Exam 3
Norepinephrine
-Alpha-1 -Beta-1 -Beta-3
Epinephrine
-Beta-1 -Beta-2
Acetylcholine
-Nicotinic -Muscarinic
Muscadine, a chemical produced by certain mushrooms, binds to muscarinic receptors mimicking the effect of acetylcholine. How do you think administering this chemical would change body function? The drug would ______________.
-change the functionality of the heart -change the functionality of the smooth muscles within the digestive system -change the functionality of certain exocrine and endocrine glands
Norepinephrine (NE)
-postganglionic neuron from the sympathetic nervous system
Acetylcholine (ACh)
-somatic motor neuron -preganglionic neuron from the parasympathetic nervous system -postganglionic neuron from the parasympathetic nervous system -preganglionic neuron from the sympathetic nervous system
Rank the sequence of events at the NMJ that initiate an action potential in the muscle fiber, from first to last.
1. Action potential arrives at the axon terminal 2. Calcium ions enter the axon terminal 3. Synaptic vesicles fuse to membrane of axon terminal 4. Acetylcholine is released into the synaptic cleft 5. Acetylcholine binds to its receptors on the junctional folds 6. Junctional folds become depolarized 7. Action potential is initiated on the sarcolemma
Thick and thin filaments overlap within the
A band
The cross bridge cycle is a series of molecular events that occur after excitation of the sarcolemma. What is a cross bridge?
A myosin head bound to actin {As soon as the activated myosin head forms a cross bridge with actin, the power stroke begins}
A structure that when bound to a ligand opens a divalent channel for the movement of both Na+ and K+
ACh receptor-channel
Muscle relaxation requires
ATP
After a power stroke, the myosin head must detach from actin before another power stroke can occur. What causes cross bridge detachment?
ATP binds to the myosin head
Thick filaments have
ATPase activity and actin binding sites
Drag and drop each of the following phrases into the correct sequential order. Rank from earliest to latest. To rank items as equivalent, overlap them.
Acetylcholine is released from motor neuron——> action potential travels down the T-tubule——> Ca2+ is released from the sarcoplasmic reticulum——> myosin generates the power stroke——> Ca2+-ATPase channels actively pump Ca2+ back into the sarcoplasmic reticulum——> Ca2+ unwinds from Troponin——> actin filaments slip back to rest position
Which of the following is a similarity between the somatic motor and autonomic pathways?
Acetylcholine is secreted from the neuron that originates in the CNS
A type of chemically-gated ion channel located on the junction along folds of the muscle fiber
Acetylcholine receptor
Enzyme located in the synaptic cleft that breaks down acetylcholine
Acetylcholinesterase
Which of the following best describes the contraction phase of the excitation-contraction coupling reaction?
Actin and myosin filaments slide past each other to shorten the sarcomere, bringing Z disks closer together.
Which of the following statements is true about smooth muscle?
Actin and myosin generate force through the crossbridge cycle.
In the autonomic nervous system, neurotransmitter activation of its receptor terminates when the neurotransmitter is broken down by enzymes or when it diffuses away. Which other mechanism leads to termination of neurotransmitter activity?
Active transport into surrounding cells
In contrast to autonomic synapses, the synapses between neurons and skeletal muscle (neuromuscular junctions)
All answers are correct -are always excitatory -produce end-plate potentials that almost always bring the postsynaptic muscle cell to threshold -almost always produce muscle contractions when the synapse is active -are always excitatory and produce end-plate potentials that almost always bring the postsynaptic muscle cell to threshold -produce end-plate potentials that almost always bring the postsynaptic muscle cell to threshold and almost always produce muscle contractions when the synapse is active
Motion sickness is probably caused by miscommunication between which of the following systems?
