A guide to the gastrointestinal system

The gastrointestinal (GI) system, also known as the digestive system, is responsible for breaking down food, absorbing nutrients, and eliminating waste. This guide will cover the GI system’s anatomy, physiology, common conditions, and preventive health tips.

Anatomy of the gastrointestinal system¹

The GI system consists of several organs and structures that work together to process food.

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Mouth and
salivary glands

Pharynx and
oesophagus

Stomach

Small intestine

Large intestine

Accessory organs

Mouth and salivary glands
Digestion begins in the mouth, where food is chewed and mixed with saliva. Saliva contains enzymes that start breaking down carbohydrates.

Pharynx and oesophagus
The pharynx serves as a pathway for food to travel from the mouth to the oesophagus. The oesophagus is a muscular tube that moves food to the stomach through peristalsis.

Stomach
The stomach secretes gastric juices, including hydrochloric acid and enzymes, to break down proteins. It churns food into a semi-liquid form called chyme.

Small intestine
The small intestine consists of three parts: the duodenum, jejunum, and ileum. It is the primary site for nutrient absorption. Digestive enzymes from the pancreas and bile from the liver aid in breaking down food.

Large intestine
The large intestine absorbs water and electrolytes from indigestible food matter and forms solid waste (faeces). It includes the colon, rectum, and anus.

Accessory organs
The liver, gallbladder, and pancreas play crucial roles in digestion. The liver produces bile, the gallbladder stores bile, and the pancreas secretes digestive enzymes.

Physiology of the respiratory system¹

The respiratory system’s main function is to facilitate gas exchange, providing oxygen to the body and removing carbon dioxide.

Ingestion
Food intake begins in the mouth, where it is chewed and mixed with saliva to form a bolus.

Digestion
Mechanical digestion occurs through chewing and stomach churning, while chemical digestion involves enzymes breaking down food into smaller molecules.

Absorption
Nutrients are absorbed primarily in the small intestine. The inner surface of the small intestine is lined with villi and microvilli, which increase the surface area for absorption.

Elimination
Waste products and indigestible food matter are expelled from the body through the large intestine and anus.

Common gastrointestinal conditions²

Several conditions can affect the respiratory system. Here are the top five common respiratory conditions:

Gastroesophageal reflux disease (GERD)

GERD occurs when stomach acid frequently flows back into the oesophagus, causing heartburn and irritation.

Irritable bowel syndrome (IBS)

IBS is a functional disorder characterised by abdominal pain, bloating, and changes in bowel habits. It can cause diarrhoea, constipation, or both.

Inflammatory bowel disease (IBD)

IBD includes Crohn’s disease and ulcerative colitis, which cause chronic inflammation of the GI tract. Symptoms include abdominal pain, diarrhoea, and weight loss.

Celiac disease

Celiac disease is an autoimmune disorder where ingestion of gluten leads to damage in the small intestine. Symptoms include diarrhoea, bloating, and malnutrition.

Gallstones

Gallstones are hard deposits that form in the gallbladder. They can block the bile ducts, causing severe pain and digestive issues.

Preventive health tips^3,4,5

Maintaining GI health involves adopting healthy habits and managing risk factors. Here are some tips to help prevent gastrointestinal conditions:

Eat a balanced diet Consume a diet rich in fruits, vegetables, whole grains, lean proteins, and healthy fats. Avoid excessive intake of processed foods, sugar, and saturated fats.

Stay hydrated Drink plenty of water to aid digestion and prevent constipation.

Exercise regularly Physical activity helps maintain a healthy weight and promotes regular bowel movements.

Avoid smoking and excessive alcohol consumption Smoking and heavy drinking can damage the GI tract and increase the risk of conditions like GERD and liver disease.

Manage stress Stress can negatively impact digestion. Practice stress-reducing techniques such as mindfulness, meditation, and yoga.

Get regular check-ups Regular medical check-ups can help detect and manage GI conditions early.

References

Digestive System. Cleveland Clinic. Available at: https://my.clevelandclinic.org/health/body/7041-digestive-system.
Digestive Disorders. Johns Hopkins Medicine. Available at: https://www.hopkinsmedicine.org/health/wellness-and-prevention/digestive-disorders.
Top health tips gastroenterologists want you to know. American Medical Association. Available at: https://www.ama-assn.org/delivering-care/public-health/top-health-tips-gastroenterologists-want-you-know.

Healthful is a digital media publisher dedicated to providing informative content about health and wellness. It is important to note that Healthful does not provide professional medical advice, diagnosis, or treatment. For personalised health concerns or before initiating any treatment plan, it is essential to consult with your healthcare provider. Stay informed, stay healthful for you.

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