Lesson 1 How is it possible for you to perform motions such as stretching and rolling your shoulders? The interaction of bones and muscles allows you to perform these motions. The Skeletal System

Lesson 1 Describe the functions of the skeletal system Identify the main divisions and types of bones of the skeletal system In this lesson, you will learn to: Lesson Objectives

Lesson 1 Functions of the Skeletal System What Does Your Skeletal System Do? Your skeletal system protects your internal tissues and organs from trauma. The skull, vertebrae, and ribs create protective cavities for the brain, the spinal cord, and the heart and lungs, respectively. Bones store minerals such as calcium and phosphorus, which are important to the health and strength of the skeleton and to various essential processes in your body. Bone marrow, a connective tissue within bones, produces new red blood cells and white blood cells.

Lesson 1 The Axial and Appendicular Skeletons Your skeletal system consists of 206 bones that can be classified in two main groups: 1.Axial skeletonAxial skeleton 2.Appendicular skeletonAppendicular skeleton Structure of the Skeleton

Lesson 1 The Skeletal System Structure of the Skeleton

Lesson 1 Types of Bones All bones are covered with an outer layer of hard, densely packed, compact bone, beneath which is spongy bone filled with red bone marrow. Long bones Short bones Flat bones Irregular bones Almost every bone in the body can be categorized by shape: Structure of the Skeleton

Lesson 1 The humerus is the bone in your upper arm. The diaphysis, or main column of a long bone, is composed of compact bone. Within the diaphysis is a narrow cavity that contains yellow bone marrow. The end of a long bone is called the epiphysis. Long Bones Humerus Structure of the Skeleton

Lesson 1 Short Bones Short bones are almost equal in length and width. Wrist Structure of the Skeleton

Lesson 1 Flat Bones Flat bones are somewhat thinner and much flatter than other bones. Flat bones, such as those in the skull, protect organs. Irregular Bones Irregularly shaped bones have unusual shapes and do not fit into the other categories. Rib Structure of the Skeleton

Lesson 1 Cartilage In some joints, such as the knee, cartilage acts as a cushion, reducing friction and allowing smooth motion.cartilage An embryo’s skeleton consists mostly of cartilage that serves as a template from which bones will form. Early in embryonic development, the cartilage hardens, which is called ossification.ossification Structure of the Skeleton

Lesson 1 Joints Some joints, such as those between the bones of the skull, do not move. Others, including the joints between vertebrae, have limited movement. Ligaments help stabilize the movements of bones at a joint.Ligaments Movement is produced because muscles are attached to bones by tendons and ligaments.tendons Structure of the Skeleton

Lesson 1 Classification of Flexible Joints Ball-and-socket joints a llow the widest range of movement in all directions. Hinge joints allow a joint to bend and straighten, promoting rotation. Pivot joints allow limited rotation or turning of the head. Ellipsoidal joints allow bones to slide over one another. Hip (ball-and-socket joint) Knee (hinge joint) Structure of the Skeleton

Lesson 1 Choose the appropriate option. Q. _______ is a strong, flexible connective tissue. 1.Cartilage 2.A ligament 3.An axial skeleton 4. A tendon Quick Review

Lesson 1 Click Next to attempt another question. A. 1. cartilage Cartilage is a strong, flexible connective tissue. Quick Review - Answer

Lesson 1 Q. Which of the following is NOT a function of the skeletal system? 1.To support the upper body and head 2.To provide a strong, stable, and mobile framework on which muscles can act 3.To connect the eyes and the brain with the heart and the lungs 4.To protect the internal tissues and organs from trauma Quick Review

Lesson 1 Click Next to attempt another question. A. 3. To connect the eyes and the brain with the heart and the lungs The skeletal system does not connect the eyes and the brain with the heart and the lungs. Quick Review - Answer

Lesson 1 Q. Which of the following is NOT a type of joint? 1.Ball-and-socket joints: e.g., hip or shoulder joints 2.Roller joints: e.g., inner shoulder joints that connect the joint to a muscle 3.Hinge joint: e.g., elbow, knee, ankle, and finger joints 4.Pivot joints: e.g., top two vertebrae Quick Review

