Brown-Orange-Abstract-Modern-Presentation_20240928_223220_0000.pdf

Anaphy and physiology chapter 6: histology of bone

1. (General Considerations of Bones, Axial
Skeleton, Appendicular Skeleton)
ANATOMY OF BONE AND
JOINTS

2. Bones
Cartilages
Tendons
Ligaments
COMPONENTS OF SKELETAL
SYSTEM

3. SKELETAL SYSTEM

4. DIVISION OF THE
SKELETAL SYSTEM

5. THE AXIAL SKELETON
The axial skeleton is the central axis of the body, comprising
the bones of the head, neck, torso, and back. It protects vital
organs like the spinal cord, heart, and lungs, and serves as an
attachment site for muscles that facilitate movement and
respiration. The distinction between axial and appendicular
skeletons is based on the type of movement the bones
enable, rather than their location.

6. THE APPENDICULAR
SKELETON
The appendicular skeleton includes all bones of the upper
and lower limbs, plus the bones that attach each limb to
the axial skeleton. There are 126 bones in the appendicular
skeleton of an adult.

7. FIGURE AT THE AXIAL AND
APPENDICULAR SKELETONS

8. BONES OF THE SKELETAL SYSTEM
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9. Support1.
Function 2.
Movement3.
Storage 4.
Blood cell production5.
SKELETAL SYSTEM FUNCTIONS

10. Bone, Cartilage, tendons, and ligaments of the skeletal system are all connective
tissues.
Their characteristics are largely determined by their composition of their
extracellular matrix.
The matrix always contains collagen, ground substance, and other organic
molecules, as well as water and minerals.
EXTRACELLULAR MATRIX

11. Collagen is a tough, ropelike protein.
Proteoglycans are large molecules consisting of many polysaccharides attaching to and
encircling core proteins.
The proteoglycans form large aggregates and attract water.
The extracellular matrix of tendons and ligaments contains large amounts of collagen
fibers, making these structures very tough, like ropes or cables.
EXTRACELLULAR MATRIX

12. The extracellular matrix of cartilage contains collagen and proteoglycans.
Collagen makes cartilage tough, whereas the water-filled proteoglycans make it smooth and
resilient.
As a result, cartilage is relatively rigid, but it springs back to its original shape after being
bent or slightly compressed.
It is an excellent shock absorber
CARTILAGE EXTRACELLULAR
MATRIX

13. The extracellular matrix of bone contains collagen and minerals, including calcium and
phosphate.
The ropelike collagen fibers lend flexible strength to the bone.
The mineral component gives bone compression (weight-bearing) strength.
Most of the mineral in bone is in the form of calcium phosphate crystals called
hydroxyapatite.
BONE EXTRACELLULAR MATRIX

14. There are four bone shape classifications: long, short, flat, and irregular.
Long bones are longer than they are wide; examples are upper and lower limb bones.
Short bones are approximately as wide as they are long; examples are the bones of
the wrist and ankle.
SHAPE CLASSIFICATION OF
BONES

15. Flat bones have a relatively thin, flattened shape; examples are bones of the skull and
sternum.
Irregular bones include the vertebrae and facial bones, which have shapes that do
not fit readily into the other three categories.
SHAPE CLASSIFICATION OF
BONES

16. LONG BONE STRUCTURES
Diaphysis:
Shaft
compact bone
tissue (on outside)
Epiphysis:
ends spongy bone tissue
Articular cartilage:
covers epiphyses
reduces friction

17. LONG BONE STRUCTURES
Epiphyseal plate:
site of growth
between
diaphysis and
epiphysis
Medullary cavity:
center of
diaphysis red or
yellow marrow

18. LONG BONE STRUCTURES
Periosteum:
membrane around
bone’s outer
surface
Endosteum:
membrane that
lines medullary
cavity

19. STRUCTURE OF LONG BONE

20. Bones contain cavities, such as the large medullary cavity in the diaphysis, as well as smaller
cavities in the epiphyses of long bones and in the interior of other bones.
These spaces are filled with soft tissue called marrow.
Red marrow is the location of blood forming
cells.
Yellow marrow is mostly fat.
BONE MARROW

21. In newborns most bones have blood making red bone marrow.
In adults red marrow in the diaphysis is replaced by yellow bone marrow.
In adults most red bone marrow is in the flat bones and the long bones of the femur and
humerus.
BONE MARROW

22. COMPACT BONE TISSUE
Location:
outer part of diaphysis (long bones)
and thinner surfaces
of other bones
Osteon:
structural unit of compact bone
includes lamella, lacunae, canaliculus,
central canal, osteocytes
Lamella:
rings of bone matrix

23. COMPACT BONE TISSUE
Lacunae:
spaces between lamella
Canaliculus:
tiny canals
transport nutrients
and remove
waste
Central canal:
center of osteon
contains blood vessels

