Digestion

• The Amoeba Sisters' podcast does not function as it should.
• If you define stomach as an organ that contains gastric glands and produces gastric juice, the platypus would not be considered to have a stomach.
• The human digestive system is able to accomplish four major tasks: ingestion, digestion, absorption, and elimination.
• Ingestion is the taking in of food, eating.
• Digestion is when biomolecule polymers are broken down physically or chemically into their building blocks.
• Absorption is important as nutrients will eventually be delivered with the help of other body systems to cells as cells need them in order to survive.
• Elimination is the removal of waste which includes anything that wasn’t digested.
• In humans, food is brought into the mouth, where saliva containing enzymes can break down some biomolecules.
• Mechanical digestion is when something physically breaks the food down, such as teeth grinding up the food.
• Saliva has enzymes and buffers to counteract acidity in the mouth, which can help prevent tooth decay.
• A condition known as “dry mouth” can be hazardous for teeth.
• Saliva also helps lubricate food, which is important as the tongue will help shape the food into a little ball called a bolus.
• The bolus will be swallowed, and when it is, it will travel down the esophagus.
• The epiglottis, a flap in the throat, blocks the windpipe when swallowing food.
• Peristalsis, which are these wave-like movements made by smooth muscle, happens in the esophagus and helps move that food down to the stomach.
• An adult human stomach can store an estimated 2 liters of food and liquid.
• The stomach is acidic and chemical digestion definitely occurs with the stomach’s gastric juices and enzymes such as pepsin which break down proteins.
• There’s mechanical digestion in the stomach, the churning of the stomach which helps bathe the contents in those gastric juices.
• The resulting substance from digestion is known as chyme.
• The human stomach has a sphincter that separates the esophagus from the stomach and another sphincter that separates the contents.
• The stomach does not digest itself due to specialized cells that line the stomach that divide often and make a protective mucus layer.
• Chyme leaves the second sphincter and enters the intestines, where the small intestine is responsible for significant chemical digestion of all four biomolecules: carbs, lipids, proteins, and nucleic acids.
• Enzymes and digestive juices are involved in digestion, along with peristalsis which moves the chyme through this segmented space.
• Most nutrient absorption occurs in the small intestine, where villi and microvilli have a high surface area for absorbing nutrients.
• The large intestine, also known as the colon, is home to many harmless and beneficial bacteria in our bodies, and its major function is to reabsorb water so that the body will not lose all of this precious water involved in digestion.
• Feces are composed of undigested contents and can contain other substances, and it can include the bacteria that we mentioned.
• The very end of the large intestine is the rectum, where feces will remain until they are expelled from the anus.
• The liver is the largest internal organ and is involved in carbohydrate and protein metabolism, and it produces bile which helps breakdown lipids.
• The gallbladder stores the bile.
• The pancreas produces pancreatic juices that have important digestive enzymes and will neutralize acid chyme.
• The small intestine is not the only part of the digestive system that has villi and microvilli for absorption, the liver, gallbladder, and pancreas also have villi and microvilli.
• The liver, gallbladder, and pancreas are not mere accessory organs, they have extremely important functions in the digestive system.
• The pancreas produces pancreatic juices that have important digestive enzymes and will neutralize acid chyme.
• The liver is involved in carbohydrate and protein metabolism and produces bile which helps breakdown lipids.
• The gallbladder stores the bile.
• The pancreas stores the pancreatic juices.
• The small intestine is not the only part of the digestive system that has villi and microvilli for absorption, the liver, gallbladder, and pancreas also have villi and microvilli.
• The liver, gallbladder, and pancreas are not mere accessory organs, they have extremely important functions in the digestive system.
• The pancreas produces pancreatic juices that have important digestive enzymes and will neutralize acid chyme.
• The liver is involved in carbohydrate and protein metabolism and produces bile which helps breakdown lipids.