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

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

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).

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

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

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

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

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?

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

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

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

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

3 Types of Muscle Skeletal Cardiac Smooth

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

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

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

Can you identify the type of muscle shown below?

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.

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

Click on the link below to view a video showing a muscle contract: http://www.3dotstudio.com/zz.html Thought Question: Based on the requirements necessary for muscle contraction, what organelle would you expect to find in high concentration in muscle cells?

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.

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