1. Skeletal System

2. Skeletal System
Bones:
22 skull
27 hand
26 foot

3. Skeletal System (cont.)
# of bones:
Adults 206
Babies 300

4. Function of Bones Support for body and organs Protection
for the brain, spinal cord, and vital organs
Movement
levers for muscles
Mineral storage – Ca, P
Blood cell formation
occurs in the marrow of bones

5. Division of Bones:
Axial skeleton – skull, vertebral column, sternum, rib cage
Appendicular skeleton –upper & lower limbs, shoulder, hip

6. Axial
Skeleton

7. Appendicular
Skeleton

8. Classification of Bones:
Long bones:
Arm and leg bones
Short bones:
Wrist bones
Flat bones:
The bones of the skull
Irregular bones:
Facial bones or vertebrae

9. Structure of Bones: Bones are living! (osteocytes)
Bones are solid networks of living cells and protein fibers that are surrounded by deposits of calcium salts.
Bones contain nerves, blood vessels & marrow

10. Compact & Spongy Bone

11. Provides strength & protection Outermost part of the bone
Compact Bone:
Dense & strong
Provides strength & protection
Outermost part of the bone

12. Less dense & contains bone marrow
Spongy Bone:
Less dense & contains bone marrow
Found in short, flat, and long bones
Surrounded by compact bone

13. Structure of Long Bone
Figure 6.3a,b

14. Structure of Long Bone
Periosteum- tough layer of connective tissue
Compact bone- found beneath periosteum
Haversian canals- network of tubes that run through compact bone & contain blood vessels and nerves.

15. Structure of Long Bone:
Spongy bone- ends of long bones & middle of short, flat bones.
Adds strength w/o mass!
Within bones are cavities that contain a soft tissue called bone marrow.

16. Structure of Long Bone:
Two types of bone marrow:
Yellow bone marrow- made up of fat cells
Red bone marrow- produces red blood cells, white blood cells, & platelets

17. Structure of Long Bone

18. Bone Structure (cont.)
Ends of Bones are lined with dense tissue: cartilage
Cushions bones
Provides support

19. Tendons: Tough fibers that connect muscle to bone
Bone Structure (cont.)
Tendons: Tough fibers that connect muscle to bone

20. Ligaments: Tough fibers that connect bone to bone
Bone Structure (cont.)
Ligaments: Tough fibers that connect bone to bone

21. Bone Cells:
Osteocytes- mature bone cells that are embedded in the matrix
Osteoclasts- break down bone
Osteoblasts- produce bone
Stop growing- late teens!
Our Bones are continuously remodel throughout our lives.

22. Osteoporosis
Osteoclast activity is faster than osteoblast activity!

23. Osteoporosis

24. Development of Bones:
Skeleton of embryo almost entirely cartilage:
Cartilage is a type of connective tissue that is made up of a network of protein fibers (both tough collagen & flexible elastin).

25. Development of Bone Cont’d:
Cartilage does not contain blood vessels!
Cartilage is replaced by bone during the process called ossification:
Osteoblasts secrete mineral deposits that replace cartilage with bone.
Osteoblasts surrounded by bone tissue – now osteocytes

26. Growth:
Long bones contain growth plates called epiphyseal lines at either ends

27. Growth:
Growth of cartilage at these plates causes the bones to lengthen.
Gradually cartilage replaced by bone- a.k.a. ossification
Late adolescence/ early adulthood growth plates replaced by bone- stop growing!
Cartilage in adults found:
- nose, external ears, attach ribs to sternum

28. Epiphyseal Fracture

29. Bone Connections
Joints- place where one bone attaches to another
Classified by movement:
Immovable
Slightly movable
Freely movable
Ligaments hold bone to bone

30. Bones are interlocked and held together by connective tissue or fused
Immovable Joints:
Allow no movement
Bones are interlocked and held together by connective tissue or fused
Example: skull bones

31. fixed

32. Slightly Movable Joints:
Permit a small amount of restricted movement
Bones are separated from each other
Example:
Joints between lower leg
Joints between adjacent vertebrae

33. inter-vertebral joints

34. Freely Movable Joints:
Permit movement in one or more directions
Grouped according to shapes of the surfaces of the adjacent bones.
Ball- and- Socket Joint
Hinge Joint
Pivot Joint
Saddle Joint

35. Ball-and-Socket Joint:
Permits movement in many directions
Allows for widest range of motion
Example:
Humerus bone and scapula

36. ball & socket

37. Permits back and forth motion Example: Femur and tibia/fibula
Hinge Joint:
Permits back and forth motion
Example:
Femur and tibia/fibula
Like open and closing a door!

38. hinge joint

39. Allow one bone to rotate around another. Humerus and radius/ulna
Pivot Joint:
Allow one bone to rotate around another.
Example:
Humerus and radius/ulna

40. pivot joint

41. Permits one bone to slide in two directions. Example:
Saddle Joints:
Permits one bone to slide in two directions.
Example:
Metacarpals with your carpals

42. saddle joint

43. Structure of Joints:
Cartilage covers the surfaces where two bones come together (protects bones)
Joint capsule helps hold bones together & consists of two layers:
Ligaments
Synovial fluid

44. Structure of Joints Cont’d:
Ligaments- hold bones together in a joint
Synovial fluid- produced by cells enables surfaces of the joint to slide over each other smoothly.

45. Cracking Knuckles Space between joints widen
Air bubble forms in the synovial fluid (joint lubricant)
Bubble bursts and makes cracking sound

46. Arthritis Bursitis Sprain Scoliosis Fracture Osteoporosis
Skeletal Conditions
Bursitis
Scoliosis
Osteoporosis
Arthritis
Sprain
Fracture

47. Bursitis
Inflammation of the bursa (sac)

48. Scoliosis
Curvature of the spine

49. Osteoporosis Inefficient bone replacement
5-10% of bone mass lost every 10 years past age of 40
Rate of bone eating cells exceeds bone building cells!

50. Ex. Rheumatoid arthritis Arthritis Joint inflammation
Lose strength & function
Ex.
Rheumatoid arthritis

51. Rheumatoid arthritis

52. Over stretching of ligaments or tendons
Sprain
Over stretching of ligaments or tendons
Torn ligaments require surgery

53. Fracture
Broken bone
Multiple types

54. Bone breaks but does not come through the skin
Types of Fractures:
Simple fracture:
Bone breaks but does not come through the skin

55. Bone protrudes through the skin
Types of Fractures:
Compound fracture:
Bone protrudes through the skin

56. Types of Fractures:
Stress fracture:
A thin crack in the bone