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1. Body Organization and Structure Chapter 15 Preview Section 1 Body Organization Section 2 The Skeletal System Section 3 The Muscular System Concept Map

2. Section 1 Body Organization Chapter 15 Bellringer In your Science Journal, match each organ system with its correct function. Organ systems: respiratory system, muscular system, digestive system, cardiovascular system Functions: to pump blood, to enable movement, to send out chemical messages, to absorb oxygen, to break down food.

3. Section 1 Body Organization Chapter 15 What You Will Learn • The levels of organization in the human body include cells, tissues, organs, organ systems, and the organism. • Human cells are differentiated to perform specific jobs in the body. • There are 11 human organ systems. • Organ systems work together to maintain homeostasis. The failure of one organ system affects the entire body.

4. Section 1 Body Organization Chapter 15 A Stable Environment • Cells, tissues, and organs work together to maintain a stable environment inside the body. • The maintenance of a stable environment inside the body is called homeostasis. • When homeostasis is not maintained, cells may not function properly or die.

5. Section 1 Body Organization Chapter 15 Cells, Tissues, and Organs • Most cells in your body are differentiated. Differentiated cells are specialized to perform specific functions for the body. • The structure of each cell is related to its function. • Similar cells are organized into groups. A group of similar cells working together to perform a common function forms a tissue.

6. Section 1 Body Organization Chapter 15 Cells, Tissues, and Organs, continued • Your body has four main kinds of tissue: epithelial tissue, nervous tissue, muscle tissue, and connective tissue. • Epithelial tissue covers and protects underlying tissue. Your skin is primarily epithelial tissue. • Nervous tissue sends electrical signals through the body. It is found in the brain, nerves, and sense organs.

7. Section 1 Body Organization Chapter 15 Cells, Tissues, and Organs, continued • Muscle tissue is made of cells that contract and relax to produce movement. • Connective tissue supports and protects the organs of the body. Connective tissue holds everything in its proper place.

8. Body Organization and Structure Chapter 15 Body Tissues Click below to watch the Visual Concept. Visual Concept

9. Section 1 Body Organization Chapter 15 Cells, Tissues, and Organs, continued • Two or more types of tissues working together to carry out a function form an organ. • The heart is an organ made of muscle, connective, and epithelial tissues. None of these tissues alone could carry out the function of the heart. • The stomach is another organ made up of four different tissues.

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11. Section 1 Body Organization Chapter 15 Cells, Tissues, and Organs, continued • Two or more organs working together to carry out a function form an organ system. • Organ systems perform jobs that organs cannot perform by themselves.

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15. Section 1 Body Organization Chapter 15 Organ Systems Working Together • Your body’s organ systems work together to maintain homeostasis. • For example, the cardiovascular system and respiratory system work together to provide oxygen to all cells of the body. • Some organs are part of more than one organ system.

16. Section 2 The Skeletal System Chapter 15 Bellringer In your Science Journal, brainstorm problems you would have if you did not have bones.

17. Section 2 The Skeletal System Chapter 15 What You Will Learn • The skeletal system includes bones, cartilage, and connective tissue. • Bones have four important functions in the body. Bones are structured to perform these functions. • Three human body joints are gliding, ball-and- socket, and hinge.

18. Section 2 The Skeletal System Chapter 15 Bones, continued • The skeletal system is made up of your bones, cartilage, and the connective tissue holding your bones together. • The functions of the skeletal system include support, protection, movement, and the production of blood cells. • Bones help maintain homeostasis by storing minerals and fat that can be used in the body.

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20. Section 2 The Skeletal System Chapter 15 Bones, continued • Bones are made of two types of bone tissue. Compact bone is dense and rigid. Spongy bone contains open spaces, but is actually responsible for most of the bone’s strength. • Blood cells are produced in larger bones that contain marrow. Red marrow makes red and white blood cells. Yellow marrow stores fat.

21. Section 2 The Skeletal System Chapter 15 Bones, continued • Bone Growth Most bones start as a flexible tissue called cartilage. As you age, most of the cartilage is replaced by bone. • Bones grow at sites called growth plates, which consist of cartilage. Children loose their growth plates as they reach adult size. • Your ears and the tip of your nose are sites that never lose their cartilage.

22. Body Organization and Structure Chapter 15 Human Bone Growth Click below to watch the Visual Concept. Visual Concept

23. Section 2 The Skeletal System Chapter 15 Joints • A place where two or more bones meet is called a joint. • Fixed joints allow little or no movement. The bones in your skull are fixed joints. • Ball-and-socket joints allow the widest range of movement. Hinge joints allow one-way movement, and gliding joints allow bones to slide over one another.

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25. Section 2 The Skeletal System Chapter 15 Joints, continued • Joints are able to withstand the stresses of movement because of their structure. • Joints are held together by ligaments. Ligaments are strong, elastic bands of connective tissue. • Cartilage also helps reduce wear and tear on joints by cushioning the areas where bones meet.

