1. THE SKELETAL SYSTEM
Kinesiology
Unit 9

2. The Basic Skeletal System

3. Has articulations  joints Ligaments: attach bone to bone
Tendons: attach muscle to bone
The Skeleton

4. THE SKELETAL SYSTEM OSTEOLOGY: THE STUDY OF BONES
ARTHOLOGY: THE STUDY OF JOINTS
MAIN FUNCTIONS OF THE SKELETAL SYSTEM:
SUPPORT FRAMEWORK FOR SOFT BODY TISSUES
PROTECTS VITAL ORGANS (EXAMPE: BRAIN WITHIN THE SKULL, LUNGS WITHIN THE THORACIC CAGE)
BLOOD CELL PRODUCTION OCCURS IN RED MARROW OF MANY BONES
PROVIDES SYSTEM OF LEVERS ALLOWING MOVEMENT
PROVIDES SHAPE TO THE BODY
MAINTAINS HOMEOSTASIS (BALANCE CALCIUM)

5. THE SKELETAL SYSTEM
BONES
&
JOINTS

6. BONES
THE SKELETON CONSISTS OF 206 – 210 BONES

7. BONES:
What is bone? - Live connective tissue - 25% water, 25% protein, 50% crysalised mineral salts
Wolff’s Law: Bone is laid down (built up) where it is needed and resorbed (broken down) where it is not needed

8. Bone Cells:
Osteoblasts: Bone building cells: synthesize and secrete collagen and other organic compounds to build up bone matrix Osteocytes:
Mature bone cells. Derived from osteoblasts that have become trapped in the bone matrix…function is to exchange nutrients and waste with blood
Osteoclasts: Bone resorbing cells Function to break down the bone matrix

9. Osteoblast and osteoclast activity  maintain homeostasis in the body…
Osteoblast and osteoclast activity  maintain homeostasis in the body… *Greater osteoblast action: bones become too thick and heavy & develop boney spurs *Greater osteoclast action: lose too much calcium = brittle and fragile bones that break easily
So… this helps the body because:
1. Renews of bone tissue before deterioration sets in
2. Redistribution of bone matrix along the lines of mechanical stress
3. Enables injured bones to heal

10. FOUR GROUPS OF BONES LONG BONES SHORT BONES FLAT BONES IRREGULAR BONES
ARE LONG
EXAMPLE: TIBIA, FIBULA, HUMERUS, RADIUS AND ILNA
SHORT BONES
ABOUT EQUAL IN LENGTH AND WIDTH
EXAMPLE: BONES OF THE WRIST AND FOOT
FLAT BONES
USED FOR PROTECTION
EXAMPLE: THEY MAKE UP THE VAULT OF THE SKULL, SCAPULA AND STERNUM AND RIBS
IRREGULAR BONES
COMPLEX AND VARIED SHAPES
EXAMPLE: BONES COMPRISING THE VERTEBRAL COLUMN, PECTORAL AND PELVIC GIRDLES, PATELLA AND SMALLBONES OF FACE

11. Example of Long Bone

12. Example of Short Bones

13. Example of Flat Bone

14. Example of Irregular Bone

15. STRUCTURE OF BONES
THERE ARE TWO TYPES OF BONY SUBSTANCE IN THE BODY: COMPACT TISSUE AND SPONGELIKE CALCELLOUS TISSUE
TENDONS: ATTACH MUSCLE TO BONE
LIGAMENTS: ATTACH BONE TO BONE

16. The Two Types of Bony Structures

17. JOINTS
THE JUNCTIONS OF THE LEVERS OR SKELETAL PARTS ARE CALLED JOINTS OR ARTICULATIONS

18. Articulations depend on:
1. Structural composition: What type of connective tissue binds the bones? -E.g. Fibrous Joints - E.g. Cartilaginous Joints - E.g. Synovial Joints
2. The extent to which movement is permitted: -E.g. synarthoses (no/ very little movement at joints) -E.g. Amphiarthroses (partially movable joints) -E.g. Diarthroses (Freely movable joints)

