The Plan… 4 March 2013

• Silent read 15 min & move to new seats…• Finish Bill Nye Video & Mark Worksheet• Review Body Systems Quiz• PowerPoint Presentation

“The Digestive & Excretory Systems”

• Desk Work: Worksheets Vocab…

• If there is time, we’ll quickly discuss the Egg Osmosis Lab The good and the bad…

(c) McGraw Hill Ryerson 2007

(c) McGraw Hill Ryerson 2007

2.2 The Digestive and Excretory Systems

• Nutrients are substances the body requires for energy, growth, development, repair, or maintenance.

• We get nutrients from what we eat and drink.

See pages 64 - 65

•Four Food Groups•Grain products•Vegetables and fruit•Milk products•Meat and alternatives

(c) McGraw Hill Ryerson 2007

Types of Nutrients

• Carbohydrates The bodies quickest source of energy Examples include: rice, vegetables,

cereal, and bread

• Proteins Used to build parts of your bodies

muscles, skin, hair, and nails Examples include: fish, meat, eggs,

nuts, soy products

See pages 66 - 69

(c) McGraw Hill Ryerson 2007

Types of Nutrients

• Fats Used to build cell membranes and can be

stored for future energy. Examples include: butter, vegetable oil,

and meat

• Minerals and Vitamins Needed in small amounts to perform

various body functions Two common minerals and vitamins are

calcium and vitamin D

See pages 66 - 69

Water is not a nutrient but is necessary for life!

(c) McGraw Hill Ryerson 2007

The Four Stages of Digestion

See page 70

• The process in which food is broken down, nutrients are absorbed, and wastes eliminated is called digestion and occurs in the digestive system.

• The fours stages of digestion are: Ingesting Digesting Absorbing Eliminating

(c) McGraw Hill Ryerson 2007

Stage 1: Ingesting

See page 71

• Ingesting, or ingestion, means to bring food into the body. This is the starting point of the digestive process.

(c) McGraw Hill Ryerson 2007

Stage 2: Digesting

See page 71

• Mechanical digestion occurs when your teeth and tongue break food into small enough pieces to swallow.

• Each small piece of food is called bolus.• Chemical digestion occurs when saliva

begins to break down the bolus.• An enzyme in your saliva begins to

break down simple and complex carbohydrates.

The Mouth

(c) McGraw Hill Ryerson 2007

Stage 2: Digesting

See page 72

• When you swallow, your food enters the esophagus.

• The esophagus is a long muscular tube that carries food to your stomach.

• The bolus is pushed through the esophagus in a process called peristalsis.

The Esophagus

(c) McGraw Hill Ryerson 2007

Stage 2: Digesting

See page 73

• Inside the stomach is gastric juice, which is very acidic.

• The stomach walls are lined with mucus to protect the tissue from being damaged by the acid.

• An enzyme called pepsin, present in gastric juice, breaks down protein.

• The bolus that enters your stomach breaks down into a liquid called chyme.

The Stomach

(c) McGraw Hill Ryerson 2007

Stage 2: Digesting

See page 74

• The first metre of the small intestine is called the duodenum.

“duːəˈdinəm”

• The pancreas adds enzymes that help break down the carbohydrates, protein, and fat in the chyme.

• The liver produces bile which is stored in the gall bladder.

• Bile breaks the globs of fat into smaller droplets.

The Small Intestine

(c) McGraw Hill Ryerson 2007

Stage 3: Absorbing

See page 75

• Absorption is the process in which nutrients and water are absorbed by the small and large intestine.

• The small intestine is covered with villi to help increase the rate at which nutrients are absorbed. Villi are structures that look like folds in

the wall of the small intestine. Each of these folds increases the surface

area available to take in nutrients.

• The large intestine absorbs water and some minerals.

The Small and Large Intestine

Small Intestine surface area = Area size of a tennis court

(250m2)

(c) McGraw Hill Ryerson 2007

Stage 4: Eliminating

See page 76

• Any solid material, undigested by the end of the large intestine is called feces.

• Feces are stored in the rectum until they are eliminated through the anus.

• Liquid and gas wastes are removed by your excretory system. The main organs in your excretory

system are your kidneys and your bladder.

(c) McGraw Hill Ryerson 2007

Eating Disorders

• Anorexia nervosa is a disorder when a person severely restricts what they eat.

• Bulimia nervosa is a disorder when a person eats large amounts of food and then vomits or takes laxatives to get rid of the food before it is completely digested.

See page 77Take the Section 2.2 Quiz

For Tomorrow…

• I need you to keep track of what you have eaten/will be eating for the rest of the day… All meals and all snacks from when you woke up till when you go to

sleep tonight

• We have a small Canada Food Guide activity to do tomorrow along with another CYU…

• REMEMBER we are trying to get Unit 2 done by Friday!!! Definitions etc.

(c) McGraw Hill Ryerson 2007

Draw this table in your book…

Meal Foods eaten

Breakfast Cereal (corn flakes), milk , coffee

Snack Food Granola Bar, Yogurt

Lunch Peanut Butter Sandwich, 4 cookies, 2 cups water

Snack Food Crackers (6) with Peanut Butter

Dinner

Snack Food

(c) McGraw Hill Ryerson 2007

Do your best to write down portions…