Chapter 9-12

________ provide information about the external environment. Interoceptors Proprioceptors Exteroceptors Somatic sensory receptors Interneurons

Exteroceptors

The ________ plexus supplies innervation to the diaphragm. thoracic sacral spinal cervical lumbar

cervical

When comparing slow fibers to fast fibers, slow fibers appear dark red... are lacking myoglobin. have much larger fiber diameters. generate much more tension. take less time to reach peak tension.

appear dark red.

Which type of synapse is most common in the nervous system? radiative mechanical chemical processing electrical

chemical

Reflexes based on synapses formed during development are ________ reflexes. acquired somatic innate visceral vegetative

innate

The layer of the meninges in direct contact with the spinal cord is the choroid plexus. arachnoid mater. pia mater. subarachnoid space. dura mater.

pia mater.

The type of muscle fiber that is most resistant to fatigue is the ________ fiber. intermediate high-density slow anaerobic fast

slow

The myotatic reflex is also known as the ________ reflex. flexor crossed extensor reciprocal stretch tendon

stretch

Within a resting skeletal muscle fiber, where is the greatest concentration of Ca 2+? (Module 9.3C) zone of overlap of the sarcomere Z lines between adjacent sarcomeres inside the transverse tubules terminal cisternae of the sarcoplasmic reticulum bound to troponin

terminal cisternae of the sarcoplasmic reticulum

The ________ reflex complements the flexor reflex by activating contralateral muscles. tendon flexor stretch reciprocal crossed extensor

crossed extensor

Which of the following associations is incorrect? 8 cervical spinal nerves 5 lumbar spinal nerves 5 sacral spinal nerves 11 thoracic spinal nerves 1 coccygeal spinal nerve

11 thoracic spinal nerves

Where do somatic motor neurons reside? 10 12 13 14 15

15

The spinal cord consists of five regions and ________ segments. 5 12 25 31 The number varies widely among individuals.

31

Where are the myosin molecules located? 4 5 6 7 8

5

Define motor unit. (Module 9.10B) A motor unit is a motor neuron and all the muscle fibers that it controls. A motor unit is the sum total of all the motor neurons going to a specific muscle. A motor unit is the maximum tension that a whole muscle can generate with maximum stimulation. A motor unit is the sensory neuron going away from and the motor neuron going to a skeletal muscle. A motor unit is the sum total of all the muscle fibers in a whole muscle.

A motor unit is a motor neuron and all the muscle fibers that it controls.

Define tendon and aponeurosis. (Module 9.2A) A tendon is a bundle of collagen fibers that connects bones together, whereas an aponeurosis is a thin layer of areolar connective tissue that surrounds each muscle fiber. A tendon is a bundle of collagen fibers that connects bones together, whereas an aponeurosis is a dense layer of collagen fibers surrounding an entire muscle. A tendon is a bundle of collagen fibers that connects a skeletal muscle to a bone, whereas an aponeurosis is a broad collagenous sheet that connects skeletal muscle to a broad area on one or more bones. A tendon is a dense layer of collagen fibers surrounding an entire muscle, whereas an aponeurosis is a fibrous layer that divides the skeletal muscle into fascicles. A tendon is a broad collagenous sheet that connects skeletal muscle to a broad area on one or more bones, whereas and aponeurosis is a bundle of collagen fibers that connects a skeletal muscle to a bone.

A tendon is a bundle of collagen fibers that connects a skeletal muscle to a bone, whereas an aponeurosis is a broad collagenous sheet that connects skeletal muscle to a broad area on one or more bones.

Which statement about excitation-contraction coupling is incorrect? Troponin binds calcium ion and signals tropomyosin to move. Tropomyosin moves to expose myosin binding sites on actin. Calcium ion is released from the transverse tubule. Calcium ion is released from the sarcoplasmic reticulum. Relaxation requires uptake of calcium ions by the sarcoplasmic reticulum.

Calcium ion is released from the transverse tubule.

