SkeletalSkeletal – striated, multinucleate, voluntary,

SmoothSmooth - found in walls of hollow visceral organs; ex. stomach, bladder, respiratory passages; visceral, nonstriated, involuntary; discuss peristalsis

CardiacCardiac – in heart only, striated, involuntary, intercalcated disks

Muscle function:• produce movement• maintain posture• stabilize joints• generate heat

Functional Characteristics:• Excitability- respond to a stimulus• Contractility- ability to shorten

forcibly when adequately stimulated • Extensibility- the ability to be

stretched• Elasticity- the ability of a muscle

fiber to resume its resting length after being stretched

Skeletal Muscle Skeletal Muscle TissueTissue

Smooth Muscle Smooth Muscle TissueTissue

Cardiac Muscle Cardiac Muscle TissueTissue

Gross Anatomy Skeletal Muscle

bundle of muscle fibers

muscle fiber(cell)

myofibril

sarcomere

Muscle Muscle AnatomyAnatomy

Muscle Fiber

Myofibril

SarcomereSarcomere

Z lines

SarcomeSarcomerere A band

SarcomeSarcomerere I bands

SarcomeSarcomerere H zone

Actin and Myosin FilamentsActin and Myosin Filaments

myosinactin

Myosin (Thick) FilamentMyosin (Thick) Filament

Actin (Thin) FilamentActin (Thin) Filament

Sliding Filament HypothesisSliding Filament Hypothesis

A

Z ZH

I I

AI I

Z ZH

Z ZHAI I

Actin & Myosin InteractionActin & Myosin Interaction

Biology 100Biology 100Human BiologyHuman Biology

Motor UnitMotor Unit

spinal cord

motor neurons

muscle bundle

muscle fibers

neuromuscular junctions

Neuromuscular Neuromuscular junctionsjunctions

branching axon branching axon to motor unitto motor unit

muscle fibersmuscle fibers

axon

plasma membrane

myofibrils

sarcomere

T tubules

sarcoplasmic reticulum

http://www.blackwellpublishing.com/matthews/myosin.html

Stimulation of Skeletal Muscle