The Skeletal System

LEQ: How does the skeletal system provide support and protection to the human body?

Activity Page 14B

How can a bone act as a lever? What do you think?

At which position is it the easiest to move the bag?

At which position does the bag move the farthest?

How does the position of a load affect the action of a lever?

Bones are living tissue

The Skeletal system is made up of connective tissue called bone.

Serves as an anchor for all of the body’s movement, provides support, and protects soft organs inside the body.

Bones are classified as long, short, irregular, and flat.

Long bone

Long bones are found in arms and legs.

Short Bones

Short bones are found in the feet and hands.

Irregular Bones

Irregular bones are found in the spine.

Flat Bones

Flat bones are found in the ribs and skulls.

Types of bone tissue

Compact Bone Spongy Bone

The hard compact bone tissue surrounds the spongy tissue.

Strong but lightweight tissue inside the bone. The calcium network is less dense.

Bone parts

1- Compact Bone – dense, gives bone strength and support body.2- Spongy Bone – less dense and lightweight.3- Bone Marrow- produces blood cells.4- Blood Vessels- nourishes the bone and carries waste away.

Think-pair-share

How is the compact bone able to give the bone strength?

How does bone receive nourishment?

Where are red blood cells formed?

The Skeleton is the body’s framework

The provides the body’s shape. It also works with other systems to

allow movement. It has two main divisions:

The axial Skeleton The appendicular Skeleton

The Axial Skeleton

Is the central part (the axis) of the skeleton.

Sitting, standing, and twisting are some of the motions that turn around the axis.

It includes the skull or the cranium (do not move), spinal column (made of many bones called vertebrae), and the rib bones.

The Appendicular Skeleton

Allowing movement is the main function.

The shoulder belongs to the upper part of the appendicular skeleton.

The lower part of the appendicular skeleton includes the legs and hip bone (support the body’s weight)

How are the axial and appendicular skeleton alike and different?

Axial Skeleton Appendicular Skeleton

1- Central part of the skeleton2- Includes the skull, spinal cord, and ribs3- Main function is to provide support and protection

1- Attached to the axial skeleton2- Includes bones of the shoulders, hips, arms, and legs3- Main function is to allow movement

1- Made up of bones2- Provides body’s shape.

The skeleton changes as the body develops and ages

Infancy – skull made up of bones with spaces between them. As the brain grown the skull also grows until the spaces close.

Childhood- The growth occur in places called growth plates (made of firm but flexible connective tissue, cartilage) The length and shape of the bones is determined by them.

The skeleton changes as the body develops and ages

Adolescence – at the end of this stage bones stop growing. The growth plate hardens, and the skull plates fuse.

Adulthood – bones do not grow, some bone breaks and new bone grows. As people age the bone density decreases.

Joints connect parts of the skeletal system

A joint is a place where two parts of the skeletal system meet.

There are three types of joints: Immovable Slightly movable Freely movable

Immovable and slightly movable joints

An immovable joint locks bones together like puzzle pieces.

The bones of your skull are connected by immovable joints.

Slightly movable joints are able to flex slightly.

Your ribs are connected to your sternum by slightly movable joints.

Freely movable joints

Allow your body to move and bend. Tissues called ligaments hold the

bones together at these joints. Other structures inside the joint

cushions the bones and keep them from rubbing together.

The entire join is also surrounded by connective tissue.

Freely movable joints Movable joints can be classified by

the type of movement they produce.

Angular movement – arm moves up, down, changing angle between your upper and lower arm. (hinge joint)

Rotational movement – arm rotates from side to side, like a doorknob. (pivot joint)

Freely movable joints

Ball and socket joint – rotational movement of the arm around in a circle.

Gliding movement – one bone slides back and forth across another, like in your backbone (the only movement this joint produces)

Activity page 19B

How was the motion you felt similar for each activity?

Based on your observations, identify two more ways that joints move.

Finish the challenge on a separate sheet and turn in for extra credit!!!!

Challenge

The joints in your hand and wrist produce three different types of movement. Using your own wrist, classify the joint movement of the finger, palm, and wrist. Support your answer.

Important review questions

What are the functions of the two types of bones?

What are the main divisions of the human skeleton?

Name three types of movement produced by movable joints and give an example of each.

Important review questions

What function do immovable joints in the skull perform? Think about the different stages of development in the human body.

Which type of movable joint allows the most movement? How does the joint’s shape and structure contribute to this?