All answers are correct -autonomic -vestibular -proprioceptive
The widespread effects of the sympathetic nervous system during the fight or flight response throughout the body is due to the fact that
All answers are correct -each preganglionic neuron synapses with several postganglionic neurons -the catecholamines released from the adrenal glands function as hormones -a given preganglionic neuron may synapse with postganglionic neurons in other ganglia of the sympathetic chain -each preganglionic neuron synapses with several postganglionic neurons and the catecholamines released from the adrenal glands function as hormones -the catecholamines released from the adrenal glands function as hormones and a given preganglionic neuron may synapse with postganglionic neurons in other ganglia of the sympathetic chain
The autonomic nervous system is involved in which of the following actions?
All answers are correct -fight or flight -pupil dilation or constriction -urination -swallowing -fight or flight, pupil dilation or constriction, and urination
Which of the following organs is/are controlled by both the sympathetic and parasympathetic branches of the autonomic nervous system?
All answers are correct -heart -urinary bladder -lungs -pancreas -heart and urinary bladder
Which of the following organs is/are controlled by both the sympathetic and parasympathetic branches of the autonomic nervous system?
All answers are correct -heart -urinary bladder -lungs -pancreases
Which of the following statements about the autonomic nervous system is (are) true?
All answers are correct -most of the functions of the autonomic nervous system are accomplished through visceral reflexes -the sympathetic and parasympathetic nervous systems function together to maintain homeostasis -the sympathetic and parasympathetic nervous systems tend to have opposing effects -most of the functions of the autonomic nervous system are accomplished through visceral reflexes and the sympathetic and parasympathetic nervous systems tend to have opposing effects
Symptoms of diabetic neuropathy that involves the autonomic nervous system may include
All answers are correct -urinary incontinence -erectile dysfunction -lack of awareness of hypoglycemia -urinary incontinence and erectile dysfunction
In smooth muscle, the release of calcium from the sacroplasmic reticulum is regulated by
All answers are incorrect
Which of the following statements about the activation of adrenergic receptors in the sympathetic nervous system are true?
All answers are incorrect
Drag and drop each of the following phrases so that they occur in the correct sequential order. Rank from earliest to latest. To rank items a equivalent, overlap them.
An action potential that travels down the T-tubule changes the structural confirmation of the DHP L-type Ca2+ channel——> Ryanodine receptor channels open——> Ca2+ leaves the sarcoplasmic reticulum——> acting and myosin bind to one another——> myosin head utilizes energy from ATP hydrolysis to produce the power stroke——> actin filaments slide toward the M line, shortening the sarcomere
Skeletal muscle moves a bone at a joint, such as flexing the forearm at the elbow. How is the opposite action produced (for example, extension at the elbow)?
An antagonistic muscle produces the opposite movement
Drag and drop each of the following pathways into the appropriate column.
Autonomic nervous system- parasympathetic pathways, sympathetic pathways, adrenal sympathetic pathways
An area that contains many synaptic vesicles filled with acetylcholine
Axon terminal of motor neuron
Put the events of the crossbridge cycle in the correct order, starting with the binding of myosin to actin: a. binding of ATP b. release of Pi c. release of ADP d. power stroke
B, D, C, A
Smooth muscle is similar to skeletal muscle in which of the following ways?
Both possess actin and myosin
"Dual innervation" refers to an organ receiving
Both sympathetic and parasympathetic nerves
Why is Buproprion used to help people who have chosen to quit smoking?
Buproprion mimics the effects of nicotine by keeping dopamine around at synapses.
Put the following in order of largest to smallest: A. Myofibril B. Muscle Fiber C. Fascicle D. Thick Filament
C, B, A, D
How does the process of smooth muscle contractions differ from contraction in skeletal muscle?
Ca+ comes from the extracellular fluid and the SR
Which ion stimulates shape changes at the beginning of skeletal muscle contraction?
Ca2+
Which of the following is the most direct cause of muscle relaxation?
Ca2+ unbinds from troponin, which results in tropomyosin re-covering myosin binding sites.
Which of the following best describes the role of calcium (Ca2+) in the excitation-contraction coupling reaction?
Ca2+ will bind to troponin, which leads to a conformational shift in tropomyosin, allowing for actin and myosin to attach.
