1. Lesson 1 Transport and Defense
Chapter 7
Lesson 1
Transport and Defense

2. Body’s Organization Groups of organs work together in an Organ system
The organs systems work together to maintain homeostasis
Homeostasis- maintaining constant internal conditions when external conditions change

3. Digestion The body needs nutrients and substances from food
Digestion is the process that breaks down food into small molecules so they can be absorbed and moved into the blood.
Two types of Digestion
Mechanical
Chemical

4. Mechanical Digestion Food is chewed, churned, mixed, grinded etc.
Major organs that use mechanical digestion are the teeth, mouth, and stomach

5. Chemical digestion
Chemical reactions occur that break down large molecules of food into smaller molecules
There are several enzymes that help digestion
An enzyme is a special protein that speeds up a chemical reaction but does not get used up or changed in the reaction
Ex- amylase in saliva

6. Organs of Digestion Digestive Tract Mouth Esophagus Stomach
Small intestine
Large intestine
Rectum
Anus
Accessory organs
Tongue
Teeth
Salivary glands
Liver
Gall bladder
Pancreas

7. Mouth Both mechanical and chemical digestion
Food is chewed, grinded, and made into smaller pieces with the help of the tongue (mechanical)
Saliva mixes with the food to moisten it and to start the breakdown of carbohydrates (amylase and chemical)
Saliva is produced by three sets of
glands

8. Esophagus The tongue has pushed the food into the back of the mouth
The epiglottis covers the trachea or windpipe so food does not pass into the lungs.
The esophagus is a muscular tube that pushes the food into the stomach by wave like contractions called peristalsis
Mucus lines the esophagus to keep the food moist
No Digestion

9. Stomach Both Mechanical and chemical digestion
Muscular bag that churns and mixes the food (mechanical)
Mixed with enzymes and hydrochloric acid
Hydrochloric acid works with an enzyme, pepsin, to break down proteins
The acid also kills bacteria
Stomach also produces mucus which protects the stomach from the acid and makes the food slippery

10. Chyme
Thin, watery liquid mixture of food, acid, and enzymes

11. Small intestine Only chemical digestion About 30 feet in length
Small diameter compared to the large intestine
Most digestion occurs in the upper portion called the duodenum.
Greenish chemical, bile from the liver, is mixed here
Bile emulsifies fat
Sodium bicarbonate ( baking soda) is added to neutralize the stomach acid

12. Small intestine
The pancreas makes the sodium bicarbonate and also produces insulin important in the regulation of the amount of glucose in your body
Absorption of nutrients occurs here
Villi- small finger- like projections increase the surface area for absorption of nutrients

13. Large intestine It is important for the absorption of water
Peristalsis slows down so water can be absorbed
The material becomes more solid and remains here until it is released from rectum and anus

14. Accessory organs Teeth- chewing
Tongue- moving food to the back of the throat
Salivary glands- produce saliva
Liver- produces bile
Gall bladder- storage for bile until needed
Pancreas- makes enzymes, sodium bicarbonate, and insulin for glucose regulation