The Skeletal System PART A. PowerPoint Lecture Slide Presentation by Patty Bostwick-Taylor, Florence-Darlington Technical College

Transcription

1 PowerPoint Lecture Slide Presentation by Patty Bostwick-Taylor, Florence-Darlington Technical College The Skeletal System 5 PART A

2 The Skeletal System Parts of the skeletal system Bones (skeleton) Joints Cartilages Ligaments Two subdivisions of the skeleton Axial skeleton bones that form the longitudinal axis of the body Appendicular skeleton bones of the limbs and girdles.

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5 Functions of Bones 1. Support the body 2. Protect soft organs 3. Allow movement due to attached skeletal muscles 4. Store minerals and fats (most important of which are calcium and phosphorous) 5. Blood cell formation (hematopoiesis)

6 Bones of the Human Body The adult skeleton has 206 bones Two basic types of bone tissue Compact bone Dense and looks smooth Homogeneous Spongy bone Small needle-like pieces of bone Many open spaces Figure 5.2b

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8 Classification of Bones on the Basis of Shape Figure 5.1

9 Classification of Bones Long bones Typically longer than they are wide Have a shaft with heads at both ends Contain mostly compact bone Example: Femur Humerus ** All the bones of the limbs, except the patella, carpals, and tarsals are long bones

10 Classification of Bones Figure 5.1a

11 Classification of Bones Short bones Generally cube-shape Contain mostly spongy bone Example: Carpals Tarsals

12 Classification of Bones Figure 5.1b

13 Classification of Bones Sesamoid Bones (round bones) Special type of short bone Form within tendons Best known example Patella

14 Classification of Bones Flat bones Thin, flattened, and usually curved Two thin layers of compact bone surround a layer of spongy bone Example: Skull Ribs Sternum

15 Classification of Bones Figure 5.1c

16 Classification of Bones Irregular bones Irregular shape Do not fit into other bone classification categories Example: Vertebrae Hip bones

17 Classification of Bones Figure 5.1d

18 Anatomy of a Long Bone Gross/Macroscopic Anatomy Diaphysis Shaft Composed of compact bone Epiphysis Ends of the bone Composed mostly of spongy bone

19 Anatomy of a Long Bone Figure 5.2a

20 Anatomy of a Long Bone Periosteum Outside covering of the diaphysis Fibrous connective tissue membrane Sharpey s fibers/perforating fibers Secure periosteum to underlying bone Arteries Supply bone cells with nutrients

21 Anatomy of a Long Bone Figure 5.2c

22 Anatomy of a Long Bone Articular cartilage (articulate join w/another bone) Covers the external surface of the epiphyses Made of hyaline cartilage Decreases friction at joint surfaces

23 Anatomy of a Long Bone Epiphyseal plate/growth plate Flat plate of hyaline cartilage seen in young, growing bone Epiphyseal line Remnant of the epiphyseal plate Seen in adult bones

24 Anatomy of a Long Bone Figure 5.2a

25 Anatomy of a Long Bone Medullary cavity Cavity inside of the shaft Contains yellow marrow (mostly fat) in adults In infants this area forms blood cells and red marrow is found there

26 Anatomy of a Long Bone Figure 5.2a

27 Bone Markings Surface features of bones Sites of attachments for muscles, tendons, and ligaments Passages for nerves and blood vessels Categories of bone markings Projections or processes grow out from the bone surface Depressions or cavities indentations

28 Bone Markings Table 5.1 (1 of 2)

29 Bone Markings Table 5.1 (2 of 2)

30 Microscopic Anatomy of Bone Osteon (Haversian system) A unit of bone containing central canal and matrix rings Central (Haversian) canal Opening in the center of an osteon Carries blood vessels and nerves Perforating (Volkman s) canal Canal perpendicular to the central canal Carries blood vessels and nerves from osteon to osteon

31 Microscopic Anatomy of Bone Figure 5.3a

32 Microscopic Anatomy of Bone Lacunae Cavities containing bone cells (osteocytes) Arranged in concentric rings Lamellae Rings around the central canal Sites of lacunae

