the dense layer of connective tissue that surrounds an entire skeletal muscle is the
The delicate connective tissue that surrounds the skeletal muscle fibers and ties adjacent muscle fibers together is the
An ________ can be described as a broad tendinous sheet
The repeating unit of a skeletal muscle fiber is the
The plasma membrane of a skeletal muscle fiber is called the
The region of the sarcomere containing the thick filaments is the
At rest, the tropomyosin molecule is held in place by
The area in the center of the A band that contains no thin filaments is the
zone of overlap.
Each thin filament consists of
chains of myosin molecules.
a rod-shaped structure with "heads" projecting from each end.
a double strand of myosin molecules.
two actin protein strands coiled helically around each other.
six molecules coiled into a helical structure
two actin protein strands coiled helically around eachother
At rest, active sites on the actin are blocked by
The thin filaments of striated muscle are made primarily of which protein(s)?
All of the answers are correct
The protein that regulates muscle contraction by controlling the availability of active sites on actin is called ________.
The protein that is found in the Z line of a sarcomere is called _
Thin filaments are mostly made of the protein
thick filaments are mostly made of the protein
in a neuromusuclar junction, synaptic vesicles in the motor neuron contain which neurotransmitter?
When an action potential arrives at the axon terminal of a motor neuron, which ion channels open?
voltage-gated calcium channels
What means of membrane transport is used to release the neurotransmitter into the synaptic cleft?
The binding of the neurotransmitter to receptors on the motor end plate causes which of the following to occur?
a.Binding causes voltage-gated sodium channels to open in the motor endplate.
b.Binding causes potassium voltage-gated channels to open in the motor endplate.
c.Binding causes chemically gated potassium channels to open in the motor end plate.
d.Binding of the neurotransmitter causes chemically gated sodium channels to open in the motor end plate.
How is acetylcholine (ACh) removed from the synaptic cleft?
The action potential on the muscle cell leads to contraction due to the release of calcium ions. Where are calcium ions stored in the muscle cell?
c.terminal cisternae of the sarcoplasmic reticulum
Each skeletal muscle fiber is controlled by a motor neuron at a single
Receptors for acetylcholine are located on the
b. synaptic cleft.
c. synaptic knob.
e.motor end plate.
The action potential is conducted into a skeletal muscle fiber by
a.motor end plates.
When calcium ion binds to troponin,
a. active sites on the myosin are exposed.
c.tropomyosin moves into the groove between the helical actin strands.
d.actin heads will bind to myosin.
e.muscle relaxation occurs.
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
c. oxygen debt.
e. rigor mortis.
The cytoplasm of the neuromuscular terminal contains vesicles filled with molecules of the neurotransmitter
Which statement about excitation-contraction coupling is incorrect?
a.Troponin binds calcium ion and signals tropomyosin to move.
b.Calcium ion is released from the sarcoplasmic reticulum.
c.Relaxation requires uptake of calcium ion by the sarcoplasmic reticulum.
d.Calcium ion is released from the transverse tubule.
e.Tropomyosin moves to expose myosin binding sites on actin.
A single motor neuron together with all the muscle fibers it innervates is called
an end foot.
a motor unit.
an end plate.
The type of contraction in which the muscle fibers do not shorten is called
Suppose that you try to pick up an object and discover that it is much heavier than you expected. Which process must occur in the muscle to increase tension so you can pick up the object?
A muscle produces its highest tension when in complete ________.
A single contraction-relaxation cycle in a muscle fiber produces a ________.
During the Cori cycle, in the liver
a. glucose is released from glycogen.
b. lactic acid is shuffled to muscle cells.
c. glucose is produced from lactic acid.
d. lactic acid is produced from glucose.
e. lactic acid is produced from pyruvic acid.
During the recovery period the body's need for oxygen is increased because
a. the muscles are not producing ATP.
b. the individual is panting.
c. the liver requires more oxygen to produce lactic acid.
d. muscle cells are producing energy anaerobically.
e. additional oxygen is required to restore energy reserves consumed during exercise.
A resting muscle generates most of its ATP by
b. anaerobic respiration.
c. the tricarboxylic acid cycle.
d. hydrolysis of creatine phosphate.
e. aerobic metabolism of fatty acids
a. is only formed during strenuous exercise.
b. cannot transfer its phosphate group to ADP.
c. can replace ATP in binding to myosin molecules during contraction.
d. is produced by the process of anaerobic respiration.
e. acts as an energy reserve in muscle tissue
During anaerobic glycolysis
a. oxygen is not consumed.
b. ATP is produced.
c. carbohydrate is metabolized.
d. pyruvic acid is produced.
e. All of the answers are correct.
Aerobic metabolism normally provides ________ percent of the ATP demands of a resting muscle cell.
Which of these would lead to increased oxygen consumption?
a. increased muscle activity
b. increased heat production
c. increased aerobic respiration by muscle cells
d. increased conversion of lactic acid to glucose
e. All of the answers are correct.
During activities requiring aerobic endurance
a. most of the muscle's energy is produced in mitochondria.
b. fatigue occurs in a few minutes.
c. glycogen and glycolysis are the primary sources of reserve energy.
d. oxygen debts are common.
e. oxygen is not required.