Movement in the Human Body

Your muscular system, skeletal system and nervous system work together to move your body. http://www.innerbody.com/anim/arm.html

Skeletal System & Joints Joint: A place where two or more bones meet.

Skeletal System & Joints Immovable (fixed) joints: allow little or no movement, example: joints in the skull and pelvis

Skeletal System & Joints Movable joints: allow the body to make a wide range of movements. Ligaments connect bone to bone at joints.

TYPES OF MOVABLE JOINTS Ball-and-socket joint. Examples: hip and shoulder; allows greatest range of movement

TYPES OF MOVABLE JOINTS Pivot joint. Examples: turning of the head or turning of the lower arm

TYPES OF MOVABLE JOINTS Hinge joint. Examples: knees & elbows; in fingers & toes

TYPES OF MOVABLE JOINTS Sliding joint. Examples: wrists, ankles and vertebrae

Muscular System Muscles work in pairs to move the body. http://www.sambal.co.uk/elbow.html

Muscular System Ex: To bend the arm at the elbow, the biceps muscle contracts and the triceps muscle relaxes.

Muscular System To straighten the arm, the triceps muscle now contracts and the biceps muscle relaxes.

Muscular System Muscles are attached to bones by thick bands of tissue called tendons. tendon If you tear a tendon, your muscle will not be attached to the bone correctly and you will have trouble moving the bone/body part.

A machine with only one movement Provide mechanical advantage

What is mechanical advantage? Mechanical advantage is a measure of how much help a machine is going to be when you do work. Mechanical advantage compares the force you exert (effort or input force) to the force you must overcome (resistance or output force).

Types of Simple Machines

click here for levers video clip.mov A lever is a rigid object that pivots about a point (the fulcrum) With a lever you can gain mechanical advantage and lift heavy weights easily. click here for levers video clip.mov

There are three classes of levers. Draw & label each class of levers

Examples of First Class Levers

Second Class Lever

Examples of Second Class Levers

Third Class Lever

Examples of Third Class Levers

Levers in Your Body Your skeletal system and muscular system work together to move your body like machine parts work together to move things. Bones function as levers and muscles supply the force to move your bones.

HOW IT WORKS connect muscles to bones Bones, joints, muscles, and tendons form lever systems. Bone: Joint: Muscle: Tendons: Rod/plank of lever Fulcrum Supplies input force connect muscles to bones

Simple Machines in Your Body First Class Lever- Head moving up and down: The joint at the top of the neck is the fulcrum. Neck muscles provide the effort force to move your head up and down.

Simple Machines in Your Body Second Class Lever- Raising the body up on your toes: Ball of your foot is the fulcrum. Calf muscles provide the effort force to raise the body.

Simple Machines in Your Body Third Class Lever- Bending arm: The biceps muscle contracts to provide the effort force to lift your lower arm at the elbow or fulcrum.