What causes calcium to be released from the sarcoplasmic reticulum? (Module 9.8A) Calcium is released when an action potential travels down the motor neuron. Calcium is released when acetylcholine binds acetylcholine receptors. Calcium is released when myosin heads bind to actin. Calcium is released when an action potential is generated at the neuromuscular junction. Calcium is released when an action potential reaches the triad.

Calcium is released when an action potential reaches the triad.

Contrast fast fibers with slow fibers in terms of diameter, glycogen reserves, myoglobin content, and relative abundance of mitochondria. (Module 9.14A) Compared with slow fibers, fast fibers have a larger diameter, larger glycogen reserves, less myoglobin, and relatively fewer mitochondria. Compared with slow fibers, fast fibers have a larger diameter, smaller glycogen reserves, less myoglobin, and more mitochondria. Compared with slow fibers, fast fibers have a smaller diameter, smaller glycogen reserves, more myoglobin, and more mitochondria. Compared with slow fibers, fast fibers have a smaller diameter, smaller glycogen reserves, less myoglobin, and relatively fewer mitochondria. Compared with slow fibers, fast fibers have a smaller diameter, larger glycogen reserves, more myoglobin, and more mitochondria.

Compared with slow fibers, fast fibers have a larger diameter, larger glycogen reserves, less myoglobin, and relatively fewer mitochondria.

The area in the center of the A band that contains no thin filaments is the... M line. Z line. zone of overlap. H band. I band.

H band.

In an adult, the conus medullaris is found at about L1. T6. Co1. T10. L5.

L 1.

Which statement about the microscopic anatomy of skeletal muscle fibers is not true? Cross striations result from the lateral alignment of thick and thin filaments. Muscle fibers are continuous from tendon to tendon. Tubular extensions of the sarcolemma penetrate the fiber transversely. Each fiber has many nuclei. Multiple myofibrils link end-to-end along length of the muscle cell.

Multiple myofibrils link end-to-end along length of the muscle cell.

________ are stem cells located between the endomysium and sarcolemma that function in the repair of damaged muscle tissue. Multinucleate cells Myofibrils Myoblasts Myosatellite cells Myofilaments

Myosatellite cells

How is skeletal muscle recovery different after moderate activity compared to sustained activity at higher levels? (Module 9.13A) Skeletal muscle recovery after moderate activity takes a few hours, whereas skeletal muscle recovery at higher levels can take a day. Skeletal muscle recovery after moderate activity takes a few months, whereas skeletal muscle recovery at higher levels can take a few years. Skeletal muscle recovery after moderate activity takes about a week, whereas skeletal muscle recovery at higher levels can take a few months. Skeletal muscle recovery after moderate activity takes about a minutes, whereas skeletal muscle recovery at higher levels can take a few hours. Skeletal muscle recovery after moderate activity takes several hours, whereas skeletal muscle recovery at higher levels can take about a week.

Skeletal muscle recovery after moderate activity takes several hours, whereas skeletal muscle recovery at higher levels can take about a week.

Which of the following motor units would produce the greatest tension? a motor unit in an eye muscle a motor unit in a hand muscle a motor unit in a back muscle

a motor unit in a back muscle

Explain why the propagation of action potentials along electrically excitable membranes occurs in only one direction. (Module 9.5D) All electrically excitable membranes have two poles, a positive and a negative pole, and the action potential can only travel towards the positive pole. All electrically excitable membranes have two poles, a positive and a negative pole, and the action potential can only travel towards the negative pole. The repolarization period prevents it from propagating back in the direction from which it began. The stimulation of electrically excitable membranes by neurons occurs on only one side of the membrane so it will travel to the other side. The refractory period prevents it from propagating back in the direction from which it began.

The refractory period prevents it from propagating back in the direction from which it began.

Why is the zone of overlap an important region of the sarcomere? (Module 9.4D) The zone of overlap is important because it is where myosin filaments are anchored to and overlap titin proteins. The zone of overlap is important because it is where the myosin heads can interact with the thin filaments. The zone of overlap is important because it is where actin filaments are anchored to and overlap nebulin proteins. The zone of overlap is important because it is where the troponin proteins bind acetylcholine to generate an action potential that can cause muscle contraction to occur. The zone of overlap is important because it is where one sarcomere ends and another sarcomere begins.

