Muscle Differences

Where is skeletal muscle located?

• Attaches to bones

• Exception: Tongue

What controls skeletal muscle?

Lower motor neurons ONLY

What is the twitch speed of Skeletal muscle?

10 to 100 ms (Fast)

What is the appearance of skeletal muscle?

• Striated (Stripped)

• Long parallel Fibers

• Many nuclei

What is special about skeletal muscle?

• Cant latch

• Cant regenerate

Where is smooth muscle located?

Tubes, hollow organs, eye

What does smooth muscle respond to?

• Autonomic Nervous System

• Hormones

• Stretch

• Self firing

What is the twitch speed of smooth muscle?

4000 to 6000 ms (Very slow)

What is the appearance of smooth muscle?

• Not striated

• Spindle shaped

• In Layers

What is unique about smooth muscle?

Can latch (Lock contractions)

Where is cardiac muscle located?

The heart only

What does cardiac muscle respond to?

• Influenced by Automatic Nervous System (ANS)

• Intrinsic (Self)

What is the twitch speed of cardiac muscle?

About 250 ms (varies)

What is the appearance of caridac muscle?

• Striated

• Branched and interconnected

What’s special about cardiac muscle?

Network spreads from the signal cell → cell

What is a motor unit?

• One motor neuron

• All the muscle fibers it controls

Are motor units all or nothing?

• All or nothing

• Fire the neuron → All its fibers contract together

Can a motor unit contract a singular fiber?

No, a motor neuron has to contract all its fibers not just one

What is an antagonistic pair?

• Because muscles only pull, joints need opposing pairs

• Flexor = Bends the joint

• Extensor = Straightens it

Tendon

• Attach muscle to bone

• Made of collagen (dense connective tissue) with few fibroblasts (the cells that build/repair connective tissue) and little blood → they heal SLOWLY (treated with immobilization)

• A muscle must cross at least one joint to move it.