3
If a drug was developed that interfered with the proper functioning of the microtubules found within the axons of neurons, how would you expect this to impact axonal transport processes?
Both anterograde and retrograde transport processes would cease
Arrange the events of synaptic transmission in correct sequence. (1) sodium ions diffuse into the cell and cause a local potential (2) neurotransmitter binds with receptor on postsynaptic cell (3) neurotransmitter diffuses across the synaptic cleft (4) membrane permeability to sodium ions on postsynaptic cell increases (5) action potential causes release of neurotransmitter
5 3 2 4 1
Joseph is exasperated at the request of his teacher to recite the extrinsic muscles of the eye and their function and rolls his eyes in frustration. Which muscles did Joseph use to carry out his movement?
Inferior obliques
Infraspinatus
Laterally rotates shoulder; stabilizes the head of the humerus in glenoid cavity; one of the "rotator cuff" muscles
What effect does acetylcholine have on the postsynaptic neuron?
Ligand-gated sodium ion channels open and sodium diffuses in
Which of the following actions is caused by contraction of skeletal muscle?
Moving your feet in walking
Why isn't an action potential transmitted from a postsynaptic membrane to a presynaptic terminal?
Presynaptic terminals have no acetycholine receptors
Shcwann cells differ from oliogodendrocytes in which of the following ways?
Schwann cells form a myelin sheath around a portion of only one axon, whileoligodendrocytes can surround portions of several axons.
Which type of muscle tissue has neuromuscular junctions?
Skeletal muscle
Epimysium
a sheath of fibrous elastic tissue surrounding a muscle.
Synaptic vesicles in the neuromuscular junction contain
acetylcholine
If acetylcholinesterase became mutated and nonfunctional, what would be the immediate result?
acetylcholine would build up in the synaptic cleft
The nervous system
all of the above monitors internal and external stimuli transmits information in the form of action potentials interprets or assesses information maintains homeostasis
Continuous conduction of action potentials means that
an action potential in one site generates local currents causing depolarization to threshold at the adjacent site
Which of the following analogies best represents a parallel after-discharge circuit?
an instructor instructs all students to solve the same problem
Smooth muscle and cardiac muscle are similar in that they both....
are under involuntary control
LouAnn is being treated for a neurological condition with a specific drug that target neurons deep within the brain. Which glial cell must be bypassed by this drug in order for it to be effective?
astrocyte
Along myelinated axons of the peripheral nervous system, ion currents must cross the plasma membrane of the neuron
at nodes of ranvier
Of the following muscles of the thigh, the ________________ is on the posterior side
biceps femoris
Each voltage-gated Na+ ion channel has two voltage sensitive gates: an activation gate and an inactivation gate. Which of the following would occur during depolarization?
both activation and inactivation gates are open
Alex is participating in a 50 meter dash. Predict the most important chemical process his muscles will rely on during this race.
both anaerobic respiration and creatine phosphate breakdown are correct
An inhibitory postsynaptic potential (IPSP) can result from the
both influx of cl- & outflow of K+
The strength of a stimulus is communicated through
both the frequency and the length of time action potentials are produced
The central nervous system includes the
brain and spinal cord
At the synaptic knob, voltage-gated __________ channels open, thereby stimulating the synaptic vesicles to release their neurotransmitters by exocytosis
calcium
Which of the following statements concerning smooth muscle is true?
calcium calmodulin complex initiates cross-bridge formation
A student is characterizing a muscle tissue sample in lab. She discovers that it is autorhythmic and contains striations. What type of muscle tissue is she working with?
cardiac muscle
Substances that cause facilitation of a neuron
cause the neuron to fire that may not under the same circumstances in the absence of the facilitator
A resting membrane potential of -70mV indicates that the
charges lining the inside of the plasma membrane are negative compared to the charges lining the outside
Damage to the muscle called the levator ani would result in
decreased support for the pelvic viscera
Which of the following muscles are named based on their shape?
deltoid orbicularis oris pectoralis major superior rectus teres major
Rigor mortis occurs after death because
detachment of crossbridges does not occur due to the lack of ATP
The major movement produced during quiet breathing is accomplished by the
diaphragm
Which of the following muscles contracts during forced expiration?
diaphragm
Sensory neurons carrying action potentials from pain receptors synapse within the spinal cord with interneurons. These interneurons synapse with motor neurons leading back to an effector and ascending neurons that carry action potentials toward the brain. This is an example of a/an
divergent
Which of the following connective tissue layers is outside all the others?
