anatomy muscle Pearson review
The energy comes from the hydrolysis of ATP
How does the myosin head obtain the energy required for activation?
synaptic cleft
The gap between the motor neuron and the muscle fiber it supplies at the neuromuscular junction is called the ________
calcium triggers the binding of myosin to actin
Why are calcium ions necessary for skeletal muscle contraction?
motor unit
a motor neuron and all of the skeletal muscle fibers it stimulates are termed as __________
Acetlycholine receptor
a type of chemically-gated ion channel located on the junctional folds of the muscle fiber
calcium channel
a type of voltage-gated ion channel located on the axon terminal
sodium channel
a type of voltage-gated ion channel located on the sarcolemma of the muscle fiber
neuromuscluar junction at rest
calcium channels are closed
neuromuscular junction active
calcium channels open
neuromuscluar junction at rest
chemically-gated channels closed
neuromuscular junction active
chemically-gated channels open
thin filaments
cross bridges are created when myosin heads bing to _________________
Acetylcholinesterase
enzyme located in the synaptic cleft that breaks down acetylcholine
neuromuscular junction active
less negative charges inside sarcolemma
synaptic vesicles
membranous sac located in the axon terminal that contains neurotransmitter
neuromuscluar junction at rest
more negative charges inside sarcolemma
cardiac muscle tissue
muscle tissue composed of branching cells and intercalated discs
cardiac muscle tissue
muscle tissue found only in the heart
contractility
muscle tissue has the ability to shorten when adequately stimulated, a characteristic known as ______________
smooth muscle tissue
muscle tissue that activates arrector pili muscle to stand hairs on end
smooth muscle tissue
muscle tissue that forms valves to regulate the passage of substances through internal body openings
skeletal muscle tissue
muscle tissue that is multinucleate
skeletal muscle tissue
muscle tissue that maintains posture, body position, and stabilizes joints
Acetylcholine
neurotransmitter that stimulates skeletal muscle contraction
neuromuscluar junction at rest
no Na+ diffusion
smooth muscle tissue
performs very slow, sometimes, rhythmic, contractions
involuntary
smooth muscle cells are _____________
action potential arrives at the axon terminal
step 1
Calcium ions enter the axon terminal
step 2
synaptic vesicles fuse to membrane of axon terminal
step 3
acetylcholine is released into the synaptic cleft
step 4
acetylcholine binds to its receptors on the junctional folds
step 5
junctional folds become depolarized
step 6
action potential is initiated on the sarcolemma
step 7
cardiac muscle
striated involuntary muscle tissue found in the heart is _________
cariac
striated muscle tissue is classified as ___________ muscle
sarcoplasmic reticulum
the _______ is an organelle that wraps and surrounds the myofibril and stores calcium
tendons; aponeuroses
the epimysium covering on the outside of the muscle can blend into cordlike _______ or sheelike __________
Sarcolemma
the plasma membrane of a skeletal muscle cell is called the ______________
synaptic cleft
the space between the axon terminal and junctional folds
skeletal muscle tissue
voluntary muscle tissue
muscle paralysis and atrophy occur
what happens to a muscle when the nerve supplying that muscle is cut?
directly regenerates ATP from ADP within a muscle cell
what is the function of creatine phosphate
lactic acid
what metabolic waste accumulates in muscle with excessive exertion?
calcium
what mineral is released within muscle cells to trigger contraction?
cardiac muscle
what type of muscle tissue is both striated and involuntary?
Acetylcholine
which neurotransmitter is released by motor neurons at the neuromuscular junction?
thick filaments
which one of the following is composed of myosin protein
neuromuscluar junction at rest
ACh in synaptic vesicles
neuromuscular junction active
ACh synaptic cleft
a neurotransmitter that stimulates skeletal muscle
Acetylcholine is ________
ATP binds to the myosin head
After a power stroke, the myosin head must detach from actin before another power stroke can occur. What causes cross bridge detachment?
oxygen
Anaerobic glycolysis occurs without ________
the contractile unit between 2 Z discs
A sarcomere is:
fused, or complete, tetanus
A smooth, sustained contraction is called ________
Calcium ions are stored in the sarcoplasmic reticulum
Calcium ions couple excitation of a skeletal muscle fiber to contraction of the fiber. Where are calcium ions stored within the fiber?
bind to receptors in the sarcolemma of the muscle cell
In order to excite a muscle cell, acetycholine must ________
Release of acetylcholine from the synaptic vesicles
Inadequate calcium in the neuromuscular junction would directly affect which of the following processes?
neuromuscular junction active
Na+ diffusion
A myosin head bound to actin
The cross bridge cycle is a series of molecular events that occur after excitation of the sarcolemma. What is a cross bridge?
Calcium ions bind to troponin and change its shape
What specific event triggers the uncovering of the myosin binding site on actin?
The sarcomere
What structure is the functional unit of contraction in a skeletal muscle fiber?
Motor neuron
What structure most directly stimulates a skeletal muscle fiber to contract?
resistance exercise
What type of exercise causes increase in muscle size?
Cross bridge cycling ends when sufficient calcium has been actively transported back into the sarcoplasmic reticulum to allow calcium to unbind from troponin
When does cross bridge cycling end?