Chapter 12 Lesson 1 TRANSPORT AND DEFENSE Essential

Chapter 12 Lesson 1 TRANSPORT AND DEFENSE

Essential Questions • How do nutrients enter and leave the body? • How do nutrients travel through the body? • How does the body defend itself from harmful invaders?

New Vocabulary �Organ System �Homeostasis �Nutrient �Calorie �Lymphocyte �Immunity

The Body’s Organization �Your body is composed of different organ systems working together to perform specific tasks. These provide movement, transport substances, etc. Organ systems maintain homeostasis (steady internal conditions) when external conditions change.

Digestive System �Digestion – how the human body breaks down food Food enters the digestive system through the mouth The esophagus connects the mouth to the stomach (a flexible baglike organ that contains enzymes that break down food into smaller parts to be used by the body).

Digestive System �The small intestine has 2 functions Digestion Absorption of nutrients �The liver makes bile and the pancreas makes enzymes Both break down food in the small intestine

Digestive System �The large intestine receives solid waste from the small intestine. It absorbs excess water from the waste material �The rectum of the large intestine stores the solid waste until it is expelled from your body (When you go to the bathroom) Some foods like insoluble fiber, are not digested and leave the body through the rectum

Excretory System �Removes liquid and gas waste from the body �Organs included: Lungs, skin, liver, kidneys, ureter, bladder, urethra �Liver – breaks down proteins Forms urea , which is toxic to the body �Kidneys – remove urea from the body by making urine

Excretory System �Urine then leaves the kidneys through the ureter and stored in the bladder (flexible sac) Urine is removed from the body through the urethra