Chapter Ten Vocab Flashcards
Epimysium
Surrounded entire muscle
Perimysium
Surrounds fascicles
Fascicle
Group of muscle cells
Endomysium
Separates individual cells
Electrically isolates cells
Tendon
All three layers as they merge to attach to bone
Muscle
Group of fascicles
Muscle fascicle
Group of muscle fibers (cell)
Muscle fiber
Group of myofibrils
Sarcolemma
Muscle cell membrane
Sarcoplasma
Muscle cell cytoplasm
Sarcoplasmic reticulum
Smooth endoplasmic reticulum
Stores calcium
Cisternae
Areas of the ER dedicated to CA++ storage
Actin
Major protein of thin filament
Has a binding site fore myosin allowing cross bridge with myosin to form
Tropomyosin
Long, fibrous molecule, extending over actin, and preventing interaction between actin and myosin
Troponin
Binds reversibly to calcium and able to move tropomyosin away from the actin active site
Nebulin
Holds F-actin strands together
Sarcomere
Functional and structural unit of the muscle
Repeated pattern of myofilament
Thick filaments
Myosin
thin filaments
Actin
M line
The disc in the middle of the Sarcomere
Z line
Area of attachment of the actin fibers
Crossbridge cycling
Multiple religion of attach, pull release, and reset lead to fully contracted sarcomere
Motor unit
Defined as the motor neuron and the skeletal muscle cell it innervates
Fine motor movements
(Like typing) rely on motor u it’s with relatively few fibers in contrast to those in the leg muscles, for example
Latent phase
This is the period of time from the action potential to the onset of contraction. The time delay is due to the excitation-contraction coupling.
Contraction phase
This is the time that tension is developing due to the cross-bridge cycling
Relaxation phase
This is the time that the tension is decreasing ( I.e., relaxing) and is lounger than the contraction phase. This is due to the amount of time it takes to get all the Ca2+ sequestered
Tension depends on
Frequency of action potential stimulation
Number of motor units recruited
Degree of muscle stretch
Isometric
Muscle contraction without movement
No muscle shortening
Isotonic
Muscle contraction with movement
Muscle shortens
Myoglobin
An oxygen binding protein found in muscle cells