Skeletal Muscle - Saint Louis Universitystarklab.slu.edu/PhysioLab/SkeletalMuscle.pdf(a) Skeletal muscle Nucleus Muscle fiber (cell) Striations (b) Cardiac muscle Striations Muscle

Skeletal Muscle

Types of Muscle

Skeletal Muscle Function

Organization

Ultrastructure

Fibers

Sarcomere Organization

Regulation

E-C Coupling

E-C Coupling

Electrical and Mechanical

Muscle Fiber Types

palereddark red (myoglobin)Color

Glycolytic, more anaerobic than fast-twitch

Glycolytic, more oxidative withtraining

Oxidative, aerobic, numerousmitochondriaMetabolism

Easily FatiguedFatigue ResistantFatigue ResistantEndurance

HighHighModerateCa-ATPase

ShortShortLongestContraction Duration

LargeMediumSmallDiameter

FastFastSlowMyosin ATPase

activity

FastestIntermediateSlowestTime of tension

Fast Twitch Glycolytic; White MuscleFast-Twitch Oxidative; Red MuscleSlow Twitch Oxidative; Red Muscle

Tetanus?

Knee Jerk Reflex

• Figure 13.7• Stimulus is the hammer on the patellar

tendon• Afferent Path CNS Efferent Path Muscle Contraction and forced relaxation

Summation