Muscular System Test Review

5 major functions of muscular system

1. Produce movement

2. Maintain posture

3. Stabilize joints

4. Generate heat

5. Guard opening

Excitability

ability to receive and respond to a stimulus (1st property)

Contractility

ability to shorten with force when stimulated (2nd property)

Extensibility

ability to stretched out or extended (3rd property)

Elasticity

ability of muscle fiber to return to its original or resting length (4th property)

Skeletal

voluntary; striated (multinucleai); attached to bones

Smooth

involuntary; not started; hollow organs

Cardiac

involuntary; striated; heart

Levels of organization

actin + myosin filaments, sarcomere, myofibril, muscle fiber, muscle fascicle, skeletal muscle

Insertion

bone that moves during contraction

Origin

bone that stays still during contraction

Epimysium

covers skeletal muscle

Perimysium

covers fascicle (bundles) of fibers

Endomysium

around single muscle fiber

What is a neuromuscular junction?

Where a motor neuron and skeletal muscle fiber communicate

What is a motor unit?

the basic "on/off" switch for muscle movement; consisting of one motor neuron and all the muscle fibers it controls

Axon Terminal

end of the motor neuron

Synapse

the space between neuron + muscle

Synaptic Vesicle

Vesicles hold acetylcholine

Muscle Fiber

muscle cell

Step 1: An action potential (an impulse from the brain) makes its way down a motor neuron to an axon terminal. This will cause what neurotransmitter to be released from the synaptic vesicles into the synapse…

acetylcholine (Ach)

Step 2: As the action potential travels down the sarcolemma and T-Tubules, this will be released by the sarcoplasmic reticulum…

Ca 2+ (calcium)

Step 3: Once Ca2+ has entered the sarcoplasm, it will bind with…

troponin

Step 4: Once Ca2+ bind with troponin, troponin will change shape causing what protein to also change shape and “move”…

tropomyosin

Step 5: When troponin and tropomyosin change shape, what can myosin form with action?

cross bridge

Step 6: Myosin will now side action towards the M-line, this is called a…

powerstroke

Step 7: If these two things are still present, this cycle will repeat itself

Ca 2+ (calcium) and ATP

Cube-shaped bones that contain mostly spongy bone are called

short bones

Bone-destroying cells known as osteoclasts are activated by the hormone…

parathyroid hormone

What kind of tissue is the forerunner of long bones in the embryo?

hyaline cartilage

There are four stages in the healing of a bone fracture.

hematoma formation, fibrocartilage callus formation, bony callus formation, bone remodeling