1. Chapter 36
Skeletal System

2. Skeleton Supports the body Protects internal organs
Provides for movement
Stores mineral reserves
Provides site for blood cell formation

3. 206 bones in the adult human body Axial- supports central axis
Skull, vertebral column and rib cage
Appendicular
Arms, legs, pelvis and shoulder area

4. Structure of bones
Network of living cells and protein fibers surrounded by deposits of calcium salts
Periosteum- tough connective tissue layer surrounding bone
Compact bone- dense outer bone with Haversian canals that contain blood vessels and nerves
Spongy bone- found closer to center than compact bones and the ends of long bones and middle of short, flat bones

5. Development of Bones
Early in development the structure is cartilage- a protein fiber network of collagen and elastin with no blood vessels
Ossification- process of bone replacing cartilage

6. Osteoclasts- break down bone Osteoblasts- produce new bone
these both are found lining Haversian canals
Bone Marrow- soft tissue
Yellow- made up of fat cells
Red- produces red blood cells, some white blood cells and cell fragments called platelets

8. Types of Joints Joint- where one bone attaches to another bone
Immovable Joints
Interlocked and held together by connective tissue or fused ex) skull
Slightly Movable Joints
Allow small restricted movements ex) tibia/fibula
Freely Movable Joints
Move in one or more directions

9. Freely Movable Joints Ball and socket- widest range of motion
Ex) shoulder
Hinge- back and forth motion
Ex) knee
Pivot- one bone to rotate around another
Ex) elbow
Saddle- one bone to slide in 2 directions
Ex) finger

10. More Joint Information
Ligaments- bone to bone
Tendons- bone to muscles
Synovial fluid- forms a thin film on cartilage in joint capsule to lubricate movement
Bursae- sacs of synovial fluid- reduce friction and act as a shock absorber

11. 36-2 Muscular System
3 types of muscle tissue: skeletal, smooth and cardiac
Skeletal
Attached to bones
Responsible for voluntary movements
Also called striated muscle
Smooth
Not under voluntary control
Found in hollow structures like the stomach, blood vessels and intestines
Function without nervous stimulation

12. Cardiac Found in the heart
Shares characteristics of both skeletal and smooth muscle
May have two nuclei in the cells
Usually not under the direct control of the CNS

13. Muscle Contraction
Myosin-protein found in the thick filaments of the muscle cells
Actin- protein found in the thin filaments
These filaments are arranged into a muscle fiber called a sarcomere
The ends of the sarcomeres are called Z lines

14. 36-3 Integumentary System
Means “to cover”
Includes skin, hair, nails, and glands
Function: serves as a barrier against infection and injury, helping to regulate body temp, remove waste products from the body and provide protection against UV rays from the sun

15. Skin Epidermis-outer layer of skin Dermis
Subcutaneous layer of fat and loose connective tissue that help insulate

16. Epidermis-outer layer of skin
Outer layer- made up of flat, dead cells
Begin making keratin (a tough, fibrous protein)
Inner layer is make up of living cells
Undergo rapid cell division
Melanocytes
Produce melanin- a dark brown pigment that protects the skin from damage caused by UV rays

17. Dermis
Contains collagen fibers, blood vessels, nerve endings, glands, sensory receptors, smooth muscles and hair follicles
Regulates body temperature
Two types of glands: sweat and sebaceous