How your digestive system works - Emma Bryce

Summary

The human digestive system, a complex network of organs and enzymes, processes an average of 1 to 2.7 kg of food daily, converting it into nutrients and energy. Starting with saliva in the mouth, the journey includes the stomach's muscular contractions and acid secretion, followed by the small intestine's villi for nutrient absorption. The large intestine, or colon, forms stool from indigestible remnants, completing the 30 to 40-hour digestive cycle.

Takeaways

• 🌍 Humans eat on average between 1 and 2.7 kilograms of food a day, totaling over 365 kilograms per year and more than 28,800 kilograms in a lifetime.
• 🦠 The digestive system, comprising ten organs covering nine meters and over 20 specialized cell types, is one of the most diverse and complicated systems in the human body.
• 🤝 Its parts work together to transform food into nutrients and energy, which keep you alive.
• 🌐 The digestive system has four main components: the gastrointestinal tract, the pancreas, gallbladder, and liver, enzymes, hormones, nerves, and blood, and the mesentery.
• 🚪 The digestive process begins before food reaches the tongue, with glands in the mouth producing saliva, about 1.5 liters per day.
• 🦷 Chewing and saliva turn food into a moist lump called bolus, which moves down the esophagus to the stomach through peristalsis.
• 🍴 In the stomach, muscular walls break the bolus into chunks, while acids and enzyme-rich juices dissolve food and break down proteins.
• 🧪 The liver, pancreas, and gallbladder produce digestive juices and bile, which help dissolve fats and further break down proteins and carbohydrates in the small intestine.
• 🌿 Villi in the small intestine's lower regions maximize absorption of nutrients into the bloodstream, where they are carried to the body's organs and tissues.
• 🚽 Leftover fiber, water, and dead cells form stool in the large intestine, which is eventually expelled through the anus, completing the digestive process in 30-40 hours.

Q & A

How much food does an average human consume per day?

On average, a human consumes between one and 2.7 kilograms of food per day.

What is the annual food consumption per person based on the average daily intake?

Based on the average daily intake, a person consumes over 365 kilograms of food per year.

How much food does the average person consume in their lifetime?

The average person consumes more than 28,800 kilograms of food over their lifetime.

What is the primary function of the digestive system?

The primary function of the digestive system is to transform the raw materials of food into nutrients and energy that keep the body alive.

How many main components does the digestive system have?

The digestive system has four main components: the gastrointestinal tract, the pancreas, gallbladder, and liver, the body's enzymes, hormones, nerves, and blood, and the mesentery.

What is the internal surface area of the gastrointestinal tract and how large is it relative to a badminton court?

The gastrointestinal tract has an internal surface area of between 30 and 40 square meters, enough to cover half a badminton court.

What is the role of saliva in the digestive process?

Saliva, produced by glands in the mouth, helps to moisten the food and begins the breakdown of starch through enzymes.

What is the esophagus and how does it transport food to the stomach?

The esophagus is a 25-centimeter-long tube that uses peristalsis, a series of muscular contractions, to propel food into the stomach.

What is chyme and how is it formed in the stomach?

Chyme is a frothy liquid formed in the stomach after three hours, where the food has been broken down by acids and enzyme-rich juices.

What is the role of bile in the digestive process?

Bile, a yellowish-green liquid produced by the liver and stored in the gallbladder, helps to digest fats by dissolving them in the chyme, making them accessible for further breakdown by pancreatic and intestinal juices.

What are villi and how do they contribute to the absorption of nutrients in the small intestine?

Villi are tiny projections that line the small intestine, creating a large surface area to maximize the absorption of nutrients into the bloodstream.

What is the final destination of the byproducts of digestion and how are they expelled from the body?

The byproducts of digestion, including leftover fiber and water, move into the large intestine or colon, where most of the remaining fluid is drained. The remaining soft mass, called stool, is expelled through the rectum and anus.