1. The Skeletal System

2. Introduction
The skeletal system is composed largely of a type of connective tissue called BONE
Approximately 206 bones make up the adult skeletal system
Approximately 275 bones (fetal skeleton – 12 weeks)
Cartilage and fibrous connective tissues are also present

3. Introduction The skeletal system is composed of:
Bone: strong, rigid, mineralized (calcium, phosphate) connective tissue
Cartilage: strong, flexible, protein (elastic / collagen fibres) connective tissue
Fibrous Connective Tissue: strong, flexible, protein (collagen fibres) connective tissue, forms tendons and ligaments

4. Functions of the Skeletal System
Support -Provides a structural framework and points of attachment for tissues / organs (eg.muscles via tendons)
Protection - Protects vital organs like the brain and spinal cord
Movement – some bones act as levers; results in movement together with skeletal muscles and articulations (joints)
Mineral Storage – storage of calcium (Ca) and phosphorus (P)
Blood cell production – blood cell production occurs in the red bone marrow (hematopoiesis)
Storage of Energy – fats a source of energy

5. The Skeletal System Parts of the Skeletal System Bone (skeleton)
Joints

6. Bones of the Human Body The skeleton has 206 bones
2 basic types of bone tissue
COMPACT BONE - outer structure (solid bone, does not bend easily)
SPONGY BONE – inner structure (covers the space where the marrow is stored)

7. Classification of Bones on the Basis of Shape

8. Classification of Bones
LONG BONES
Examples: femur (thing), humerus (arm)
SHORT BONES
Small cube shaped bones
Examples: wrist, ankle, toe bones
FLAT BONES
Large flat surfaces that cover organs or provide surface for large areas of muscles
Examples: skull, shoulder blades, pelvis
IRREGULAR BONES
Irregular specialized shapes
Examples: vertebrae, face
SESAMOID BONES
Formed in a tendon near a joint
Examples: patella (knee cap)

9. Anatomy of a Bone

10. Structure of Long Bones
A) Epiphysis – end of long bone consisting of outer compact and inner spongy bone filled with red bone marrow
B) Articular cartilage – covers epiphysis and facilitates joint movement
C) Diaphysis – length of long bone excluding epiphysis (shaft)
D) Medullary Cavity – inner hollow cavity along diaphysis containing bone marrow
E) Endosteum – inner connective tissue surrounding medullary cavity
F) Periosteum – outer connective tissue layer
G) Epiphyseal plate – cartilage between diaphysis and epiphysis (growth plate)

11. Bones of the Skeletal System
DIVISIONS OF THE SKELETAL SYSTEM
Axial Skeleton (green) – skull, spinal column, sternum, rib
Appendicular Skeleton (orange) – hips (pelvic girdle), shoulders (pectoral girdle), limbs

12. Skull – includes cranial bones, facial bones and mandible

13. The Spinal Column Consists of 5 sets of vertebrae
Cervical : neck (7)
Thoracic: midback (12)
Lumbar low back (5)
Sacrum: (5 fused)
Coccyx: tailbone (4 fused)
Vertebrae separated by thick disks (cushion the vertebrae and help in movement and flexibility)

14. Rib Cage: Chest Bones (sternum, ribs)
Sternum – aka breastbone
12 pairs of ribs
True ribs (7) – joined to spinal column and sternum
False ribs (3) – attached to spinal column and 7th rib
Floating ribs (2) – do not attach to sternum or other ribs

15. Shoulder (Pectoral Girdle)
Composed of the clavicle (collar bone) and scapula (shoulder blade)
These bones allow the upper limb to have free movement

16. Bones of the Arm Upper Arm Lower Arm Humerus – attaches to scapula
Forearm has 2 bones (Ulna and Radius) which attach to the bones at the wrist

17. Bones of the Hand
Carpals (8)
Metacarpals (5)
Phalanges – finger bones

18. Hips (Pelvic Girdle) Hip bones (os coxae)
Composed of 3 fused bones (ilium, ischium, pubic)
Point of attachment for the legs
Pubic symphysis – connects both halves of the pelvis in the middle

19. Bones of the Leg Femur (thigh bone) – longest bone in the body
Meets the tibia and fibula at the knee cap (patella)

20. Bones of the Feet Tarsals Metatarsals – sole Phalanges - toes
Ankle bones
Largest tarsal is the calcaneus or heel
Metatarsals – sole
Phalanges - toes