The zone of overlap is important because it is where the myosin heads can interact with the thin filaments.

Can a skeletal muscle contract without shortening? Why or why not? (Module 9.11C)

Yes, because muscles can still contract during an isometric contraction when the muscle tension is equal to the load.

Creatine phosphate... is only formed during strenuous exercise. can replace ATP in binding to myosin molecules during contraction. cannot transfer its phosphate group to ADP. is produced by the process of anaerobic respiration. acts as an energy reserve in muscle tissue.

acts as an energy reserve in muscle tissue.

The obturator nerve is distributed to the skin over the perineum. extensors of the hip. adductors of the hip. biceps femoris. skin over buttocks.

adductors of the hip.

Blood vessels traveling within ________ deliver oxygen and nutrients to the spinal cord. the pia mater all three cranial meninges the dura mater the arachnoid mater all three spinal meninges

all three spinal meninges

Neurons that are rare, small, and lack features that distinguish dendrites from axons are called anaxonic. unipolar. bipolar. tripolar. multipolar.

anaxonic

Identify the structure labeled "10." anterior white commissure anterior white column anterior gray commissure anterior white horn anterior median fissure

anterior gray commissure

The largest and most numerous neuroglia in the CNS that absorb and recycle neurotransmitters are the oligodendrocytes. ependymocytes. tanycytes. microglia. astrocytes.

astrocytes

The axon is connected to the cell body at the axon hillock. synaptic knobs. telodendria. collateral branches. synapse.

axon hillock.

In which plexus does the ulnar nerve arise? cranial lumbar brachial sacral cervical

brachial

What is the contraction in graph (d) called? incomplete tetanus treppe complete tetanus twitch wave summation

complete tetanus

Reflexes that activate muscles on the opposite side of the body as the stimulus are called contralateral. ipsilateral. collateral. bilateral. antilateral.

contralateral.

Which of the following is not a recognized function of skeletal muscle? guard body entrances and exits controlled involuntarily produce movement maintain body temperature maintain posture

controlled involuntarily

A shift of the resting transmembrane potential toward 0 mV is called non-polarization. hyperpolarization. repolarization. hypopolarization. depolarization.

depolarization

In the process of continuous propagation, all of the following are true except at threshold, sodium channels begin to open rapidly. each step takes about one millisecond. depolarization of the axonal membrane only occurs at nodes. local currents depolarize the region just adjacent to the active zone. the action potential is triggered by graded depolarization of the initial segment.

depolarization of the axonal membrane only occurs at nodes.

The subdural space lies between the pia mater and the subarachnoid space. pia mater and the dura mater. dura mater and the arachnoid mater. endosteum and the periosteum. arachnoid mater and the pia mater.

dura mater and the arachnoid mater.

The outermost connective-tissue covering of nerves is the endoneurium. perineurium. epimysium. epineurium. endomysium.

epineurium

EPSPs (excitatory postsynaptic potentials) occur when chloride ions enter a cell. extra sodium ions enter a cell. more potassium ions than usual leak out of a cell. hyperpolarizations occur. more calcium ions than usual leak out of a cell.

extra sodium ions enter a cell.

The synchronous contraction of a single motor unit is known as a(n) twitch... cross-bridge. muscle action potential. fasciculation. asynchronous motor unit summation.

fasciculation.

Damage to ependymal cells would most likely affect the transport of neurotransmitters within axons. formation of myelin sheaths. formation of cerebrospinal fluid. repair of axons. formation of ganglia.

formation of cerebrospinal fluid.

In the peripheral nervous system, Schwann cells participate in the repair of damaged nerves by regenerating cell bodies for the neurons. forming a cellular cord that directs axonal regrowth. producing new axons. producing more satellite cells that fuse to form new axons. clearing away cellular debris.

forming a cellular cord that directs axonal regrowth.

