A+P chapter 7 test
The stiffness that occurs at death, when actin and Myosin molecules stay linked to each other in a contracted state, is due to a lack of
ATP
Which of the following is one of the steps that ends contraction
Acetylcholine is broken down by acetylcholinesterase
Upon the nerve impulses arriving at the axon terminal
Acetylcholine is released
The specialized sarcolemma that contains acetylcholine receptors is the
Motor end plate
Neurotransmitters that cause skeletal muscle contraction are normally stored in
Motor neuron exam terminals
the length of time a muscle can continue to contract while supported by mitochondrial activities is referred to as
aerobic endurance
A resting muscle generates most of its ATP by
aerobic respiration
a resting muscle generates most of its ATP by
aerobic respiration
_____ exercise requires oxygen and is of _____ duration than _______ exercise
aerobic; longer; anaerobic
slow fibers are the type of muscle fibers that contain
all of the above
the axial musculature consists of
all of the above
smooth muscle cells
are spindle shaped
when muscles are actively contracting, the process requires large amounts of energy in the form of
atp
tendons are bundles of collagen fibers at the end of a skeletal muscle that
attach muscle to bone
Mitochondrial activities are relatively efficient, but their rate of ATP generation is limited by the:
availability of oxygen
The ________ contains vesicles filled with acetylcholine
axon terminal
from the following selections, choose the one that include only muscles or facial expression
buccinator, orbicularis oris, risorius, frontalis
Active sites on the actin become available for binding when
calcium binds to troponin
in response to action potentials arriving from the transverse tubules, the sarcoplasmic reticulum releases
calcium ions
the names of the muscles of the tongue are readily identified because their descriptive names end in
glossus
during moderate activity, which of the following is true regarding muscle metabolism
glucose and fatty acids are catabolized
regarding muscle fiber elongation
gravity may help lengthen a muscle fiber after elongation
voluntary control over swallowing, defecation, and urination are controlled by skeletal muscles that
guard entrances and exits
the term used to describe muscular growth in response to usage is
hypertrophy
the superficial muscles of the spine are identified by subdivisions that include
iliocostalis, longissimus, and spinalis
which of the following occurs when tension production rises to a peak and very brief periods of relaxation occur
incomplete tetanus
the process of recruitment is the smooth but steady increase in muscle tension produced by
increasing the number of active motor units
Two of the muscles comprising the rotator cuff are the
infraspinatus and teres major
Glycolysis
is an anaerobic process
anaerobic endurance
is exemplified by contractions of fast muscle fibers
which of the following occurs when glycolysis produces pyruvate faster than it can be used by the mitochondria
lactic acid produced
calcium ions are released from the sarcoplasmic reticulum during the _______ phase of contraction
latent
Regarding lactic acid regulation, which cells in the body consume extra oxygen and produce ATP for the conversion of excess lactate absorbed from the blood back to glucose?
liver cells
the ability of skeletal muscles to produce continuous contractions results in the ability of the body to
maintain posture and body position
During a specific action, the insertion is the
more movable end of a muscle
the amount of oxygen used in the recovery period to restore normal pre-exertion conditions is referred to as the
oxygen debt
bundles of muscle fibers called fasicles make up the connective tissue fibers of the
perimysium
the layer of connective tissue that contains blood vessels and nerves is the
perimysium
smooth muscle uses
primarily aerobic metabolism
fast fibers are the type of muscle fibers that
produce powerful contractions but fatigue rapidly
Highly coordinated activities such as swimming, skiing, or typing are examples of the skeletal muscle function of
producing movement
During anaerobic glycolysis
pyruvic acid is produced
the iliac crest is the origin of the
quadratus lumborum
which of the following is an accurate characteristic of slow fibers
resting slow muscle fibers contain oxygen reserves, bound to myoglobin
botulism
results from a bacterial toxin that prevents the release of acetylcholine at the axon terminals
the function of layers of skeletal muscles that comprise the abdominal wall and floor of the pelvic cavity is to
support soft tissues
the endomysium is the layer of connective tissue that
surrounds each skeletal muscle fiber and ties adjacent muscle fibers together
Acetylcholinesterase is found within the
synaptic cleft
in an isometric contraction, the
tension produced never exceeds the resistance and the length of the muscle remains constant
in an isotonic contraction, the
tension rises and the skeletal muscle length changes
the heart has to be able to regulate its contractions. Heart Muscle, unlike skeletal muscle, cannot go into a tetanus. this is because
