DIGESTIVE SYSTEM

• Across the whole planet, humans eat on average between one and 2.7 kilograms of food a day
• That's over 365 kilograms a year per person, and more than 28,800 kilograms over the course of a lifetime
• Every last scrap of food makes its way through the digestive system
• Digestive system


  • Comprised of ten organs covering nine meters
  • Contains over 20 specialized cell types
  • One of the most diverse and complicated systems in the human body
• Digestive system


  Continuously works in unison to transform the raw materials of food into the nutrients and energy that keep you alive
• Main components of the digestive system


  • Gastrointestinal tract
  • Pancreas, gallbladder, and liver
  • Body's enzymes, hormones, nerves, and blood
  • Mesentery
• Gastrointestinal tract


  • A twisting channel that transports food
  • Has an internal surface area of between 30 and 40 square meters, enough to cover half a badminton court
• Pancreas, gallbladder, and liver


  • Break down food using an array of special juices
• Body's enzymes, hormones, nerves, and blood


  • Work together to break down food, modulate the digestive process, and deliver its final products
• Mesentery


  • A large stretch of tissue that supports and positions all digestive organs in the abdomen, enabling them to do their jobs
• Digestive process


  1. Anticipation of food triggers saliva production

  2. Chewing and saliva turn food into a moist lump called the bolus

  3. Peristalsis propels the bolus into the stomach

  4. Stomach walls break down the bolus

  5. Hormones trigger release of acids and enzymes to dissolve and break down food

  6. Bile, pancreatic and intestinal juices break down fats, proteins and carbohydrates in the small intestine

  7. Villi in the small intestine absorb molecules into the bloodstream

  8. Leftover fiber, water and dead cells make it to the large intestine where most fluid is drained out

  9. Remaining soft mass is squeezed into the rectum and expelled as waste through the anus
• The digestive process typically lasts between 30 and 40 hours
• Secretion - release of substances from cells or organs to the outside of the body or another part of the body.
• Stomach secretes hydrochloric acid and pepsinogen enzymes to continue mechanical and chemical breakdown of food.
• The liver plays a crucial role in detoxifying harmful substances in the body, such as alcohol and drugs.
• The digestive system is the organ system that breaks down food into nutrients, which are then absorbed by cells.
• The liver is responsible for producing bile, which helps in the digestion and absorption of fats.
• The mouth contains teeth and tongue used to break up food mechanically.
• The liver stores essential nutrients like vitamins and minerals, releasing them into the bloodstream as needed.
• The esophagus connects the pharynx to the stomach and transports food from the throat to the stomach.
• The mouth is where food enters the body through chewing and swallowing.
• Ingestion


  The process of taking in food through the mouth
• Absorption


  The process by which the products of digestion are absorbed by the blood to be supplied to the rest of the body
• Assimilation


  The process of absorbing nutrients during digestion and distributing them to the body for growth and repair
• Egestion


  The process of removal of undigested food material from the alimentary canal