Skeletal Muscle Additional

Neuromuscular Junction

Synapse between a somatic motor neuron and a skeletal muscle fiber, where muscle action potentials arise

Synaptic End Bulb

Swelling at the end of an axon terminal of a neuron where neurotransmitters are stored

Synaptic Vesicles

Stores neurotransmitters (ACh) in synaptic end bulbs

Acetylcholine

Neurotransmitter

Motor End Plate

Region of sarcolemma directly across from synaptic end bulb, receives neurotransmitter and creates action potential

ACh Receptors

Integral membrane proteins that respond to the bonding ACh

Synaptic Cleft

Space between synaptic end bulb and sarcolemma

Motor Neuron

Stimulates muscle contraction

Motor Unit

Motor neuron + the skeletal muscle fibers it innervates, one per muscle fiber

Axon Terminals

Branches of axons in a neuron, form neuromuscular junctions

Creatine Phosphate

High-energy molecule unique to muscle fibers, energy for short bursts of activity (15 secs)

Anaerobic Cellular Respiration

ATP producing reaction without O2, energy for about 2 min

Aerobic Cellular Respiration

ATP producing reaction that requires O2, long term energy

Wave Summation

Increased strength of contraction resulting from 2nd stimuli before muscle has relaxed from 1st stimuli

Incomplete (unfused) Tetanus

Sustained muscle contraction that permits partial relaxation between stimuli

Complete (fused) Tetanus

Sustained contraction that lacks even partial relaxation between stimuli

Red Muscle Fibers

Fibers with high myoglobin content, more mitochondria, and more capillaries

White Muscle Fibers

Fibers with low myoglobin content, less mitochondria, and less capillaries

Slow Oxidative Fibers

Smallest and least powerful muscle fibers, dark red, aerobic cellular respiration, fatigue resistant

Long-Distance Running

Slow Oxidative Fibers

Fast Oxidative-Glycolytic Fibers

Intermediate diameter and powerful fibers, dark red, aerobic respiration and glycolysis, moderate fatigue resistance

Sprinting

Fast Oxidative-Glycolytic Fibers

Fast Glycolytic Fibers

Largest and most powerful fibers, white, glycolysis, fatigues quickly

Weight Lifting

Fast Glycolytic Fibers

Regeneration

No division, limited capacity