Copy of Lab 13 Mini Lesson Learning Guides

Isometric Twitch Contraction

Occurs when a skeletal muscle fiber generates tension without changing its length.

Latent Period

The brief delay between the stimulus and the start of tension development in muscle contraction.

Isotonic Twitch Contraction

Occurs when the muscle changes length while generating tension.

Summation in Isometric Frequency-Tension Relation

Individual twitches sum to produce greater tension when stimuli are delivered in rapid succession.

Isometric Length-Tension Relation

Tension varies with muscle length due to overlap of actin and myosin filaments.

Creatine Phosphate

A rapid but short-lived ATP source for muscle contraction.

Glycolysis

Anaerobic pathway that produces moderate ATP.

Oxidative Phosphorylation

Slow but sustained ATP production using oxygen.

Slow-Oxidative (Type I) Fibers

Skeletal muscle fibers suited for endurance activities.

Fast-Oxidative-Glycolytic (Type IIa) Fibers

Intermediate skeletal muscle fibers suitable for moderate activities.

Fast-Glycolytic (Type IIx) Fibers

Skeletal muscle fibers suited for short bursts of power.

Muscle Fatigue (High-intensity)

Caused by ion imbalances and lactate accumulation.

Myostatin Function

Regulates muscle growth, mutations lead to excessive muscle growth.

Smooth Muscle

Located in blood vessels and digestive tract; regulates involuntary movements.

Calcium-mediated Tension Development in Smooth Muscle

Calcium activates MLCK, which phosphorylates myosin to initiate contraction.

Single-Unit Smooth Muscle

Cells contract as a unit via gap junctions.