Skeletal System

• Functions: Supports the body; Protects organs (ribs, sternum, skull); Place for

muscles to attach; Stores Ca; Makes blood (hematopoiesis)

• Varieties: Long (arms, legs); Short (toes, fingers); Flat (skull); Irregular

(kneecap) Greatest number of bones in the hands and feet

• Anatomy of a Long Bone: Periosteum: a seran-wrap covering over the whole bone; contains blood

vessels (protection) Cartilage: shiny, bendable tissue at the end of the bone (articular); few

blood vessels (protection)

Compact Bone: solid (no holes); the middle of the bone; high in Ca Spongy Bone: has holes; the ends of the bone; low in Ca Red Marrow: makes blood; center of the bone Yellow Marrow: makes fat; ends of the bone

• Ossification: Process of cartilage turning into bone Infants (“soft spot”); Males long bones (21); Females long bones (18) Osteoclasts eat cartilage and primitive bone cells appear (osteoblasts); Osteoblasts mature

into osteocytes Begins at the diaphysis (center) Primary Ossification Center Continues at the epiphyses (ends) Secondary Ossification Center Epiphyseal Disk: last place for cartilage to turn into bone (growth plate)

• Haversian Canals: microscopic view of bone concentric circles of blood vessels and cells

• Human Adult Skeleton (206 bones)

• Axial Skeleton: skull, vertebrae, thorax (80) Skull: (cranium); protects the brain; depressions called sinuses; cartilage in infant skull

to make birth easier/allow the brain to grow (fontannels); Bones include: frontal, temporal, parietal, occipital (foramen magnum)

Ear Bones: (3); smallest bones in the body

Facial Bones: hyoid (tongue); Mandible (lower jaw); Maxillary (upper jaw)

Sternum: breast bone (protects the heart); ribs attach to it

Ribs: (12 pairs); protect the lungs; true ribs (1-8); false ribs (9-12); floating ribs (11-12); intercostal muscles

Vertebrae: backbone; axis (yes); atlas (no);cervical (7); thoracic (12); lumbar (5); intervertebral disks (cartilage); slipped disk/herniated disk; kyphosis (hunchback); lordosis (swayback); scoliosis

Pelvis: (pelvic girdle) hips; females (wider and stronger)

Sacrum: fusion of 5 bones; wider in women; spina bifida

Coccyx: tailbone

• Appendicular Skeleton: Includes pectoral girdle (126) Clavicle: collar bone Scapula: shoulder bone; contain bursa (sacks of liquid); bursitis

Femur: thigh bone; longest bone Patella: kneecap (sesmoid bone) Tibia: shin bone (front); shin splints Fibula: calf bone (back) Tarsals: (7) ankle Metatarsals: (5) arch; “flat feet” Phalanges: (14) toes; bunions

Humerus: upper arm bone Radius: lower arm bone (up from thumb) Ulna: lower arm bone (up from little finger) Carpals: (8) Metacarpals: (5) palm Phalanges: (14) fingers

Joints

• Articulations; any place where 2 bones come together

• Types of Joints: Fibrous (immovable): sutures Cartilaginous: intervertebral disks

Synovial: freely move (with synovial fluid) Hinge: move in 1 plane (knee, elbow) Ball & Socket: rotate (hips, shoulders) Gliding: wrist, ankle Pivot: crossing over (radius-ulna)

• Ligament: an elastic band that connects a bone to a bone• Tendon: an elastic band that connects a bone to a muscle

• Skeletal System Conditions:• Fracture: a broken bone (simple-compound) Reduction: open vs. closed Dislocation: a bone is forced out of its normal position Hematoma: a bruise

• Sprain: ligaments or tendons are stretched• Osteoporosis: brittle bones; women after menopause • Arthritis: inflammation at the joints• Bursitis: inflammation at bursa• Rickets: decrease in Ca and vitamin D: bowed condition• Gout: uric acid crystals accumulate at big toe joint

Muscles

• Involve movement

• Work in antagonistic pairs (one muscle stretches/the other muscle contracts); extensor/flexor (triceps/biceps)

• Origin: place where muscle begins (on an immovable bone)

• Insertion: place where muscle ends (on a movable bone)

• Muscle Types: Skeletal (striated): moves the bones of the skeleton;

voluntary; bands called striations

Cardiac: branching bands; in the heart; involuntary

Smooth Muscle: wavy; in all organs that cannot be controlled; involuntary (intestines, uterus, stomach)

• Exercise: Isotonic: Muscles stretched out against an immovable object Isometric: Muscles push against something that gives Cross-training: combination of isotonic and isometric

• Muscular Conditions: Charley Horse: knot in muscles; lack of O2

Cramps: muscles contracting too fast; use a muscle relaxer Strain: a pulled muscle Steroids: build up muscle mass; long period with side effects