24. STRUCTURE OF BONE TISSUE

25. Spongy bone
• It is located at the epiphyses of long bones and center of other bones.
• It has trabeculae, which are interconnecting rods, and spaces that contain marrow.
• It has no osteons.
SPONGY (CANCELLOUS) BONE TISSUE

26. SPONGY BONE TISSUE

27. Osteoblasts: responsible for the formation of bone and the repair and remodeling of bone.
Osteocytes: cells that maintain bone matrix and form from osteoblast after bone matrix has
surrounded it.
Osteoclasts: contribute to bone repair and remodeling by removing existing bone, called
bone reabsorption.
BONE CELLS

28. Ossification is the formation of bone by osteoblasts.
Bone formation that occurs within connective tissue membranes is called intramembranous
ossification.
Bone formation that occurs inside hyaline cartilage is called endochondral ossification.
Both types of bone formation result in compact and spongy bone.
BONE FORMATION

29. Intramembranous ossification occurs when osteoblasts begin to produce bone within
connective tissue.
This occurs primarily in the bones of the skull.
Osteoblasts line up on the surface of connective tissue fibers and begin depositing bone
matrix to form trabeculae.
INTRAMEMBRANOUS
OSSIFICATION

30. The process begins in areas called ossification centers and the trabeculae radiate out from
the centers.
Usually, two or more ossification centers exist in each flat skull bone and mature skull bones
result from fusion of these centers as they enlarge.
The trabeculae are constantly remodeled and they may enlarge or be replaced by
compact bone.
INTRAMEMBRANOUS
OSSIFICATION

31. BONE FORMATION IN THE FETUS

32. Endochondral bone formation is bone formation within a cartilage model.
The cartilage model is replaced by bone.
Initially formed is a primary ossification center, which is bone formation in the diaphysis
of a long bone.
A secondary ossification center is bone formation in the epiphysis.
ENDOCHONDRAL OSSIFICATION

33. 1. Chondroblasts build a cartilage model, the chondroblasts become chondrocytes.
2. Cartilage model calcifies (hardens).
3. Osteoblasts invade calcified cartilage and a primary ossification center forms diaphysis.
4. Secondary ossification centers form epiphysis.
5. Original cartilage model is almost completely ossified and remaining cartilage is
articular cartilage.
STEPS IN ENDOCHONDRAL
OSSIFICATION

34. ENDOCHONDRAL OSSIFICATION OF A
LONG BONE

35. Bone growth occurs by the deposition of new bone lamellae onto existing bone or other
connective tissue.
As osteoblasts deposit new bone matrix on the surface of bones between the periosteum
and the existing bone matrix, the bone increases in width, or diameter.
This process is called appositional growth.
BONE GROWTH IN WIDTH

36. Growth in the length of a bone, which is the major source of increased height in an
individual, occurs in the epiphyseal plate.
This type of bone growth occurs through endochondral ossification.
Chondrocytes increase in number on the epiphyseal side of the epiphyseal plate.
BONE GROWTH IN LENGTH

37. Then the chondrocytes enlarge and die.
The cartilage matrix becomes calcified.
Much of the cartilage that forms around the enlarged cells is removed by osteoclasts,
and the dying chondrocytes are replaced by osteoblasts.
BONE GROWTH IN LENGTH

38. The osteoblasts start forming bone by depositing bone lamellae on the surface of the
calcified cartilage.
This process produces bone on the diaphyseal side of the epiphyseal plate.
BONE GROWTH IN LENGTH

39. ENDOCHONDRAL BONE GROWTH

40. Bone remodeling involves:
• removal of existing bone by osteoclasts and
• deposition of new bone by osteoblasts
• occurs in all bones
• responsible for changes in bone shape, bone
• repair, adjustment of bone to stress, and
• calcium ion regulation
BONE REMODELING

41. 1. Broken bone causes bleeding and a blood clot forms.
2. Callus forms which is a fibrous network between 2 fragments.
3. Cartilage model forms first then, osteoblasts enter the callus and form
cancellous bone this continues for 4-6 weeks after injury.
4. Cancellous bone is slowly remodeled to form compact and cancellous bone.
BONE REPAIR

42. BONE REPAIR

43. Bone is a major storage site for calcium
Movement of calcium in and out of bone helps determine blood levels of calcium
Calcium moves into bone as osteoblasts build new bone
Calcium move out of bone as osteoclasts break down bone
Calcium homeostasis is maintained by parathyroid hormone (PTH) and calcitonin
BONE AND CALCIUM HOMEOSTASIS

44. CALCIUM HOMEOSTASIS

45. Foramen:
• hole
• Example - foramen magnum
Fossa:
• depression
• Example - glenoid fossa
Process:
• projection
• Example - mastoid process
BONE ANATOMICAL TERMS