epimysium
Functionally, smooth muscle
exhibits autorhythmic contractions
The presence of calcium in the sarcoplasm is directly responsible for
exposing the binding sites on actin
The lateral and posterior neck muscles are involved in which types of head movements?
extension lateral flexion rotation
The ____________ muscle extends the big toe
extensor hallicus longus
Some people suffer involuntary urination due to incompetence of what muscle?
external urethral sphincter
If a person drums their fingers on the table, they would be using which of the following muscles?
flexor digitorum profundus
A neuron is receiving a stimulus which gets stronger and stronger. The result is
frequency of occurrence of action potentials increases
The adductor longus is named for its _________
function and size
The rectus femoris is an example of which muscle shape?
fusiform
Groups of related nerve cell bodies located outside of the central nervous system are called
ganglia
Structures called ___________ are involved in electrical synapses
gap junctions
Which of the following is part of a thin myofilament?
globular g actin
Which inhibitory neurotransmitter is blocked in strychnine poisoning?
glycine
A student observes a stained slide of brain tissue under the microscope. She notices a large number of neuron cell bodies and dendrites. What type of brain tissue is she looking at?
gray matter
Receptor molecules in synapses
have a high degree of specificity.
The rotator cuff muscles
hold the head of the humerus in the glenoid fossa of the scapula.
In a laboratory experiment, the resting membrane potential of a muscle is measured and is found to be more negative. Which of the following has occurred?
hyperpolarization
Action potentials occur _____________
in the unmyelinated regions of an axon
The ____________ is part of the rotator cuff muscle group
infraspinatus
Facial muscles are unusual in that they
insert and sometimes originate on skin and connective tissue.
If it were possible to move the terminal cisternae farther away from the T-tubules, it would
interfere with the signal required for the release of calcium from the sarcoplasmic reticulum (when active, RyR1 allows an efflux of calcium from the sarcoplasmic reticulum into the sarcoplasm)
When voltage-gated sodium channels are open, sodium flows _____________ the neuron making the inside of the cell more _______________.
into; positive
Physiological contracture
is a condition in which cross-bridges cannot release.
A fascicle
is surrounded by the perimysium
The central nervous system
is the site for processing information
muscle tone
it is a constant tension produced by muscle for long periods of time
The time between application of the stimulus to a motor neuron and the beginning of a contraction is called the _______ phase
latent or lag
The time between application of the stimulus to a motor neuron and the beginning of contraction is called the ____________ phase
latent/lag phase
Where would the intrinsic thenar muscles be located?
lateral side of the palm
The pelvic diaphragm is formed by the
levator ani and coccygeus muscles
Which of the following muscles of facial expression is not innervated by the facial nerve?
levator palpebrae superioris
The ______________ elevates the scapula
levator scapulae
Graded potentials result from the opening of
ligand-gated channels
A myelin sheath is composed primarily of __________.
lipids
Athletes who train at high altitudes increase their red blood cell count, which increases their oxygen supply during exercise. Increased oxygen supply results in
longer aerobic respiration
Which of the following muscles does NOT extend the neck?
longus capitis
The _________ is a muscle involved in chewing gum
masseter
A facial muscle that originates on the mandible is the
mentalis
The antidote that holds the most promise to counteract the effects of tubocurarine is one that _________________________.
modifies acetylcholine receptors so that they bind acetylcholine stronger than tubocurarine
Depolarization occcurs
more sodium ions diffuse into the cell than potassium ions diffuse out of it
Smooth muscle
muscle tissue in which the contractile fibrils are not highly ordered, occurring in the gut and other internal organs and not under voluntary control...................................................................
Identify the statement concerning general functional characteristics of muscle that is true
muscle tissue shortens forcefully but lengthens passively
constant tension produced by muscles for long periods of time
muscle tone
White matter is composed of
myelinated axons
Which of the following structures contains the other four items listed?
neuromuscular junction
Which of the following events occurs on the postsynaptic membrane?
neurotransmitter combines with a receptor molecule
Assume in a laboratory you were able to isolate a neuron and remove the Acetylcholine receptors from the postsynaptic membrane. The substance _________________ would no longer cause facilitation of this neuron.
nicotine
Botulinum toxin causes muscle paralysis because _______
no acetylcholine enters the synaptic cleft
Visceral smooth muscle
occurs in sheets and exhibits numerous gap junctions.
