Chapter 8 Lesson 2 The Skeletal System Bellringer

Chapter 8 Lesson 2 The Skeletal System Bellringer Identify areas of your body where joints allow movement of your skeleton. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 8 Lesson 2 The Skeletal System Objectives • Describe the functions of the skeletal system. • Explain how the skeletal system changes with age. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 8 Lesson 2 The Skeletal System Start Off Write How do bones help your body? Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 8 Lesson 2 The Skeletal System Bones and Joints • Bones A bone is an organ of the skeletal system. Bones are hard because they store minerals. • Bone Marrow Inside a bone is soft tissue called bone marrow. Bone marrow makes blood cells for the body. • Joints A joint is a place where two or more bones meet. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 8 Lesson 2 The Skeletal System Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 8 Lesson 2 The Skeletal System Bone and Joint Development • Cartilage Before birth, most of the bones in a baby’s body are made of cartilage. Cartilage is a soft, flexible tissue. • Bone Formation Cartilage starts changing to bone before a baby is born. The soft tissue hardens and becomes bone tissue as minerals, such as calcium, build up in the bone. This change is not finished until a person is around 18 years old. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 8 Lesson 3 The Muscular System Bellringer Make a list of places in your body where muscles are constantly at work. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 8 Lesson 3 The Muscular System Objectives • Describe three different types of muscle. • Explain the three different types of muscle. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 8 Lesson 3 The Muscular System Start Off Write Why do muscles work in pairs? Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 8 Lesson 3 The Muscular System Many Kinds of Muscles • Skeletal Muscle Skeletal muscle is muscle that is attached to bones. • Smooth Muscle Smooth muscle is muscle that forms some internal organs. • Cardiac Muscle Cardiac muscle is muscle that forms the heart. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 8 Lesson 3 The Muscular System Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 8 Lesson 3 The Muscular System Muscles and Movement • How Muscles Move Bones When skeletal muscles contract, they pull on bones. When a muscle contracts, its two ends are pulled towards its center. If the two ends are attached to different bones, the bones are pulled towards each other. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 8 Lesson 3 The Muscular System Muscles work in pairs. Here, the biceps and triceps move the bones of the arm by pulling them in opposite directions. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 8 Lesson 4 The Digestive System Bellringer List the organs that make up your digestive system. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 8 Lesson 4 The Digestive System Objectives • Explain how the body uses food. • Explain four ways that the body releases waste products. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 8 Lesson 4 The Digestive System Start Off Write Why do people need food? Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 8 Lesson 4 The Digestive System Food and Nutrients • What Is Digestion? Digestion is the process of breaking down food into a form your body can use. • What Are Nutrients? Nutrients are substances in food that the body needs to work properly. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 8 Lesson 4 The Digestive System Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 8 Lesson 4 The Digestive System Solid Waste • The Large Intestine and Food Material The large intestine absorbs water and salts from the remaining food material. The parts of food that the body cannot use become solid waste. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 8 Lesson 4 The Digestive System Nondigestive Waste Removal • The Kidneys The kidneys mix wastes with water to form urine. Urine is released from the body by the urinary system. • The Lungs Carbon dioxide is released from the body when you breathe. • The Skin Sweat glands in the skin remove salt and water by sweating. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

Quote of the Day “The human body is a machine which winds its own springs. ” —Julien Offroy de la Mettrie, L’Homme Machine Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.