Function and Anatomy of Skeletal Muscle

What are the basic properties of muscle tissue?

Excitability (the ability to respond to stimuli), contractility (the ability to shorten and exert a pull or tension), extensibility (the ability to continue to contract over a range of resting lengths), and elasticity (the ability to rebound toward its original length)

What are the functions of skeletal muscle?

Produce skeletal movement, maintain posture and body position, support soft tissue, regulate entering and exiting of material, and maintain body temperature

What are the concentric layers of connective tissue in skeletal muscles?

epimysium, perimysium, and endomysium

Epimysium

a layer of dense irregular connective tissue surrounding the entire skeletal muscle; outermost layer

Perimysium

divide the muscle into internal compartments; central layer

Endomysium

surrounds each skeletal muscle fiber (individual skeletal muscle cell), binds each muscle fiber to its neighbor, and supports the capillaries that supply the individual fiber; outermost layer

Myosatellite Cells

precursor cells to skeletal muscle cells; repair damaged muscle tissue

Epimysium, perimysium, and endomysium
converge to form _____

tendons

Tendon

structure that attaches the muscle to bone

Aponeurose

thick, flattened sheets that connect a
muscle to a muscle

Nerves innervate the muscle through penetration of the _____

epimysium

Where does chemical communication between a neuron and a skeletal muscle fiber occur?

at neuromuscular junctions

Neuromuscular Junction (NMJ)

a synapse between a neuron and a muscle cell

How many neuromuscular junctions does each muscle fiber have?

one

What is the purpose of blood vessels in skeletal muscles?

to deliver the oxygen and nutrients needed to produce energy in the form of ATP for contraction

Fibromyalgia

a disorder characterized by widespread,
chronic musculoskeletal pain usually accompanied by fatigue and disturbances in sleep, memory, and mood

Are skeletal muscle cells mono- or multi- nucleate?

multinucleate

Myoblasts

Embryonic cells that form skeletal muscle fibers

Transverse (T) Tubules

tubular extensions of the sarcolemma that conduct electrical impulses, called action potentials, to stimulate muscle fiber contraction

Myofibrils

fine cylindrical fibers contained in the sarcoplasm that are responsible for the contraction of muscles; attached to the sarcolemma at each end of the muscle cell

Myofilaments

fine protein filaments composed of the contractile proteins actin (thin filaments) and myosin (thick filaments)

Sarcoplasmic Reticulum

the storage and release site of calcium ions and plays an essential role in controlling individual myofibril contraction

Triad

The combination of a pair of terminal cisternae plus a T tubule