Consists of bone tissue, bone marrow, cartilage and periosteum (the membrane around bones.
Functions of the skeleton and bone tissue:
> support – framework for attachment of soft connective tissues such as muscles.
> Protection – protect internal organs (ribs protect lungs)
> movement – muscles contract to move bones for movement
> mineral storage- store minerals to be released when needed (calcium)
> blood cell production – most blood cell formation occurs in red bone marrow
> storage of energy – yellow bone marrow stores lipids for energy
--- Major bones involved in movement
> Long bones absorb shock and distribute pressure. eg. most arm and leg bones… femur, radius, fibula, tibia.
> Other types of bone by shape: short bones (wrists, ankles, fingers), flat bones (skull, breastbone), irregular bones (vertebra, facial bones, shoulder blade)
> Other types of bone by location: sesamoid bones which are small bones in tendons where pressure develops (patella), sutural bones which are small bones located between joints (between cranial bones).
Axial skeleton forms the axis of the body, includes the skull, vertebra, ribs, sternum and hyoid bone. Protects spinal cord, consists of 24 movable vertebrae in three sections (7 cervical, 12 thoracic, 5 lumbar), 5 fused bones in the sacrum, 4 fused bones to form the coccyx.
Appendicular skeleton inludes bone of the pectoral (shoulder) girdle and above, bones of the pelvic (hip) girdle and below.
--- Structure and function of joints
> fibrous – bones have no joint cavity, held together by strong connective tissue eg skull.
> cartilaginous – bones have no joint cavity, held together by cartilage eg pubic bone, sternum, vertebra.
> synovial (moving) – have a joint cavity, held together by ligaments and separated by synovial fluid in joint cavity eg. hinge (humerous/ulna), pivot (radius/ulna), condyloid ( femur/tibia), ball and socket (humerous/scapula).
Structures in synovial joints:
> articular capsule – capsule that encloses the joint cavity
> articular cartilage – connective tissue covering the surf of articulating bones
> synovial fluid – secretion that lubricates and nourishes articular cartilage
> bursa – small sac containing synovial fluid, located in friction sites in joints
Structures around synovial joint providing support and function:
> tendons – fibrous cords of dense connective tissue attaching muscle to bone.
> ligaments – dense connective tissues that attaches bone to bone.
Types of synovial joints:
> gliding joint – side/side, back/forth (carpals/metacarpals)
> hinge joint – one joints convex joint fits into the concave of another, concave joint moves (elbow, knee)
> pivot joint – rotating joint where one bone articulates movement with depression or opening of the other (radius/ulna)
> ellipsoid/condyloid joint – saddle joint moving on the ridge of another (femur/tibia)
> saddle joint – Saddle shaped bone moving perpendicular to another saddle joint. (thumb – carpal and metacarpal)
> ball and socket joint – rounded ball like bone fits into cup like joint (shoulder, hip)
--Major muscles involved in movement
> Skeletal Muscle is attached to bones to move skeleton. Contraction is under our direct control so the muscle is said to be voluntary.
> Cardiac Muscle forms most of the heart. It is involuntary, as we don’t need to think about it.
> Smooth Muscle is located on the walls of our internal structures (stomach, blood vessels, intestines). Movement is usually involuntary.
The basic function of muscle tissue contracting and relaxing is to produce movement (run, digest, excrete), provide stabilization of posture and internal organs, and generate heat to…