1. The Skeletal System

2. Parts of the Skeletal System
Axial skeleton
Skull and bones that support it
Includes vertebra and ribs
80 bones
Appendicular skeleton
Limbs
126 bones

3. Axial Skeleton
AppendicularSkeleton

4. Functions of Skeletal System
SUPPORT: Hard framework that supports and anchors the soft organs of the body.
PROTECTION: Surrounds organs such as the brain and spinal cord.
MOVEMENT: Allows for muscle attachment therefore the bones are used as levers.
STORAGE: Minerals (Calcium and Phosphorus) and lipids are stored within bone material.
BLOOD CELL FORMATION: The bone marrow is responsible for blood cell production.

5. Classification of Bones
Compact: dense; looks smooth
Spongy: small needlelike pieces and lots of open spaces
Long: longer than they are wide; have a shaft and heads at both ends
Short: cube-shaped; mostly spongy bone
Flat: think, flattened, usually curved
Irrigular bone: bones that do not fit into any preceeding category (ex: hip and vertabrae)

7. Epiphysis: Ends of the bone.
Features of a Long Bone:
Epiphysis: Ends of the bone.
Diaphysis: The shaft of the bone which surrounds the medullary cavity.
Articular Cartilage: Cushions the ends of the bones and allows for smooth movement.
Epiphyseal Plate:
Areas made of cartilage allowing for the growth of the bone.

8. Contains blood vessels and nerve
Connects central canals to lacunae

9. Central Canal
w/ blood vessels,
nerves
Osteon
Lacunae w/
bone cells

10. Epiphyseal Plate
(Growth)

11. Bone Formation, Growth and Remodeling
Ossification: use of hyaline cartilage “model” which is later covered by bone via “osteoblasts” (Bone Formation)
Growth:
“osteoblasts” build up bone in the periosteum while “osteoclasts” break down bone from the inner face of the diaphysis = widening bone (appositional growth).
Influenced by growth and sex hormones; ends during adolesence. Note: Could also happen in an adult who works out with heavy weights, etc.
Remodeling: the dynamic/active process by which bone changes shape via:
Calcium levels in the blood
Pull of gravity and muscles over time

12. Calcium Control

13. Calcium Control When serum Ca+ falls Parathyroid hormone released
Causes osteoclasts to be released
Osteoclasts go to the bones and “lyse” or breakdown bone to release calcium for reapsorption into the blood stream = increases serum Ca+
Parathyroid hormone release also causes decrease in urinary excretion of Ca+ = raising serum levels
“Puts and/or keeps Calcium in the blood.”

14. Calcium Control When serum Ca+ rises
Parathyroid release is inhibited when CALCITONIN is released from the Thyroid
Osteoclast release is inhibited = decrease serum Ca+
Increase in urinary excretion of Ca+ = decreasing/normalizing serum levels
This process stabilizes or lowers Calcium in the blood.

15. Homeostatic Imbalance
Rickets:
A disease of children in which bones fail to calcify.
Bones are soft and bow with weight bearing.
Usually due to lack of calcium or vitamin D in the diet; can happen in infants who are nursed by mothers who have dietary deficiency of Ca++ and Vit D.

16. Bone Markings
Bones are shaped by the tissues that act upon and around them
Bones display bulges, depressions and holes which serve as sites of muscle, ligament and tendon attachment, points of articulation, or as conduits for blood vessels and nerves
Projections from the bone surface include heads, trochanters, spines, and others
Depressions include fossae, sinuses, foramina, and grooves

17. Bone Markings
Tuberosity - a large rounded projection which may be roughened
tibial tuberosity

18. Bone Markings Bone Markings
Crest - A narrow ridge of bone; usually prominent
Crest of the ilium

19. FYI: Male vs Female Pelvis

20. Bone Markings Bone Markings
Trochanter - A very large, blunt, irregularly shaped process
Greater trochanter of femur

21. Bone Markings Bone Markings
Line - Narrow ridge of bone; less prominent than a crest
Intertrochanteric line

22. Bone Markings Bone Markings
Tubercle - Small rounded projection or process
adductor tubercle

23. Bone Markings Bone Markings
Epicondyle - raised area on or above a condyle
medial epicondyle of the humerous

24. Bone Markings Bone Markings
Spine - A sharp, slender, often pointed projection
Spinous process of vertebrae

25. Bone Markings Bone Markings
Head - Bony expansion carried on a narrow neck
head of the humerus

26. Bone Markings Bone Markings
Facet - Smooth, nearly flat articular surface
facet on transverse process of thoracic vertebrae
Facet

27. Bone Markings Bone Markings Condyle - Rounded articular projection
lateral condyle of femur

28. Bone Markings Bone Markings Ramus - Armlike bar of bone
ramus of the pubis

29. Bone Markings Bone Markings Meatus - canal-like passageway
External auditory meatus

30. Bone Markings Bone Markings
Sinus - Cavity within a bone, filled with air and lined with mucous membrane
nasal sinus

31. Bone Markings Bone Markings
Fossa - Shallow, basinlike depression in a bone often serving as an articular surface
Olecranon fossa

32. Bone Markings Bone Markings
Groove - a narrow furrow in the surface of the bone
radial groove

33. Bone Markings
Bone Markings
Fissure - Narrow, slitlike opening

34. Bone Markings Foramen - Round or oval opening through a bone
Foramen magnum

35. Fractures

36. Bone Fractures

37. BoneFractures
Common in Osteoporosis

39. Bone Fractures

40. Bone Fractures Homeostatic Imbalance
Reduction: used to realign ends of broken bones
Closed: realignment done manually
Open: realignment done in surgery
Healing time (following reduction, casting/traction) is 6-8 weeks or longer if it is a larger bone or an elderly person.

