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6 Unit 1 Chapter 6. 6 Unit 1 Support Protection Leverage- for motion Mineral Homeostasis Blood cell production Hemopoiesis in red bone marrow Triglyceride.

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Presentation on theme: "6 Unit 1 Chapter 6. 6 Unit 1 Support Protection Leverage- for motion Mineral Homeostasis Blood cell production Hemopoiesis in red bone marrow Triglyceride."— Presentation transcript:

1 6 Unit 1 Chapter 6

2 6 Unit 1 Support Protection Leverage- for motion Mineral Homeostasis Blood cell production Hemopoiesis in red bone marrow Triglyceride Storage

3 6 Unit 1 Long bones- longer than wide e.g. thigh, leg, arm, forearm, fingers & toes Short bones- almost cube shaped Most wrist & ankle bones Flat bones- thin & extensive surface E.g. Cranial bones sternum, ribs & scapulae Irregular bones- don’t fit above E.G vertebrae and some facial bones

4 6 Unit 1 Parts of a long bone: Diaphysis Epiphysis Metaphysis Articular cartilage Periosteum Medullary cavity Endosteum

5 Figure 6.1a

6 Figure 6.1b

7 6 Unit 1 Matrix= 25% water, 25% collagen fibers, 50% crystallized mineral salts Osteogenic cells- in periosteum Osteoblasts- secrete collagen fibers- Build matrix and become trapped in lacunae Become osteocytes- maintain bone Osteoclasts – formed from monocytes Digest bone matrix for Normal bone turnover

8 6 Unit 1 few spaces, right below periosteum Units = osteons (Haversian system) Central canal- blood vessels, nerves, lymphatics Concentric lamellae- layers of matrix Lacunae- “lakes” contain osteocytes Canaliculae- little canals nutrient flow from canals and between osteocytes

9 Figure 6.2a

10 6 Unit 1 units containing trabeculae spaces between trabeculae often contain Red Marrow No osteons but include lacunae & canaliculae

11 Figure 6.2b

12 6 Unit 1 Ossification 1. initially in embryo & fetus 2. Growth 3. remodeling 4. repair of fractures

13 6 Unit 1 Mesenchyme model - replaced with bone Intramembranous - Bone forms directly in mesenchyme layers (membrane like) Endochondrial - forms within hyaline cartilage developed from mesenchyme

14 6 Unit 1 Development of ossification center- Cells differentiate=> osteogenic=> osteoblasts Osteoblasts secrete organic matrix Calcification- cells become osteocytes In lacunae they extend cytoplasmic processes to each other Deposit calcium & other mineral salts Formation of trabeculae- spongy bone Blood vessels grow in and red marrow is formed Mesenchyme=> periosteum

15 6 Unit 1 Develop a cartilage model- Growth- chondroblasts secrete cartilage Perichondrium forms on surface Internal chondrocytes in lacunae die and form small cavities

16 Figure 6.3

17 6 Unit 1 Ossification proceeds inward with nutrient artery from surface perichondrium In disintegrating cartilage osteogenic cells=> osteoblasts and create a primary ossification center As bone forms perichondrium => periosteum

18 6 Unit 1 First spongy bone is formed Osteoblasts breaks some down=> Center develops a cavity wall of diaphysis => compact bone Near birth, blood vessels enter epiphysis Secondary center is developed Hyaline cartilage at end => articular cartilage


20 6 Unit 1 Length- chondrocytes in the epiphyseal plate divide and increase cartilage layer On diaphyseal side they die and are replaced by bone Stops during adolescence Periosteum supports surface growth for thickness

21 6 Unit 1 Remodeling in response to use- resorption by osteoclasts and deposition by osteoblasts Repair after a fracture Dead tissue removed Chondroblasts => fibrocartilage => spongy bone by osteoblasts => remodeled to compact bone

22 6 Unit 1 Partial- incomplete break (crack) Complete- bone in two or more pieces Closed (simple)- not through skin Open (compound)- broken ends break skin

23 6 Unit 1 Adequate minerals (Ca, Mg, P) Vitamins A, C, D Hormones Before puberty: hGH + insulin-like growth factors Thyroid hormone & insulin also required Sex steroids help adolescent growth spurt and cause closure of epiphyseal plate. Weight-bearing activity

24 6 Unit 1 Blood levels of Ca 2+ controlled Negative feedback loops Parathyroid hormone => increased osteoclast activity + decreased loss in urine Calcitonin=> decreased osteoclast activity

25 Figure 6.5

26 6 Unit 1 Bone strengthened in response to use Reabsorbed during disuse e.g. Bone loss during bed rest, fractures in cast, astronauts with no gravity

27 6 Unit 1 Two divisions: axial & appendicular Axial- around body axis E.g. head, hyoid, ribs, sternum, & vertebrae Appendicular- bones of upper & lower limbs plus girdles that connect them

