Understanding the Skeletal System: Functions, Structure, and Health

1. Chapter 5 The Skeletal System

2. Do Now • What are the major organs of the skeletal system? • What are the major functions of the skeletal system? • What are the 4 different types of tissues?

3. Bones through Life

4. By looking at bones you can determine: • Age • Sex • Some information about an individuals lifestyle

5. Cartilage before bone • Bones develop from cartilage • If cartilage is present bones can still grow • Bones are young if they have cartilage

6. Growing and Changing • All during life minerals are deposited and removed from bone • Childhood – minerals deposited faster than lost • Middle age – deposit = lost • Old age – minerals are lost faster than they are deposited

7. As people age the rib bones gradually change shape over the years – they become cup-shaped and jagged

8. Pelvic Girdle Changes • Females have wider pelvises than males – necessary for childbearing and childbirth

9. Male Female

10. Male or Female? • Female skull is rounder and smaller than the male’s • The female forehead is longer vertically and the jaw is smaller • Female sacrum is wider and shorter than the male’s • Female tailbone is more moveable than in a male

11. Skulls Grow • Young people’s skulls have bones that are not fused together – fontanelles or soft spots • Adults have skull bones that are fused together

13. Bones Tells a Story • To determine whether someone is right or left handed, you can compare the size of the bones • Limbs that are used are slightly larger • Broken bones can be detected by hairline scars • Arthritis and osteoporosis can also be seen in skeletal remains

15. Do Now • What are the major organs of the skeletal system? • What are the major functions of the skeletal system? • What are the 4 different types of tissues?

16. Chapter 5 The Skeletal System

17. Major Functions of the Skeletal System • Protects the body • Motion

18. The Skeleton is divided into two divisions: • Axial Skeleton – spine, ribs, skull • Appendicular Skeleton – Appendages – arms, legs and hips

20. Major Organs of the Skeletal System • Joints – place where two bones meet • Cartilages – flexible connective tissue, flexible matrix ex. Nose, ears • Ligaments – joins bone to bone at joints • Bones – hard, rigid connective tissue, matrix – lots of calcium

21. Bones: An Overview

22. Functions of the Bones

23. The Five Functions that bones perform: • Support – supports and anchors all soft organs • Protection – protects soft body organs

24. Movement – muscles attach to bones by tendons - bones are used as levers to move the body • Storage – stores fat, minerals (Ca and P) • Blood Cell Formation – Hematopoiesis – occurs in marrow cavities

26. Classification of Bones • 206 bones

27. Two Types of Bone Tissue • Compact Bone – dense and smooth • Spongy bone – small needlelike pieces of bone and open space

28. Bones are classified into 4 groups based on shape

29. 1. Long Bones • Longer than wide • Shaft with a head at both ends (compact bone) Ex. Arms and legs

30. 2. Short Bones • Cube shaped, spongy bones Ex. Wrist and ankle bones

31. 3. Flat Bones • Thin, flattened and usually curved • Compact sandwiches spongy

32. 4. Irregular Bones • Do not fit in another group Ex. Hips, vertebrae

34. Structure of a Long BoneGross Anatomy • Diaphysis (shaft) – length of bone, compact bone • Periosteum – membrane around the bone that contains blood vessels and nerves • Epiphyses – ends of a long bone

35. Epiphyseal Plate – growth plate – young bones lengthwise growth of a bone • Bone Markings – sites of attachment for muscles, tendons and ligaments – blood vessels and nerves pass through

36. Red Marrow – forms RBC’s – tips of bones • Yellow marrow – storage area for fat – middle of bones

38. Bones – Microscopic Anatomy

39. Osteocytes • Mature bone cells • Osteocytes – formed from – • Osteoblasts-bone forming cells (building) – capable of depositing calcium

40. Osteoclasts – bone destroying cells – capable of reabsorbing calcium • Osteocyctes are responsible for bone growth and changes in bone shape

41. Bones have their hardness because of calcium deposits. • Haversian canals run through the bones and contain blood vessels and nerves.

42. Bone Formation, Growth and Remodeling

43. Ossification is the process of bone formation • Bone is an active and dynamic tissue

44. Bones are continually remodeled in response to changes in two factors: • Calcium levels in the blood • The pull of gravity and muscles on the skeleton

45. Rickets • A disease of children in which bones fail to calcify • As a result, bones soften and a definite bowing of the weight bearing bones of the legs occurs

48. Bone Fractures

49. Despite their remarkable strength bones are subject to breaks (fractures)

50. Compound fracture