33 Microscopic Anatomy of Bone Figure 5.3b c

34 Microscopic Anatomy of Bone Canaliculi Tiny canals Radiate from the central canal to lacunae Form a transport system connecting all bone cells to a nutrient supply

35 Microscopic Anatomy of Bone Figure 5.3b

36 Macro/Micro Labeling Diaphysis Periosteum Central (Haversian) canal Epiphyseal plate/line Canaliculus Epiphysis Lacuna Compact bone Osteocyte Spongy bone Perforating (Volkman s) canal Medullary cavity Lamella Yellow/Red bone marrow Osteon (Haversian system) Articular cartilage

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44 Formation of the Human Skeleton In embryos, the skeleton is primarily hyaline cartilage During development, much of this cartilage is replaced by bone Cartilage remains in isolated areas Bridge of the nose Parts of ribs Joints

45 Bone Growth (Ossification) Epiphyseal plates allow for lengthwise growth of long bones during childhood New cartilage is continuously formed Older cartilage becomes ossified Cartilage is broken down Enclosed cartilage is digested away, opening up a medullary cavity Bone replaces cartilage through the action of osteoblasts

46 Bone Growth (Ossification) Bones are remodeled and lengthened until growth stops Bones are remodeled in response to two factors Blood calcium levels Pull of gravity and muscles on the skeleton Bones grow in width (called oppositional growth)

47 Long Bone Formation and Growth Hyaline cartilage Articular cartilage Spongy bone New center of bone growth Medullary cavity Epiphyseal plate cartilage New bone forming Growth in bone width Bone starting to replace cartilage Bone collar Hyaline cartilage model Growth in bone length Blood vessels New bone forming Epiphyseal plate cartilage In an embryo In a fetus In a child (a) Figure 5.4a

48 Long Bone Formation and Growth Bone starting to replace cartilage In an embryo Bone collar Hyaline cartilage model (a) Figure 5.4a, step 1

49 Long Bone Formation and Growth New center of bone growth Hyaline cartilage Medullary cavity Bone starting to replace cartilage Growth in bone length Blood vessels Bone collar Hyaline cartilage model In an embryo In a fetus (a) Figure 5.4a, step 2

50 Long Bone Formation and Growth Hyaline cartilage Articular cartilage Spongy bone New center of bone growth Medullary cavity Epiphyseal plate cartilage New bone forming Growth in bone width Bone starting to replace cartilage Bone collar Hyaline cartilage model Growth in bone length Blood vessels New bone forming Epiphyseal plate cartilage In an embryo In a fetus In a child (a) Figure 5.4a, step 3

51 Long Bone Formation and Growth Figure 5.4b

52 Types of Bone Cells Osteocytes mature bone cells Osteoblasts bone-forming cells Osteoclasts bone-destroying cells Break down bone matrix for remodeling and release of calcium in response to parathyroid hormone Bone remodeling is performed by both osteoblasts and osteoclasts

53 **HOMEOSTATIC IMBALANCE** - Rickets - a disease in children in which bones fail to calcify - bones soften and show bowing - due to a lack of calcium or vitamin D

54 Bone Fractures Fracture break in a bone Types of bone fractures Closed (simple) fracture break that does not penetrate the skin Open (compound) fracture broken bone penetrates through the skin Bone fractures are treated by reduction realignment of bone ends, and immobilization by cast or traction

55 common types of fractures: 1. Comminuted - bone breaks into many fragments 2. Compression - bone is crushed 3. Depressed - broken bone portion is pushed inward 4. Impacted - broken bone ends are forced into each other 5. Spiral - ragged break occurs when excessive twisting forces are applied to a bone 6. Greenstick - bone breaks incompletely, like a green twig breaks

56 Common Types of Fractures Table 5.2

57 Repair of Bone Fractures Hematoma (blood-filled swelling) is formed Break is splinted by fibrocartilage to form a callus Fibrocartilage callus is replaced by a bony callus Bony callus is remodeled to form a permanent patch (bone remodeling)

