Support System: Bones, Joints and Muscles

SEPUP Unit B: Activity 16

FunctionsSkeletal System

(aka Bones)

Support

Movement

Protect internal organs

Make blood cells

Maintain body’s calcium

balance

What are

bones

made of?

Structure of Bones

Living bone cells

surrounded by minerals,

Hard and extremely

strong

Contain channels for blood vessels and nerves

Spongy bone is in the center of

bones.

Spongy bone contains bone

marrow.

Function of bone marro

w?

Bone marrow in long bones makes blood cells

Red Blood cells

White blood cells

Platelets

What are the

different types of bones?

Bone growth?300 bones at birth

Cartilage at birth forms into bone.

Some bones fuse together.

Adults have 206 bones.

Most bones grow until age 20.

Importance of Calcium

Calcium is a

mineral.

• Makes bone hard.• Needed through out

the body.• Bones provide

calcium to the body if there is not enough in your diet.

• Eating dairy and calcium-rich foods is important in youth and adults to prevent osteoporosis.

Muscles Made of muscle cells. Contract and relax. Contraction causes muscles to shorten. Work in pairs.

Do this…. Hold your arm out straight. Feel what the muscles are doing when you bend it

toward your face. Feel the biceps and the triceps muscles.

Tendons Silvery, shiny tissue. Attach muscle to the bone. Tendons attach muscles to bones so that bones

can move.

Types of muscles? Skeletal muscles. Cardiac muscles. Smooth muscles.

Characteristics of Skeletal Muscle?

Attach to bones for movement and to protect inner organs.

Bundles of muscle fibers are surrounded by a connective sheath.

Muscle cells are striated (striped) depending on how much actin and myosin they contain.

Movement of skeletal muscles is voluntary.

Characteristics of Cardiac Muscle?

Found only in the heart. Can beat or pulse on their

own. When cardiac muscle cells

touch each other they beat together.

Has characteristics of Smooth and Skeletal muscle.o Are involuntary (like smooth

muscle).o Striated like skeletal muscle.

Characteristics of Smooth Muscle?

Found in the walls of hollow organs like the digestive tract and walls of blood vessels.

Cells are thin and long. They form sheets rather than

bundles. Control slow, involuntary movement.

Examples of Smooth Muscle Movements?

Contraction of the walls of the stomach and intestines.

Contraction of arteries to regulate the blood pressure and the flow of blood.

Smooth Muscle

Cardiac Muscle

Skeletal Muscle

Voluntary and Involuntary Movements?

Voluntary – Actions that are under your control. Involuntary – Actions that are not under your

control.

Voluntary: Actions that are under your control.

Skeletal muscles – walking, talking, bending.

Involuntary: Actions that are not under your control.

Smooth and Cardiac muscles – breathing, digesting, heart beating.

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Joints and Ligaments Joint - Place where two bones meet. Ligaments connect one bone to another bone. Ligaments stabilize the joint and allow it to move.

Types of Joint

s

How do muscles, joints and bones work?

The skeletal/muscle system works like a lever.