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Bone - Fast Facts
1. 1 of 4 types of connective tissue.
2. The SECOND hardest tissue in the human body. (Only dental enamel is harder.)
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Types of bone tissue.
- Periosteum: Outermost covering; tough, fibrous.
- Compact bone: Protective outer layer of bone; dense, hard, very strong.
Spongy bone: Found in ends and inner portions of long bones; lighter than compact bone. Red marrow is located within spongy bone.
- Medullary cavity: Located in shaft of long bones; surrounded by compact bone.
- Endosteum: Lining of medullary cavity.
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Bone Marrow
- 1. Red bone marrow: Located within spongy bone. Hemopoeitic tissue; manufactures:
- .....a. red blood cells
- .....b. hemoglobin
- .....c. white blood cells
- .....d. thrombocytes
2. Yellow bone marrow: Located in medullary cavity. Fat storage area which contains mostly fat cells.
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Cartilage
1. Shock absorber between bones; smooth rubbery blue-white connective tissue.
- 2. More elastic than bone; makes up flexible parts of skeleton (examples: nose tip, outer ears)
- 3. Two types are: Articular cartilage and Meniscus.
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Articular cartilage
1. Covers surfaces of bones as they come together to form joints.
2. Makes smooth joint movement possible.
3. Keeps bones from rubbing against each other.
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Meniscus
Curved fibrous cartilage found in some joints (examples: knee & temoromandibular joint of jaw)
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Diaphysis
Shaft of a long bone.
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Epiphysis
1. Wide end(s) of a long bone.
2. Covered in articular cartilage.
3. Proximal end located nearest midline of body.
4. Distal end located farthest from the midline..
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Foramen
- Opening in bone - pass through for:
- .....* blood vessels
- .....* nerves
- .....* ligaments
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Process
1. Normal projection on the surface of a bone.
2. Serves as an attachment for muscles and tendons.
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Joints
1. Place of union between 2 or more bones.
- 2. Classified according to:
- .....a. Construction
- .....b. Degree of movement they allow
- 3. There are 3 basic types of joints:
- .....a. Fibrous
- .....b. Cartilaginous
- .....c. Synovial
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Fibrous joints
1. Consist of inflexible layers of dense connective tissue.
2. Hold bones tightly together.
3. Do not allow any movement.
4. Also known as sutures - in infants and very young children these joints are movable before they solidify.
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Fontanelles
- 1. 2 soft spots on infant's skull:
- .....* anterior
- .....* posterior
2. Normally present in the skull of a newborn.
- 3. Allow for:
- .....a. passage through birth canal
- .....b. Growth of skull during first year of life.
4. Sutures - fibrous joints - gradually harden and fontanelles close.
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Cartilaginous joints
1. Allow only slight movement
2. Consist of bones connected entirely by cartilage.
- 3. Examples include:
- ..... * Ribs connect to sternum - allow breathing
- ..... * Pubic symphysis:
- ..........* Between pubic bones in anterior of pelvis
- ..........* Allow spreading for childbirth
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Pubic symphysis
1. Cartilaginous joint that allows some movement to facilitate childbirth.
2. Located between public bones in anterior of the pelvis.
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Synovial joints
1. Created where 2 bones articulate to permit a variety of motions.
- 2. Described based on type of motion:
- .....a. Ball and socket joints:
- ..........*Wide range of movement
- ..........* In many directions
- ......... * Examples: hip & shoulder
- .....b. Hinge joints
- ..........* Movement primarily in one direction or plane
- ..........* Examples: knee & elbow
- 3. Consist of several components in the synovial cavity:
- .....a. Synovial capsule
- .....b. Synovial membrane
- .....c. Synovial fluid
- .....d. Ligaments
- .....e. Bursa
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Synovial Capsule
1. Outermost layer of strong, fibrous tissue.
2. Resembles a sleeve as it surrounds the joint.
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Synovial membrane
1. Lines the capsule.
2. Secretes synovial fluid.
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Synovial fluid
1. Flows within synovial cavity
2. Acts as a lubricant to allow smooth joint movement.
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Ligaments
- 1. Bands of fibrous tissue that form joints by:
- .....a. connecting bone to bone or
- .....b. joining bone to cartilage
- 2. Complex hinge joints such as the knee are made up a series of ligaments that permit movement in different directions.
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Bursa
1. Fibrous sac
2. Acts as a cushion in area that a subject to friction where a tendon passes over a bone.
3. Exampes: Shoulder, elbow, and knee joints
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