Chapter 6 Skeletal System

Osteology

Study of bone structure and treatment of bone disorders

5 Primary Functions

1) Support

2) Storage (minerals, lipids)

3) Hemopoiesis/Blood cell production

4) Protection

5) Leverage

4 Types

Long, short, flat, irregular

Structure of a long bone 

• Diaphysis (shaft)

• Epiphysis (wide part at each end)

4 Types of Bone Cells

Osteoclasts, osteoprogenitor, osteocytes, osteoblasts

Osteoprogenitor Cells

Unspecialized stem cells that form almost all of connective tissue

Osteocytes

Mature bone cells; do not undergo cell division; maintains daily metabolism and bone structure/repairs

Osteoblasts

• Osteogenesis (production of new bone)

• Ossification/calcification (hardening)

Osteoclasts

Osteolysis (breaks down bone) to release stored minerals

Osteon/Haversion System 

Basic functional unit

Central canal/Haversian Canal 

Contain blood vessels within osteocytes arranged in layers

Perforating Canals

Provide passageways to link blood vessels; perpendicular to central canals

Lucunae

Spaces containing osteocytes

Lamellae

Thin plates surrounding lucunae; rings of calcified matrix around the canals

Canaliculi

Small canals connecting lacunae and blood vessels; allows exchange of nutrients and waste products

Spongy bone

Important sites of blood cell formation

Ossification

Process of replacing other tissues with bone

Intramembranous Ossification

Within membrane

Endochondral Ossification

Cartilage is replaced with bone

Ossification Center

Site where bones will develop

Calcification

Mineral salts deposited, cells become hardened

Gliding Joints

• Flattened or slightly curved faces

• Like 2 plates sliding across each other

• i.e. carpal bones of the wrist

Hinge Joints

• Angular motion in a single plane

• Flexion and extension without sliding or deviation

• i.e. elbow joint between the humerus and ulna

Pivot Joints

• Rotation only turning motions without sideways displacement or bending

• i.e. joint between first and second cervical vetebrae

Ellipsoid Joints/Condyloid

• Oval articular face within a depression

• Present between the knuckle joints, wrist joints, metacarpophalangeal joints and metatarsophalangeal joints of fingers

Saddle Joints

Base of thumb

Ball and Socket Joints

• Round articular face in a depression

• Found in shoulder and hip

Calcium Salts

Maintain normal concentrations of calcium and phosphate

Endosteum

Structure that lines the marrow cavity and other inner surfaces of the bone

During endochondral ossification, bone formation first occurs at the ____

diaphysis surface

Fracture Hematoma

Forms and closes off injured blood vessels in a fracture

Osteopenia

Inadequate ossification

Facet

Small, flat articular surface on a bone

Trochanter

Large, rough projection

Periosteum

Covers outer surface of the bone

Condyle

Rounded articular process of the bone

Acetabulum

Pelvic joint cavity/socket that articulates with the head of the femur to form the hip joint

Diarthroses

Freely movable joints

Occipital Condyles

Site of articulation between the skull and vertebral column

Kyphosis

Exaggerated curvature of the thoracic curve of the vertebral column

Scapular spine 

Divides the posterior surface of the scapula into two regions 

Radial tuberosity 

Marks the attachment site of the biceps brachii 

Synarthrosis

Functionally immovable joint

Rheumatism

Describes pain and stiffness in the skeletal and/or muscular system