Skeletal System Functions 1 Supports body 2 Protects

Skeletal System Functions: 1) Supports body 2) Protects internal organs 3) Provides for movement 4) Stores mineral reserves 5) Provides a site for blood cell formation

Skeletal System ► Has 206 bones ► Divided 1) 2) into two sections: Axial: skull, vertebral column, ribs, and sternum Appendicular: all other bones

Structure of Bones ► Bones are living tissue!! ► Periosteum – tough layer of connective tissue surrounding bone ► Compact bone – beneath the periosteum (dense but not solid) ► Haversian canals– tubes that run through compact bone and contain blood vessels and nerves

Structure of Bones ► Spongy bone – inside outer layer of compact bone ► Osteocytes – digest away old bone ► Osteoclasts – maintain healthy bone ► Osteoblasts – make new bone

3 -D Section of Bone Tissue

Bone Homeostasis ► 1. Most of our skeleton is constantly being broken down, and built back up ► 2. Amount of bone built up = amount of bone broken down ► 3. This balance of breakdown and buildup is called bone homeostasis

► Bone marrow – soft tissue center of bone § Maintains the balance of minerals § Serves as a storage for minerals (Ca, P) § Two Types: 1) Yellow – made mostly of fats, aids in Red Blood Cell (RBC) production 2) Red – produces RBCs, white BC, and cells to help clotting

Skeletal Development ► The skeleton of the embryo is made of cartilage ► Bone begins to replace cartilage by 9 th week of development (known as ossification)

Joints – where two or more bones meet ► Most allow movement ► Some are fixed (no movement): skull ►

Pelvis, Sexual Dimorphism

Types of Joints ► Five types: 1) Ball and socket: allows rotational movements (shoulder, hip) Ball and Socket Movement

Types of Joints, Cont’d 2) Pivot: bones twist against each other (atlas and axis of your vertebrae) Pivot Joint in Arm

Types of Joints Cont’d 3) Hinge: back and forth movements much like a door (elbow, knee)

Types of Joints 4) Gliding: bones slide against each other (wrist) 5) Saddle: Freely moveable joint found only in the thumb

Joint support ► Ligaments: bands of tissue that connect bone to bone § Surrounds joints with wide range of motion and little skeletal support ► Cartilage: covers bone ends and allows for smooth movement. Can also be found in joint to provide cushion (meniscus) ► Bursa: sacs of fluid that act as shock absorbers ► Tendons: bands of tissue that connect muscle to bone (patella tendon, Achilles)

Problems with Skeletal System Breaks ► Complete/Incomplete (Greenstick) ► Displaced ► Simple/Compound (breaks skin) ► Impacted or Comminuted ► Spiral ► Hairline

Breaks - Complete & Displaced

Breaks - Incomplete/Greenstick

Breaks - Spiral

Breaks - Compound

Breaks - Comminuted

Breaks - Hairline

Osteoporosis

Problems with Skeletal System Rheumatoid arthritis ► Inflammation in joints ► Redness, warmth, swelling, pain, fatigue ► Occurs on both sides of body ► Genetic, environmental, hormonal factors; immune system attacks the joints and other organs

Rheumatoid arthritis

Problems with Skeletal System Dislocation Normal Dislocated

Dislocation Normal Dislocated