Axons crossing from one side of the spinal cord to the other within the gray matter are found in the posterior gray horns. anterior gray horns. white commissures. gray commissures. lateral gray horns.

gray commissures.

Axons crossing from one side of the spinal cord to the other within the gray matter are found in the posterior gray horns. white commissures. lateral gray horns. gray commissures. anterior gray horns.

gray commissures.

If the membrane potential of a neuron is -80 mV, it is... hyperpolarized during the refractory period at resting potential. depolarized. repolarized. at threshold.

hyperpolarized during the refractory period

Opening of each of the following types of channels will contribute toward a graded potential except closed voltage-gated sodium channel. sodium leak channel. chemically gated acetylcholine receptor. mechanically gated sodium channel. inactivated voltage-gated sodium channel.

inactivated voltage-gated sodium channel.

Muscular force can be adjusted to match increased loads by... increasing the frequency of action potentials in motor neurons. recruiting smaller motor units. recruiting fewer motor units. decreasing the frequency of action potentials in motor neurons. None of these answers are correct.

increasing the frequency of action potentials in motor neurons.

The stretch reflex is an example of a polysynaptic reflex. is voluntary. is activated when a smooth muscle lengthens. is important in regulating muscle length. involves a receptor called the Golgi tendon organ.

is important in regulating muscle length.

Which of these would not lead to increased oxygen consumption? increased aerobic respiration by muscle cells increased heat production lactic acidosis increased muscle activity increased conversion of lactic acid to glucose

lactic acidosis

The muscle weakness of myasthenia gravis results from... insufficient acetylcholine release from presynaptic vesicles. loss of acetylcholine receptors in the end-plate membrane. the motor neuron action potential being too small to shock the muscle fibers. excessive acetylcholinesterase that destroys the neurotransmitter. All of the answers probably contribute to the muscle weakness.

loss of acetylcholine receptors in the end-plate membrane.

Bill contracts a viral disease that destroys cells in the posterior gray horns in his spinal cord. As a result, which of the following would you expect? uncontrollable sweating of his feet problems with moving his arms inability to breathe loss of sensation in his torso problems with moving his legs

loss of sensation in his torso

The Na +/K + ion pump is responsible for... amplifying signals using ATP maintaining the sodium/potassium concentration gradients constant. diffusing chloride across the plasma membrane. transferring messages from enzyme-linked receptors to the cell nucleus. initiating action potentials.

maintaining the sodium/potassium concentration gradients constant.

In a(n) ________ reflex, a sensory neuron synapses directly on a motor neuron. motor polysynaptic integrative sensory monosynaptic

monosynaptic

When acetylcholine binds to receptors at the motor end plate, the end plate membrane becomes... more permeable to calcium ions. repolarized. less permeable to potassium ions. more permeable to sodium ions. less permeable to sodium ions.

more permeable to sodium ions.

During activities requiring aerobic endurance... glycogen and glycolysis are the primary sources of reserve energy. oxygen is not required. most of the muscle's energy is produced in mitochondria. fatigue occurs in a few minutes. oxygen debts are common.

most of the muscle's energy is produced in mitochondria.

Reflexes, controlled by the spinal cord, act by sensory input to reflex centers in the brain. sensory output over cranial nerves to effectors. motor output over spinal nerves to effectors. sensory input over cranial nerves to the spinal cord. motor input to reflex centers in the spinal cord.

motor output over spinal nerves to effectors.

In an isotonic contraction... the peak tension is less than the load. tension rises and falls but the muscle length is constant. muscle tension exceeds the load and the muscle lifts the load. flexion is produced. many twitches fuse into one.

muscle tension exceeds the load and the muscle lifts the load.

Each skeletal muscle fiber is controlled by a motor neuron at a single...

neuromuscular junction.

The gray horns of the spinal cord contain mainly columns. meninges. neuron cell bodies. nerve tracts. cerebrospinal fluid.

neuron cell bodies.

The basic functional unit of the nervous system is the nerve. spinal cord. brain. glial cell. neuron.

neuron.

