Chapter 6: The Muscular System
an individual muscle cell
Endomysium covers _____________.
bind to receptors in the sarcolemma of the muscle cell
In order to excite a muscle cell, acetylcholine must __________.
axon terminals of the motor neuron
Neurotransmitters are released upon stimulation from a nerve impulse by the _________.
motor unit
One neuron and all the skeletal muscles it stimulates is known as a ________.
involuntary
Smooth muscle cells are _______.
cardiac
Striated involuntary muscle tissue is classified as _______ muscle.
sarcoplasmic reticulum
The ____________ is an organelle that wraps and surrounds the myofibril and stores calcium.
insufficient intracellular quantities of ATP due to excessive consumption
The condition of skeletal muscle fatigue can be best explained by ___________.
synaptic cleft
The gap between the axon terminal of a motor neuron and the sarcolemma of a skeletal muscle cell is called the ________.
synaptic cleft
The gap between the motor neuron and the muscle fiber is supplies at the neuromuscular junction is called the _________.
cross bridges
The heads of the myosin myofilaments are called _________ when they link the thick and thin filaments together during skeletal muscle contraction.
origin
The least movable point of muscle attachment to a bone is termed its _________.
a sliding of thin filaments past thick filaments
The mechanical force of contraction is generated by _________.
adduction
The movement opposite to abduction is _________.
sarcolemma
The plasma membrane of a skeletal muscle is called the _________.
origin
The point of attachment to an immovable or less movable bone is known as the ___________.
skeletal
Which type of muscle tissue contracts most quickly upon stimulation?
motor unit
A motor neuron and all of the skeletal muscles it stimulates are termed a ___________.
the contractile unit between two z discs
A sarcomere is ____________.
the muscle twitch is a brief "jerky" movement, while the tetanic contraction is prolonged and continuous
A skeletal muscle twitch differs from a tetanic contraction in that ____________.
fused, or complete, tetanus
A smooth, sustained contraction is called ___________.
calcium triggers the binding of myosin to actin
Why are calcium ions necessary for skeletal muscle contraction?
a neurotransmitter that stimulates skeletal muscle
Acetylcholine is __________.
sarcoplasmic reticulum
An elaborate and specialized network of membranes in skeletal muscle cells that function in calcium storage is the ___________.
oxygen
Anaerobic glycolysis occurs without __________.
oxygen
Anaerobic glycolysis requires __________ to make ATP.
isometric contractions
Contractions in which muscles shorten and produce movement are known as ___________.
storing energy that will be transferred to ADP to resynthesize ATP
Creatine phosphate (CP) functions within the muscle cells by ___________.
thin filaments
Cross bridges are created when myosin heads bind to __________.
actin filaments
During skeletal muscle contraction, myosin heads attach to binding sites associated with ________.
contractility
Muscle tissue has the ability to shorten when adequately stimulated, a characteristic known as __________.
antagonists
Muscles that perform opposite actions to one another are termed ________.
tendons; aponeuroses
They epimysium covering on the outside of the muscle can blend into cordlike _______ or sheet-like ______.
z discs
When a skeletal muscle is fully contracted, the _________ are closer to the thick filaments.
sarcomere
Which of the following can actually shorten during a muscle contraction?
pushing against an immovable wall
Which of the following is an example of an isometric contraction?
thick filaments
Which of the following is composed of myosin protein?
hematopoiesis
Which of the following is not a function of the muscular system?
acetylcholine (ACh) causes temporary permeability to sodium
Which of these events must occur first to trigger the skeletal muscle to generate an action potential and contract?