A & P

What does the central nervous system use to determine the strength of the stimulus?

frequency of action potentials.

Which muscle cells have the greatest ability to regenerate?

smooth

Exhaustion of glycogen storage within a muscle fiber would have the biggest effect on ________.

fast glycolytic fibers.

Addition of more myoglobin to a muscle fiber would have the largest effect on ________.

fast oxidative and slow oxidative fibers.

Bipolar neurons are commonly ________.

found in the retina of the eye

Collections of nerve cell bodies outside the central nervous system are called ________.

ganglia.

Which of the following is NOT a function of dendrites?

generate nerve impulses and transmit them away from the cell body.

When a sensory neuron is excited by some form of energy, the resulting graded potential is called a(n) ________.

generator potential.

An anaerobic metabolic pathway that results in the production of two net ATPs per glucose plus two pyruvic acid molecules is _______.

glycolysis.

Reduction in blood flow to a muscle fiber would have the greatest effect on ________.

slow oxidative fibers.

Which of the following surrounds an individual muscle cell?

endomysium.

Which of the following will occur when an excitatory postsynaptic potential (EPSP) is being generated on the dendritic membrane?

A single type of channel will open, permitting simultaneous flow of sodium and potassium.

Sarcomeres are functional units of _________ muscle.

B and C only. (cardiac and skeletal)

Curare is a poisonous plant extract. Curare molecules have a chemical structure like the neurotransmitter ACh. Curare can bind to the ACh receptor site on the chemically gated ion channels in the motor end plate. Even though curare will bind to the receptor site it will not open the ion channel and no ions will pass through. What do you think the symptoms of curare poisoning would look like?

Curare will only affect muscles with ACh receptors, paralyzing them.

The sliding filament model of contraction involves _________.

actin and myosin sliding past each other and partially overlapping.

Is a muscle fiber were to suddenly and permanently stop producing ATP the fiber would no longer be able to actively transport calcium out of the cytoplasm (sarcoplasm) and the intracellular calcium concentration would rise. Which of the following would you expect to happen?

Myosin would be able to bind to the exposed binding sites on thin filaments but it would not be able to detach.

Troponin, a major protein in thin filaments, is a globular protein with three polypeptide subunits. Which of the following is NOT a function of the troponin?

One subunit binds to potassium ions.

Although all the anatomical parts of muscle work together to give it its characteristics, which of the following proteins listed below would be most associated with the characteristics of excitability?

acetylcholine receptors in the motor end plate.

Some nerve fibers of the peripheral nervous system have the ability to regenerate after damage has occurred. Which of the following cells is most responsible for aiding this regulation?

Schwann cells.

The 100-meter dash is a quick and short run requiring explosive speed. On completion of the dash, the runners will continue to breathe hard for several seconds to minutes even though they are no longer running. Which of the following is the best explanation for why this is so?

The runner' use of stored oxygen, glucose, and creatine phosphate is being replenished and this requires a prolonged increase of oxygen intake.

The depolarization phase of an action potential is punctuated by the closing of the inactivation gates in the voltage gated sodium ion channels. All of the following are consequences of this inactivation except one. Choose the statement below that is not a consequence of the closing of inactivating gates.

This allows for the efflux (diffusion out) of potassium ions, resulting in the repolarization of the cell.

What is the role of tropomyosin in skeletal muscles?

Tropomyosin serves as a contraction inhibitor by blocking the myosin binding sites on the actin molecules.

Which of the following is an excitatory neurotransmitter secreted by motor neurons innervating skeletal muscle?

acetylcholine.

After nervous stimulation stops, what prevents ACh in the synaptic cleft from continuing to stimulate contraction?

acetylcholinesterase breaks apart the ACh.

Most skeletal muscles contain ________.

a mixture of fiber types

Which of the following is false or incorrect?

a nerve impulse occurs if the excitatory and inhibitory effects are equal.

If a postsynaptic cell is stimulated to threshold by temporal summation this implies that __________.

a presynaptic neuron is sending frequent EPSP.

Muscle tone is ________.

a state of sustained partial contraction.

An action potential is regarded as a an example of positive feedback. Which of the following examples below best illustrates the positive feedback aspect of an action potential?

a threshold stimulus will cause the opening of voltage gated sodium ion channels that will cause further depolarizing stimulus. This stimulus will open still more voltage gated sodium ion channels.