the heart muscle has to be able to consistently contract and pump blood in a controlled fashion
the final step involved in skeletal contraction is
the muscle cell relaxes and returns passively to its resting length
Which statement regarding isometric contractions is true
the tension produced never exceeds the load
The enzyme acetylcholinesterase causes acetylcholine to
to break down
of the following selections, the one that includes muscles that move the shoulder girdle is the
trapezius, levator scapulae, pectoralis minor, and subclavius
a single stimulus-contraction-relaxation sequence in a muscle fiber is known as a
twitch
the muscular floor of the pelvic cavity is formed by muscles that make up the
urogenital and anal triangle
thin filaments at either end of the sarcomere are attached to interconnecting filaments that make up the
z lines
the origin of the frontalis muscle is the
galea aponeurotica
Steps of muscle contraction
1. Nerve impulse arrives at synapse 2. Acetylcholine is produced 3. Action potential is generated along the sarcolemma 4. Calcium is released into muscle call cytoplasm 5. Actin and myosin molecules continuously cross link, with actin molecules being pulled inward
fast fibers
Have high glycogen reserves
which of the following is true about red muscles
Red muscles are slower than white muscles
athletes training to develop anaerobic endurance perform
frequent, brief, intensive workouts
the command to contract is distributed throughout a muscle fiber by the
T tubules
an example of an activity that requires anaerobic endurance is
a 50-yard dash
choose the correct statement regarding motor units
a motor neuron may control only two or three muscle fibers of the eye muscle
the neurotransmitter released from the synaptic vesicles that initiates an action potential in the sarcolemma is
acetylcholine
skeletal muscle fiber contraction begins when
acetylcholine is released into the neuromuscular junction and binds to receptors on the sarcolemma
the thin filaments of a sarcomere consist of
actin
muscle cells
can only contract
the presence of intercalacted discs is a characteristic unqiue to
cardiac muscle cells
which of the following is characteristic of cardiac muscles
cardiac muscle cells are striated
A muscle that inserts on the body of the mandible is probably involved in
chewing
during which phase is the stimulus frequency so high that the relaxation phase is eliminated
complete tetanus
the primary energy reserve in muscle tissue is
creatine phosphate (CP)
from the following selections, choose the one that includes the muscles that move the upper arm
deltoid, teres major, latissimus dorsi, pectoralis major
the dense layer of collagen fivers that surrounds an entire skeletal muscle is the
epimysium
the three layers of connective tissues comprising each muscle are
epimysium, perimysium, and endomysium
Muscles that insert on the olecranon process of the ulna can act to
extend the forearm
When the gluteus maximus contracts it
extends the thigh backward
in humans, slow fibers are not found in the muscles of the
eyes and hands
when energy reserves in a muscle are exhausted or lactic acid levels increase,
fatigue occurs
during activities requiring aerobic endurance
most of the muscles energy is produced in mitochondria
why do individual muscle twitches have to be added together, as in summation or tetanus
multiple twitches add up to an increase in muscle fiber tension, which increases the strength of the muscle
which statement regarding "heat loss" is true
muscle contractions play an important role in the maintenance of normal body temp
exhaustion of energy reserves or decline in pH due to production and dissociation of lactic acid causes
muscle fatigue
which statement regarding the relaxation phase of a muscle twitch is true
muscle tension falls to resting levels
which of the following occurs as a result of motor units in a particular muscle being always active, even though their contractions do not produce enough movement to cause contraction
muscle tone
After death, rigor mortis lasts until
myofilaments are broken down
the thick filaments of a sarcomere consist of
myosin
The additional oxygen required during the recovery period to restore the normal pre-exertion levels is called the __________.
oxygen debt
the smallest functional unit of the muscle fiber is the
sarcomere
in response to action potentials arriving from the transverse tubules, calcium ions are released from the
sarcoplasmic reticulum
a twitch is the type of contraction represented by a
single stimulus contraction relaxation sequence
a person whose genetic makeup makes him or her a better marathon runner than a sprinter probably has more _____ in his or her leg muscles
slow fibers
nonstriated involuntary muscle
smooth
the type of muscle cells that contract either automatically or in response to environmental or hormonal stimulation are
smooth muscle cell
the type of muscle tissue that lacks myofibrils, sarcomeres, and striations is
smooth muscle tissue
As a skeletal muscle contraction is initiated, acetylcholine binding alters the motor end plate membrane's permeability to
sodium ions
creatine phosphate serves to
supply energy for the synthesis of ATP