Musculoskeletal System Main Parts Head cranial bones protection

Musculoskeletal System

Main Parts Head- cranial bones (protection of brain) - Jaw (movement for chewing) 2. Thorax- ribs, sternum (support & protection of heart, lungs etc. ) 3. Spinal column-protection of spinal cord - movement of trunk 4. Upper limbs-movement (raise arm, grab) Lower limbs- movement of body - support of trunk 1.

Bones l l l 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 l l l 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 l l Cubic shape, spongy bone Wrists & heels

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

Functions of the Bones 1. 2. 3. 4. 5. 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 l l l 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 2. Semi-filled- protection of spinal cord, flexibility of spine 3. Freely moveable- elbow, hip 1.

Movements 1. 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

3. Rotation: - movement of bone around an axis

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

Functions 1. 2. 3. 4. 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 370 C

Three Types of Muscles l l 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

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

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