The Skeletal and Muscular Systems Chapter 13 Sections 2 and 3
The Skeletal and Muscular Systems
Chapter 13 Sections 2 and 3
The Skeletal System
Five functions:1. Provides shape and support2. Enables you to move3. Protects your organs4. Produces blood cells5. Stores mineral and other materials
Backbone
a.k.a Vertebral ColumnMade of 26 bones (vertebrae)
Joint: where two bones come together
Joints allow bones to move in different ways
Backbone
LigamentsConnective tissue that
holds bones together
CartilageConnective tissue that
is more flexible than bone
Covers the ends of the bones
Prevents friction
Bones are Living!Bones grow and develop over timeBones have an outer membraneBlood and nerves enter the bone through this
membrane
Layers of boneCompact bone: Dense, but not solidSpongy bone: Has many small spacesMarrow: fills large spaces in the bone
Red marrow produces blood cellsYellow marrow stores fat (energy reserve)
Layers of bone
Bone characteristicsBones are…
StrongLightweightHard (contain phosphorus and calcium)Continually forming new bone tissue throughout your life
Keeping your bones healthyEat a balanced diet (get enough calcium!)Exercise regularlyAs you age, you lose minerals
This can lead to osteoporosis
The Muscular System
.• You have more than 600 active muscles in your body.
• Voluntary: you control their movements
• Involuntary: move without your conscious control
• 3 types of muscle [smooth, skeletal, and
cardiac.]
Skeletal Muscle
• Skeletal muscles are attached to your bones
• Tendon: connective tissue that attaches muscle to bone
• Skeletal muscles are also called striated muscle because they look striped!
Skeletal (Striated) Muscle
Smooth Muscle
• Smooth muscle is involuntary
• Smooth muscle lines many internal organs
• Smooth muscle allows your esophagus and stomach to move and digest your food
http://dante.med.utoronto.ca/skeletalmuscle/publicationpictures4.htm
• Smooth muscle tires less easily than skeletal muscle.
Cardiac Muscle
• Cardiac muscle is found only in the heart
• Cardiac muscle does not get tired!
http://www.bio.psu.edu/faculty/strauss/anatomy/skel/atlas.htm
Muscles Contract!
• Muscles work by contracting (getting shorter)
• They cannot stretch out again, so they have to work in pairs.
• After a muscle contracts, it’s partner contracts to stretch the first one out.
Exercise!
• Exercise makes muscle cells grow wider, thicker, and stronger.
• It helps your flexibility and strength.
• If you get a strain or a cramp, rest the injured muscle to allow it to heal.