The period after an initial stimulus when a neuron is not sensitive to another stimulus is the ________.

absolute refractory period.

During muscle contraction, myosin cross bridges attach to which active sites?

actin filaments.

Which of the following describes the nervous system integrative function?

analyzes sensory information , stores information, makes decisions.

It is important for newly developed neurons to form synapses with other neurons. Which cells are most responsible for guiding the formation of these particular junctions?

astrocytes.

The concentration of ions in the chemical environment surrounding the neurons must be tightly regulated for neurons to function properly. Which of the following cells is most responsible for this?

astrocytes.

The term central nervous system refers to _______.

brain and spinal cord.

Which of the following is true about smooth muscle?

certain smooth muscle cells can actually divide to increase their numbers.

In an isotonic contraction, the muscle ________.

changes in length and moves the "load".

When a neurotransmitter like acetylcholine is acting in an excitatory manner which of the following is likely a result of the acetylcholine acting on the post synaptic cell?

chemically gated sodium channels will open.

The ability of muscle to shorten forcibly when adequately stimulated is know as _______, and sets muscle apart from other issue types.

contractility.

Addition of more mitochondria to a muscle fiber will have the greatest effect on ________.

slow oxidative fibers.

The effect of acetylcholine can be stimulating or inhibiting. Which of the following gives the best explanation for why this is so?

different postsynaptic cells will have different receptors.

Although all the anatomical parts of muscle work together to give it its characteristics, which of the following proteins listed below would be most associated with the characteristics of extensibility?

elastin (thin) filaments.

What is the functional role of the T tubules?

enhance cellular communication during muscle contraction.

These cells in the CNS have cilia that move in order to circulate cerebrospinal fluid.

ependymal cells.

When a neurotransmitter like GABA is acting in an inhibitory manner which of the following is likely a result of the GABA acting on the postsynaptic cell?

hyperpolarization of the postsynaptic cell membrane.

An inhibitory postsynaptic potential (IPSP) is associated with ________.

hyperpolarization.

Loss of function in the enzyme acetylcholine esterase would result in which of the following?

inability to destroy and remove acetylcholine from the synaptic cleft.

The strongest muscle contractions are normally achieved by _________.

increasing the stimulation up to the maximal stimulus.

Which of the following is NOT a function of the autonomic nervous system?

innervation of skeletal muscles.

A neuron that has as its primary function the job of connecting other neurons is called a(n) ________.

interneuron.

Which of the following correctly describes a graded potential?

it can have amplitudes of various sizes.

During vigorous exercise, there may be insufficient oxygen available to completely break down pyruvic acid for energy. As a result, the pyruvic acid is converted to ________.

lactic acid.

Immediately following the arrival of the stimulus at a skeletal muscle cell there is a short period called the ________ period during which the neurotransmitter is released by exocytosis, diffuses across the synaptic cleft, and binds to it's receptors.

latent.

Which of the following is a factor that affects the velocity and duration of muscle contraction?

load on the fiber.

Meningitis can be caused by infection of the central nervous system by bacteria. Which cells would be most responsible for removing the infection?

microglia.

What part of the sarcolemma contains acetylcholine receptors?

motor end plate.

Which of the choices below describes the ANS?

motor fibers that conduct nerve impulses from the CNS to smooth muscle, cardiac muscle, and glands

Which of the following is the correct sequence of events for muscle contractions?

motor neuron action potential, neurotransmitter release, muscle cell action potential, release of calcium ions from SR, ATP-driven power stroke, sliding of myofilaments.

Which of the following would be recruited later in muscle stimulation when contractile strength increases?

motor units with larger, less excitable neurons.

During development embryonic cells will fuse to form muscle fibers. This will result in _________.

multinucleated muscle fibers that can extend as long as 30 centimeters.

If given the exact same amount of ATP, which of the three fiber types would be able to contract for the longest amount of time?

slow oxidative fibers.

Saltatory conduction is made possible by ________.

myelin sheath.

The contractile units of skeletal muscles are _____.

myofibrils.

The oxygen-binding protein found in muscle cells is ______.

myoglobin.

Like all cells, the neurons' internal organization dictates its function. Neurons have relatively many mitochondria, an extensive network of rough endoplasmic reticulum and many clusters of ribosomes. These cellular features indicate all of the following EXCEPT ________.

neurons have stable, relatively unchanging internal environments.

Rigor mortis occurs because ________.

no ATP is available to release attached actin and myosin molecules.