46. Condyle:
• smooth, rounded end
• Example - occipital condyle
Meatus:
• canal-like passageway
• Example - external auditory meatus
Tubercle:
• lump of bone
• Example - greater tubercle
BONE ANATOMICAL TERMS

47. The axial skeleton is composed of the skull, the vertebral column, and the thoracic cage.
The skull has 22 bones divided into those of the braincase and those of the face.
The braincase, which encloses the cranial cavity, consists of 8 bones that immediately
surround and protect the brain.
The bony structure of the face has 14 facial bones.
AXIAL SKELETON

48. Thirteen of the facial bones are rather solidly connected to form the bulk of
the face.
The mandible, however, forms a freely movable joint with the rest of the skull.
There are also three auditory ossicles in each middle ear (six total).
AXIAL SKELETON

49. Frontal bone
• Anterior part of cranium
Parietal bones
• Sides and roof of cranium
Occipital bones
• Posterior portion and floor of cranium
Temporal bones
• Inferior to parietal bones on each side of the cranium
• Temporomandibular joint
CRANIAL BONES

50. Sphenoid bone
• Forms part of cranium floor, lateral posterior portions of eye orbits, lateral
portions of cranium anterior to temporal bones
• Sella turcica
Ethmoid bone
• Anterior portion of cranium, including medial surface of eye orbit and
roof of nasal cavity
• Nasal conchae
CRANIAL BONES

51. Maxillae
• Form upper jaw, anterior portion of hard palate, part of lateral walls of
nasal cavity, floors of eye orbits
• Maxillary sinus
Palatine bones
• Form posterior portion of hard palate, lateral wall of nasal cavity
FACIAL BONES

52. Zygomatic bones
• Cheek bones
• Also form floor and lateral wall of each eye orbit
Lacrimal bones
• Medial surfaces of eye orbits Nasal bones
• Form bridge of nose
FACIAL BONES

53. Vomer
• In midline of nasal cavity
• Forms nasal septum with the ethmoid bone
Inferior nasal conchae
• Attached to lateral walls of nasal cavity Mandible
• Lower jawbone • Only movable skull bone
FACIAL BONES

54. THE SKULL

58. THE SKULL

59. THE SKULL

60. THE SKULL

61. THE SKULL

62. Several of the bones associated with the nasal cavity have large cavities
within them, called the paranasal sinuses which open into the nasal cavity.
The paranasal sinuses are:
• Frontal
• Ethmoid
• Sphenoid
• Maxillary
PARANASAL SINUSES

63. PARANASAL SINUSES

64. The hyoid bone is an unpaired, U-shaped bone that is not part of the skull and
has no direct bony attachment to the skull or any other bones.
The hyoid bone has the unique distinction of being the only bone in the body
that does not articulate with another bone.
The hyoid bone provides an attachment for some tongue muscles, and it is an
attachment point for important neck muscles that elevate the larynx.
HYOID BONE

65. HYOID BONE

66. The vertebral column, or spine, is the central axis of the skeleton, extending from
the base of the skull to slightly past the end of the pelvis.
In adults, it usually consists of 26 individual bones, grouped into five regions.
The adult vertebral column has four major curvatures: cervical, thoracic, lumbar and
sacrococcygeal.
The cervical region curves anteriorly.
The thoracic region curves posteriorly.
The lumbar region curves anteriorly
The sacral and coccygeal regions together curve posteriorly
VERTEBRAL COLUMN

67. 7 cervical vertebra
12 thoracic vertebra
5 lumbar vertebra
1 sacrum
1 coccyx
Atlas:
• 1 st vertebra
• holds head
Axis:
• 2nd vertebra
• rotates head
VERTEBRAL COLUMN

68. Supports body weight
Protects the spinal cord Allows spinal nerves to exit the spinal cord
Provides a site for muscle attachment
Provides movement of the head and trunk
FUNCTIONS OF VERTEBRAL COLUMN

69. VERTEBRAL COLUMN

70. VERTEBRA

71. REGIONAL DIFFERENCES IN VERTEBRAE

72. SACRUM

73. Protects vital organs
12 pair of ribs
Sternum:
• breastbone
True ribs:
• attach directly to sternum by cartilage
False ribs:
• attach indirectly to sternum by cartilage
Floating ribs:
• not attached to sternum
THORACIC CAGE

74. THORACIC CAGE

75. Scapula:
• shoulder blade
Clavicle:
• collar bone
BONES OF THE PECTORAL
GIRDLE

76. PECTORAL GIRDLE

77. SCAPULA AND CLAVICLE

78. Humerus:
• upper limb
Ulna:
• forearm
Radius:
• forearm
Carpals:
• wrist
Metacarpals:
• hand
UPPER LIMB BONES

79. UPPER LIMB BONES

80. THE HUMERUS

81. ULNA AND RADIUS

82. BONES OF THE WRIST AND HAND

83. THAT'S ALL THANK
YOU!!!