26. Section 2 The Skeletal System Chapter 15 Skeletal System Injuries and Diseases • Despite their strength and flexibility, bones can break, or fracture. • Joints can become dislocated when bones move out of their proper positions. • A sprain occurs when the ligaments of a joint have been stretched too far or have torn.

27. Section 2 The Skeletal System Chapter 15 Skeletal System Injuries and Diseases, continued • Osteoporosis is a disease of the skeletal system. In osteoporosis, bones become less dense, which makes them break more easily. • Arthritis is a painful disease that affects joints. In arthritis, joints become swollen and stiff. • As people age, they are more likely to have osteoporosis or arthritis.

28. Section 3 The Muscular System Chapter 15 Bellringer List at least five parts of your body that you use to drink water. Record your answers in your Science Journal.

29. Section 3 The Muscular System Chapter 15 What You Will Learn • There are three kinds of muscle tissue: cardiac, smooth, and skeletal. • Bones and muscles work together to form levers, which increase the mechanical advantage of most movements. • The two kinds of exercise include resistance exercise and aerobic exercise.

30. Section 3 The Muscular System Chapter 15 Kinds of Muscle • The muscular system is made up of the muscles that let you move. Muscles also let you breathe and hold you upright. • The muscular and skeletal systems work together to provide a structural framework for movement. • The combined organ systems are sometimes called the musculoskeletal system.

31. Section 3 The Muscular System Chapter 15 Kinds of Muscle, continued • Muscle actions can be voluntary or involuntary. Voluntary actions are under your control. Involuntary actions happen without your control. • Smooth muscle is found in the digestive tract and blood vessel walls. Their actions are involuntary. • Cardiac muscle is found only in the heart. Its action is involuntary.

32. Section 3 The Muscular System Chapter 15 Kinds of Muscle, continued • Skeletal muscle is attached to bones and allows you to move. Their actions can be voluntary or involuntary. • An example of an involuntary skeletal muscle action is an eye blink that happens without your awareness. • You can also blink your eyes voluntarily.

33. Section 3 The Muscular System Chapter 15 Movement • When you want to move, signals travel from your brain to your skeletal muscle cells. • The muscle cells then contract, or get shorter. • Tendons connect the muscles to the bones. As muscles contract, they pull on the tendons which move the bones.

34. Section 3 The Muscular System Chapter 15 Movement, continued • Skeletal muscles often work in pairs, as the biceps and triceps of the arm. • Usually, one muscle in the pair bends a part of the body. The other muscle in the pair straightens the part of the body. • Bending muscles are called flexors. Extending muscles are called extensors.

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36. Body Organization and Structure Chapter 15 Muscular Movement and Bones Click below to watch the Visual Concept. Visual Concept

37. Section 3 The Muscular System Chapter 15 Levers in the Human Body • The action of a muscle pulling on a bone can work like a lever. • A lever is a rigid bar that pivots at a fixed point known as a fulcrum. A lever is a type of simple machine. • Levers increase the amount of work that can be done. This increase in work is called mechanical advantage.

38. Section 3 The Muscular System Chapter 15 Levers in the Human Body, continued • In your body, the rigid bar, or lever, is the bone. The fulcrum, or pivot point, is the joint. • Any force applied to a lever is called the effort force. Any force that resists the motion of the lever is called the load. • In your body, the effort force is supplied by muscles.

39. Section 3 The Muscular System Chapter 15 Levers in the Human Body, continued • There are three classes of levers. First and second class levers increase the amount of force applied to the load. • Third class levers increase the speed of the motion. Most of the moving joints in the body are third class levers. • The class of a lever is determined by the location of the fulcrum, load, and effort force.

40. Section 3 The Muscular System Chapter 15 Levers in the Human Body, continued • The joint at your neck acts as the fulcrum in a first class lever. • The action of raising up onto your toes is due to a second class lever. • Lifting a textbook uses a third class lever. Your elbow is the fulcrum, the book is the load, and the biceps muscle provides the effort force.

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42. Section 3 The Muscular System Chapter 15 Use It or Lose It • When skeletal muscles are not used, they become smaller and weaker. Exercised muscles are larger and stronger. • Resistance exercise uses resistance, or weight, to strengthen muscles. • Aerobic exercise strengthens the heart and increases endurance. Endurance allows muscles to work longer without getting tired.

43. Section 3 The Muscular System Chapter 15 Muscle Injury • A strain occurs when a muscle or tendon is overstretched or torn. Stretching and warming-up can help prevent strains. • Tendonitis occurs when a damaged tendon becomes swollen and painful. • Use of anabolic steroids to strengthen muscles can cause long-term damage to the heart, liver, kidneys, and bones.

44. Body Organization and Structure Chapter 15 Concept Map Use the terms below to complete the concept map on the next slide.

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46. Body Organization and Structure Chapter 15 Concept Map