Warm-Up Take out HW & place on desk Write down in correct sequence all the organs (at least 5) through which their food passes as it travels along the digestive tract. Then try to list any glands or organs that are found along the digestive tract, but through which food does not pass.

Human Digestive System

Major Functions of Digestive System 1. To take in food (ingestion) 2. To digest (break down) food into a usable form; large organic molecules into small organic molecules 3. To absorb & assimilate nutrients into the blood so they can be used by cells to carry out metabolic activities. 4. To remove indigestible matter (egestion)

Comparing Humans & Other Organisms: (Table 1-1 pg 13 RB) Types of Digestion MECHANICAL - Changes the physical form of food (physical changes) Mouth- teeth chew (masticate) & crush food stomach muscles (rugae) grinds & churns 2. CHEMICAL- Changes the chemical composition of food into a new substance with the aid of digestive enzymes (chemical changes). Comparing Humans & Other Organisms: (Table 1-1 pg 13 RB) 1. Corresponding Life Process/Function: NUTRITION 2. Corresponding Cell Organelle : vacuoles and lysosomes - contain enzymes for unicellular organisms to carry out intracellular digestion, we use organs to carry out extracellular digestion. paramecium

Quick Review: Which type of digestion (mechanical or chemical)? Chewing a saltine? Saliva breaking the saltine down into molecules of glucose? Your tongue breaking pieces of a hamburger apart? Pepsin (an enzyme) in your stomach breaking the hamburger into amino acids?

Other Digestive Enzymes and Substances (found in the small intestine) Nutrient Digestive End Product (aka: Building Blocks) Chemical Digestion Begins here Digestive Enzymes & substances Carbohydrate (Starch)   Mouth (saliva) Amylase Proteins Stomach Pepsin (and hydro chloric acid- HCl) Lipids (Fats) Small intestine Bile and lipase Simple sugars (glucose) Amino acids Fatty Acids and glycerol Other Digestive Enzymes and Substances (found in the small intestine) Pancreatic and Intestinal juices contain enzymes that break down ALL nutrient types Bile – made in the liver and stored in the gall bladder

Gastro Intestinal Tract (One way digestive tube) Pathway in the digestive tube : mouth  esophagus  stomach small intestine  large intestine  rectum  anus Accessory organs (important, but not part of the tube -food does NOT pass through these organs): tongue, salivary glands, liver, gall bladder, pancreas

A Closer Look: Small Intestine Completes chemical digestion Absorbs nutrients into blood through the villi by the process of diffusion Villi - finger-like projections where absorption occurs Figure 1. A Villus

Drawing of Transport –label it too Following the completion of chemical digestion, there is a high concentration of nutrients (amino acids, sugars, fatty acids, etc…) in the small intestine. These nutrients are absorbed into the blood/lymph by diffusion, moving from high concentration to low concentration. The blood then transports these building blocks to our cell’s, where they are used to build (synthesize) new organic compounds or to make energy (ATP) during cell respiration. Drawing of Transport –label it too IN: Nutrients & O2 To the cells Artery OUT: CO2

Systems Working With Systems to Maintain homeostasis 1. The digestive system works with the: circulatory system Describe relationship : The nutrients in the small intestine are absorbed into the blood, which transports them to the body cells 2. The digestive system works with the: respiratory system Describe relationship : Respiratory system provides oxygen and the digestive system supplies glucose. These are the reactants needed for respiration to occur (ATP production)

Digestive Homeostasis Disorders Ulcers- open sores in the lining of the stomach or the small intestine generally associated with some kind of irritant or bacterial infection. Constipation – condition in which the feces are evacuated infrequently and with difficulty- results from sluggish peristalsis that allows excess water to be removed from the feces (fecal matter hardens) – may result from insufficient fiber in the diet Diarrhea-opposite of constipation- associated with disturbances frequently caused by infections or stress – prolonged diarrhea may result in severe dehydration of body tissues

4. Gallstones- small hard particles made of cholesterol or calcium salts which form and collect in the gall bladder – may block the bile duct causing pain and discomfort – treated by surgical removal of the gall bladder. 5. Diabetes - when a person is either insulin deficient or insulin resistant causing them to have trouble allowing glucose to enter cells. This creates high blood sugar which can be very dangerous to the body. 6. Colon Cancer - One of the most common types of cancers in North America It is caused by a diet low in fiber which causes feces to move too slow through colon; can also be hereditary

Digestive System Fill-In

Digestive System Fill-In Answers