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Skeletal System

Skeletal System. Provides body with rigid framework of support and structure Bones are living organs. Can change and help body respond to changing environment Specialized cells allow bone to grow in size and shape as we grow. Functions. Support : supporting framework for body

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Skeletal System

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  1. Skeletal System • Provides body with rigid framework of support and structure • Bones are living organs. Can change and help body respond to changing environment • Specialized cells allow bone to grow in size and shape as we grow

  2. Functions • Support: supporting framework for body • Protection: skull protects brain, breastbone and ribs protect vital organs (heart, lungs), vital tissue (red bone marrow- blood cell forming tissue • Movement: muscles anchored to bone, contract and shorten, pull on bones and move • Storage: Maintain homeostasis of blood Calcium (bones store extra calcium in blood, when blood calcium low, bone releases calcium (can lead to osteoporosis) • Hemo (blood) poiesis (to make): blood cell formation in red marrow- found in spongy bone located in ends of long bones Infant: (cartilage skeleton turns to bone as cartilage is replaced with bone) . Increased red marrow turns into yellow marrow (inactive fatty tissue)

  3. Microscopic structure of bone and cartilage 2 major types of Connective Tissue • Bone • Cartilage

  4. BONE • Different appearance and texture depending on location • Outer bone layer: (hard & dense) Dense or Compact bone • Porous bone in end of long bones: Spongy bone (contains many spaces that can be filled with marrow) Trabeculae (in spongy bone- threads surround network of spaces) ( text 89)

  5. Compact or Dense Bone • No network of open spaces • Matrix of Haversian Systems (multiple layers of calcified matrix in rings called concentric lamella that surround Haversian canal which contains blood vessels • Bone cells: osteocytes, found between hard layers of lamella, in little spaces called lacunae. • Tiny passageways-canals: canaliculi connect lacunae with each other and the central canal in Haversian system (text 90, 91, overheads A9, A10)

  6. Nutrients pass from blood vessels in Haversian canal through canaliculi to osteocytes (in lacunae that are in concentric lamella) • Many blood vessels from outer periosteum enter bone -> Haversian canals (with blood vessel)

  7. Osteoclasts: bone absorbing cellsallow bone tissue present to be absorbed/removed Osteocytes and osteoclasts required for bones to grow and heal. Osteoblasts: bone forming cells

  8. Cartilage • Like bone consists of intercellular substances and cells • Collagenous fibers reinforce matrix of both tissues In cartilage: fibers are embedded in firm gel matrix gives flexibility In bone: hard, calcified matrix gives rigidity

  9. Chondrocytes: cartilage cells (like osteocytes in bone) are located in lacunae, but lacunae suspended in cartilage (gel) matrix (compared to bones concentric lamella) No blood vessels in cartilage. Nutrients must diffuse through matrix to reach cells (text 92, A11) Study guide part 1

  10. Structure of Long Bones • Diaphysis: (Shaft) Hollow tube made of hard compact bone- rigid, strong, structure. Light weight, easy movement • Medullary cavity: Hollow area inside diaphysis of bone contains soft yellow marrow (fatty) • Epiphysis: Ends of bone where red marrow fills in small spaces in spongy bone (trabeculae) that composes epiphysis • Articular cartilage: Thin layer of cartilage covering each epiphysis- functions like rubber cushion around joint • Periosteum: Strong fibrous membrane covering long bone, except at joint surfaces (where it’s covered by articular cartilage) (text 93, 94, overhead A9, A11)

  11. Epiphyseal fracture • Young children susceptible to fracture • Epiphyseal plate (growth plate) can be separated from diaphysis or epiphysis. • As soon as plate replaced with calcified matrix, growth is complete (text 94, 95, overhead A11)

  12. Bone formation and growth • Skeleton of baby before birth- cartilage & fibrous structures shaped like bone • Transforms into bone when cartilage replaced with calcified matrix deposited by osteoblasts, (bone forming cells) • Combined action of : Bone forming osteoblasts and bone absorbing osteoclasts sculpts bone into adult shapes. • Laying down of calcium salts in matrix  calcification makes bones hard. (XS Ca from blood stored in bone, low Ca in blood, Ca removed from bone osteoporosis • Vitamin D (made in dermis with UV exposure) aids is Ca absorption. (milk w/ vitamins A and D added) (text 94, overhead A11)

  13. Bone growth cont’d • Diaphysis: grows in both directions toward both epiphyses, and both epiphysis grow toward diaphysis • Continues until all epiphyseal cartilage has been transformed to bone • IF epiphyseal cartilage still present, growth still occurring. • If epiphyseal cartilage absent, adult growth attained. • Ossification: cartilage undergoes ossification and becomes bone. Occurs in shaft of diaphysis and then in epiphyses. (overhead A11) study guide part 2 and diagram 1 structure of human bone and diagram ws Skeletal Lab with Chicken Bones

  14. Types of bones

  15. flat bone Thin bones that protect certain organs, including most of the bones of the skull as well as the scapula.

