Biology of Muscles Flashcards
Which of the following is a recognized function of skeletal muscle?
- produce movement
- maintain body temperature
- guard body entrances and exits
- maintain posture
- all of the above
- all of the above
Which of the following is not a function of smooth muscle tissue?
- epimysium.
- tendon.
- perimysium.
- endomysium.
- fascicle.
- epimysium.
The plasma membrane of skeletal muscle is called the..
- sarcolemma.
- sarcomere.
- sarcoplasm.
- sarcoplasmic reticulum.
- sarcosome.
- sarcolemma.
Which of the following best describes the term sarcoplasmic reticulum?
- largely made of myosin molecules
- protein that accounts for elasticity of resting muscle
- storage and release site for calcium ions
- repeating unit of striated myofibrils
- thin filaments are anchored here
- storage and release site for calcium ions
The repeating unit of a skeletal muscle fibre is the..
- sarcoplasmic reticulum.
- sarcolemma.
- myofibril.
- myofilament.
- sarcomere.
- sarcomere.
After death, muscle fibers run out of ATP and calcium begins to leak from the sarcoplasmic reticulum into the sarcoplasm. This results in a condition known as..
- rigor mortis.
- depolarization.
- treppe.
- tetany.
- oxygen debt.
- rigor mortis.
Interactions between actin and myosin filaments of the sarcomere are responsible for..
- the striped appearance of skeletal muscle.
- muscle relaxation.
- the conduction of neural stimulation to the muscle fibre.
- muscle contraction.
- muscle fatigue.
- muscle contraction.
Which of the following best describes the term Z line?
- thin filaments are anchored here
- protein that accounts for elasticity of resting muscle
- repeating unit of striated myofibrils
- storage site for calcium ions
- largely made of myosin molecules
- thin filaments are anchored here
The type of contraction in which the muscle fibres do not shorten is called..
- isotonic.
- treppe.
- tetany.
- isometric.
- concentric.
- isometric.
The action potential is conducted into a skeletal muscle fiber by..
- transverse tubules.
- motor end plates.
- sarcoplasmic reticulum.
- triads.
- neuromuscular junctions.
- transverse tubules.
Each thin filament consists of..
- a double strand of myosin molecules.
- chains of myosin molecules.
- two protein strands coiled helically around each other.
- a rod-shaped structure with “heads” projecting from each end.
- six molecules coiled into a helical structure.
- two protein strands coiled helically around each other.
When a muscle is stimulated repeatedly at a high rate, the amount of tension gradually increases to a steady maximum tension. This is called..
- a twitch.
- recruitment.
- wave summation.
- complete tetanus.
- incomplete tetanus.
- complete tetanus.
Each skeletal muscle fiber is controlled by a motor neuron at a single..
- synaptic knob.
- sarcomere.
- transverse tubule.
- neuromuscular junction.
- synaptic cleft.
- neuromuscular junction.
When calcium ion binds to troponin,
- tropomyosin moves into the groove between the helical actin strands.
- myosin shortens.
- active sites on the myosin are exposed.
- actin heads will bind to myosin.
- muscle relaxation occurs.
- tropomyosin moves into the groove between the helical actin strands.
In response to action potentials arriving along the transverse tubules, the sarcoplasmic reticulum releases..
- acetylcholine.
- hydrogen ions.
- potassium ions.
- calcium ions.
- sodium ions.
- calcium ions.
Which of the following best describes the term titin?
- repeating unit of striated myofibrils
- largely made of myosin molecules
- storage site for calcium ions
- thin filaments are anchored here
- protein that accounts for elasticity of resting muscle
- protein that accounts for elasticity of resting muscle
Fast fibers…
- have low resistance to fatigue.
- rely on aerobic metabolism.
- have many mitochondria.
- have twitches with a very brief contraction phase.
- have low resistance to fatigue and have twitches with a very brief contraction phase.
- have low resistance to fatigue and have twitches with a very brief contraction phase.
During anaerobic glycolysis..
- pyruvic acid is produced.
- oxygen is not consumed.
- ATP is produced.
- all of the above
- B and C only
- all of the above
Which of the following statements is (are) true regarding human muscles?
- Eye muscles are composed entirely of fast fibers.
- Most have both slow and fast fibers.
- Slow fibers are abundant in the calf muscles.
- Slow fibers are abundant in the back muscles.
- All of the above.
- All of the above.
1) Which of the following is a recognized function of skeletal muscle? A) produce movement B) maintain posture C) maintain body temperature D) guard body entrances and exits E) All of the answers are correct.
E) All of the answers are correct.
Muscle tissue, one of the four basic tissue groups, consists chiefly of cells that are highly specialized for
Contraction
The dense layer of connective tissue that surrounds an entire skeletal muscle is the
Epimysium
Nerves and blood vessels that service the muscle fibers are located in the connective tissues of the
Perymysium
The delicate connective tissue that surrounds the skeletal muscle fibers and ties adjacent muscle fibers together is the
Endomysium
The bundle of collagen fibers at the end of a skeletal muscle that attaches the muscle to bone is called a(n)
Tendon
The advantage of having many nuclei in a skeletal muscle fiber is the ability to
The ability to produce large amounts of the enzymes and structural proteins needed for contraction.
Skeletal muscle fibers are formed from embryonic cells called
Myoblasts
At each end of the muscle, the collagen fibers of the epimysium, and each perimysium and endomysium, come together to form a
Tendon
Individual muscle cells are surrounded by what connective tissue?
endomysium
________ are stem cells located between the endomysium and sarcolemma that function in the repair of damaged muscle tissue.
Myosatellite cells
The plasma membrane of skeletal muscle is called the
Sacrolemma
The region of the sarcomere containing the thick and thin filaments is the
A Band
The region of the sarcomere that always contains only thin filaments is the
I Band
The area in the center of the A band that contains no thin filaments is the
H band
The skeletal muscle complex known as the triad consists of
a transverse tubule and two terminal cisternae.
receptors for acetylcholine are located on the
motor end plate
the most important factor in decreasing the intracellular concentration of calcium ion after contraction is
active transport of calcium into the sarcoplasmic reticulum
which of the following acts as an ATPase during the contraction cycle of muscle
the head portion of myosin molecule
in rigor mortis..
ATP is depleted, the myosin heads are attached to actin, calcium ions keep binding to troponin, sustained contractions occur
In a sarcomere, cross-bridge attachment occurs specifically in the
zone of overlap
physical evidence that supports the sliding filament theory of muscle contraction includes
decreased width of H band during contraction
triggering of the muscle action potential occurs after
acetylcholine binds to chemically gated channels in the motor end plate
when acetylcholine binds to receptors at the motor end plate, the sarcolemma becomes
more permeable to sodium ions
the rapid rise and fall in force produced by a muscle fiber after a single action potential is a
twitch
when a muscle is stimulated repeatedly at a high rate, the amount of tension gradually increases to a steady maximum tension. this state of maximum tension is called
complete tetanus
a muscle producing almost peak tension during rapid cycles of contraction and relaxation is said to be in
incomplete tetanus
if a second stimulus arrives before the relaxation phase has ended, a second, more powerful contraction occurs. This addition of one twitch to another is called
wave summation
a single motor neuron together with all the muscle fibers it innervates is called a
motor unit
the increase in muscle tension that is produced by increasing the number of active motor units is called
recruitment
