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The Digestive System
Transcript of The Digestive System
The journey of food through the digestive system begins in the mouth. The mouth can preform 2 types of digestion, mechanical and chemical. Mechanical digestion occurs using the teeth. They compact the food into what is called a bolus, or ball of food. The chemical digestion occurs in the mouth by way of the saliva and the enzymes in saliva such as salivary amylase. The bolus is then swallowed by the tongue into the pharynx and then goes to the esophagus.
The Salivary Glands
Hi! My name is Chadington and I am a bite of food. I was once a broccoli, but now I am here to inform you about the digestive system.
The salivary glands produce saliva which helps to moisten the mouth and food, chew and swallow, aids in digestion, and fights off pathogens.
The esophagus is a tube that leads from the mouth to the stomach. In total, it takes the bolus about 10 seconds to reach the stomach. The esophagus uses a process called peristalsis to force the food into the stomach. In peristalsis, the muscle behind the bolus contracts while the muscle in front of the bolus relaxes. Mechanical digestion occurs in the esophagus when it squeezes the food during peristalsis.
The stomach is a j-like organ that similarly to the mouth, it preforms both types of digestion. It preforms the mechanical digestion by physically squeezing the food to aid in digestion by churning the food. The stomach preforms chemical digestion by using hydrochloric acid and enzymes such as pepsin. When the bolus leaves the stomach, it is no longer a bolus, it is now a sludge like acidic mixture called chyme. Food spends 4-6 hours in the stomach
The pancreas produces digestive juices that aid in digestion. It then releases these juices and enzymes into the duodenum by way of the pancreatic duct. The pancreas also regulates blood sugar. Also, food does not go throgh the pancreas but it is considered a part o the digestive system because it aids in digestion.
The Liver and Gallbladder
The liver filters the blood of toxins such as alcohol. It also breaks down drugs and produces bile which aids in the breaking down of fats. The liver then sends this bile to the gallbladder where it is held for storage until it needs to be released through the common bile duct and into the duodenum. Food aso does not go through the gallbladder or liver.
The Small Intestine
The small intestine has 3 parts, the duodenum(Beginning), jejunum(Middle), and ilium(End). The small intestine is actually longer than the large intestine(The small intestine is 7 m.) but is called small because it is small in diameter(2.5 cm.). The small intestine has numerous folds to increase the surface area. Also, villi which are finger-like projections also increase the surface area and give the small intestine a velvet-like texture. Also, the most absorption of nutrients occurs in the small intestine. Food spends 3-6 hours in the small intestine. Once the chyme has made its way through the many twists and turns of the small intestine it is now in the large intestine(Colon)
Villi and Microvilli
Villi are finger-like projections into the small intestine. There are about 10-40 per each square inch of the small intestine. Most absorption occurs in the villi. The villi have even tinier projections called micro villi which further increase the small intestine's surface area until it is about the surface area of a tennis court. The are about 30 billion microvilli per square centimeter ot small intestine. Villi alsocontain capillaries within them. The nutrients are absorbed by the absorbtive cells and then diffuse across the thin wall of the caplillaries so that the nutrients can be given to each cell in the body.
The Large Intestine/Colon
The large intestine or colon is actually shorter in length but is about 1 cm. longer in diameter than the small intestine at anywhere from 2.5 cm. to 10 cm.. This organ is horseshoe shaped and wraps around the small intestine. It also turns the chyme into solid waste. This process takes about 6-8 hours and involves absorbing water back from the waste so we do not become dehydrated. It is important to eat fiber because even though annot be digested, it softens feces/stoll and keeps you from becoming constipated.Once the chyme is turned into solid waste it is sent to the rectum.
The Rectum and Anus
The rectum is the holding place for solid waste until it can be excreted through the anus and out into the world. After about 30-40 hours, the process of digestion is complete.
Digestion, a Presentation by: Chris Ruano
All in all, the digestive system is important because it allows us to get energy and nutrients from the food that we eat and give that energy to our cells so that they can function properly. Without the digestive system, we could not get energy or nutrients from our food
The Digestive System
The digestive system allows us to get nutrients and energy from the things that we eat and drink. It breaks down food so that the nutrients and energy can be absorbed and brought to the cells. However, nutrients such as vitamins, minerals, and water are absorbed without digestion. Fats, carbohydrates, and proteins need to be broken down by chemicals called enzymes. Each enzyme breaks down a different nutrient. For example, prolease breaks down protein into amino acids, amylase breaks down starches into sugars, and lypase breaks down fats into fatty acids and glycerol. All in all, the digestive system is essential to the proper function of the body.