  16. short bone Bones shaped somewhat like cubes that facilitate flexibility of the joints; examples include the bones of the wrist and ankle.

  17. long bone Elongated bone to which powerful muscles, such as those of the leg and arm, are attached.

  18. irregular bone Bones of varying shapes and sizes, such as the vertebrae and certain bones of the skull or pelvis.

  19. Divisions of Skeleton • Axial: bones of skull, spine, chest, hyoid • Appendicular: bones of upper extremities (shoulder, pectoral girdle, arms, wrists, hands), bones of lower extremities (hip, pelvic girdle, legs, ankles, feet). (text 96, 97, overhead A12, A13 review parts/terms/location) Interactive Drag and Drop. Simulations/Virtual surgeries Articulated/Disarticulated Skeleton and joints

  20. Axial Skeleton • SKULL: cranium (8 bones) face (14 bones) middle ear (6 bones) Sinuses: spaces/cavities inside some of cranial bones 4 pairs: frontal maxillary sphenoid ethmoid

  21. Openings into nose referred to as paranasal sinuses Inflammation of mucus membrane: swollen, painful frontal sinusitis (text 102, 103, overheads A14, A15) study guide diagram 4 and 5

  22. Mastoiditis • Inflammation of airspaces within mastoid portion of temporal bone from infection of middle ear. • Mastoid cells don’t drain into nose like paranasal sinuses. • Infectious material may erode bony partition to brain and spread infection to covering membranes (text 102, overhead A15)

  23. Axial skeleton cont’d • SPINE: (Vertebral column) Consists of series of separate bones (vertebrae), connected to form flexible rod 7 cervical region 12 thoracic region 5 lumbar region 1 sacrum region 1 coccyx region (text 104, overhead A16)

  24. Axial skeleton cont’d • Vertebrae: spinous process 2 transverse processes vertebral foramen (hole in center) • Tip head forward. Run finger down back of neck to shoulder level. Feel tip of 7th cervical vertebra’s spinous process • 7 cervical vertebrae form supporting framework of neck (text 104, 106, overhead A16)

  25. Axial skeleton cont’d 4 Curves of the spine: Neck and small of back curve slightly inward/forward Chest area of spine and lower lumbar curve opposite creating 4 curves • Cervical and lumbar curves: concave (in) • Thoracic and sacral: convex (out) Cervical: concave (in) develop Thoracic: convex (out) Lumbar: concave (in) develop Sacral: convex (out) (text 104, overhead A16) Concave in Convex out Concave in Convex out

  26. Axial skeleton cont’d Newborn: continuous convex curve from top to bottom. Gradually changes • Holding head up: concave neck-cervical (in) • Stand up: concave lumbar (in) Creates the 4 curves of the spine Normal curves important: Strength to support body, balance to stand, walk on 2 feet. Curved structure has increased strength (text 104, overhead A16)

  27. Axial skeleton cont’d • Poor posture/disease can cause curves to become abnormally exaggerated • Swayback or Lordosis: lumbar curve exaggerated lumbar

  28. Kyphosis or Huntchback: thoracic curve exaggerated • Scoliosis: abnormal side to side curvature • (text 105)

  29. Axial skeleton cont’d • THORAX or CHEST 12 prs of ribs Sternum (breastbone) Thoracic vertebrae All form bony cage/protection • Each of 12 prs of ribs attaches posteriorly to a vertebra • All ribs except lower 2 prs attach to sternum giving them anterior and posterior anchorage • Prs 1-7 true ribs: attach to sternum by costal cartilage • Prs 8, 9, 10 false ribs: attach to cartilage of 7th • Prs 11, 12 floating ribs: don’t attach to any costal cartilage (text 104, overhead A16)

  30. Appendicular Skeleton • 126 of 206 bones appendicular • Bones in shoulder & pectoral girdle attach the bones of arm, forearm, wrist and hands to axial skeleton of thorax • Bones in hip and pelvic girdle attach the bones of thigh, leg, ankle and feet to axial skeleton of pelvis

  31. Upper ExtremityPectoral girdle • Scapula (shoulder blade) and clavicle (collar bone) compose shoulder (pectoral girdle) which functions to attach upper extremity to axial skeleton (in thorax)

