skeletal system bones - the organs of the skeletal system

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Skeletal System Bones - the organs of the skeletal system.

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Page 1: Skeletal System Bones - the organs of the skeletal system

Skeletal System

Bones - the organs of the skeletal system.

Page 2: Skeletal System Bones - the organs of the skeletal system

2 Divisions

• The human skeleton has two divisions – Axial skeleton – Consist of the skull,

vertebrate column, and the rib cage– The Appendicular Skeleton - Consist the

bones of the arms and legs, shoulder, and the pelvic girdle .

• The Skeleton of Humans is composed of a special connective tissue called BONE

• There are 206 bones in the human body

Page 3: Skeletal System Bones - the organs of the skeletal system

Meet BONES

Page 4: Skeletal System Bones - the organs of the skeletal system

Functions of the Skeletal System

• support - it forms the body's framework to support the muscles and organs.

• protection - the skeletal systems protects by 1) forming the bony cavities around organs, – the thoracic cavity protects the heart and lungs– the cranial cavity protects the brain.

2) the yellow marrow in bones produces white blood cells which protect against invading microorganisms.

• movement - bones form joints which provide levers for movement such as walking, lifting, etc.

• hematopoiesis (blood cell production) - the red marrow produces red blood cells.

• mineral storage and homeostasis - the skeleton forms a reservoir of minerals, especially calcium, for maintenance of homeostasis.

Page 5: Skeletal System Bones - the organs of the skeletal system

2 Basic types of bone tissue:

• 1. Compact bone - dense, smooth. Contains few spaces. Covers spongy bone tissue. Provides protection and support and helps long bones resist stress of weight.

• 2. Spongy bone - composed of small needle-like pieces and open spaces filled with red marrow. Makes up most of short, flat and irregular shaped bones and most of the epiphysis of long bones.

Bones are classified by their shape1. Long bones (humerus, femur)2. Flat bones (skull)3. Short bones (fingers)4. Irregular bones (vertebrae)

Page 6: Skeletal System Bones - the organs of the skeletal system
Page 7: Skeletal System Bones - the organs of the skeletal system

Joints• JOINTS WHERE TWO BONES MEET • Cartilage is responsible for keeping bones far enough apart so they

do not rub against each other as they move. At the same time, joints hold the bones in place.

• Joints work by attaching muscles which work in in pairs - ANTOGONISTIC MUSCLES - flexors & extensors

• Muscles attach to bone via connective tissue called TENDONS• Bones attach to bones via connective tissue called LIGAMENTS

Page 8: Skeletal System Bones - the organs of the skeletal system

There are two kinds of joints:There are two kinds of joints:1. IMMOVABLE JOINT

THEY ARE OFTEN CALLED FIXED JOINTS, AND ALLOW NO MOVEMENT BETWEEN BONES.

– These joints are interlocked and held together by Connective Tissue, or they are fused together.

– The places where the bones of the SKULL meet (SUTURE) meet are examples of immovable joints.

– Immovable joints are located in bones of the skulls and the ribsImmovable joints are located in bones of the skulls and the ribs

2. MOVABLE JOINTSMOST OF THE JOINTS OF THE BODY ARE FREELY MOVABLE JOINTS. – In Freely Movable Joints, the ends of the bones are covered with a

layer of Cartilage that provides a smooth surface at the joint. Joints are Joints are a place where two or more bones come together. a place where two or more bones come together.

– Examples are the ball-and-socket, pivot, hinge, and glidingExamples are the ball-and-socket, pivot, hinge, and gliding

Page 9: Skeletal System Bones - the organs of the skeletal system
Page 10: Skeletal System Bones - the organs of the skeletal system

Moveable JointsMoveable JointsBall-and-socket joint Ball-and-socket joint

– Ball-and-socket joints allow the greatest range of Ball-and-socket joints allow the greatest range of motion. They can be found in the shoulder where the motion. They can be found in the shoulder where the top of the arm bone fits into the deep, bowl-like socket top of the arm bone fits into the deep, bowl-like socket of the scapula (shoulder blade). of the scapula (shoulder blade).

– This joint allows you to swing your arm freely in a This joint allows you to swing your arm freely in a circle, your hips also have ball-and-socket jointscircle, your hips also have ball-and-socket joints

Page 11: Skeletal System Bones - the organs of the skeletal system

Moveable JointsMoveable JointsHinge jointHinge joint

• Permits a back-and-forth motion. – The Knee enables

your leg to flex and extend.

– The Elbow, which allows you to move your forearm toward and away from your body.

Page 12: Skeletal System Bones - the organs of the skeletal system

Moveable JointsMoveable JointsPivot Joint Pivot Joint

– A pivot joint allows one bone to rotate around another A pivot joint allows one bone to rotate around another – A pivot joint can be found in the top of your neck, A pivot joint can be found in the top of your neck,

which gives you limited ability to turn your head from which gives you limited ability to turn your head from side to sideside to side

Page 13: Skeletal System Bones - the organs of the skeletal system

Moveable JointsMoveable JointsGliding JointGliding Joint

• A gliding joint allows A gliding joint allows one bone to slide over one bone to slide over another bone another bone – The joint located in The joint located in

your wrist is an your wrist is an example of a gliding example of a gliding joint this joint enables joint this joint enables you to bend and flex you to bend and flex your wrist, as well as your wrist, as well as make limited side-to-make limited side-to-side motions. side motions.

Page 14: Skeletal System Bones - the organs of the skeletal system

Joint ActivityJoint Activity

What types of joints are What types of joints are involved in the following involved in the following activities: activities:

1. Move your arm in a circle 1. Move your arm in a circle

2. Push open a door 2. Push open a door

3. Lift a book off the table 3. Lift a book off the table

4. Kneel down 4. Kneel down

5. Wave your hand 5. Wave your hand

6. Twist your head from side 6. Twist your head from side to sideto side

Answers: Answers:

1. Arm = ball-and-socket joint 1. Arm = ball-and-socket joint

2. Door = hinge joint (elbow) 2. Door = hinge joint (elbow)

3. Book = Gliding joint (wrist) 3. Book = Gliding joint (wrist)

4. Kneeling = hinge joint 4. Kneeling = hinge joint (knee) (knee)

5. Hand = gliding joint (wrist) 5. Hand = gliding joint (wrist)

6. Head = Pivot joint (neck)6. Head = Pivot joint (neck)