How can we help?

You can also find more resources in our Help Center.

Anatomy

1. The tendency of a stretched muscle fiber to return to its original length is called ______. 2. One motor nerve fiber and all the muscle fibers innervated by it are called a _________ _______. 3. A plasma membrane is said to be ______________ if there is a difference in charge on opposite sides of it. 4. The ____________ ___________ theory is the current model of how a muscle fiber contracts. 5. A resting muscle is normally in a state of partial contraction called _________________. 6. A muscl…
STUDY
PLAY
In a resting muscle, the __________ contains a concentrated solution of calcium.
sarcoplasmic reticulum
Motor nerve fibers release a neurotransmitter called ____, which make skeletal muscle fibers contract.
AcH
e tendency of a stretched muscle fiber to return to its original length is called ______.
elasticity
One motor nerve fiber and all the muscle fibers innervated by it are called a _________ _______.
motor unit
A plasma membrane is said to be ______________ if there is a difference in charge on opposite sides of it.
polarized
The ____________ ___________ theory is the current model of how a muscle fiber contracts.
sliding filament
A resting muscle is normally in a state of partial contraction called _________________.
tonus
A muscle fiber will not contract unless it is depolarized to a voltage called its __________.
threshold
Several body orifices are regulated by circular muscles called
sphincters
Muscle fibers are arranged in bundles called
fascicles
A muscle that prevents unwanted movement of a bone is called a
synergist
Each muscle fiber is surrounded by its own connective tissue sheath called the
endomysin
The bone at a muscle's __ shows little or no movement when that muscle contracts
orgin
A __ is a muscle that contracts to move a bone
Skeletal
The muscle of the lips is the
orbicularis oris
The prime mover of neck flexion which allows us to bow out head is the
sternocleidomastoid
The largest muscle of the upper back is the
latissimusdorsi
The linea alba seperates the right and left ___ muscles
rectus abdominus
The hamstring muscles are the
1.Biceps femoris, 2.semimembranosus, 3.semitendinosus
The ___ closes the eye, makes us blink and squint
orbicularis oculi
A broad flat tendon is an
aponeurosis
A smile is produced by a contractoin of the?
zygomaticus muscle
The deepest muscle of the abdominal wall is the
transversus abdominis
The longest muscle of the human body is the
sartorius
A quick cycle of muscle contractin and relaxation is called a
twitch
What lowers the pH of the sarcoplasm and contributes to muscle fatigue
lactid acid
Contraction in which a muscle develops tension but does not shorten is called
isometric
The ____ zone becomes narrower during muscle contraction
H band
The oxygen storage molecule in muscle is
myoglobin
Contraction in which a muscle shortens and moves the load is called
isotonic
A state of physiological inability to contract, even though the muscle may still be recieving stimuli is
muscle fatigue
A high energy molecule stored in muscles that transfers a phosphate group to ADP to form ATP after stored ATP is consumed is
creatine phosphate
During long periods of exercise, muscles consume ____________, ___________, _____________, ___________, _______________ and ___________________. This produces
1.glucose 2. glycogen 3.oxygen 4.pyrubic acid 5.fatty acids 6.amino acids
After about 30 minutes, _____ becomes the major energy feuls of muscles
fat
The amount of oxygen required after exercise to replenish stores of oxygen, ATP, creatine phosphate, and glucose is called
oxygen debt
Which muscle is voluntary
skeletal
Muscles stores energy in
glycogen
In a relaxed muscle fiber, the active sites of actin are blocked
tropomysin
Each end of sarcomere is marked by a
Z disc
During the time that a muscle is shortening but maintaining constant tension it is undergoing _____________ contraction.
isotomic
The region of a sarcomere where actin and myosin overlap is the _______ band.
A
When there is not enough oxygen to create ATP by aerobic respiration, a muscle fiber can produce ATP by borrowing phosphate groups from
Creatine phosphate
Regulatory proteins of the myofilaments are ____________________ and ___________________.
troponin and tropomysin
Contractile proteins of the myofilaments are _________________ and ___________________.
actin and myosin
Which of these processes occurs during the contraction of skeletal muscle?
Z discs move closer together
73. Which of the following is NOT found in the thin filaments of striated muscle?
A. F actin B. ATPase C. troponin D. tropomyosin E. Ca2+ receptors
B. ATPase
In contrast to red muscle fibers, white fibers
fatigue more quickly
The loss of muscle mass from disuse is called
atrophy
Posture is maintained mainly by
slow motion fibers
A motor unit is
One nerve fiber and all the muscle fibers innervated together
80. After a muscle fiber has exhausted its stores of ATP and creatine phosphate, it switches to _______ as a source of energy.
A. glycolysis B. fat oxidation C. aerobic respiration D. anaerobic fermentation E. creatine kinase
D
If a poison inhibits the activity of acetylcholinesterase, a muscle
May be unable to relax
Fatigue of muscle is due to the build up of
lactic acid
A bundle of muscle fibers is
fascicle
The thick filament of a sarcomere of a skeletal muscle cell contains
myosin
The union between a nerve fiber and a muscle fiber is the
neuromuscular junction
The thin filament of a sarcomere of a skeletal muscle cell contains
Actin
The movable end of a muscle is the
intertion point
The immovable end of the muscle is the
orgin
What chemical is realeased from the neuron end plates?
AcH
When myosin heads bind to the actin sites, and actin-myosin____ is formed
cross bridge
A single stimulus to a muscle fiber results in a
muscle twitch
Refers to a single, sustained muscle contraction
tetanus
A motor unit must be polarized to its ___ before action potential will occur
threshold
the three phases of a twitch are
1.latent 2.contraction 3.relaxation
What contraction is the force generated by the muscle does not change, but the muscle's length changes
isometric
In what is glucose used to create a small amount of ATP without using oxygen?
fermentation
In what is ATP produced in greater quantity, but oxygen is required
Aerobic respiration
Smooth muscle is found primarily in the
walls of hollow organs
On ___ muscle fibers can divide
Skeletal
When smooth muscle is stretched, it responds by
contracting