1. Human Body Systems Muscular System Skeletal System Circulatory System
Integumentary System
Muscular System
NervousSystem
Skeletal System
Circulatory System
Human Body Systems
Digestive System
Respiratory System
Excretory System
Reproductive System
Lymphatic System
Endocrine System

2. The Skeleton Bone Structure Bone Development Joints
The Skeletal System
The Skeleton
Bone Structure
Bone Development
Joints

3. The adult human skeleton has 206 bones and is divided into two parts:
The Human Skeleton
The adult human skeleton has 206 bones and is divided into two parts:
Skull
Sternum
Ribs
Vertebral column
Axial Skeleton - Supports the central axis of the body.
Metatarsals
Metacarpals
Phalanges
Clavicle
Scapula
Humerus
Radius
Pelvis
Ulna
Carpals
Femur
Patella
Fibula
Tibia
Tarsals
Appendicular Skeleton - The bones of the appendages (arms, shoulder area, legs, and pelvis).

4. Functions of the Skeleton
Support – hold up the body
Protection – rib cage, skull, and pelvic girdle protect important organs
Movement – skeletal muscle attaches to the bones of the skeleton to allow movement
Storage – bones store fat, calcium, minerals
Hematopoeisis – blood cell formation

5. Bone Structure
Periosteum – tough layer of fibrous connective tissue that surrounds bone
Compact Bone – dense bone that makes up the bulk of the skeleton
Haversian Canals – canals that run through compact bone that contain blood vessels and nerves
Spongy Bone – porous bone found in the ends of long bones and in the middle of short and flat bones
Bone Marrow – found in the cavities of bones
Bone - a solid network of living cells and fibers that are supported by deposits of calcium salts

6. Bone Marrow red marrow is in spongy bone
production of blood cells
yellow marrow is found in the central cavity of long bones
stores fat and acts as an energy reserve

7. Cartilage cushions the ends of bones provides structure
elbows, hips, and knees
provides structure
nose and ears
much of a newborn's skeleton is made of cartilage

8. Bone Development
Cartilage pre-cursor – cartilage is slowly replaced by bone through a process called ossification
Osteoblasts – bone forming cells
Osteoclasts – bone destroying cells
Osteocytes – regulate cellular activities of bone
Thought Question:
What disease is caused by an imbalance between Osteoblast and Osteoclasts?

9. Joints
Ball and Socket Joint (shoulder) - bones can rotate while moving back and forth and side to side
Hinge Joint (knee) - allows movement back and forth in one plane
Pivot Joint (top of neck and base of skull) - one bone rotates around another

10. Joints Immovable – fibrous, fixed; example - skull bones
Ball-and-Socket Joint
Pivot Joint
Clavicle
Ball-and-socket joint
Scapula
Humerus
Humerus
Radius
Pivot joint
Ulna
Saddle Joint
Hinge Joint
Femur
Patella
Hinge joint
Tibia
Fibula
Metacarpals
Carpals
Saddle joint
Immovable – fibrous, fixed; example - skull bones
Slightly movable – cartilaginous; example – intervertebral discs
Freely movable – synovial; examples shown above

11. The Knee Thought Question:
Based on the diagram, what is the difference between a tendon and a ligament?
Muscle
Tendon
Femur
Patella
Bursa
Ligament
Synovial fluid
Cartilage
Fat
Fibula
Tibia
Tendon - connective tissue attaching muscle and bone.
Ligament – connective tissue attaching bones

12. Types of Muscle Tissue Muscle Contraction
The Muscular System
Types of Muscle Tissue
Muscle Contraction

13. 3 Types of Muscle
Skeletal
Cardiac
Smooth

14. Smooth Muscle
Found in internal tubes and vessels – digestive and circulatory systems
Moves food, blood, and other substances through the body
Involuntary - not under conscious control
Not striated
uninucleated

15. Cardiac Muscle The muscle of the heart Main function is to pump blood
Striated
Involuntary

16. Skeletal Muscle Attached to bones of the skeleton Allows for movement
Striated – alternating light and dark bands
Voluntary – under conscious control
Multinucleated
Also called muscle fibers
Complete muscle tissue = muscle fibers, connective tissues, blood vessels, and nerves

17. Can you identify the type of muscle shown below?

18. Structure of Skeletal Muscle
Muscle cells are bundled together and are surrounded by a connective sheath.
Actin
Skeletal muscle
Myosin
Bundle of muscle fibers
An individual muscle cell is a long fiber with many nuclei. Each muscle cell contains a central cable made of a rodlike structures called myofibrils
Sarcomere
Z disc
Myofibril
Muscle fiber (cell)
Myofibrils are composed of two types of protein, actin and myosin They make up the light and dark bands in functional units called sarcomeres.

19. How a Muscle Contracts
Relaxed Muscle
Z disc
Myosin
Actin
Z disc
Movement of Actin Filament
Actin
Cross-bridge
Sarcomere
Binding sites
Contracted Muscle
Myosin
myosin - thick filaments, have many bump-like projections called "heads"
actin - thin filaments, like a string of twisted beads, the ends of the actin strands are attached to Z lines
Cross-bridges
Z disc
1. myosin heads attach to the actin filaments forming cross bridges
2. the heads of the myosin filaments “walk” along the actin filaments, pulling them toward the center of the sarcomere

20. Click on the link below to view a video showing a muscle contract:
Thought Question:
Based on the requirements necessary for muscle contraction, what organelle would you expect to find in high concentration in muscle cells?

21. Muscle Contraction 1
Myosin forms cross-bridge with actin 5 2
Myosin returns to original shape
Cross-bridge changes shape 4 3
Cross-bridge releases actin
Actin pulled
When a muscle contracts, the heads of the myosin filaments “walk” along the actin filaments, pulling them toward the center of the sarcomere. As this occurs simultaneously in sarcomeres throughout the cell the muscle cell contracts.

22. Essays
When a person decides to move, his skeletal muscles contract. Explain how a muscle contracts by discussing:
What the contractile/functional unit of a muscle is called.
What two proteins are involved in muscle contraction.
Discuss the steps of skeletal muscle contraction (use the terms: Sarcomere, Actin, Myosin, Crossbridge, Z-Discs)
Explain how the human skeleton accomplishes the following functions:
a) Allows movement, protects internal organs, store mineral reserves, and provide a site for blood cell formation.
b.) Be sure to explain where in the bones these tasks occur.
c.) Explain two diseases that disrupt homeostasis by preventing these functions. 22