Microscopic anatomy
The endomysium surrounds these individual structures
muscle fibers / myofibers
The ability to be stretched is called...
extensibility
the space containing extracellular fluid between the end of an axon and a single muscle cell
synaptic cleft
what chemical is held in the motor neuron?
Acetylcholine
define motor unit
moror neuron and all muscle fibers it innervates
the myofibril is intracellular and covered by this...
sarcoplasmic reticulum
Recoiling to resting length after being stretched is called...
elasticity
these zones disappear during contraction..
H- zones
At the threshold
T/F each axon only innervates on muscle fiber
F (innervates many muscle fibers)
sarcolemma
A characteristic of muscle tissue that no other tissue type has...
At the neuromuscular junction, acetylcholine receptors are found on this...
sarcolemma
all or nothing
muscles with few fibers per motor unit (4-10) perform _________ movements
fine movements
What are the three parts of the thin filaments?
G actin, tropomyosin, and troponin
Muscle and nervous tissue have this characteristic...
excitability
term describing the state at which the inside of the cell is negative relative to the outside and is at the resting membrane potential...
polarized
Which side of the cell membrane is negative relative to the other?
the inside
muscles with several hundred fibers per motor unit perform ______________ movements
large
This band is dark and consists of entire myosin filaments and overlapping thin
filaments.
A band
Muscles serve four main functions. What are they?
movement, posture, stabilize joints, heat
Chemically gated channels give some depolarization, but these channels give much more and will change the charge of the cell.
voltage-gated channels
T/F a large action potential causes a more forceful contraction
F - action potentials do not vary in size, only in frequency
What are three ways that force can vary in the muscle?
which units, how many units, frequency of nervous stimulation