41. Bone Fractures Healing Process Hematoma formation
Fibrocartilage callus forms
Bony callus forms
Bone remodeling occurs
Click Here

42. Axial Skeleton

43. While it sounds strange, skull bones are, in fact, FLAT!
Cranium
frontal bone
coronal suture
parietal bone
sagittal suture
lambdoidal
suture
occipital bone
While it sounds strange, skull bones are, in fact, FLAT!

44. Cranium (Side View)

45. Cranium (Top – Down View)
Pituitary lives here

46. Cranium (Under Side)

47. Cranium (Frontal View)

48. Paranasal Sinuses
Hollow portions of bones surrounding the nasal cavity
Figure 5.10

49. Paranasal Sinuses Functions of paranasal sinuses Lighten the skull
Give resonance and amplification to voice
Figure 5.10

50. The Hyoid Bone
The only bone that does not articulate with another bone
Serves as a moveable base for the tongue
Figure 5.12

51. The Fetal Skull
The fetal skull is large compared to the infants total body length
Figure 5.13

52. The Fetal Skull
Fontanelles – fibrous membranes connecting the cranial bones
Allow the brain to grow
Convert to bone within 24 months after birth
Figure 5.13

53. The Vertebral Column

54. The Vertebral Column (Curvatures)
Vertebrae separated by intervertebral discs
The spine has a normal curvature
Each vertebrae is given a name according to its location
Secondary
Primary
Secondary
Primary
Figure 5.14

55. The Vertebral Column
Before birth = 33 (later, 9 fuse to form the sacrum and the coccyx)
After birth = 24
7 - cervical
12 - thoracic
5 – lumbar
Sacrum (5 fused)
Coccyx (4 fused)
Memory Trick: Recall the 3 meal times

56. C 3,4,5 to Stay Alive

57. Hey! Where’s my Ventilator?
Look Ma! I can push myself!
I’m coming! I’m coming! Can’t you see I can’t move my legs!
Hey! I don’t think I’m going to make it to the bathroom!

58. Homeostatic Imbalance

59. Homeostatic Imbalance
Scoliosis

60. Homeostatic Imbalance

61. Structure of a Typical Vertebrae
Spinal Cord Passes Through Here
Figure 5.16

62. Regional Characteristics of Vertebrae
Figure 5.17a–b

63. Regional Characteristics of Vertebrae
Figure 5.17c–d

64. Sacrum and Coccyx

65. Not attached to sternum

66. Appendicular Skeleton

67. Appendicular Skeleton (in red)

68. Pelvis
Coccyx
Pubic Arch

69. Femur

70. Joints (Articulations)
Joint Movement:
Synarthroses – immovable
Amphiarthroses – slightly movable
Diarthroses – freely movable

71. Joints (Three Main Categories)
Cartilaginous
Synovial

72. Joints (Types) Click Here Plane Joint
Plane, hinge and pivot joints are types of synovial joints
Plane Joint

73. Developmentally Speaking…
Embryonic bone starts as “hyaline cartilage.”

74. Homeostatic Imbalance
Dislocations: when a bone is forced out of its normal position

75. FYI
Tendons: Connect Muscle to Bone
Ligaments: Connect Bone to Bone

76. Homeostatic Imbalance
Bursitis: inflammation of bursae or synovial membrane
Sprain: ligaments/tendons are damaged by excessive stretching
Strain:  when a muscle becomes overstretched and tears.
Arthritis: 100 different inflammatory or degenerative diseases that damage the joint; marked by inflammation, deformity, pain, stiffness
Osteoarthritis (OA): Most common; chronic degenerative condition typically in the aged; 85% of Americans; “wear and tear” on joints; bone spurs could develop; could be unilateral
Rheumatoid Arthritis (RA): chronic inflammatory disorder; usually between 40-50; 3 times more women; occurs bilaterally; AUTOIMMUNE/Systematic (any part of the body). Inflamed synovial membrane thickens into a pannus (rag). As cartilage is eroded, bones fuse = ankylosis. Marked by morning stiffness. Exacerbation and Remission.

77. Homeostatic Imbalance

78. Homeostatic Imbalance
Arthritis (con’td):
Gouty Arthritis: uric acid accumulates in the blood and is depositied as needle-shaped crystals in the soft tissues of joints; very painful; often appears at the great toe as “tophi”; more common in men; before 30; runs in families. Exacerbation and Remission.

79. Homeostatic Imbalance
Gout

80. Homeostatic Imbalance
Osteoporosis:
bone-thinning disease; calcium deficiency; afflicts half of women over 65; makes bones fragile and easy to break.
Causes: menopause, poor calcium and vit D intake, smoking, lack of weight bearing exercise
Pathological fractures: breaks that occur without apparent injury

81. Homeostatic Imbalance