28 Figure 6.6

29 6 Unit 1 Cranial bones: Frontal, 2 parietal, 2 temporal, occipital, sphenoid, and ethmoid Facial bones: 2 nasal, 2 maxillae, 2 zygomatic, mandible, 2 lacrimal, 2 paltine, 2 inferior nasal conchae, & the vomer

30 Figure 6.7a

31 Figure 6.7b

32 Figure 6.7c

33 Figure 6.8

34 Figure 6.9

35 Figure 6.10a

36 Figure 6.10b

37 6 Unit 1 Sutures- immoveable joint between skull bones Coronal, sagittal, lambdoidal, squamous Paranasal sinuses-cavities Located in bones near nasal cavity Fontanels- soft spot in fetal skull Allow deformation at birth Calcify to form sutures

38 Figure 6.11

39 6 Unit 1 Encloses spinal cord Supports head Point of attachment for muscles of back, ribs and pelvic girdle 7 cervical 12 thoracic 1 sacrum & 1 coccyx

40 6 Unit 1 4 normal curves Relative to front: cervical & lumbar curves are convex Thoracic & sacral curves are concave They increase strength, help in balance and absorb shocks

41 Figure 6.12a

42 Figure 6.12b

43 6 Unit 1 Body- disc-shaped front part Vertebral arch- extends back from body creates with the body a hole called vertebral foramen 7 processes- Transverse process extending laterally on each side Spinous process extending dorsally Two each of Superior and inferior articular processes- attach to neighboring vertebrae

44 Figure 6.13

45 6 Unit 1 region is number from top to bottom Cervical (C1-C7) Spinous process often bifid and have transverse foramina on transverse process C1- specialized to support head- called the atlas- articulates with head Lacks body and spinous process C2 – axis- has body & spinous process Also dens- that creates a pivot for head rotation

46 Figure 6.14

47 6 Unit 1 Thoracic (T1-T12 ) Larger than cervical Have facets for articulating with ribs Lumbar (L1-L5) Largest & strongest. Processes short & thick Sacrum (S1-S5 fused to one unit) Foundation for pelvic girdle Contain sacral foramina for nerves and blood vessels Coccyx- 4 fused coccygeal vertebrae

48 Figure 6.12a

49 Figure 6.12b

50 Figure 6.15

51 Figure 6.16

52 6 Unit 1 Thoracic cage = Sternum, costal cartilages & ribs and bodies of T1- T12 Sternum- form by 3 bones that fuse by age ~25yrs = manubrium, body, xiphoid process Ribs- 12 pairs 1-7 articulate with sternum directly costal cartilage= true ribs

53 Figure 6.17

54 6 Unit 1 Attach bones of upper limbs to axial skeleton Right & left Clavicle & Scapula

55 Figure 6.18

56 6 Unit 1 Humerus = arm bone Articulates with scapula at shoulder Articulates with radius & ulna at elbow Ulna – medial bone Radius- lateral bone (thumb side)

57 Figure 6.19

58 Figure 6.20a

59 Figure 6.20b

60 6 Unit 1 Carpus (wrist) -8 bones Metacarpals – 5 bones of hand Number 1-5 starting with thumb Phalanges- 14 bones of fingers Numbered like metacarpals each finger but the thumb has proximal, medial & distal Thumb only proximal & distal

61 Figure 6.21

62 6 Unit 1 Pelvic girdle includes two hip bones Joined in front at pubic symphysis At back- attached to sacrum = sacroiliac joint Pelvic (hip) bone also called coxal bones

63 Figure 6.22a

64 Figure 6.22b

65 6 Unit 1 3 bones fuse by age 23 to form coxal Ilium- largest & most superior Ischium- lower posterior part Pubis lower anterior part

66 Figure 6.23

67 6 Unit 1 Femur- thigh bone Articulates with hip proximally and the tibia and fibula distally Patella = kneecap in front of knee joint Tibia- large medial, weight bearing bone of leg Fibula- lateral to tibia and smaller

68 Figure 6.24

69 Figure 6.25

70 6 Unit 1 Tarsus (ankle) has 7 bones Large talus (ankle bone) and Calcaneus (heel bone) Metatarsals (foot bones) Numbered from medial to lateral Phalanges (toe bones) Big toe has proximal and distal phalanges while others have proximal, medial and distal phalanges. Numbered like metatarsals

71 Figure 6.26

72 Figure 6.27

73 6 Unit 1 Males usually have heavier bones Related to muscle size & strength Female pelvis is wider and shallower than the males- allows for birth

74 6 Unit 1 Birth through adolescence more bone formed than lost Young adults- gain & loss about equal As levels of sex steroids decline with age: bone resorption > bone formation Bones become brittle and lose Calcium

75 Figure 6.28

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