ANATOMY

Unit 4 Notes:

Muscle Parts

(1) Types of Muscle

•Skeletal

•Cardiac

•Smooth

Cardiac Muscle

Skeletal Muscle

Smooth Muscle

(2) Skeletal Muscle

• Type of Movement:

– Voluntary

– Allows overall body mobility

– Contracts fast w/great force, tires fast also

• Location:

– On top of bones & connecting them

(3) Cardiac Muscle

• Types of Movement:

– Involuntary

– Steady, consistent movement

– Heartbeat (rate gauged by nervous system)

• Location:

– Heart

(4) Smooth Muscle

• Type of Movement:

– Involuntary

– Slower, yet consistent movement

– Forces fluids & solids through channels

• Location:

– Digestive & excretive organs

– Respiratory passageways

(5) Muscle Function

• Produce movement

– Bones = attachment points

– Internal organs (move nutrients, waste, etc.)

• Maintain posture

– Unique to Bipedalism

• Stabilize joints

– Allows for wider range of movement and use of force

• Generate heat

– During contraction

(6) Levels of Organization

• Muscle (whole organ)

• Fascicle (portion of muscle)

• Muscle Fiber (single muscle cell)

• Myofibril (muscle cell organelle)

• Sarcomere (portion of myofibril)

• Myofilaments—Actin + Myosin

(part of sarcomere)

Macroscopic

Microscopic

Muscle (organ)Fascicle

Muscle Fiber (cell)

Muscle Fiber

(with many nuclei)

Myofibril

Sarcomere

Thin Filament (actin)

Thick Filament (myosin)