Bone Basics & Functions
Name two functions of the skeletal system
Support, protection, movement, mineral storage, blood cell production
What is the hard outer layer of bone?
Compact bone
What is a joint?
Where two bones meet
What chemical is released from the neuron to start contraction?
Acetylcholine
Which muscle type is voluntary?
Skeletal muscle
Which two bones protect the brain and heart?
Skull and rib cage
What is found inside the medullary cavity?
Yellow bone marrow
What type of joint is the knee?
Hinge joint
What ion is released inside the muscle to continue contraction?
Calcium (Ca²⁺)
What is the main job of muscles?
To contract and produce movement
Why are bones considered living tissue?
They contain cells, blood vessels, and can repair themselves
Where are blood cells made?
Red bone marrow
What connects bone to bone?
Ligaments
What two proteins slide past each other?
Actin and myosin
What is the muscle doing the main action called?
Agonist (prime mover)
What happens to bones if they are not used regularly?
They weaken (lose density)
What type of bone tissue helps absorb shock?
Spongy bone
What movement decreases the angle between bones?
Flexion
What provides energy for muscle contraction?
ATP
What type of contraction is holding a weight still?
Isometric
Why is calcium important for bones AND muscles?
Bones store calcium; muscles need it for contraction
Why is the periosteum important?
Helps bone grow and repair + contains blood vessels
Why are synovial joints able to move freely?
They have synovial fluid and a joint cavity
Why does a muscle stop contracting when calcium is removed?
Binding sites are covered → myosin cannot attach to actin
Why do muscles get tired after long activity?
Less ATP / buildup of waste (like lactic acid)