  32. Sternoclavicular joint:Only direct point of attachment between clavicle & sternum (breastbone)- very small attachment-  provides wide range of motion but susceptible to injury b/c ↑ pressure can occur at joint (text 96, 97, overheads A12, A13)

  33. Upper Extremity cont’d • Humerus: long bone of arm, 2nd longest in body • Attaches to scapula at its proximal end and articulates with 2 bones of forearm, the radius (thumb side) and ulna • Elbow: Ex of structure that determines function • Long bony process of ulna (olecranon process), fits into large depression on posterior surface of humerus (olecranon fossa) makes joint movement • Radius and ulna of forearm articulate with each other and distal end of humerus at elbow joint. • Radius and ulna touch each other distally for articulation with wrist bones (text 106, 107 overhead A17)

  34. Upper Extremity cont’d • Anatomical position: ulna medial (inside) radius lateral (outside-thumbside) Wrist and hands: manybones • 8 carpal (wrist bones) (vs 7 tarsals/ankle) • 5 metacarpal (form support structure for palm) • 14 phalanges (finger bones) (distal, middle, proximal) 27 total many bones, joints, =  increased dexterity but more bones to break (text 108, 109, overheads A18)

  35. Lower Extremity • Hip (pelvic girdle) attaches legs to trunk • Consists of 2 large innominate bones, 1 located on each side of pelvis • 2 innominate bones, sacrum, coccyx: provides strong base of support for torso- serves to attach lower extremities to axial skeleton • Infant: Innominate bone consists of 3 bones: ilium, ischium and pubis that grow to become 1 innominate bone in adult (text 119 review parts/location)

  36. Lower Extremity cont’d • Femur: thigh bone, longest bone in body • articulates proximally (toward hip) with innominate bone in deep cup shaped socket (acetabulum) • Articulation of acetabulum more stable than articulation of head of humerus with scapula in upper extremity • Hip dislocation less common than shoulder • Distally, femur articulates with knee cap (patella) and tibia (shin bone). • Fibula: slender outer (lateral) border of lower leg (text 112, 113, overhead A17)

  37. Lower Extremity cont’d • Toe bones: (phalanges) same # (14) as finger bones: (proximal, middle, distal) • Foot bones: 5 metatarsals (similar to hand/palm metacarpals) and 7 tarsals (vs 8 carpals in hand) • Feet: standing features for support • Big toe: more solid vs thumb, but less mobile • Foot bones, held together to form springy arches increase support, strength stable base Fallen arches: (flat feet) foot ligaments/tendons weaken 3 arches: medial longitudinal arch (inside) lateral longitudinal arch (outer edge) transverse or metatarsal arch (extends across ball of foot) (text 114, 118, overheads A19) study guide part 3 and diagram 2 and 3 axial/appendicular diagram ws LAB

  38. Male vs Female Skeleton • Size: male skeleton larger vs female (no functional importance) • Hip bone structural differences: (functional importance) • Female pelvis made so baby can be cradled before birth and pass through at birh • Male: Innominate (hip) bones larger and narrower Funnel Shaped • Female: pelvis broader, shallow basin shape, and pelvic inlet wider (text 119 review parts, location) study guide part 4 and with pgs 115-117 part 5 Male vs Female Pelvis Activity Bone Development and Osteoporosis worksheet Sports Injuries worksheet

  39. Osteoporosis • Osteoporosis: bone disease characterized by xs loss of calcified matrix and collagenous fibers from bone. • (xs calcium stored in bone, when calcium levels low, calcium removed from bone leaves bones brittle, degeneration increased fractures and curvature of spine • Sex hormones important role in stimulating osteoblast activity after puberty. Decreased hormone levels in elderly reduces new bone growth and maintenance. • Treat with hormone therapy, dietary supplements (calcium and vitamin D to help absorb calcium. ***Dermis cells exposed to UV rays make vitamin D (remember) to help absorption of calcium also vitamins A and D added to milk! Drink your milk!

  40. Joint Articulations • Every bone in body connects to another bone via joints- except hyoid bone in neck (tongue attaches to) • Joints perform 2 functions: 1. Holds bones together securely 2. Makes movement possible between bones Type of joint determines type and range of movement 3 kinds of joints based on degree of movement 1. Synarthroses 2. Amphiarthroses 3. Diarthroses (text 120, 121 overheads A20 and binder)

  41. Types of Joints cont’d • Synarthroses: joint where fibrous connective tissue grows between articulating (joining) bones, holding them close together sutures Ex. Cranial bones

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