Acetylcholine causes an end-plate potential by triggering the ______
opening of sodium channels (end-plate potential is a local depolarization due to the influx of sodium)
Closing or puckering the lips is the action of the _____ muscle.
orbicularis oris
The sternocleidomastoid muscle extends from the mastoid process of the temporal bone to the sternum and medial clavicle. When both sternocleidomastoid muscles contract, the head is flexed. The end of the muscle that connects to the sternum is the
origin
The elevated oxygen consumption relative to activity level after exercise has ended is called
oxygen recovery excess post-exercise oxygen consumption
Which of the following muscles is involved in swallowing?
palatopharyngeus
Muscles that have their fasciculi arranged like barbs of a feather along a common tendon are called
pennate
An inhibitory postsynaptic potential results from the opening of
potassium and/or chloride channels
Neurotransmitters are released from the ____________
presynaptic terminal
The ________ of a neuron release(s) neurotransmitters
presynaptic terminals
Graded potentials are produced within the ________ segment of a neuron
receptive
The abdominal muscle that has its origin at the pubic crest and symphysis pubis is the
rectus abdominis
When an intramuscular injection is given in the anterior aspect of the thigh, the injection is in the
rectus femoris lab
_________________ the time between signals sent from the same presynaptic terminal increases the strength of the graded potential. This is an example of _____________________summation
reducing; temporal
Facial wrinkles, such as glabellar or "frown" lines, appear with aging as a result of natural, repetitive muscle contractions. Botox® helps alleviate the appearance of these wrinkles by _________________.
relaxing the facial muscles that cause the wrinkles
The following information best describes the ________ phase of an action potential a membrane potential reading of +10mV inactivated voltage-gated sodium channels open voltage-gated potassium channels
repolarization
The charge difference across the plasma membrane of an unstimulated cell is called the _________________
resting membrane potential
Suppose that a new virus is discovered that specifically infects motor neurons. Assume that this virus enters neurons in conjunction with choline molecules. Once inside the cell, the virus enters the nucleus and replicates. Which direction describes the axonal transport route taken by this virus?
retrograde transport
Which type of neural circuit is best for producing a prolonged output
reverberating circuit
Which muscle retracts, rotates, and fixes the scapula?
rhomboideus major
In order for the excitation-contraction coupling to occur, the production of an action potential must occur within the ______ of a muscle fiber.
sarcolemma
What is a muscle cell membrane called?
sarcolemma the sarcolemma is the muscle cell plasma membrane
T tubules are invaginations of the
sarcolemma that extend to each muscle fiber they transmit depolarization signals to the SR and trigger the release of calcium
Theresa has been diagnosed with a disease that demyelinates the somatic motor neurons. This disease is destroying the __________ associated with neurons that control __________.
schwann cells skeletal muscle
The neuron that conduct information towards the CNS are
sensory neurons
If body temperature drops. muscles respond by contracting rapidly in order to produce heat, a process known as
shivering
Hypertrophy of skeletal muscles from weight lifting is caused by an increase in the
size of muscle fibers
Depolarization of the cell membrane occurs when there is a rapid influx (inflow) of .........
sodium ions
Normally, sodium and potassium leakage channels differ because ___________________.
sodium ions diffuse through leakage channels into the cell, but potassium ions diffuse through leakage channels out of the cell
The concentration of _____ ions is much greater outside the cell as compared to inside the cell, whereas the concentration of _____ ions is much greater inside the cell as compared to outside the cell
sodium potassium
The _____________ nervous system communicates with the skeletal muscles and the __________ nervous system communicates with the smooth and cardiac muscle as well as glands
somatic, autonomic
Choosing from the lateral neck muscles, which muscle is the prime mover for flexion of the head at the neck?
sternocleidomastoid
The muscle shape that has the capacity to shorten to the greatest degree is
straight
Muscle tension can be increased with ______ which involves increasing the force of contraction of the muscle fibers, as well as with __________ which involves increasing the number of muscle fibers contracting
summation; recruitment
Acetylcholine (ACh) is released from motor neurons and enters the _________
synaptic cleft (ACh-filled synaptic vesicles are released from the axon terminal, and they subsequently diffuse across the synaptic cleft)
As a result of calcium ions diffusing into the presynaptic cell,
synaptic vessels migrate to the plasma membrane and release acetylcholine.
