ANATOMY PHYSIOLOGY Skeletal System Unit 3 Functions of

ANATOMY & PHYSIOLOGY Skeletal System Unit 3

Functions of bones • Lower extremities support body weight • Support & protect soft body organs • Movement • Storage • Production of RBC’s

Shapes of Bones • Long • Flat – Support weight – Withstand force – Arms & legs • Short – cube-like – Wrist & ankles – thin, flat, curved – Protection – Ribs, sternum & cranium • Irregular – different shapes – Hip, vertebrae

Compact Bone Characteristics • Dense, hard osseous, tightly packed • Shafts of long bones & outer surface of other bones • Haversion system • Blood vessels run lateral

Cancellous Bone Characteristics • Spongy bone • No haversian systems • Trabeculae – Bony plates separated by irregular spaces • Decrease weight of bone • Contain red bone marrow

Functions of Red & Yellow Bone Marrow • Red – Spongy bone – Blood supply for spongy bone – Produces blood cells for body to use • Yellow – Medullary cavity – Storage for fat – In adults, not associated with blood cell production (hematopoiesis)

Parts of Long Bones • Diaphysis – Long shaft – Mostly compact bone – Provides strength • Epiphysis – Enlarged ends – Consists of thin compact bone layer overlying spongy bone – Covered by cartilage – Articulates second bone at a joint

Parts of Long Bones • Epiphyseal disc – Band of hyaline cartilage at ends between epiphysis & diaphysis • Growth plate = longitudinal growth • Medullary cavity – Hollow center of diaphysis • Endosteum – Lining of the inside of the medullary cavity

Parts of Long Bones • Periosteum – Tough fibrous connective tissue covering all outside surfaces of diaphysis except articular cartilage • Protection of the bone • Point of attachment • Contains blood vessels • Articular cartilage – Found on outer surface of epiphysis – Smooth shiny surface decreases friction

Bone Growth & Repair Ossification Flat bones • Osteoblasts – bone forming cells – Migrate to center of thin connective tissue forming flat bone – Secrete calcium & other minerals into spaces between connective tissue = bone Long bones • Osteoblasts invade cartilage, gradually replaced with bone • Articular cartilage & epiphyseal disc not replaced

Growing Bones • Longitudinal growth – Epiphyseal disc • Cartilage next to epiphysis multiplies & grow toward diaphysis • Osteoblasts invade cartilage next to diaphysis which becomes ossified • Bone lengthens as long as cartilage continues to form • Sensitive to hormones – GH = growth – Sex hormones = fuse (seal) discs • Injury to disc = retard bone growth

Growing Bones • Thicker & wider growth – Osteoblasts • Building bone on the outside – Osteoclasts • Breaking down bone tissue on the inside (bone resorption)

Bone Markings Functions • Bone surface irregular & bumpy Know. Table 8 -1 – Projections • Markings that stick out, points of attachment for muscles, tendons & ligaments – Styloid process – tongue, larynx muscles – Mastoid process – neck muscles – Grooves & depressions • Form routes for blood vessels & nerves *Projections & depressions help form joints*

Skeletal Divisions • Axial – – Skull bones Middle ear bones Vertebral column Bony thorax • Appendicular – Extremity bones – Hip bones – Shoulder girdle

Skull Bones • Cranium & facial bones • Cranium = 8 bones – – – Frontal Parietal (2) Temporal (2) Occipital Sphenoid Ethmoid

Cranium Associated Areas • Temporal area bone markings External auditory meatus Zygomatic process Styloid process Mastoid process • Occipital bone Foramen magnum • Sutures Coronal Squamous Lambdoidal

Facial Bones • 14 bones Mandible • Temporomandibular joint Maxillary (2) Palatine (2) Zygomatic (2) Others (nasal, lacrimal, vomer)

Other Associated Areas • Sinuses – Air cavities – 4 paranasal • • Frontal Ethmoidal Sphenoidal Maxillary • Fontanels – “soft spots” • Anterior • Posterior

Vertebral Column Regions • Vertebrae – 26 bones – Cervical (C 1 -C 7) • C 1 – atlas; support • C 2 – axis; pivot – Thoracic (T 1 -T 12) – Lumbar (L 1 -L 5) – Sacrum – Coccyx • Associated areas – Intervertebral disc – Vertebral foramen

Thoracic Cage • Sternum Manubrium Body Xiphoid process • Ribs – True ribs = 1 -7 – False ribs = 8 -10 – Floating = 11 & 12 – Costal cartilage

Shoulder • Pectoral or shoulder girdle – Clavicle – Scapula • Acromion process

Arm • Upper extremities – Humerus – Radius – Ulna

Hand • Hand – Carpals (8) – Metacarpals (5) – Phalanges (14)

Pelvis • Differences: – Female = broader/shallower – Male = narrower / funnel-like • Sacrum • Coccyx Pelvic girdle – 2 coxal (hip) bones joined together Ilium • Iliac crest Ischium • Ischial tuberosity Pubis • Symphysis pubis * Obturator foramen * Acetabulum

Leg • Lower extremity – Femur • Greater & lesser trochanter – Patella – Tibia • Medial malleolus – Fibula • Lateral malleolus

Foot • Foot – Tarsals (7) – Calcaneus – Metatarsals (5) – Phalanges (14)

JOINTS 2 Functions =Hold bones together =Provide flexibility 3 Classification groups =immovable =slightly movable =freely movable (synovial)

Synovial Joints • Structures – Articular cartilage – Joint capsule – Synovial membrane – Synovial fluid – Bursae (bursa) – Supporting ligaments

Synovial Joints Classifications – Hinge – Ball & socket – Pivot – Saddle – Gliding – Condyloid

Movement of Synovial Joints • Flexion • Adduction • Extension • Inversion • Plantar flexion • Eversion • Dorsiflexion • Supination • Hyperextension • Pronation • Abduction • Circumduction