musculoskeletal system

functions of a skeleton system

1. supports body

2. work with muscular system to move the body

3. protection (skull, rib cage for hearts and lungs)

4. produces blood cells

5. stores minerals (calcium, phosphate) and fats

cells of the skeletal system

1. osteocytes

2. osteoblast

3. osteoclast

tissues of the skeletal system

1. connective tissues

organs of the skeletal system

1. bone

2. cartilage

3. ligaments

what are osteoblasts

for forming new bone and found in growing portions of bone, including the periosteum and endosteum

what are osteocytes

maintain mineral concentration of the matrix via the secretion of enzymes

what are osteoclasts

for bone resorption or breakdown

two basic types of bones

1. compact bone: dense, smooth, homogeneous

2. spongy bone: porous (permeable) bone enclosing numerous large spaces that give a honeycombed or spongy appearance. designed for strength

bones are classified as

1. long (ie: humerus, bicep there)

2. short (ie: talus, ankle there)

3. flat (ie: sternum, rib cage there)

4. irregular (ie: vertebra, pelvic area there)

anatomy of a LONG bone

1. epiphysis (ends of a bone): composed mostly of spongy bone enclosed by thin layer of compact bone

2. epiphyseal plate/line: flat plate of hyaline cartilage seen in young, growing bone (spongy bone area); causes lengthwise growth of a long bone

3. articular cartilage: covers the external surface of the epiphyses, made of hyaline cartilage and decreases friction at joint surfaces (top of spongy bone)

4. diaphysis: shaft; makes up most of bone length, composed of compact bone

5. periosteum: outside covering of the diaphysis, fibrous connective tissue membrane

6. marrow (medullary) cavity: cavity inside the shaft, contains yellow marrow, mostly fats, in adults (red marrow is situated in cavities of spongy bone and epiphyses some long bones) , contains red marrow for blood cell formation in infants.

axial skeleton

• midline of body

• skull, sternum, ribs, vertebral, column, sternum

appendicular skeleton

• bones of the appendages and their attachment structures

• pectoral girdle, arms, pelvic gridle, legs

what does the skull co sist of

1. cranial bones

2. facial bones

whats hyoid bone

• does not articulate with any other bone

• attachment for muscles of tongue, larynx, pharynx

axial skeleton that forms midline of the body

1. skull

2. hyoid bone

3. vertebral column

4. ribs and sternum

cranial bones

1. frontal bone

2. parietal bone

3. temporal bones

4. sphenoid bone

5. ethmoid bone

6. occipital bone

facial bones

1. maxilla

2. palatine bone

3. vomer bone

4. zygomatic bone

5. nasal bone

6. lacrimal bones

intervertebral disks

cushion vertebral, assist in movement and flexibility

ribs and sternum

1. protect thoracic cavity

2. ribs protect: lungs and heart

• have 12 pairs, 10 pairs are attached to vertebrate in back, sternum in front

• lowest 2 pairs are “floating” attached to vertebrate but NOT sternum

3. sternum protects: heart and breastbone

pectoral girdle consists of (shoulder)

1. clavicles (collarbones)

2. scapulas (shoulder blades)

arms

• humerus (upper arm)

• radius, ulna (forearm)

• carpal bones (wrist)

• metacarpal bones (palm)

• phalanges (fingers)

pelvic girdle consists of (hip)

1. coxal bones

2. sacrum

3. public symphysis

legs

• femur (thigh)

• patella (knee cap)

• tibia, fibula (calf)

• tarsal bones (ankle)

• metatarsals (foot)

• phalanges (toes)

3 types of muscles

1. skeletal (strength and mobility)

2. cardiac (heart)

3. smooth (digestive tract, blood vessels, uterus)

muscles providing movements

• voluntary: conscious control over movement (picking up a pen)

• involuntary: unconscious control over movement (heart beat)

resist movement

• maintenance of posture

• maintenance of blood pressure

synergistic muscles

work tgt to create the same movement

antagonistic muscles

muscles that oppose each other

functions of joints (articulations)

• hold bones tgt

• allow for mobility

fibrous joints

generally immovable

cartilaginous joints

immovable or slightly movable

synovial joints

• freely movable

• separated by joint cavity

• synovial fluids found in joint cavity

• features of the joints:

1. articular cartilage

2. articular capsule

3. joint cavity

4. reinforcing ligaments

types of synovial joints (everything here ends w joints)

• plane

• hinge

• pivot

• condylar

• saddle

• ball-and-socket

shoulder joint (glenohumeral joint)

• largest range of motion of any joint

• lack of structural support and thus enhanced mobility is offset by loss of stability

hip joint (ball-and-socket)

• carries the weight of the body and thus requires strength and stability during standing and walking

• range of motion is more limited than at shoulder joint

elbow joint (synovial joint)

• point of articulation of three bones: humerus of the arm, radius and ulna of the forearm

• functionally a hinge joint allowing movement in only one plane (uniaxial)

knee joint (synovial joint)

• connects three bones: femur, tibia, patella

• functions as hinge joint, allowing flexion and extension of the leg

• knee joint is the largest and possibly most stressed joint