1. Musculoskeletal System
Physiology
Mrs. Brown

2. 5 Functions of the Skeletal System
1. Haemopoiesis:
Formation of blood cells in red bone marrow
Main sites of haemopoiesis

3. 5 Functions of the Skeletal System (con’t)
2. Storage of minerals (calcium, phosphorous, etc.)
3. Support of body
4. Protection of body organs
5. Movement- attached to skeletal muscle

4. Types of Bones
Fig. 7.1

5. Total Bones in the Skeletal System = 206
Fig. 7.15

6. Major Divisions of Skeleton
Axial = 80 bones
Appendicular = 126 bones
Fig. 7.15

7. The Axial Skeleton: Skull
Fig. 7.17
Fig. 7.19
Fig. 7.31

8. The Axial Skeleton: Thoracic Region
Ribs
12 pairs of ribs
1-7 true ribs
8-10 false ribs
11-12 floating ribs
Sternum
Manubrium, body, xiphoid process
Thoracic vertebrae
Fig. 7.38

9. The Axial Skeleton: Spinal Column
Fig. 7.16
24 total vertebrae
7 cervical (neck) vertebrae
12 thoracic (chest) vertebrae
5 lumbar (lower back) vertebrae
Sacrum
5 fused vertebrae with tubercules and
sacral foramina
Coccyx
4 fused vertebrae
Figs. 7.32, 7.37

10. The Spinal Column (cont’d)
Vertebrae
Body vs. intervertebral discs
Pedicles & laminae fuse to become the spinous process
Transverse process
Vertebral foramen- hole for spinal cord
Superior and inferior articular processes
Interverterbal foramina
Fig. 7.36

11. The Appendicular Skeleton: Arms & Legs
Figs. 7.40, 7.45, 7.47, 7.48, 7.53

12. -lined with hyaline cartilage -compact bone forms exterior
Bone Structure, Gross Anatomy
Fig. 7.2
Epiphysis-
-lined with hyaline cartilage
-compact bone forms exterior
-spongy bone forms interior
-contains epiphyseal plates
Diaphysis- -compact bone forms exterior
-center composed of the medullary cavity containing marrow (red or yellow)

13. Bone Structure, Fine Anatomy
Fig. 7.3
Fig. 7.4

14. Bone Cells Fig. 7.13 OSTEOCYTES = “bone” “cells”
OSTEOBLASTS
“bone builders”
OSTEOCLASTS
“bone crushers”
repair
maintain
when minerals are needed
BONE IS NEVER AT REST =
homeostasis!!!
Fig. 7.13

15. Bone Growth
Fig. 7.8

16. Growth occurs in the epiphyseal plate
Bone Growth, con’t.
Fig. 7.9
Postnatal Growth
Growth in length
Growth occurs in the epiphyseal plate
Cartilage cells proliferate in tall columns, causing the entire bone to lengthen
Cartilage cells at the bottom of the column die and osteoblasts replace it with spongy bone

17. Bone Repair
pgs

18. Joints Definition: the site where two or more bones meet
1. Fibrous joints
Immovable
2. Cartilaginous joints
Limited Movement
Fig

19. Joints, con’t. Fig. 8.7 & 8.8 3. Synovial Joints Movable
Synovial Joint Structure Hyaline cartilage
Joint cavity/capsule Synovial fluid (Ligaments)

20. How do you move your bones?
MUSCLES!!
All muscles cross at least one joint
Each muscle pulls from an origin (the immovable end) to an insertion (the movable end)
Each muscle produces a specific movement or action
Fig. 9.22

21. Muscles work in pairs
The pairs are located on opposite sides of a joint
Muscles ‘pull’- never ‘push’. They work together to ‘undo’ the action of its pair
Prime mover or agonist- provides the major force for a specific movement
Antagonist-opposes or reverses the prime mover

22. Muscle Actions
Joint movements describe the axis in which the body part moves
Figs

23. Major Muscles
Figs & 9.24

24. Anatomy of a Muscle
Muscle cells (aka muscle fibers) bundled together are called fascicles
Groups of fascicles are wrapped in a connective tissue called the epimysium
Fig. 9.2

25. FIne Anatomy of a Muscle
Zoom in on one muscle fiber/cell and you will see that
Each muscle cell contains many myofibrils
Myofibrils are made of functional units called sarcomeres
Fig. 9.4

26. Fine Anatomy cont: The Sarcomere
Sarcomeres consists of 2 overlapping filaments with a repeated pattern
Thick filament-myosin
Thin filament-actin
Figs. 9.4 & 9.5

27. Skeletal Muscle Contraction
Actin
helps to control the myosin-actin interactions in muscle contraction.
Myosin
Myosin heads form cross bridges between myosin and actin
Fig. 9.6

28. The Sliding Filament Model
Fig. 9.10

29. The Sliding Filament Model
Fig. 9.11

30. Muscle Metabolism ATP Background Information
1. “ATP” = Adenosine TriPhosphate
* phosphate groups are attached by high- energy bonds
2. When the terminal phosphate group is cleaved off, energy is released.
3. ATPADP + Pi + energy
4. This energy is available to perform cellular work

31. Muscle Metabolism, cont.
Aerobic Metabolism/Cellular Respiration
Occurs in mitochondria & requires oxygen
Chemical Formula:
Glucose + oxygen  carbon dioxide + water + energy (36 ATP)
When this system is used:
prolonged, endurance activities which maintain a constant heart rate
As long as there is enough oxygen available, a muscle will utilize aerobic metabolism.

32. Muscle Metabolism, cont.
Anaerobic Metabolism/Glycolysis
Sometimes your muscles will temporarily run out of O2
This pathway can occur in the absence of oxygen
Chemical Formula:
Glucose  lactic acid +energy (2 ATP)
When this system is used:
When large amounts of ATP are needed for periods of exercise about 90 seconds long.

33. Muscle Metabolism, cont.
Anaerobic Metabolism/Creatine Pathway
Utilizes stored energy in the molecule creatine phosphate
Chemical Formula:
Creatine phosphate + ADP  Creatine + ATP (1ATP)
When this system is used:
Mobilized at the beginning of exercise, before other pathways ‘kick in’.
Creates enough energy for about 10 seconds of contraction.