Download Skeletal System

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)
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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
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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
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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
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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
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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