Skeletal System Flashcards
Osteoblasts
Bone forming cells which secrete a substance that mineralizes bone tissue.
Osteocytes
Matured osteoblasts which become trapped in the bone matrix.
Osteoclasts
Cells that break down and remodel bone.
Compact bone
Forms the outer shell of bones and around 80% of the bone’s mass.
Osteon
Unit of compact bone. Cylindrical and runs lengthwise.
Haversian canal
Lengthwise canal at the centre of an osteon. Contains blood vessels, lymphatic vessels and nerves.
Volkmann canals
Transverse canals that connect Haversian canals. Contain blood and lymphatic vessels and nerves.
Types of ossification
Endochondral and intramembranous.
Long bones
Bones which are longer than they are wide.
Short bones
Generally small, cuboid bones with multiple articulating surfaces.
Flat bones
Bones with a broad, flat surface
Irregular bones
Oddly shaped bones
Sesamoid bones
Round bones embedded in tendons and ligaments.
Bone shapes
Long, short, flat, irregular and sesamoid.
Diaphysis
Cylindrical shaft of a long bone.
Medullary cavity
Hollow space within the diaphysis. Filled with bone marrow.
Periosteum
Connective tissue covering over the diaphysis. Contains blood vessels, nerves and osteoblasts.
Epiphysis
End of a long bone.
Articular cartilage
Hyaline cartilage which covers the articulating surfaces of the epiphysis.
Purpose of articular cartilage
Allows for smoother movements.
Epiphyseal plate
A line of cartilage near the end of growing bones. Becomes the epiphyseal line when growth is complete.
Metaphysis
The neck portion of a long bone. Contains the epiphyseal plate.
How many bones in the axial skeleton?
80
Bone of the axial skeleton
Skull, vertebral column, sternum and ribs.
How many bones in the skull?
29
How many bones in the vertebral column?
26
How many pairs of ribs?
12
How many bones in the appendicular skeleton?
126
Bones of the appendicular skeleton
Shoulder girdles, upper extremities, pelvic girdles and lower extremities.
How many bones in the arm?
30
How many bones in the shoulder girdle?
2 each
How many bones in the pelvic girdle?
6
How many bones in each leg?
30
Types of joints
Fibrous, cartilagenous and synovial.
Fibrous joints
Bones are connected by dense fibrous connective tissue. Typically synarthrotic.
Cartilagenous joints
The joint consists of fibrocartilage of hyaline cartilage and allows for some movement. Typically amphiarthrotic.
Synovial joints
The joint contains a joint capsule with a synovial membrane and fluid. Typically diarthrotic.
Synarthrotic
A joint with limited movement.
Synarthrotic joint examples
Teeth and skull
Amphiarthrotic joint
A slightly movable joint.
Amphiarthrotic joint examples
Vertebrae, pubic symphysis
Diarthrotic joint
A freely moveable joint.
Synovial fluid purpose
Provide lubrication and nutrients to the articular cartilage.
Labrum
A ring of fibrocartilage around the edge of the articular cartilage of a synovial joint. Increases surface area.
Bursae
Flattened saclike structures between ligaments and tendons which reduce friction.
Fat pads
Pads of fat around some synovial joints to protect the articular cartilage.
Synovial sheaths
Elongated bursae which surround tendons to increase gliding capacity.
Menisci
Crescent shaped fibrocartilagenous pads found in the knee and jaw. Allows joints to fit together more smoothly.
Joint types which are uniaxial
Hinge and pivot.
Joint types which are biaxial
Saddle and ellipsoid
Saddle joint
A joint with a concave and a convex surface articulating together.
Ellipsoidal joint
An elliptical ball and socket joint.
Joint types which are multiaxial
Ball and socket and gliding.
