Skeletal System Flashcards
What are the (5) functions of the skeletal system?
- Support 2. Protection 3. Levers for muscular action 4. Storehouse for minerals (calcium & phosphorus) 5. Site for fat storage & blood cell formation (marrow cavities)
How are bones classified?
Location and shape. Axial skeleton includes flat and irregular bones, appendicular skeleton includes long, short and sesamoid bones.
What makes up the axial skeleton?
The skull, vertebral column, hyoid apparatus, ribs and sternum
What makes up the appendicular skeleton?
Pectoral limbs, pelvic limbs
What is the structure of the long bones?
The long bone is made up of a diaphysis (the long shaft), epiphyses (the flared ends), metaphysis (where epiphysis and diaphysis meet, where the growth plate is/was)
Describe how the growth plate functions in young to mature bones.
During growth, each epiphysis is separated from diaphysis by a plate of growing cartilage called the epiphyseal plate. At maturity, cartilage stops growing and epiphysis fuses with diaphysis, leaving the metaphysis.
What are the characteristics of long bones that assist in articulation?
The ends of long bones are enlarged and smooth and covered by hyaline cartilage to diminish risk of dislocation and to increase weight bearing surface.
Where are the short bones and what characterizes them?
Short bones are found in the carpus and tarsus (hands and feet) and characterized by having many surfaces or being flat.
What are the characteristics and locations of sesamoid bones?
Found near freely moveable joints, formed in tendons, usually only possess one articular surface which glides on a flat or convex surface of one or more of the long bones. They alter the course of tendons and protect them where greatest friction is developed.
What is the functions and locations of flat bones?
Flat bones are found in the skull and rib for protection of organs and cavities.
What are the locations and characteristics of irregular bones?
Irregular bones are found in the vertebral column, pelvis and bones of skull that are not flat. They are characterized by processes for muscular and ligament attachments and articulations.
What are the three cells found in the bone?
Osteocytes, Osteoblasts and Osteoclasts
Where are osteocytes found and how do they exchange with blood capillaries since diffusion cannot take place in calcified matrix?
Osteocytes are found in cavities called lacunae (lacuna, singular) throughout the lamellae (layers) of the bone matrix. They exchange blood and nutrients with blood capillaries through canaliculis, little “rivers” that flow from the Haversian canals to the lacunae.
Where are the osteoblasts located, formed?
Osteoblasts are located along the surface of the bone tissue, lined up like simple epithelium. As cell matures and secretes matrix, cells remain in contact with each other by cytoplasmic extensions. Once trapped in matrix, cells become osteocytes.
Where are osteoclasts found and what is their purpose?
Osteoclasts are giant cells with 6-50 nuclei that resorb bones, break them down. They are found on bone surfaces where remodeling occurs.