Hypothetically, if a muscle were stretched to the point where thick and thin filaments no longer overlapped, ________.

no muscle tension could be generated.

Which of the following is NOT a chemical class of neurotransmitter?

nucleic acid.

Schwann cells are functionally similar to ________.

oligodendrocytes.

Nerve impulses are sent to slow the hearts rate of contraction. The nerve fibers sending theses signals will most likely belong to which division of the nervous system?

parasympathetic division.

Approximately 80% of a muscle fiber's volume are the myofibrils. This characteristic reflects muscles ability to ________.

produce movement through contractile force.

What is the primary function of wave summation?

produce smooth, continuous muscle contraction.

When a muscle is unable to respond to stimuli temporarily, it is in which of the following periods?

refractory period.

Which of the following is correct order for the phases of a muscle twitch?

relaxation, contraction, latent.

What structure in skeletal muscle cells functions in calcium storage?

sarcoplasmic reticulum

Cranial nerve II, the optic nerve sends nerve impulses to the brain carrying information about the things we see. These nerve fibers most likely belong to which division of the nervous system?

sensory (afferent) division.

Nerve impulses leading to the brain carry information about cool temperatures on the skin. The nerve fibers sending these signals will most likely belong to which division of the nervous system?

sensory (afferent) division.

Which of the following statements best illustrates the fact that skeletal muscle is voluntary muscle?

skeletal muscle fibers are innervated by somatic motor neurons.

Of the following items listed below, which is the best description for why skeletal muscle stores glycogen.

skeletal muscle is a heavy consumer of energy.

Of the following muscle types, which has the longest muscle cells and has obvious stripes called striations?

skeletal muscles.

Oxygen starved tissues can release chemical signals into the blood that can change the diameter of nearby blood vessels delivering oxygen and nutrients to the tissues. In doing so the blood vessels will respond through vasodilation (widening of the vessel). Which muscle type is responsible for this vasodilation?

smooth muscle.

Nerves impulses leading to the skeletal muscle carry information to direct movement. The nerve fibers sending these signals will most likely belong to which division of the nervous system?

somatic nervous system.

Myoglobin _______.

stores oxygen in muscle cells.

Creatine phosphate functions in the muscle cell by ________.

storing energy that will be transferred to ADP to resynthesize ATP.

Which of the following statements is true?

striated muscle cells are long and cylindrical with many nuclei.

When a sarcomere contracts and thin filaments move over thick filaments you would expect to see ________.

the I bands to appear smaller.

What is the most distinguishing characteristic of muscle tissue?

the ability to transform chemical energy into mechanical energy to move the body.

What does excess postexercise oxygen consumption represent?

the difference between the amount of oxygen needed for totally aerobic muscle activity and the amount actually used.

If a postsynaptic neuron is stimulated to threshold by spatial summation this implies that ________.

the postsynaptic cell has many synapses with many presynaptic neurons.

The mechanism of contraction in smooth muscles is different from skeletal muscle in that ______.

the site of calcium binding site differs.

Select the correct statement regarding chemical synapses.

the synaptic cleft uses the action potential to transmit a chemical signal to the postsynaptic cell.

During the release refractory period of an action potential, a larger than normal stimulus is needed to cause another action potential. This is due to the fact that ________.

the voltage gated potassium ion channels remain open long enough to hyperpolarize the axon membrane.

Smooth muscle is characterized by all of the following EXCEPT_________?

there are more thick filaments than thin filaments.

Which of the following is NOT a characteristic of neurons?

they are mitotic.

Which of the following describes the cells of unitary smooth muscle?

they exhibit spontaneous action potentials.

Although all the anatomical parts of muscle work together to give it its characteristics, which of the following proteins listed below would be most associated with the characteristics of contractility?

thick (myosin) filaments.

A potential benefit if recruiting slow oxidative fibers for contraction before recruiting fast oxidative and fast glycolytic fibers might be _______.

to allow for fine control with delicate contractile force with a small stimulus.

Which ion channel opens in response to a change in membrane potential and participates in the generation and conduction of action potentials?

voltage-gated channel.

Immediately after an action potential has peaked, which of the following channels will open?

voltage-gated potassium channels.

Myasthenia gravis is a disease that is believed to be caused by autoimmune disorder, resulting in the loss of ACh receptors at the motor end plate of muscle fibers. Which of the following is likely to be a symptom of myasthenia gravis?

weakness of muscle.