Muscle Tissues Flashcards
3 layers of muscle connective tissue
Epimysium
Perimysium
Endomysium
Epimysium
On top
Exterior collagen layer
Connected to deep facia
Separates muscle from surrounding tissue
Perimysium
Inside the muscle it’s self
Surrounds muscle fibers and contains blood vessel and nerve
Endomysium
Surrounds individual cell
Contains capillaries and nerve fibers and myosatellite cells
Characteristics of skeletal muscle
Very long
Many nuclei
Striated
Sacrolemma
Plasma membrane of muscle fiber that surrounds sacroplasm
It has transmembrane potential
Transverse tubules
T tubules
Action potentials travel through them to trigger muscle contraction
Myofibrils
Made up of myofilaments that are responsible for skeletal muscle contraction
Thin filaments
Made up of actin
Thick filaments
Made up of myosin
Sarcomeres
Smallest functional unit of muscle fiber
Triad
T tubules and SR form this
A band of sarcomere
Myosin— thick filament
Dark in color
I band of sarcomere
Actin thin filament
Light in color
Thin filament contains G actin
This molecule contains active site where myosin can bind
During resting tropomysin covers the sites
Tropomyosin
Attaches the actin and there can be no contraction
Troponin
Gets tropomyosin off of actin
Cross bridges
During contraction myosin heads pull actin
Depolarization
Influx of sodium ions— the membrane potential becomes LESS negative
Hyper polarization
The movement of potassium ions out of the cell—- the membrane potential becomes MORE negative
Action potential
Only travels one way
Neuromuscular junction (NMJ)
Communication between neurons and muscle fiber
Made up of axon terminal, motor end plate and synaptic cleft