1. The Skeletal System

2. Functions Allows Movement SupportProtection Red Blood Cell Production Mineral Storage

3. Overview A newborn baby has 305 bones in it’s body, and it continues to develop to the age of 25 At that age the bones fuse together to obtain maximum strength.

4. Overview The average adult skeleton has 206 bones The largest bones are in the thigh (Femur) and in the upper arm (Humerus). The smallest bones are the 3 tiny bones in you middle inner ear

5. Overview All bones are living organs, which contain living materials (cells), and non- living (mineral) materials

6. Functions Support: Bones provide support for tendons and ligaments and the framework for body shape Tendons= cords of thick, strong fibres that connect muscle to bone Ligaments= cords of thick, strong fibres that connect bone to bone

7. Functions Protection: Bones such as the cranium, ribs and sternum provide vital protection for internal organs such as the brain, heart and lungs

8. Functions Movement: Bones work together with skeletal muscles to help produce movement Muscles, which are usually arranged in pairs, are attached to the skeleton, when one contracts…the other relaxes, etc…

9. Functions Muscles move the bones, bones meet (articulate) at the joints, and the whole body then becomes mobile

10. Functions Mineral Storage: Bones are a site for storage and the release of minerals. Foods that contain more calcium and phosphorus than the body are stored in the bones in the form of collagen. Collagen = A strong, flexible material produced by bone cells. Forms the main part of connective tissue such as tendons and ligaments

11. Mineral Storage

12. Functions Blood Cell Production: Bones are responsible for the production of new blood cells. The body makes millions of these cells every second The spaces between the spongy bone are filled with red bone marrow

13. Functions Red Bone Marrow is bone tissue that makes Red Blood Cells and some White Blood Cells

14. What’s in a Bone? Periosteum Is a tough membrane. Contains blood vessels that enter the bone at many points nourishing the cells inside. Contains the cells for growth and repair.

15. What’s in a Bone? Compact bone lies beneath the periosteum and as the name suggests it is hard and dense. Compact bone covers the spongy bone at either end of long bone.

16. What’s in a Bone? Compact bone is at it’s thickest at the shaft of the bone. Compact bone gives strength, whilst spongy bone acts as a shock absorber

17. What’s in a Bone? Yellow Bone Marrow fills the shaft of the long bone and is used as a fat storage site. It is mostly made of fat cells

18. Developing Bones A baby’s bones contain cartilage, a tough, strong tissue is not as hard as bone. Cartilage is more flexible and tends to bend a little without breaking **Check the end of your nose**

19. Developing Bones As the child grows this cartilage is replaced by bone, becoming harder and less flexible Therefore it is easier for a teenager to break a bone than it is for a child. Note: If the bone is flexible it will bend under strain before snapping!

20. Developing Bones Bone cells are constantly replaced throughout our lives. During our growth spurt in puberty our bones grow longer, stronger and heavier

21. Developing Bones The body shrinks in old age, mainly due to the discs between the vertebrae becoming smaller and more compacted.

22. Developing Bones Peak Bone Mass = The formation of mineral deposits and compact bone that helps give maximum strength to bone The formation of mineral deposits and compact bone that helps give maximum strength to bone

23. Developing Bones Osteoporosis = A condition which results in loss of bone mass and strength, making bones more fragile and likely to break or fracture

24. Exercise & Bones By the late teens, skeletal growth is almost complete Activities that are weight- bearing in nature and high impact (gymnastics, running, basketball, etc) are believed to be of the greatest benefit in bone formation

25. Exercise & Bones These types of activities help bones form heavier mineral deposits with thicker layers of compact bone **This reduces the risks of fractures and osteoporosis later in life

26. Exercise & Bones Weight / Resistance training can also have positive effects on bone mass through the stress placed upon the bones during muscular contractions

27. Exercise & Bones Note: However, irreversible joint damage is known to occur, particularly in young males who have not finished growing when they undergo strenuous weight training…. So be careful!!!