When you "pull your tummy in" and compress your abdomen, you use the rectus abdominis, external abdominal oblique, internal abdominal oblique, and transversus abdominis muscles. This is an example of muscles working as
synergists
A sustained muscle contraction is knows as
tetanus
The type of muscle fatigue known as "psychological fatigue" is the result of
the emotional state of an individual
Hyperpolarization, or afterpotential, occurs because
the increased potassium ion permeability lasts slightly longer than the time required to bring the membrane potential back to its resting level.
Hundreds of mutations have been identified in RyR1 that contribute to multiple muscular diseases. Assume that a new mutation was discovered that causes this receptor to continually remain open. Based on what you know about the function of this receptor, how would you expect this new mutation to impact contraction?
the mutation will increase levels of calcium in the sarcoplasm, which will induce continued muscle contraction
Increased strength of a trained muscle is due to
the nervous system's ability to recruit a large number of motor units simultaneously.
Which muscle will depress the scapula or elevate the ribs
the pectoralis minor
For a typical neuron, what limits the maximal frequency attainable of action potentials moving down an axon?
the refractory period
The plasma membrane of an excitable cell is more permeable to potassium ions because .....
there are more leak channels for K+ than Na+
If demyelination occurs, why don't action potentials occur at regions of the axon that were previously myelinated?
these regions lack the appropriate concentration of voltage-gated sodium channels
All of the following are typical characteristics of neurotransmitters except
they are released into the bloodstream before reaching the postsynaptic cell
Drugs called calcium channel blockers may be used to lower blood pressure by causing arteries to vasodilate. How do you suppose these drugs work?
they prevent calcium from entering smooth muscle, thus allowing the muscle to relax
levator palpebrae superioris muscle
thin muscle that controls the eyelid and can be easily damaged during makeup application
The motor (efferent) division of the peripheral nervous system
transmits impulses from the cns to effectors such as skeletal muscle??????????
An action potential arriving at the presynaptic terminal causes
voltage-gated calcium ion channels to open, and calcium ions to diffuse into the cell.
Thin filaments connect to and extend from either side of a ______________. These thin filaments are composed largely of the myofilament
z disc, actin
Which of the following is not a function of the muscular system?
Immune system support
What is the role of pacemaker cells?
A. can rapidly develop action potentials
You are hired to work in a laboratory to measure the rate of human muscle contraction. Which of the following might decrease in quantity in muscle cells undergoing contractions?
ATP
Myosin heads directly use ______________ to transition to their _____________________ conformation, which enables them ready to bind to actin.
ATP: energized
Identify the statement that best differentiates gray matter and white matter
Gray matter consists of cell bodies and dendrites whereas white matter consists mostly of myelinated axons
Each _____ includes a Z disk and extends from each side of the Z disk to the ends of the myosin myofilaments.
I band
The plasma membrane of a neuron is more permeable to K+ because
There are many more K+ leak channels than Na+ leak channels in the plasma membrane.
Which of the following statements concerning fast-twitch muscle fibers is true?
They split ATP rapidly
Indicate the summative effect that brings the initial segment closest to threshold.
Two EPSPs in proximity to each other
Which of the following is not an age-related change in skeletal muscle?
decreased recovery time
The enzyme choline acetyltransferase catalyzes the reaction between acetyl-CoA and choline resulting in the formation of the neurotransmitter acetylcholine. This enzyme is produced within the cell body of neurons, but the synthesis of acetylcholine occurs within the axon terminals. Which statement best describes the axonal transport mechanism associated with this process?
choline acetyltransferase is transported in the anterograde direction
The flexion of the elbow represents a
class III lever system
The flexion of the elbow represents a __________
class III lever system
Muscle myofibrils
contain myosin and actin myofilaments
The capacity of a muscle cell to shorten forcefully is known as...
contractility
The zygomaticus major muscle
contributes to laughing and smiling.
Triangular muscles like the pectoralis major are also called ___________ muscles
convergent
The equilibrium centers of the brain receive information from inner ear structures as well as the retina of the eyes. This arrangement is an example of a _________ circuit.
converging
gray matter on the surface of the brain
cortex
The peripheral nervous system includes the ___________
cranial nerves
If there was a high concentration of acetylcholine within the synaptic cleft, but little to no response at the motor end-plate, you would expect _______ to be the responsible neuromuscular-blocking agent.
curare
Demyelinating diseases cause a/an _____________ in the conduction velocity of action potentials
decrease
Which of the following is not an age related change in skeletal muscle?
decreased recovery time