Skeletal System Flashcards
Hemopoiesis
The active formation of blood cells
Skeletal system (skeleton)
An active, living tissue responsible for support, movement, protection, storage, and formation of blood cells
Structural functions of bone
Giving support to the soft tissues of the body and providing attachment sites for most muscles
Skeletal system storage
Stores calcium, phosphorus, fat, sodium and potassium
Skeleton system production
Production site for blood cells within the circulatory system including red blood cells, certain white blood cells, and platelets
Bone shape classifications
Long, short, flat, and irregular
Long bones
Classified by being longer than they are wide (long axis); they make up the majority of the skeleton
Short bones
Classified by having approximately the same length and width
Flat bones
Classified by being thin and typically curved
Irregular bones
Have diverse shapes, excluding them from the other classifications of bone shape
Cortical bone
Compact, dense bone found in the shafts of long bones and the vertebral endplates
Trabecular bone
Spongy or cancellous bone composed of thin plates that form a honeycomb pattern; predominantly found in the ends of long bones and the vertebral body
Cortical shell
Makes up roughly 75% of the skeletal system
Trabecular network
Makes up roughly 25% of the skeletal system
Cortical bones function
Provides strength, tendon attachment sites for muscle, and organ protection without excessive weight
Trabecular bones function
Provides a large surface area for mineral exchange, and helps maintain skeletal strength and integrity
Long bone structures
Diaphysis, proximal epiphysis, and distal epiphysis
Diaphysis
Shaft of the long bone
Proximal epiphysis
End of a long bone closest to the midline of the body
Distal epiphysis
End of a long bone furthest from the midline of the body
Medullary cavity
Hollow space inside the diaphysis and is used as a storage site for fat
Endosteum
Thin layer of connective tissue lining the medullary cavity
Red marrow
Resides in the trabecular tissue of certain long bones epiphysis; essential in the manufacture of red blood cells, most white blood cells, and platelets
Epiphyseal cartilage
Separates the diaphysis and epiphyseal in children and young adults, providing means for the bone to lengthen
Epiphyseal line
Bone that replaces the epiphyseal cartilage as skeletal growth is completed
Periosteum
The layer of dense connective tissue that covers the outer surface of bone
Remodeling
The process of continually reshaping and rebuilding the skeleton
Osteoblasts
Process of building new bone
Osteoclasts
Process of breaking down bone
Wolff’s law
Bone is capable of increasing its strength in response to stress by laying down more bone
Axial skeleton
The 74 bones of the skull, vertebral column, sternum, and ribs; provides the main axial support for the body well protecting the central nervous system and major organs
Vertebral column
Composed of 33 vertebrae, categorized by region
Appendicular skeleton
The 126 bones of the upper and lower limbs, pectoral girdle, and pelvic girdle
Pectoral girdle
Clavicle and scapula, attached to the axial skeleton only at the sternum; offers little support the large range of movements
Pelvic girdle
Composed of the ileum, ischium, and the pubis; supports the body’s weight and has extensive attachments to the axial skeleton through its articulation with the sacrum
Os coxae
The ileum, ischium, and pubis as a collective
Pubic symphysis
Strong joint made of cartilage that unites each side of the pelvic girdle
Articulation
Juncture where two bones meet; a joint
Joint types
Fibrous, cartilaginous, and synovial
Fibrous joints
Classified as synarthroidal; held tightly by fibrous connective tissue allowing little or no movement
Synarthroidal joints
Joints considered immovable
Cartilaginous joints
Joints connected by cartilage and allow little to no movement
Synovial joints
Most common type of joint; characterized by free movement
Synovial joints characteristic traits
Articular cartilage, articular capsule, synovial membrane, and synovial fluid
Articular cartilage
Hyaline cartilage that covers the surface of long bones
Articular capsule
Encloses the joint with a double layered membrane
Ligament
Strong connective tissue that connects one bone to another
Synovial membrane
Inner layer of the articular capsule; well supplied by capillaries and produces synovial fluid
Synovial fluid
Thick liquid that nourishes the articular cartilage and lubricates the joint surface
Axis of rotation
Imaginary line that forms a right angle to the plane of movement a joint rotates on
Uniplanar joints (uniaxial)
Joints that move in one plane and have one axis of rotation
Biplanar joints (biaxial)
Joints that allow movement in two planes that are perpendicular to each other
Multiplanar joints (triaxial)
Joints that allow movement in three axes of rotation
Synovial joint general movements
Gliding, angular, circumduction, and rotation
Gliding movements
Synovial joint movements that occur when the surfaces of two adjoining bones move back-and-forth on each other (such as the movement between the base of a rib and its associated)
Angular movements
Synovial joint movements of flexion, extension, abduction, and adduction
Circumduction movements
Synovial joint movements that occur when a joint is capable of incorporating all four angular movements to create one motion
Rotation movements
Synovial joint movements of a bone around a longitudinal axis
