EXAM ONE REVIEW
thin filaments are primarily composed of which protein?
F actin
Anaerobic fermentation produces the same amount of ATP as aerobic respiration. (T/F)
False
A term refers to a sheet of connective tissue that separates neighboring muscles or muscle groups
Fascia
The sarcolemma of smooth muscle cells has pockets called ______ that contain calcium channels
caveolae
with skeletal muscle contraction, what is excitation?
process by which action potentials in a nerve fiber lead to action potentials in a muscle fiber
When excitation of a muscle fiber stops, the SR __________?
reabsorbs calcium
What occurs when calcium binds to troponin?
the troponin-tropomyosin complex changes shape and exposes the myosin binding sites (active sites)
What is excitation-contraction coupling?
events that link the action potential of the arcolemma to the activation of the myofilament contraction
What is the process by which action potentials of a nerve fiber lead to action potentials in the muscle fiber called
excitation
What phase of contraction links the action potential in the sarcolemma to the activation of the myofilament?
excitation- contraction coupling
What is most likely to be the action of the extensor digitorum? (Hint: What does the name mean?)
extend the digits
property allows muscle cells to stretch to as much as three times their contracted length?
extensibility
A term refers to bundles of muscle fibers, wrapped in connective tissue, within a muscle Compartments Striations Fascicles Tendons
fascicles
biceps brachii and the gastrocnemius are examples of ______ muscles
fusiform
The glycogen-lactic acid system utilizes what molecule(s) as fuel to generate ATP?
glucose
Muscle cells contain _____ a starch-like carbohydrate that provides energy during intense exercise.
glycogen
term refers to a muscle that produces most of the force during a particular joint action?
agonist
What is myosin ATPase?
an enzyme located in the myosin head that hydrolyzes ATP
The glycogen-lactic acid system relies on which form of metabolism
anaerobic
Lactic acid and a small amount of ATP are produced during which process
anaerobic fermentation
What are the two most important pathways by which ATP is generated in muscle cells?
anaerobic fermentation and aerobic respiration
Which is NOT a step of skeletal muscle contraction?
breakdown of creatine phosphate
When a nerve signal arrives at a synaptic knob, which voltage-gated channels open in the knob?
calcium channels
In smooth muscle, which protein does calcium bind to?
calmodulin
What regulatory protein is associated with the thick filament of smooth muscle and activates myosin light-chain kinase?
calmodulin
Under the microscope, muscle that has alternating light and dark regions is said to be which of the following?
striated
Skeletal muscle exhibits alternating light and dark bands called
striations
Smooth muscle is named for the fact that it has no?
striations
Connective tissue structures that attach bone to muscle are called __________?
tendons
Which occurs during muscle contraction?
the overlapping of myofilaments increases
What is muscle tone?
the partial contraction of resting muscles
What is a power stroke during muscle contraction?
the ratcheting of myosin head
genetic condition in which an abnormal form of the dystrophin protein is produced results in __________ dystrophy
Muscular dystrophy
How much does a muscle fiber shorten from a single cycle of power and recovery strokes by all the myosin heads?
1% of its resting length
Within a sarcomere, the overlap of actin and myosin produce the __________ bands.
A bands
What is the perimysium? 1) A layer of loose connective tissue layer surrounding each individual muscle cell 2) A connective tissue sheath bundling many muscle fibers into a fascicle 3) The plasma membrane of an individual muscle cell 4) A connective tissue sheath surrounding an entire muscle
A connective tissue sheath bundling many muscle fibers into a fascicle
What is calmodulin?
A protein that replaces troponin in smooth muscle cells
During contraction, each power stroke consumes one molecule of what
ATP
energy needed for short bursts of intense activity is provided by which of the following?
ATP and creatine phosphate
What is a motor unit?
All of the muscle fibers innervated by a single motor nerve fiber.
In flexing the elbow, the prime mover is the
Brachialis
What is the immediate trigger for the contraction of smooth muscle?
Calcium ions
What must occur before tropomyosin can shift, revealing the active sites that allow myosin heads to bind to the actin filaments
Calcium must bind to troponin
What is the ability of muscle cells to shorten called? Multiple choice question.
Contractility
The "cocking" of the myosin head, hydrolysis of ATP and the power stroke occur during which phase of skeletal muscle contraction?
Contraction
Place the following events in synaptic transmission at a cholinergic synapse in order: A - A postsynaptic potential is produced; B - Voltage gated calcium channels open and calcium enters the cell; C - ACh is released and diffuses across the synaptic cleft; D - A nerve signal arrives at a synaptic knob; E - Ligand gated sodium channels open and sodium enters the cell.A) B, C, D, E, AB) D, B, C, E, AC) B, D, C, A, ED) D, B, E, A, C
D, B, C, E, A (A nerve signal arrives at a synaptic knob, Voltage gated calcium channels open and calcium enters the cell, ACh is released and diffuses across the synaptic cleft, Ligand gated sodium channels open and sodium enters the cell, A postsynaptic potential is produced)
Which term refers to the loose connective tissue layer that surrounds each individual muscle cell Epimysium Endomysium Perimysium Fascia
Endomysium
In a sarcomere, the thick filaments attach to the __________ line, found in the middle of the H band
M-line
perimysium is a connective tissue sheath that surrounds which of the following? Individual muscle fibers Groups of muscles Muscle fascicles The entire muscle
Muscle fascicles
Knowing the innervation to each muscle enables clinicians to diagnose which of the following
Nerve, spinal cord, and brain stem injuries
The perimysium contains which of the following (select what applies) Blood vessels Nerves bone tissue Muscle spindles
Nerves Muscle spindles blood vessels
From excitation through contraction, the SR
Releases and reabsorbs calcium (Ca2+)
Which of the following are functions of endomysium? 1) Contains stretch receptors called muscle spindles 2) Separates individual muscle fibers 3) Provides the extracellular chemical environment for each muscle fiber 4) Creates room for capillaries and nerve fibers to reach every muscle fiber
Separates individual muscle fibers Provides the extracellular chemical environment for each muscle fiber Creates room for capillaries and nerve fibers to reach every muscle fiber
What is the function of a T tubule?
