Musculoskeletal System

Bones 206 bones grouped by head, trunk, limbs Bones are hard solid organ that form part of the skeleton Continuously renewed Spongy and compact 4 categories: long, short, flat, irregular

Long Bones Thin body(diaphysis), thick extremities(epiphyses) Mainly compact bone Centre contains bone marrow (soft, fatty, tissue) Helps to make blood cells Limbs ex. Humerus, femur

Short Bones Cubic shape, spongy bone Wrists & heels

- irregular shape, mainly in spine Flat Bones Thin, flat, curved, 2 thin layers of compact with spongy in middle ex. Skull, ribs, sternum, scapula Irregular Bones - irregular shape, mainly in spine

Functions of the Bones (RBC, WBC, platelets) Support- framework, posture, - supports organs, muscles Protection- protect internal organs ex. Skull-brain, Ribs- heart, lungs Movement-rigid & flexible - lever(movement of muscles) Storage- fats, minerals (Ca, P) Production blood cells- bone marrow (RBC, WBC, platelets)

Joints Function between two or more bones Some joints contain synovial fluid Ligaments- fibrous bands, reinforce joints - connects 2 bones - cushion of cartilage

Mobility of Joints Fixed- bones of skull Semi-filled- protection of spinal cord, flexibility of spine 3. Freely moveable- elbow, hip

Muscles have the ability to contract causing our bodies or our internal organs to move.

Movements Extension and Flexion: - extension increases angle, while flexion decreases angle ex. Nodding head

2. Abduction and Adduction: - abduction increases between limb and body - adduction decreases distance ex. Lifting arm out straight

Rotation: - movement of bone around an axis

Functions Movement: limbs (voluntary ex. leg) or organs (involuntary ex. Stomach churning) Posture Maintenance: muscles contract and release Joint Stabilization: keeps joints together Heat release: energy turned to heat to maintain body temp. at 370C

Three Types of Muscles Skeletal: attached to bones by tendons, voluntary, contract (shortens) and relaxes (lengthens), rapid with force over short time Muscles are bundles of fibres covered in conjunctive tissues

Smooth Muscles: walls of some internal organs (stomach etc Smooth Muscles: walls of some internal organs (stomach etc.), involuntary, move substances from place to place, have endurance but weaker than skeletal

Cardiac: muscles of heart, involuntary, similar to skeletal, great strength and endurance, form the ventricles of heart