Chapter 8 Unit Chapter 8 Unit 22

The Skeletal SystemThe Skeletal System

Structure of the BoneStructure of the Bone• Skeletal system is made up of bone

tissue

• Bones have their own system of blood vessels and nerves which allow circulation to occur within the bone.

Components of bone change Components of bone change from conception to old age.from conception to old age.

– An embryo’s skeleton is made up of cartilage– In the 2nd/3rd month after conception, calcium

deposits in the bone.– Calcium continues to deposit throughout life

• This is why a small child’s bones are more flexible than the bones of a 30 year old.

– The added calcium makes bones harder less flexible and more brittle.

• A 60 year old may lose calcium in the bone and this makes the bones porous so that is beaks more easily

Functions of the BoneFunctions of the Bone

• Serve as a framework– Gives structure and support

• Protects internal structures, such as brain and spinal cord.

• Acts as a storage area for Calcium – Ca is used in the blood if the diet does not

provide enough Ca

• Produces blood cells– Red blood cells are produced in red bone

marrow

4 Types of bones4 Types of bones• Long bones-bones that are longer that their width

– humerous –radius –ulna –femur –tibia

• Short Bones-length and width are nearly the same– Carpal and Tarsal (Wrist and ankle bones)

• Flat bones-two layers of bone divided by narrow span– Skull –sternum –costals(ribs) –scapula(shoulder blade)

• Irregular Bones-bones that do not fit into the shapes of the other three groups– Face –spine –hip

http://www.bio.psu.edu/people/faculty/strauss/anatomy/skel/skeletal.htmhttp://www.bio.psu.edu/people/faculty/strauss/anatomy/skel/skeletal.htm

Groups of bonesGroups of bones• Divided into two groups

– Axial Skeleton• Includes 80 bones• Include the skull, vertebrae, ribs and

sternum

– Appendicular Skeleton• Includes 126 bones• Arms, legs, hands, feet, pelvis

JointsJoints• The point where two bones meet is a joint• Three groups-depends on movement they

allow– Immovable joints

• Cranium (suture joints)

– Slightly moveable joints• Vertebral discs, symphysis pubis, sacroiliac jts.

– Freely moveable joints• Shoulder, elbow wrist and finger, knee and ankle

LigamentsLigaments• Connect bone to bone and hold

bones together

Types of JointsTypes of Joints• Hinge

A hinge joint allows extension and retraction of an appendage.

• Saddle A saddle joint allows movement back and forth and up and down, but does not allow for rotation like a ball and socket joint.

• Ball and Socket A ball and socket joint allows for radial movement in almost any direction. They are found in the hips and shoulders

• Gliding In a gliding or plane joint bones slide past each other. Midcarpal and midtarsal joints are gliding joints

Common disorders of Common disorders of skeletal systemskeletal system

Pg 153 153 in book

http://healbrokenbone.com/http://healbrokenbone.com/fractures.htmfractures.htm

I stubbed my phalange on the chair.Use your cranium to find the answer.I broke my humerus, but it's not funny.I scraped my patella when I fell off my bike.I was hit in the mandible by a fly.

• I hurt my femur when I fell off the swing.Put your left tarsals in, put your left tarsals out...Mandible-breaker, the candy.Do the sternum stroke in swimming.Mandibles, the movie.Pass a chicken phalange and some turkey femurs.

• http://www.klbschool.org.uk/interactive/science/skeleton.htm