Chapter One. Table of Contents Section 1 Body Organization Section 2 The Skeletal System Section 3 The Muscular System Section 4 The Integumentary System.

Chapter One

Table of Contents

Section 1 Body Organization

Section 2 The Skeletal System

Section 3 The Muscular System

Section 4 The Integumentary System

Objectives

• Describe how tissues, organs, and organ systems are related.

• List 11 major organ systems.

• Identify how organ systems work together to maintain homeostasis.

Cells, Tissues, and Organs

• The many kinds of cells in your body help your internal environment stay stable.

• The maintenance of a constant internal state in a changing environment is called homeostasis.

Cells, Tissues, and Organs, continued

• Cells Form Tissues A group of similar cells working together forms a tissue. Your body has four main kinds of tissue.

Cells, Tissues, and Organs, continued

• Tissues Form Organs Two or more tissues working together to carry out a specialized function form an organ.

Working Together

• Organs Form Systems Organs that work together make up an organ system.

• Organ systems work together to maintain homeostasis.

• Your body has 11 major organ systems.

Objectives

• Identify the major organs of the skeletal system.

• Describe four functions of bones.

• Describe three types of joints.

• List three injuries and two diseases that affect bones and joints.

Bones

• Bones, cartilage, and the connective tissue that holds bonds together make up your skeletal system.

• Bone Structure Bone tissue without any visible open spaces is called compact bone. Bone tissue that has many open spaces is called spongy bone. Bones contain a soft tissue called marrow.

• Bone Growth Most bones start out as a flexible tissue called cartilage. Eventually, most cartilage is replaced by bone.

Joints

• A place where two or more bones meet is called a joint.

• Joints are held together by ligaments.

Skeletal System Injuries and Diseases

• Bones may be fractured or broken.

• Ligaments can be stretched or torn.

• Arthritis is a disease that causes the joints to swell or stiffen.

• Osteoporosis is a disease that causes bones to become less dense.

Objectives

• List three kinds of muscle tissue.

• Describe how skeletal muscles move bones.

• Compare aerobic exercise with resistance exercise.

• Describe two muscular system injuries.

Kinds of Muscle• The muscular system is made up of the muscles that let you move.

• Involuntary muscle found in the digestive tract and the walls of the blood vessels is called smooth muscle. Involuntary muscle found in your heart is called cardiac muscle.

• Muscle attached to your skeleton for movement is called skeletal muscle. Skeletal muscle can be voluntary or involuntary.

Movement

• Muscles Attach to Bones Tendons are strands of tough connective tissue that connect your skeletal muscles to your bones.

• Muscles Work in Pairs Skeletal muscles often work in pairs. A muscles that bends part of your body is called a flexor. A muscle that straightens part of your body is an extensor.

Use It or Lose It

• Resistance Exercise During resistance exercise, people work against the resistance, or weight, of an object to strengthen their skeletal muscles.

• Aerobic Exercise Steady, moderately intense activity is called aerobic exercise, and strengthens the heart and increases endurance.

Muscle Injury

• A strain is an injury in which a muscle or tendon is overstretched or torn.

• People who exercise too much can hurt their tendons. Inflamed tendons is called tendonitis.

• Some people try to make their muscles stronger by taking drugs. These drugs are called anabolic steroids and can cause long-term health problems.

Objectives

• List four functions of skin.

• Describe the two layers of skin.

• Describe the structure and function of hair and nails.

• Describe two kinds of damage that can affect skin.

Functions of Skin• Your skin, hair, and nails make up your integumentary system.

• Skin protects you by keeping water in your body and foreign particles out of your body.

• Nerve endings in your skin let you feel things around you.

• Skin helps regulate your body temperature. Skin also helps get rid of waste chemicals.

Layers of Skin

• Epidermis The epidermis is the outermost layer of skin. Most cells in the epidermis are dead.

• Dermis The thicker layer of skin that lies beneath the epidermis is the dermis.

Hair and Nails

• A hair forms at the bottom of a tiny sac called a hair follicle. Hair helps protect skin from ultraviolet light and helps regulate body temperature in most mammals.

• A nail grows from living cells in the nail root at the base of the nail. Nails protect the tips of your fingers and toes.

Skin Injuries

• Skin is often damaged, but fortunately can repair itself. However, damage to the genetic material in skin cells can cause skin cancer.