58 Stages in the Healing of a Bone Fracture Hematoma Internal callus (fibrous tissue and cartilage) External callus New blood vessels Bony callus of spongy bone Healed fracture Spongy bone trabecula Hematoma formation Fibrocartilage callus formation Bony callus formation Bone remodeling Figure 5.5

59 Stages in the Healing of a Bone Fracture Hematoma Hematoma formation Figure 5.5, step 1

60 Stages in the Healing of a Bone Fracture Hematoma External callus Internal callus (fibrous tissue and cartilage) New blood vessels Spongy bone trabecula Hematoma formation Fibrocartilage callus formation Figure 5.5, step 2

61 Stages in the Healing of a Bone Fracture Hematoma Internal callus (fibrous tissue and cartilage) External callus New blood vessels Spongy bone trabecula Bony callus of spongy bone Hematoma formation Fibrocartilage callus formation Bony callus formation Figure 5.5, step 3

62 Stages in the Healing of a Bone Fracture Hematoma Internal callus (fibrous tissue and cartilage) External callus New blood vessels Bony callus of spongy bone Healed fracture Spongy bone trabecula Hematoma formation Fibrocartilage callus formation Bony callus formation Bone remodeling Figure 5.5, step 4

63 II. Joints - joints are also called articulations - 2 functions are to join bones together securely but also give the rigid skeleton mobility A.Functional Classification of Joints: 1. Synarthroses - immovable joints 2. Amphiarthroses - slightly movable joints 3. Diarthroses - freely movable joints

64 B. Structural Classification of Joints: 1. Fibrous joints - bones are united by fibrous/dense connective tissue - examples sutures of the skull

65 2. Cartilaginous joints- bone ends are connected by cartilage - examples: pubic symphysis of the pelvis (amphiarthrotic) - intervertebral joints of the spinal column - joints between the first ribs and the sternum (synarthrotic)

66 3. Synovial joints - articulating bone ends are separated by a joint cavity containing synovial fluid - synovial joints account for all joints in the limbs

67 C. Types of Synovial Joints Based on Shape 1. Plane joint - articular surfaces are flat - only short slipping & gliding movements are allowed - examples: intercarpal and intertarsal joints 2. Hinge joint - cylindrical end fits into trough-shaped end of another bone - examples: elbow joint, knee joint, and joints between the phalanges of the fingers

68 3. Pivot joint - rounded end of one bone fits into sleeve or ring of bone - examples: proximal radioulnar joint and the first two vertebrae atlas and axis 4. Condyloid joint - egg-shaped articular surface of one bone fits into oval concavity of another bone - examples: metacarpophalangeal joints/knuckles

69 5. Saddle joint - each articular surface has both concave & convex surfaces - examples: carpometacarpal joints in the thumb 6. Ball-and-Socket joint - spherical head of one bone fits into a round socket in another - examples: shoulders and hips

70 **HOMEOSTATIC IMBALANCES** 1. Bursitis - inflammation of the bursae or synovial membranes 2. Sprain- when the ligaments or tendons reinforcing a joint are damaged by excessive stretching or are torn away from the bone poorly vascular

71 **HOMEOSTATIC IMBALANCES** 3. Arthritis - inflammation of the joints/pain, stiffness, and swelling of the joint - most widespread progressive disease in the US 4. Osteoarthritis - chronic degenerative condition typically affecting the aged - over the years, the cartilage softens, frays, and eventually breaks down - most common in the fingers, cervical & lumber joints of the spine, and the large weight-bearing joints of the lower limbs (knees & hips)

72 **HOMEOSTATIC IMBALANCES** 5. Rheumatoid Arthritis - chronic inflammatory disorder - affected joints are in the fingers, wrists, ankles, and feet in a symmetrical manner - RA is an autoimmune disorder - a disorder in which the body's immune system attempts to destroy its own tissues