The Skeletal System Chapter 14 Section 2

Key Concepts no cares about 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?

Vocabulary Skeleton Vertebrae Joint Ligament Cartilage Compact bone Spongy bone Marrow Osteoporosis

What the Skeletal System Does Can a building stand without a frame?

Five major skeletal functions Just as a building cannot stand without frame you would collapse without your skeleton Functions Provides shape and support Enable you to move Protects your organs Produces blood cells Stores mineral and other materials until your body needs them

Shape and Support The skeleton provides a framework that supports and protects many other body parts The backbone or vertebral column is the center of the skeleton The bones in the skeleton are in some way connected to this column You can feel 26 small bones if your move your fingers down the center of your back Bend forward at the waist and feel the bones adjust as you move Think of each individual vertebra as a bead on a string it is flexible and able to bend

Production and Storage of Substances Some of your bones produce substances that your body needs The long bones of your arms and legs can be thought of as factories that make certain blood cells Bones also store minerals such as calcium and phosphorus When the body needs these minerals the bones release small amounts of them into the blood

Joints of the Skeleton Joints allow bones to move in different ways as they are the place in the body where two bones come together There are two kinds of joints Movable and immovable joints

Immovable Movable Joints Some joints in the body connect bones in a way that allows little or no movement Bones of the skull are held together by immovable joints Most joints in the body are movable they allow the body to make a wide range of movements Movable joints are held together by connective tissues called ligaments They also have a second type of connective tissue called cartilage which is more flexible than bone

Movable joints Hinge Joint-allows forward or backward motion Your knee is a hinge joint as well as your elbow

Ball and Socket Joint Allows the greatest range of motion The ball and socket joint in your shoulder allows you to swing your arm freely in a circle Hips also have ball and socket joints

Pivot Joint Allows one bone to rotate around another Pivot joint in your neck allows you to turn your head from side to side

Gliding Joint Allows one bone to slide over another Your wrist or ankle enables you to bend and flex as well as make limited side to side motions

Cartilage Covers the ends of the bones and keeps them from rubbing against each other

Bones-Strong and Living Bones are complex living structures that undergo growth and developments

Bone Structure (1) Femur is the body’s longest bone and connects the pelvic bones to the lower leg bones A thin tough membrane covers all of the bone except the ends Blood vessels and nerves enter and leave the bone through the membrane Beneath the bones outer membrane is a layer of compact bone which is hard and dense but not solid

Bone Structure (2) Small canals run through the compact bone These canals carry blood vessels and nerves from the bone’s surface to the living cells within the bone Just inside the compact bone is a layer of spongy bone

Spongy Bone Like a SPONGE, spongy bone has many small spaces within it This spongy structure makes spongy bone tissue lightweight but strong It is also found at the ends of the bone Spaces in the bones contain a soft connective tissue called marrow

Two types of Marrow Red and Yellow Red bone marrow produces some of the body’s blood cells As a child most of your bones contain red bone marrow As a teenager only the ends of your femurs, skull, hip and breastbone contain red marrow Other bones contain yellow marrow This marrow stores fat that can serve as an energy reserve

Bone Strength The structure of bone makes it both strong and lightweight They are so strong they absorb more force without breaking than can concrete or granite rock Bones are hard because they contain minerals-phosphorus and calcium You can jump up and down or turn cartwheels without breaking bones

Bone Development The tip of your nose contains cartilage As an infant much of your skeleton was cartilage Over time the cartilage is replaced with hard bone tissue This replacement of cartilage by bone tissue usually is complete by the time you stop growing

Bone Growth Bones are alive-they contain cells and tissues such as blood and nerves They also form new bone tissue as you grow as they are alive Even after you are grown however, bone tissue continues to form within your bones

Taking care of your bones A combination of a balanced diet and regular exercise are important for a lifetime of healthy bones Diet and exercise are some ways of taking care of your bones

Osteoporosis As people become older their bones begin to lose some of the minerals they contain Mineral loss can lead to osteoporosis a condition in which the body’s bones become weak and break easily It is more common in women than men

1. What are five functions of the skeleton? Provide shape and support Enable you to move Protect your organs Produce blood cells Store minerals and other materials

2. What are four types of movable joints? Hinge Ball and socket Pivot gliding

3. What are three types of tissue in bone? Compact bone Spongy bone Marrow

4. Which function of the skeletal system gives you a clue that bones are not dead or solid? Bones make certain blood cells and release small amounts of minerals into the blood when needed.

5. Where is marrow produced? In the spaces in bone

6. Does new bone tissue stop forming after you stop growing? No, bones make new tissue when they absorb the force of your weight and when a bone has broken

7. What do ligaments do? They hold together the bones in movable joints.

8. What substance keeps bones from rubbing against each other? cartilage

9. What other functions does the skeletal system perform besides providing support and protection? Produces certain blood cells Stores minerals

10. Why are vertebrae important? The are the bones that make up your backbone, and all other bones are connected to the backbone.