The Skeletal System. Chapter 4

Transcription

1 The Skeletal System Chapter 4

2 FUNCTIONS OF THE SKELETAL SYSTEM Support o Provides shape Protection o Internal organs Movement o Provides structure for muscle to act upon Storage o Minerals & fat Blood cell formation o hematopoiesis

3 ORGANIZATION OF BONE 2 different types of tissue o Cortical - dense o Trabecular spongy Outer layer always composed of cortical

4 CLASSIFICATION OF SHAPE

5 CLASSIFICATION OF BONES Long bones o Long round shaft made of cortical bone o Bulbous knobs of trabecular bone at ends o Major bones of arm and leg

6 GROSS ANATOMY OF LONG BONE

7 CLASSIFICATION OF BONES Short bones o Shaped like a cube o Mainly trabecular bone o Bones of wrists and ankles

8 CLASSIFICATION OF BONES Flat Bones o Thin o Large surface area o Curved to some extent Structurally: o 2 thing layers of cortical bone with a layer of trabecular in between

9 CLASSIFICATION OF BONES Irregular bones o Do not fit in other categories o Individualized shapes

10 MICROSCOPIC ANATOMY OF BONE Osteon (Haversian System) o Unit of bone Central (Haversian) Canal o Opening in center of osteon o Carries blood vessels & nerves Perforating (Volkmann s) Canal o Canals that run perpendicular to the central canal

11 MICROSCOPIC ANATOMY OF BONE Lacunae o Cavities containing bone cells (osteocytes) o Arranged in concentric rings Lamellae o Rings around the central canal o Sites of lucunae Canaliculi o Tiny sideways canals

12 TYPES OF BONE CELLS Osteocytes o Mature bone cells Osteoblasts o Bone building cells Osteoclasts o Bone destroying cells o Break down bone for remodeling and calcium release Bone remodeling is a process by both osteoblasts & osteoclasts

13 BONE FORMATION In embryos the skeleton is primarily hyaline cartilage During development cartilage is replaced by bone Cartilage remains in: o Bridge of nose o Parts of ribs o Joints

14 BONE GROWTH Ossification o Process of bone formation Two phases o Bone matrix cell covers the hyaline cartilage through osteoblast activity o Osteoclasts resorb the hyaline cartilage creating a medullary cavity

15 BONE GROWTH Longitudinal growth o At epiphyseal plates o Through adolescence Circumference growth o Throughout most of life

16 ADULT BONE When we age o Loss of collagen (elasticity) o Increase in bone brittleness Bone mineral peaks o Women: o Men: Women have smaller bones, therefore more problematic

17 BONE GROWTH Hypertrophy o Subject to larger (stronger forces) o Increase in density and growth at the site of force o Physically active: denser and stronger o Bone accounts for 15% of body weight Atrophy o Subject to reduced forces o Loss of bone mineral and density o Bedridden people o Swimmers o Astronauts

18 THE AXIAL SKELETON Designed to provide stability to the core of the body o Skull o Vertebral (spinal) column o Thoracic cage

19 THE SKULL 22 bones divided into 2 groups: o Cranial 8 bones o Facial 14 bones

20 THE CRANIUM Parietal bone

21 FACIAL BONES 2 nasal 2 maxillary 2 zygomatic 2 lacrimal 2 palantines 2 inferior nasal conchae Mandible Vomer

22 THE SPINE 33 stacked individual vertebrae Differ in size and shape 5 different regions

23 REGIONS OF THE SPINE

24 VERTEBRAE

25 THE THORACIC CAGE (BONY THORACIC) Ribs Sternum Thoracic vertebrae Work together to form a protective bony cage Surround the heart and lungs in thoracic cavity

26 THE THORACIC CAGE (BONY THORACIC)

27 THE APPENDICULAR SKELETON Body s appendages Upper extremity Lower extremity 126 bones Built for motion

28 THE SHOULDER COMPLEX Shoulder girdle Left & right clavicles Left and right scapula o Coracoid process o Acromiolclavicular joint o Sternoclavicular joint o Glenohumeral joint

29 THE ARM - HUMERUS

30 THE FOREARM RADIUS & ULNA

31 WRIST & HAND 54 bones (R & L) Carpal (8) Metacarpal (5) Phalanges (14) o Proximal o Medial o Distal

32 WRIST & HAND

33 THE PELVIC GIRDLE Shelters the reproductive organs, bladder, and large intestines

34 THE PELVIC GIRDLE

35 UPPER LEG - FEMUR Longest and strongest Fits snugly into acetabulum Neck of femur o Most vulnerable o Hip fractures

36 LOWER LEG TIBIA & FIBULA Tibia o Shinbone o Bears most weight Fibula o Serves as site for muscle attachments

37 THE ANKLE & FOOT Foot acts like a spring that stores and releases energy Two largest talus (ankle) and calcaneus o Bear most the weight

38 JOINTS Determine the direction of movement of the bones Classified in different ways o Complexity o Number of axes o Joint structure o Joint function Three main categories (with regard to function) o Immovable o Slightly moveable o Freely moveable

39 IMMOVEABLE JOINTS Synarthroses o syn means together o arthron means joint Absorb shock but permit little to no movement Two types o Sutures Sutures of the skull o Syndesmoses held by bands Tibiofibular joint

40 SLIGHTLY MOVEABLE JOINTS Amphiarthroses amphi - on both sides Cartilaginous joints allow more motion Two types o Synchondroses Sternocoastal joints, epiphyseal plates o Symphyses Pubic symphysis, vertebral joints

41 FREELY MOVEABLE JOINTS Diarthroses Also referred to as synovial joints Six different types o Gliding o Hinge o Pivot o Condyloid o Saddle o Ball & socket

42 SYNOVIAL JOINTS

43 SYNOVIAL JOINTS

44 BONE INJURIES Common fractures Simple bone ends remain in the surrounding tissue Compound one or both ends protrude from the skin Greenstick incomplete break (more common in children since their bones are more flexible due to higher collagen) Comminuted when the bone is splintered Impacted broken ends are forced into each other (breaking a fall with arms

45 BONE INJURIES

46 OSTEOPOROSIS

47 SPRAINS

48 ARTHRITIS

49 LONG BONE IMMOBILIZATION Long Bone Immobilization Video

50 Male vs. Female Skull

51 Male vs. Female Pelvis