Skeletal Systems Flashcards
Axial Skeleton
Bones of the skull, vertebral column, ribs, and sternum
Appendicular Skeleton
Bones of the upper and lower limbs
Cartilage
Avascular form of connective tissue consisting of extracellular fibers embedded in a matrix that contains cells localized in small cavities. Nourished by diffusion (no blood vessels, lymphatics, or nerves)
Functions of cartilage (3)
- Support soft tissue
- Provide smooth, gliding surface for bone articulations at joints
- Enable the development and growth of long bones
Hyaline Cartilage
Most common type of cartilage; Matrix contains a moderate amount of collagen fibers (i.e. articular surfaces of bones)
Elastic Cartilage
Matrix contains collagen fibers along with a large number of elastic fibers, (i.e. external ear)
Fibrocartilage
Matrix contains a limited number of cells and ground substance amidst a substantial amount of collagen fibers (i.e. intervertebral discs)
Bone
Calcified, living, connective tissue that forms the majority of the skeleton. Consists of intercellular calcified matrix which also contains collagen fibers and several types of cells within the matrix. Vascular and innervated
Bone functions (5)
- Supportive structure for body
- Protectors of vital organs
- Reservoirs of calcium and phosphorus
- Levers on which muscles act to produce movement
- Containers for blood-producing cells
Compact Bone
Dense bone that forms outer shell of all bones and surrounds spongy bone
Spongy Bon
Consists of spicules of bone enclosing cavities containing blood-forming cells (marrow)
Long bones
Tubular (humerus, femor)
Short bones
Cuboidal (bones of wrist and ankle)
Flat bones
Consist of two compact bone plates separated by spongy bone (skull)
Irregular bones
Bones with various shapes (bones of face)
Sesamoid bones
Round or oval bones that develop in tendons
Periosteum
Fibrous connective tissue membrane that surrounds bones except in area of joint where articular cartilage is present. Required for bone to survive. Receives blood vessels whose branches supply outer layers of compact bone. Supplied with numerous sensory nerve fibers (unlike bone itself) and very sensitive to any type of injury.
Bone comes from ____
From mesenchyme by either
- Intramembranous ossification (mesenchymal models of bone undergo ossification)
- Endochondral ossification (cartilaginous models of bones form from mesenchyme and undergo ossification)
Red marrow
aka Myeloid Tissue
Most marrow is red at birth.
Give rise to red blood cells, platelets, and most white blood cells arise.
More red marrow is converted into yellow marrow within the medulla of the long and flat bones.
Yellow marrow
Dominated by large fat globules
Makes a few white cells
Hemopoietic stem cells
Stem cells of bone marrow that give rise to white blood cells, red blood cells, and platelets.
Mesenchymal stem cells
Stem cells of bone marrow that differentiate into structures that form bone, cartilage, and muscle
Bone fractures typically caused by
Abnormal load or stress, poor quality (osteoporosis)
Avascular necrosis
Cellular death of bone resulting from a temporary or permanent loss of blood supply to the bone
Osteoporosis
Bone mineral density is significantly reduced, common in postmenopausal women
Factors leading to osteoporosis
Poor diet, steroid usage, smoking, premature ovarian failure
Synovial joints
Connections between skeletal components where the elements involved are separated by a narrow articular cavity.
Described based on shape and movement
Hyaline cartilage
Covers articulating surfaces of skeletal elements in synovial joints
Synovial membrane
Attaches to margins of the synovial joint surfaces at the interface between the cartilage and bone and encloses the articular cavity
Fibrous membrane
Formed by dense connective tissue and surrounds and stabilizes the synovial joint, parts may thicken to form ligaments
Joint capsule
Consists of an inner synovial membrane and an outer fibrous membrane
Articular discs
Absorb compression forces, adjust to changes in the contours of joint surfaces during movements, and increase the range of movements that can occur at joints.
Fat pads
Usually occur between the synovial membrane and the capsule and move into and out of regions as joint contours change during movement
Plane joints
Allow sliding or gliding movements when one bone moves across the surface of another
Hinge joints
Allow movement around one axis that passes transversely through the joint; permits flexion and extension
Pivot joints
Allow movement around one axis that passes longitudinally along the shaft of the bone; permit rotation
Bicondylar joints
Allow movement mostly in one axis with limited rotation around a second axis; formed by two convex condyles that articulate with concave or flat surfaces
Condylar (ellipsoid) joints
Allow movement around two axes that are at right angles to each other; the articular surfaces are saddle shaped; permit flexion, extension, abdustion, adduction, and circumduction
Ball and socket joints
Allow movement around multiple axes; permit flexion, extension, abduction, adduction, circumduction, and rotation
Solid joint
Connections between skeletal elements where the adjacent surfaces are linked together either by fibrous connective tissue or by cartilage. More restricted movement
Sutures
Fibrous joint, occurs only in skull where adjacent bones are linked by a thin layer of connective tissue termed a sutural ligament
Gomphoses
Fibrous joint, occur only between the teeth nd adjacent bone
Syndesmoses
Fibrous joint, two adjacent bones are linked by a ligament
Synchondroses
Cartilaginous joint, occurs where two ossification centers in a developing bone remain separated by a layer of cartilage.
Joints allow bone growth and eventually become completely ossified
Symphyses
Cartilaginous joint, occurs where two separate bones are interconnected by cartilage
Degenerative joint disease
Osteoarthritis or osteoarthrosis. Commonly caused by decreases in water and proteoglycan content within cartilage
Arthroscopy
Technique of visualizing the inside of a joint using a small telescope placed through a tiny incision in the skin
