2 How many different systems do you see? Digestive-Breaks down and absorbs nutrients2. Respiratory- absorbs oxygen3. Circulatory – transports nutrients
3 glucose + oxygen carbon dioxide + water + energy C6H12O O CO H2O + 36 ATPglucose + oxygen carbon dioxide + water + energy1. Where does the glucose come from? Food 2. Where does the oxygen come from? Breathing 3. What are the final products of cellular respiration? CO2, H2O, ATP 4. In which organelle does this take place in our cells? Mitochondria
4 Evolutionary Trends of the Digestive System Types of digestive systems:Filter feederDigestive cavity:1 opening(Gastrovascular cavity)Digestive tract:2 openingsDescription of systemAquatic animals that strain tiny floating organisms from waterDigestive chamber with food entering and waste exiting through one opening.2 openings: mouth, anus.Picture of systemExamplesSpongesJellyfish, Sea Anemone, Corals, Portuguese Man-of-War, Planaria (flatworm)Snails, oysters, squid, octopus, starfish, sand dollar, crayfish, spiders, crabs, butterflies, humans
5 Function of The Digestive System The function of the digestive system is to help convert foods into simpler molecules that can be absorbed and used by the cells of the body; eliminates waste.
6 The Digestive System (aka. Alimentary Canal) Includes: MouthPharynxEsophagusStomachSmall IntestineLarge Intestine/ColonRectum(Accessory organs:salivary glands, liver,gallbladder, pancreas)
7 The MouthTeethCutting, tearing, and crushing food into small fragments.Begins the process of mechanical digestion or physical breakdown.SalivaSecreted by the salivary glands.Helps moisten the food and make it easier to chew.Contains amylase, a digestive enzyme that begins the breakdown of carbohydrates.Begins the process of chemical digestion, where chemicals breakdown the large pieces into smaller pieces.
9 The Esophagus Bolus – Chewed clump of food. From the throat, the bolus passes through the esophagus, or food tube, into the stomach.Food travels through the esophagus to the stomach by smooth muscle contractions (wave-like) called peristalsis.The epiglottis (small flap covering the trachea) separates the food from air when swallowing
10 The StomachFood from the esophagus empties into a large muscular sac called the stomach.The stomach continues the mechanical and chemical digestion of food.Mechanical: Stomach muscles contract to churn and mix stomach fluids and food, gradually producing a mixture known as chyme.Chemical:Gastric glands release mucous to protect the stomach wallGastric glands produce hydrochloric acid and pepsin, which begins the complex process of protein digestion.Amylase is denatured by the stomach acid so carbohydrate breakdown does not occur in the stomach.
11 The Small IntestineMost of the chemical digestion and beginning absorption of the food you eat occurs in the small intestines.
12 The Small Intestine Divided into three parts: Together average about DuodenumJejunumIleumTogether average about6 meters (19.7 ft) long.
13 Duodenum The first of three parts of the small intestine. It is where almost all of the digestive enzymes enter the intestine.The pancreas and the liver release digestive enzymes and fluids to help with digestion in the small intestine.
14 Absorption in the Small Intestine By the time chyme enters the jejenum and the ileum parts of the small intestine, much of the chemical digestion has been completed.Chyme is now a rich mixture of medium and small nutrient molecules.
15 Absorption in the Small Intestine The small intestine is specially adapted for absorption of nutrients.The folded surfaces of the small intestine are covered with fingerlike projections called villi.Villi increases the surface area for absorption of nutrients
16 Absorption of Nutrients in the Small Intestine Nutrients are absorbed through the wall of the small intestine directly into the capillaries (blood) by the process of diffusion.Diffusion – movement of substances from an area of high concentration to an area of low concentration
17 Absorption in the Small Intestine By the time food is ready to leave the small intestine, it is basically nutrient-free.The complex organic molecules have been digested and absorbed, leaving only water, cellulose, and other undigestible substances behind.
18 The Large IntestineWhen the chyme leaves the small intestine, it enters the large intestine, or colon.Primary Function: Remove water from the undigested material that is left.The concentrated waste material (feces) that remains after the water has been removed passes through the rectum and is eliminated from the body.
20 Accessory Structures of Digestion PancreasLiverGallbladderSalivaryGlands
21 Pancreas Located just behind the stomach. Gland that serves three important functions:Produces insulin that regulate blood sugar levels.Produces enzymes that break down carbohydrates, proteins, lipids, and nucleic acids.Produces sodium bicarbonate, a base that neutralizes stomach acid so that these enzymes can be effective.
22 LiverAssisting the pancreas is the liver, a large organ located just above and to the right of the stomach.Produces bile; to help digest fatsBile acts like a detergent, dissolving and dispersing the droplets of fat found in fatty foods.Makes it possible for enzymes to reach the smaller fat molecules and break them down.Bile is stored in a small, pouch-like organ called the gallbladder.
23 Gallbladder A pouch like organ that stores the bile (dr. oz)A pouch like organ that stores the bileThe bile is brought to the small intestine by the bile duct20 million ppl get gallstones, small hard mineral deposits due to excess cholesterol buildup
24 Salivary Glands There are 3 salivary glands: Parotid gland – largest of the salivary glands that secretes saliva to assist with chewing and swallowing; located in the cheek area inferior to the earSubmandibular gland – secretes amylase to help breakdown starches in the mouth; located below and inferior to the parotid glandSublingual gland – secretes mucous that helps coat the food being swallowed; located in front of the submandibular gland on the floor of the mouth
25 Levels of Organization Digestive SystemLevels of Organizationepithelium, villi, smooth muscleMouth, esophagus, stomach, small & large intestines, etc…digestiveEpithelial cells, Liver cell, stomach cell, pancreatic cell, etc….
27 A. SALIVARY GLANDSB. MOUTHC. ESOPHAGUSD. STOMACHF. LARGE INTESTINEE. SMALL INTESTINEH. ANUSG. RECTUM
28 Digestive System Disorders Peptic UlcerHole in the stomach wallMost peptic ulcers are caused by bacteria and most can be cured by antibiotics.Diarrhea or ConstipationIf not enough water is absorbed by the large intestine, diarrhea occurs.If too much water is absorbed from the undigested materials, constipation occurs.(constipation)