Chapter 13 Preview Questions • 3. The bigger the change in an object’s motion, the • a. smaller the push or pull required. • b. bigger the push or pull required. • c. more likely the object will move in • more than • one direction. • d. more likely the object will stop • moving.

Chapter 13 Preview Questions • 3. The bigger the change in an object’s motion, the • a. smaller the push or pull required. • b. bigger the push or pull required. • c. more likely the object will move in more than • one direction. • d. more likely the object will stop moving.

Chapter 13 Preview Questions • 4. When you use your foot to stop a rolling ball, you are • a. pulling on the ball. • b. pushing on the ball. • c. changing the direction in which the • ball rolls. • d. changing the force that started the • ball rolling.

Chapter 13 Preview Questions • 4. When you use your foot to stop a rolling ball, you are • a. pulling on the ball. • b. pushing on the ball. • c. changing the direction in which the ball rolls. • d. changing the force that started the ball rolling.

A cat sleeps on one end of a seesaw, while a mouse crouches on the other end. The cat wakes up and walks away. How will the forces acting on the ends • change? How will the forces change if the cat runs across the board toward the mouse? How do the physical principles of forces and machines relate to the functions of your muscles and skeleton?

Latin Word Origins involuntary muscle Type of muscle that is not under a person’s conscious control in- not

Latin Word Origins ligament Connective tissue that holds bones together ligare to tie

Latin Word Origins osteoporosis A condition in which bones lose minerals, develop larger openings than normal bones, and become weak porus a tiny opening or hole

Latin Word Origins resistance force The force that a lever exerts against an object resistere to place against

Latin Word Origins voluntary muscle Type of muscle that is under a person’s conscious control voluntas free will

Apply It! 1. How does the meaning of the Latin word ligere help you to understand what a ligament is? Ligare means to tie and a ligament holds bones together. 2. What two key terms in the table come from the Latin word voluntas? What does this Latin word mean? Voluntary muscle and involuntary muscle. It means free will.

End of Chapter 13 Preview

Section 13.1 Organ Systems and Homeostasis • What are the levels of organization in the body? • What systems are in the human body, and what are their functions? • What is homeostasis?

The 5 Levels of Organization. • The Cell= The Smallest unit • Different cells do different tasks • All cells depend on each other • Cells form tissue

TISSUES • Tissues= cells that work together • Blood tissue • Skin tissue • Bone tissue

The 4 Types of Body Tissues. • Muscle • Makes your body move • Ability to contract • Peristalsis • Your heart • Connective • Supports & unites the body from the head to toe • bone • blood • fat • Nerve • Caries messages from the brain to the body. • Epithelial • Protects your outside surfaces • Lines the mouth, nose, eyes, ears • It is your skin.

ORGANS • Organs = tissues that work together • Skin • Heart • Brain • eyes

The Epidermis • In some ways, the skin is the body’s largest organ.

Organ Systems • Organ Systems= organs that work together • Skeletal system • Nervous system • Reproductive system

Organs and Organ Systems • Each organ in your body is part of an organ system, which is a group of organs that work together to perform a major function.

Section 13.2: The Skeletal System • What are the functions of the skeleton? • What role do joints play in the body? • What are the characteristics of bone, and how can you keep your bones strong and healthy?

The Skeletal System • The Skeletal System= The bones and the ligaments that hold bones together • There are 206 bones in the body • Your backbone has 26 vertebrae • Bones are light. 20% of your weight comes from your bones • Bones come together at joints

What the Skeletal System Does • Your skeleton has 5 major functions. • It provides shape and support • enables you to move • protects your organs • produces blood cells • stores minerals until your body needs them.

The Skeletal System • Joints of the skeleton: • Immovable joints don’t move. They are the bones in the skull and sternum • Movable joints= various range of motion • Ball and socket (shoulder and hips) • Pivot joints (neck and head) • Gliding joints (wrist and ankles) • Hinge joint (knee and elbow)

Joints of the Skeleton • A joint is a place in the body where two bones come together. Joints allow bones to move in different ways.

Bones—Strong and Living • Bones are complex living structures that undergo growth and development.

Section 13.3: The Muscular System • What types of muscles are found in the body? • Why do skeletal muscles work in groups?

The Muscular System • Muscles = Long fibers that run parallel to each other • Always work in pairs (biceps and triceps) • There are 600 in the body • Elephant trunk = 40,000 muscles • Muscle = 40% of our body weight • Skeletal: • attach to bone • Connected by tendons • Voluntary muscle • Smooth: • Involuntary muscle • Control breathing, heartbeat, digestion • Cardiac: • Found only in the heart

Types of Muscles • Your body has three types of muscle tissue: • skeletal muscle • smooth muscle, and • cardiac muscle.

Muscles at Work • Because muscle cells can only contract, not extend, skeletal muscles must work in pairs. While one muscle contracts, the other muscle in the pair relaxes to its original length.

Section 13.4: Machines and the Body • How are force and work related? • How does a lever make work easier? • How do bones and muscles function as levers in the body?

Force and Work • A lever is a simple machine that makes lifting heavy objects easier.

Levers • A lever is a ridged bar that is free to pivot, or rotate, on a fixed point.

Levers • Levers are classified according to the location of the fulcrum relative to the input and output forces.

Simple Machines in the Body • Most of the machines in your body are levers that consist of bones and muscles.

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