Active neurons need ATP to support all of the following except the... movement of materials to the soma by axoplasmic transport. movement of materials from the soma by axoplasmic transport. opening of voltage-gated channels. recovery from action potentials. synthesis of neurotransmitter molecules.

opening of voltage-gated channels.

Nerves and blood vessels that service the muscle fibers are located in the connective tissues of the... perimysium. sarcomere. sarcolemma. myofibrils. endomysium.

perimysium

The nerve crucial for breathing that originates within the cervical plexus is called the ________ nerve. transverse cervical ansa cervicalis great auricular supraclavicular phrenic

phrenic

The ________ of each spinal nerve innervates the skin and muscles of the back. white ramus communicans gray ramus communicans anterior ramus dermatome posterior ramus

posterior ramus

The advantage of having many nuclei in a skeletal muscle fiber is the ability to contract... A) produce more ATP with little oxygen. B) store extra DNA for metabolism. C) produce large amounts of the muscle proteins needed for muscle contraction. D) All of the answers are correct.

produce large amounts of the muscle proteins needed for muscle contraction.

Identify the structure labeled "5." posterior root ganglion autonomic ganglion anterior root autonomic nerve rami communicantes

rami communicantes

Which of the following is a type of glial cell found in the peripheral nervous system? ependymal cells astrocytes oligodendrocytes satellite cells microglia

satellite cells

If the posterior root of a spinal nerve is severed, output to visceral organs would be blocked. the brain would not be able to communicate with that level of the spinal cord. sensory input would be blocked. output to skeletal muscles would be blocked. the spinal cord would not be able to process information at that level.

sensory input would be blocked.

In the condition ________, a virus infects posterior root ganglia, causing a painful rash whose distribution corresponds to that of the affected sensory nerves as seen in their dermatomes. shingles polio mumps rubella myasthenia gravis

shingles

A posterior and anterior root of each spinal segment unite to form a spinal ganglion. lumbar enlargement. spinal meninx. cervical enlargement. spinal nerve.

spinal nerve.

The site of intercellular communication between a neuron and another cell is the A) telodendria. B) synaptic terminals. C) collateral. D) hillock. E) synapse.

synapse.

Identify the structures labeled "5." Figure 11-1 axosomata telodendria dendritic spines synaptic terminals axons

synaptic terminals

If the axon terminal of a motor neuron suddenly became permeable to calcium ions, the motor end plate will be hyperpolarized. neurotransmitter release will be blocked. the neuron will become unable to stimulate the muscle cell. the neuron will fire an action potential. the motor end plate will be depolarized.

the motor end plate will be depolarized.

Which of the following become connected by myosin cross-bridges during muscle contraction? thick filaments and titin filaments Z disks and actin filaments thin filaments and thick filaments thick filaments and T tubules thin filaments and T tubules

thin filaments and thick filaments

At rest, active sites on the actin are blocked by calcium ions... tropomyosin molecules. ATP molecules. myosin molecules. troponin molecules.

tropomyosin molecules.

When calcium ion binds to troponin... tropomyosin moves into the groove between the helical actin strands. active sites on the myosin are exposed. myosin shortens. troponin shifts to expose the active sites on actin. muscle relaxation occurs.

tropomyosin moves into the groove between the helical actin strands.

In a(n) ________ neuron, the dendrites and axon are continuous or fused.

unipolar

A gated channel that responds to changes in transmembrane potential is called a(n) ________ channel. chemically gated leak-gated mechanically gated voltage-gated ATP

voltage-gated

Which type of membrane channels are found in axons? chemically gated Na+ and K+ channels voltage-gated K+ channels voltage-gated Na+ and K+ channels voltage-gated Ca2+ channels voltage-gated Na+ channels

voltage-gated Na + and K + channels

If a second stimulus arrives before the relaxation phase has ended, a second, more powerful contraction occurs. This is called... incomplete tetanus. complete tetanus. treppe. wave summation. recruitment.

wave summation.

Which of the following is not a type of motor fiber? red-slow twitch pink-fast twitch white-fast twitch type I white-slow twitch

white-slow twitch