20. Synarthroses: Fibrous/ Synarthrodial joints
Held tightly together by fibrous connective tissue
Permit little/ no movement

21. 3 Types of Synarthroses joints:
1. Suture: *Fibrous joint composed of a thin layer of dense connective tissue *Irregular interlocking edges add strength to the joint
2. Syndesmosis: *Greater distance/ space between articulating bones * Contains more fibrous connective tissue than a suture joint…therefore allowing slightly more movement
3. Gomphosis: * Joint in which cone-shaped peg fits into a socket

22. Amphiarthroses Joints:
Cartilaginous joints
Held together by strong ligaments
Slightly movable joints:

23. 2 types of Amphiarthoses:
1. Syndnchrondrosis Hyaline cartilage is the connecting substance Primary cartilaginous joint is later replaced by bone E.g. Ribs
2. Symphysis Ends of articulating bones are covered with cartilage but bones are connect by a broad, flat disc of fibrocartilage E.g. Pelvis  labour

24. Diarthroses Diarthrodial/ Synovial Joints:
Articulating surfaces of synovial joints are covered with articular cartilage
Cartilage ensures a smooth, frictionless surface
Articular capsule: surrounds synovial joint and encloses the synovial cavity
Strong, yet flexible fibrous capsule consisting of dense, irregular tissue

25. Synovial membrane: Inner layer of articular surface
Synovial fluid: Forms thin layer over articulating surface
Synovial fluid has several functions: 1. Lubrication 2. Supplies nutrients 3. Removes waste products Contains phagocytes

26. Synovial joints/ Diarthrodial joints:
1. Planar joint: Gliding joint - Joint surfaces are fairly flat - Permit side to side; back to forth movements - Non-axial  doesn’t rotate around 1 axis - E.g. Knee, wrist
2. Hinge joint: Ginglymus joint - Convex surface of 1 joint fits into concave surface of other joint - Produces angular opening and closing motion - Uniaxial joint (1 axis) E.g. Elbow or jaw

27. 3. Pivot joint: Trochoid joint - Rounded or pointed surface of 1 joint articulates with ring formed partly by another bone - Uniaxial joint -E.g. Axis of skull
4. Condyloid Joint: Ellipsoidal joint - Convex oval projection of 1 bone fits into the oval shaped depression of another bone Bi- axial joint - E.g. Scaphoid and lunate bones in hand

28. 5. Saddle Joint: Sellaris Joint - Articular surface is saddle shaped and articulating surface of other bone fits into the “saddle” - Biaxial Joint - E.g. Thumb
6. Ball and Socket Joint: Spherio Joint - Ball like surface of 1 bone fits into a cup like surface of another bone - Multiaxial E.g. Shoulder, hip

29. CLASSIFICATION OF JOINTS
COMMON NAME
TECHNICAL NAME
MOVEMENT
EXAMPLE
Immovable (Synarthrodial)
Fibrous
1.Suture
2.Syndesmosis
None
1.Sutures Of Skull
2.Distal Tibiofibuls
Slightly Movable (Amphiarthrodial)
Cartilaginous
1.Synchrondosis
2.Symphysis
Negligible (Very little)
1.Sternocostal
2.Epiphyseal Plates
3.Pubic Symphysis
Freely Movable (Diarthrodial)
1.Ball and Socket
2.Condyloid
3.Gliding
4.Hinge
5.Pivot
6.Sadle
1.Enarthrosis
2.Ellipsoidal
3.Arthrodial
4.Ginglymus
5.Trochoid
6.Sellar
1.Triaxial
2.Braxial
3.Nonaxial
4.Uniaxial
5.Uniaxial
6.Triaxial
1.Hip and Shoulder
2.Wrist
3.Intercarpal and Inter-tarsal
4.Elbow
5.Atlanot-Axial
6.Carpometacarpal of the Thumb

31. End of Unit