Complete unit planner by writing today’s activities and homework in the appropriate spaces. Answer the following question as today’s bellringer: Think back over our study of the circulatory system. It’s major purpose was to transport needed materials to cells and tissues throughout the body. How might the circulatory system and the digestive system work together to accomplish this?

Carbohydrates - Food and Energy In addition to providing energy, carbohydrates provide the raw materials to make cell parts.

- Food and Energy Fats Many foods contain saturated, unsaturated, and trans fats. Unsaturated fats are considered to be more healthful than saturated fats and trans fats.

Proteins - Food and Energy Proteins are needed for tissue growth and repair. They also play an important role in chemical reactions within cells.

Vitamins and Minerals - Food and Energy Vitamins act as helper molecules in a variety of chemical reactions in the body.

Vitamins and Minerals - Food and Energy Nutrients that are not made by living things are called minerals. Minerals are present in soil and are absorbed by the roots of plants. Thus, how do you obtain minerals in your diet?

- Food and Energy Water Water is the most important nutrient because the body’s vital processes – including chemical reactions such as the breakdown of nutrients – take place in water.

Functions of the Digestive System - The Digestive Process Begins Functions of the Digestive System The digestive system has three main functions. First, it breaks down food into molecules the body can use. Then, the molecules are absorbed into the blood and carried throughout the body. Finally, wastes are eliminated from the body.

Methods of the Digestion - The Digestive Process Begins Methods of the Digestion Mechanical digestion – foods are physically broken down into smaller pieces Chemical digestion – chemicals produced by the body break down foods into their smaller chemical building blocks

The Mouth - The Digestive Process Begins Both mechanical and chemical digestion begin in the mouth.

The Mouth - The Digestive Process Begins The shape of an enzyme molecule is specific to the shape of the food molecule it breaks down. Here an enzyme breaks down a starch into sugars.

INDEPENDENT PRACTICE… Draw a Venn diagram comparing and contrasting mechanical and chemical digestion.

TICKET OUT… Which of the following activities represent mechanical digestion and which represent chemical digestion: 1. The teeth cut and grind food 2. The stomach churns food 3. Enzymes in saliva break down carbohydrates in food 4. Enzymes break down proteins in food

Protein Digestion - The Digestive Process Begins A scientist performed an experiment to determine the amount of time needed to digest protein. He placed small pieces of hard-boiled egg white (a protein) in a test tube containing hydrochloric acid, water, and the enzyme pepsin. He measured the rate at which the egg white was digested over a 24-hour period. His data are recorded in the graph.

Protein Digestion - The Digestive Process Begins Reading Graphs: What do the values on the y-axis represent? Percentage of egg white digested

Protein Digestion - The Digestive Process Begins Interpreting Data: After about how many hours would you estimate that half of the protein was digested? About 14 hours

Protein Digestion - The Digestive Process Begins Interpreting Data: How much digestion occurred in 16 hours? About 70%

Protein Digestion - The Digestive Process Begins Drawing Conclusions: During which four-hour period did the most digestion take place? From 13 to 16 hours

Complete unit planner by writing today’s activities and homework in the appropriate spaces. Answer the following question as today’s bellringer: Describe as best you can the process that turns food into nutrients that cells can use. A Great Illustration of Digestion

The Epiglottis and the Esophagus - The Digestive Process Begins The Epiglottis and the Esophagus The epiglottis is flap of cartilage located in the throat behind the tongue and in front of the larynx. When a person swallows the epiglottis folds backward to cover the entrance of the larynx so food and liquid do not enter the windpipe and lungs. The epiglottis is flap of cartilage located in the throat behind the tongue and in front of the larynx. The epiglottis is usually upright at rest allowing air to pass into the larynx and lungs. When a person swallows the epiglottis folds backward to cover the entrance of the larynx so food and liquid do not enter the windpipe and lungs. After swallowing the epiglottis returns to its original upright position. The epiglottis is a thin lid-like flap of cartilage tissue that is attached to the root of the tongue. It is situated in front behind the tongue and in front of the entrance to the larynx (voice box). When resting, the epiglottis allows air to pass through the larynx and into the rest of the respiratory system. When swallowing, it covers the entrance to the larynx to prevent food and drink from entering the windpipe. If both the air passage and the food passage were open when someone swallowed, air could enter the stomach and food could enter the lungs. The epiglottis is the way that this is prevented from happening, basically acting like a lid every time we swallow.

The Epiglottis and the Esophagus - The Digestive Process Begins The Epiglottis and the Esophagus The esophagus is a muscular tube that extends from the neck to the abdomen and connects the back of the throat to the stomach. The esophagus squeezes the mass of food with rhythmic muscle contractions called peristalsis. Peristalsis forces the food into the stomach. Peristalsis Demo The esophagus is a muscular tube that extends from the neck to the abdomen and connects the back of the throat to the stomach. Its inner lining, or mucosa, normally consists of flat cells (known as squamous cells) which are similar to those of the skin.

The Stomach - The Digestive Process Begins Most mechanical digestion and some chemical digestion occur in the stomach. The stomach is a muscular, saclike, digestive organ attached to the lower end of the esophagus. The stomach continues the mechanical digestion of your meal by squeezing the food with muscular contractions. While this squeezing is taking place, tiny glands in the stomach produce enzymes and acid. The enzymes and acid work together to break food into nutrients. Stomach acid also kills most bacteria that you might swallow with your food. After a few hours of combined mechanical and chemical digestion, your meal has been reduced to a soupy mixture called chyme.

Mechanical and chemical digestion takes place in the stomach. - Final Digestion and Absorption “The Stomach” Mechanical and chemical digestion takes place in the stomach. Food is squeezed by muscular contractions. Tiny glands in the stomach produce enzymes and acid. Food is reduced to a soupy mixture called chyme.

The Small Intestine - Final Digestion and Absorption The small intestine is the part of the digestive system where most chemical digestion takes place.

The Small Intestine - Final Digestion and Absorption Tiny finger-shaped projections called villi line the inside of the small intestine. Villi absorb nutrient molecules. The molecules pass from the villi into blood vessels.

Chemical digestion takes place in the small intestine. - Final Digestion and Absorption “The Small Intestine” Chemical digestion takes place in the small intestine. Food mixes with enzymes and secretions. Starches, proteins, and fats are digested chemically. Enzymes and secretions are produced by the small intestine, liver, and pancreas.

The Large Intestine Most commonly known as the colon… - Final Digestion and Absorption Most commonly known as the colon… The Large Intestine The large intestine takes 12 to 25 hours to finish up the remaining processes of the digestive system. Food is not broken down any further in this stage of digestion. The large intestine simply absorbs vitamins that are created by the bacteria inhabiting the colon. It is also very important in absorbing water and compacting the feces, it also stores fecal matter in the rectum until eliminated through the anus. It is also responsible for passing along solid waste.

Graphic Organizer In the mouth, the teeth break food into smaller pieces and saliva begins to break down starches. Esophagus pushes food from mouth to stomach. In the stomach, food is churned and mixed with digestive juices that break down protein. In the small intestine, almost all chemical digestion and absorption occurs. Large intestine absorbs water and eliminates waste.

TICKET OUT… Identify each of the following statements as true or false… 1. Digestion begins when food reaches the stomach. 2. Breaking, crushing, and mashing food is an example of chemical digestion. 3. Saliva contains enzymes, which begin the chemical digestion of food. 4. The esophagus connects the mouth with the small intestine directly.