Lesson 1 Click Next to attempt another question. A. 2. roller joints The following is NOT a type of joint: roller joints, e.g., inner shoulder joints that connect the joint to a muscle. Quick Review - Answer

Lesson 1 Q. The ligament that holds the bones in your forearm together and helps form the pivot joint affects your ability to move your hand and arm. True False Choose the appropriate option. Quick Review

Lesson 1 Click Next to attempt another question. A. True. The ligament that holds the bones in your forearm together and helps form the pivot joint affects your ability to move your hand and arm. Quick Review - Answer

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Lesson 1 The Axial and Appendicular Skeletons Your skeletal system consists of 206 bones that can be classified in two main groups: 1.Axial skeletonAxial skeleton 2.Appendicular skeletonAppendicular skeleton The axial skeleton consists of the 80 bones of the skull, spine, ribs, vertebrae, and sternum, or breastbone. Structure of the Skeleton

Lesson 1 Your skeletal system consists of 206 bones that can be classified in two main groups: 1.Axial skeletonAxial skeleton 2.Appendicular skeletonAppendicular skeleton The appendicular skeleton is composed of 126 bones of the upper and lower limbs, shoulders, and hips. The Axial and Appendicular Skeletons Structure of the Skeleton

Lesson 1 Cartilage In some joints, such as the knee, cartilage acts as a cushion, reducing friction and allowing smooth motion. An embryo’s skeleton consists mostly of cartilage that serves as a template from which bones will form. Early in embryonic development, the cartilage hardens, which is called ossification. Cartilage is a strong, flexible connective tissue. Structure of the Skeleton

Lesson 1 Cartilage In some joints, such as the knee, cartilage acts as a cushion, reducing friction and allowing smooth motion. An embryo’s skeleton consists mostly of cartilage that serves as a template from which bones will form. Early in embryonic development, the cartilage hardens, which is called ossification. Ossification is the process by which bone is formed, renewed, and repaired. Structure of the Skeleton

Lesson 1 Joints Some joints, such as those between the bones of the skull, do not move. Others, including the joints between vertebrae, have limited movement. Ligaments help stabilize the movements of bones at a joint. Movement is produced because muscles are attached to bones by tendons and ligaments. A ligament is a band of fibrous, slightly elastic connective tissue that attaches bone to bone. Structure of the Skeleton

Lesson 1 Joints Some joints, such as those between the bones of the skull, do not move. Others, including the joints between vertebrae, have limited movement. Ligaments help stabilize the movements of bones at a joint. Movement is produced because muscles are attached to bones by tendons and ligaments. A tendon is a fibrous cord that attaches muscle to the bone. Structure of the Skeleton

Lesson 1 A. Correct! Cartilage is a strong, flexible connective tissue. Click Next to attempt another question. Quick Review - Answer

Lesson 1 You have answered the question incorrectly. Go back to try again, or click Next to view the correct answer. Quick Review - Answer

Lesson 1 A. Correct! The skeletal system does NOT function: to connect the eyes and the brain with the heart and the lungs. Click Next to attempt another question. Quick Review - Answer

Lesson 1 You have answered the question incorrectly. Go back to try again, or click Next to view the correct answer. Quick Review - Answer

Lesson 1 A. Correct! The following is NOT a type of joint: roller joints, e.g., inner shoulder joints that connect the joint to a muscle. Click Next to attempt another question. Quick Review - Answer

Lesson 1 You have answered the question incorrectly. Go back to try again, or click Next to view the correct answer. Quick Review - Answer

Lesson 1 A. Correct! The ligament that holds the bones in your forearm together and helps form the pivot joint affects your ability to move your hand and arm. Click Next to attempt another question. Quick Review - Answer

Lesson 1 You have answered the question incorrectly. Go back to try again, or click Next to view the correct answer. Quick Review - Answer