28. Bone Classifications Bones can vary in size and shape based upon the function that they serve within the body. These are: 1.Long Bones 2.Short Bones 3.Flat Bones 4.Irregular Bones

29. Long Bones Consist of a long shaft covered by hard bone around a hollow centre which contains yellow marrow The two ends contain spongy bone and red marrow

30. Long Bones These bones are light but very strong, and are the major weight- bearing bones of the body EG: The Femur in the thigh the thigh

31. Short Bones These bones are chunky, compact bones that are strong and reinforced by thickening of the bone tissue. They contain spongy bone and allow a variety of movements at joints EG: Carpals in the hand the hand

32. Flat Bones These bones are made up of two strong layers of spongy bone. They give protection to organs beneath them and allow for large areas of muscle attachment EG: The Scapula (Shoulder Blade) (Shoulder Blade)

33. Irregular Bones These bones are made up of a thin layer of compact bone containing a mass of spongy bone Irregular bones are reinforced where extra strength is required EG: Vertebrae

34. Divisions of the Skeleton The skeleton is divided into 2 parts: 1.The Axial Skeleton 2.The Appendicular Skeleton

35. Divisions of the Skeleton The Axial Skeleton refers to all bones that are grouped along the midline (middle) of the body. These include: the skull, spinal column & chest.

36. Divisions of the Skeleton The Appendicular Skeleton refers to appendages that are attached to the axial skeleton. These include: the pelvic girdle, arms & legs (126 bones)

37. The Skull At birth the bones of the skull, or cranium, have spaces between them This allows them to move and make the baby’s head smaller as it passes through the birth canal

38. The Skull Some of these bones fuse in the months following birth, but the rest of the cranium is not completely fused until adolescence (teens)

39. Spinal Column To cope with the constant pressure of standing upright, the vertebral column has 2 distinct curves. One is in the neck region (Cervical Curve)

40. Spinal Column The other is in the lower back (Lumbar Region) The S- shape of the spine allows it to carry more weight

41. Spinal Column The vertebrae in the lower back are bigger as they carry more weight than those in the neck The regions of the spine are: the spine are:

42. The Thorax The ribs of the chest connect with the vertebral column at the back and the sternum at the front via cartilage The cartilage allows the chest to expand the chest to expand and contract as we and contract as we breathe breathe

43. The Thorax The lower ribs do not attach at the front, and are known as floating ribs. Their job is to protect the heart and lungs. There are 12 pairs of ribs in the average of ribs in the average adult skeleton adult skeleton

44. The Shoulder The connections of the shoulder blade, collar bone, sternum and humerus form the shoulder girdle This enables the arm to move in a wide circle

45. The Shoulder The shoulder blades (scapula) do not meet the vertebral column directly, but are attached to it by strong muscles

46. The Arm & Hand The arrangement of bones in the arm allows rotation movements, such as turning a door handle There are 60 bones in the arms, 54 of these are in the hands

47. The Arm & Hand The hand is very flexible because the bones in it are so small The most significant factor is the position of the thumb on the hand It (the thumb) allows for a larger range of manipulations to occur

48. The Pelvis The hips bear the weight of the head, arms and trunk The Pelvis is actually constructed of three bones fused together: the ilium, ischium and the pubis

49. The Pelvis The Pelvis is broader in females The joint where the Femur meets the Pelvis is a Ball & Socket joint. The joint is under constant strain as it allows for movement whilst supporting the trunk

50. Legs & Feet The largest. Strongest and heaviest bones in the body are the Femurs The leg bones are arranged in a similar fashion to the arms & hand

51. Legs & Feet The rotation of the hip is more limited than the shoulder The Knee joint absorbs more stress than any other part of the body The foot bones are also much more rigid than those in the hand because they bear more weight

52. Types of Joints The main types of joints are: 1.Fibrous- immovable/ fused (skull, pelvis) 2.Cartilagenous- semi- moveable (pubic bones, ribs to sternum) 3.Synovial- freely moveable (shoulder, knee, ankle) knee, ankle)

53. Synovial Joints The features of Synovial Joints include: Hyaline Cartilage- lines the bones, protects & reduces friction Joint Capsule- surrounds the joint, adds stability & seals the joint Synovial Membrane- lines the joint capsule & secretes Synovial Fluid

54. Synovial Joints Synovial Fluid- lubricates the joint Ligaments- holds bones together & controls movement

55. Types of Synovial Joints 1.Ball & Socket: Shoulder & Hip 2.Pivot: Neck (Atlas & Axis vertebrae) 3.Saddle: Base of the Thumb 4.Hinge: Knee & Elbow 5.Gliding: Wrist & Ankle

56. Activities 1.Answer “Coursework” questions 1 & 3 on pg. 261 of textbook 2.Answer “Checkpoints” questions 1- 4 on pg. 261 of textbook