T tubules carry the action potential through the sarcoplasm
Aerobic respiration is important for producing energy for long term energy needs. (T/F)
TRUE
Skeletal muscle contraction helps produce body hear (T/F)
TRUE
What causes skeletal muscle cells to be striated?
The alternating light and dark regions of the sarcomeres
What does the length-tension relationship suggests about the generation of muscle tension?
The amount of tension generated during a contraction depends on the degree of stretch of shortening prior to contraction
Which is true of the light bands in skeletal muscles?
They are called I bands and are bisected by Z disc
What is a fascia?
Thick sheet of connective tissue separating neighboring groups of muscles
What is a myoglobin?
a molecule that stores oxygen in muscles
Myosin ATPase is an enzyme in the myosin head that hydrolyzes ATP to release energy. (T/F)
True
Because skeletal muscle is under the conscious control it is said to be?
Voluntary
During contraction, what causes a power stroke?
When myosin releases ADP and ratchets to low energy postion
When an overly shortened or overly stretched muscle fiber is stimulated, what kind of contraction is generated?
a weak contraction
At the synaptic knob of the motor neuron, calcium stimulates exocytosis of the synaptic vesicles to release the neurotransmitter ______ into the synapse
acetycholine
I bands are composed primarily of which protein?
actin
Which provides long term energy for a cell?
aerobic
Which process produces the most ATP?
aerobic respiration
What term is another word for prime mover? synergist antagonist agonist fixator
agonist
characteristic that allows muscles to pull on bones and organs to create movement is called
contractility
The step in which the muscle fiber develops tension and may shorten is called ______.
contraction
During short bursts of intense activity, ATP for muscle contraction is supplied by which of the following?
creatine phosphate
What protein links actin fibers to the inner face of the sarcolemma?
dystrophin
When muscles stretch and recoil, they recoil to a shorter length. What is this property called?
elasticity
Fatigue resistance is improved by ______ exercise which enhances the delivery and use of oxygen
endurance
Epimysium is a connective tissue sheath that wraps around which of the following?
entire muscle
The connective tissue layer that covers the entire muscle is called the ___________?
epimysium
What term refers to the connective tissue layer that surrounds the entire muscle Perimysium Endomysium Fascia Epimysium
epimysium
Which of the following is true of endurance exercise?
increases oxygen transport
The _____ of a muscle refers to the identity of the nerve that stimulates it.
innervation
Which describes smooth muscle?
it is slow to relax and slow to contract
All of the muscle fibers innervated by a single nerve fiber constitute a __________ unit.
motor unit
What does the sliding filament describe?
muscle contraction
Which can be measured by attaching stimulating electrodes to a nerve-muscle preparation and a recording device?
muscle strength
partial contraction of a resting muscle is known as which of the following?
muscle tone
Muscle cells contain __________ a red pigment that stores oxygen needed for muscular activity.
myoglobin
protein found in muscle cells that stores and then releases oxygen when needed is called
myoglobin
A record of the timing and strength of a muscle's contraction is called a
myogram
In a myofibril, a thick filament is composed of pairs of _____ molecules intertwined together.
myosin
Which protein makes up the thick filaments of a myofibril
myosin
A synapse is the point where a nerve fiber meets a target cell. When the target cell is a muscle fiber, this type of synapse is called a __________ junction.
neuromuscular junction
rectus abdominis and the sartorius are examples of ______ muscles
parallel
A muscle of uniform width with fascicles aligned along its longitudinal axis would be classified as a __________ muscle.
parallel muscle
Projections extending from the inner surface of the epimysium form which of the following Sarcolemma fascia endomysium perimysium
perimysium
The connective tissue layer that wraps fascicles is called the __________?
perimysium
term refers to the loose connective tissue layer that surrounds skeletal muscle fascicles
perimysium
Which stage of contraction occurs when the myosin releases ADP and flexes, pulling the thin filament toward the M line?
power stroke
Within skeletal muscle cells, what extends from one Z disc to the next and constitutes one contractile unit
sarcomere
portion of a myofibril from one Z disc to the next is called a
sarcomere
What does the term "brevis" mean in the name of a muscle?
short
What is a neuromuscular junction
site where a nerve fiber communicates with the muscle fiber
The prevailing theory regarding muscle contraction is called the _________ filament theory.
sliding filament theory
__________ muscle cells are uninucleate, non-striated, and fusiform shaped
smooth
__________ muscle tissue is typically slow to contract and slow to relax.
smooth
What describes a fusiform muscle? Thick in the middle and tapered at the ends fascicles are aligned in a uniform fashion along long axis of muscle forms ring around body opening feather-shaped with fascicles inserting into tendon
thick in the middle and tapered at the ends.
During contraction, the cocked myosin head binds to an exposed active site on the actin protein of the __________ filament to form a cross-bridge.
thin filament
A muscle that is broad at one end and narrower at the other is classified as a ___________ muscle.
triangular
pectoralis major and temporalis muscles are examples of ______ muscles
triangular
When a muscle is at rest, what molecule blocks the active sites on the actin molecules
tropomyosin
In a thin filament, each tropomyosin molecule has a small calcium-binding protein called _____ bound to it.
troponin
Which of the following are found in thin filaments (multiple)
troponin F actin Tropomyosin
How does an action potential move deep into the muscle cell?
via the T-tubules
