders

• Colon Polyps: Abnormal growths on the inner lining of the colon, which may be benign but can sometimes progress to cancer.
• Ischemic Colitis: Reduced blood flow to the colon, which can lead to tissue damage and inflammation.
• Colonic Abscess: A collection of pus within or near the colon, often resulting from untreated infections or conditions like diverticulitis.

SMALL INTESTINE

Structure

The small intestine is divided into the duodenum, jejunum, and ileum. The small intestine follows the general structure of the digestive tract in that the wall has a mucosa with simple columnar epithelium, submucosa, smooth muscle with inner circular and outer longitudinal layers, and serosa.

Functions

• Systematically breaks food down.
• Absorbs nutrients.
• Extracts water.

Diseases or Disorders

• Carcinoid Tumors: Slow-growing tumors that can develop in the small intestine, often originating from hormone-producing cells.
• Intussusception: A condition where one segment of the small intestine telescopes into another, causing blockage and potential damage.
• Malrotation: A congenital abnormality where the small intestine isn't properly positioned during development, potentially leading to complications.

APPENDIX

Structure

The appendix or vermiform appendix is a muscular structure attached to the large intestine in the human body. It is a narrow tube resembling a worm and is named after the Latin word "vermiform" which means 'worm-shaped'.

Functions

• One proposed function of the appendix is that it may serve as a "reservoir" for beneficial gut bacteria. In case of severe diarrhea or illness that flushes out the gut microbiota, the appendix may help repopulate the intestines with beneficial bacteria.

However, it's important to note that while this is a current area of research, the exact function of the appendix is not yet fully understood and further studies are ongoing.

Diseases or disorders

Appendicitis: This is the inflammation of the appendix, usually due to a blockage in the appendix that leads to bacterial overgrowth and infection. It is a serious condition that requires prompt medical attention. Appendiceal Tumors: These can be either benign (non-cancerous) or malignant (cancerous) growths that develop in the appendix.