A type fo voltage-gated ion channel located on the axon terminal
Calcium channel
Calcium ions couple excitation of a skeletal muscle fiber to contraction of the fiber. Where are calcium ions stored within the fiber?
Calcium ions are stored in the sarcoplasmic reticulum.
What specific event triggers the uncovering of the myosin binding site on actin?
Calcium ions bind to troponin and change its shape. {The shape change caused by the binding of calcium to troponin shifts tropomyosin away from the myosin binding sites on actin.}
Which of the following is/are targets of the efferent nervous system?
Cardiac muscle, glands, smooth muscle, skeletal muscle.
The sympathetic nervous system can exert effects on specific organs via the
Collateral ganglia
The sympathetic nervous system can exert effects on specific target organs via the
Collateral ganglia
When does cross bridge cycling end?
Cross bridge cycling ends when sufficient calcium has been actively transported back into the sarcoplasmic reticulum to allow calcium to unbind from troponin.
When an action potential travels along the sarcolemma of a muscle cell
DHP receptors in the T-tubule undergo a conformational change and Ca2+ flows down its concentration gradient through the ryanodine receptors
What terminates smooth muscle contraction?
Dephosphorylation of myosin by a phosphatase
Which is NOT a property of single-unit smooth muscles?
Each cell functions independent of its neighbor
Which of the following statements about muscle contraction is (are) true?
Each myosin head completes about five cross bridge cycles per second, but each thick filament has hundreds of myosin heads
Which of the following statements is true?
Eccentric contractions perform a lengthening action
Muscle fatigue likely arises mainly from failure in
Excitation-contraction coupling
Which type of skeletal muscle causes two bones to move away from one another?
Extensor
The binding of acetylcholine to muscarinic receptors causes
G protein activation
A location outside of the central nervous system where autonomic signals can synapse ___________.
Ganglion
With an up-regulation of receptors, how would you predict that a person would need to change the amount of nicotine consumed to get the same effects as they did in the beginning?
Increase use, because there are more receptors available for the chemical to bind to.
Which of the following is likely to occur when someone stands up quickly?
Increased release of norepinephrine and increased activity at adrenergic receptors
With paralytic chemical agents or drugs, such as curare, what factor must be taken into consideration to keep the patient alive?
Interference at the neuromuscular junction can cause paralysis of the respiratory muscles.
The adrenal medulla is important to the sympathetic branch of the autonomic nervous system because it
Is a source of catecholamines, is considered a modified sympathetic ganglion, and releases epinephrine and norepinephrine directly into the blood
How is the energy released by ATP hydrolysis used during the contractile cycle in skeletal muscle?
It causes rotation of the myosin head, thus "cocking" it.
In what way(s) is cardiac muscle similar to smooth muscle?
It contains gap junctions, it possesses pacemaker cells, and it is innervated by autonomic neurons.
Which statements apply to the parasympathetic division of the nervous system?
It is dominant during "resting and digesting" and its ganglia are nearby, on or near their target organs.
Which of the following processes produces 36 ATP?
Krebs cycle and oxidative phosphorylation
Which is NOT a correct comparison of cardiac myocytes to other muscle cell types?
Like skeletal muscle, contraction of cardiac muscle is under autonomic nervous control.
Which is the main enzyme responsible for the breakdown of catecholamines?
Monoamine oxidase
What structure most directly stimulates a skeletal muscle fiber to contract?
Motor neuron
Which of the following best summarizes the events of excitation-contraction coupling?
Muscle action potentials initiate calcium signals that activate a contraction-relaxation cycle.
Which of the following is the smallest structure?
Myosin
Which loss of function would occur if you introduced a chemical that functioned as an inhibitor of the ryanodine receptor channel?
Myosin would not be able to bind to actin in order to cause shortening of the sarcomere
What would be the effect of ACh binding to its receptor on a skeletal muscle cell?
Na+ would flow into the cell, and K+ would flow out of the cell
Drag each tile to the appropriate bin to indicate whether it shows the neuromuscular junction at rest or active (in the process of transmitting a signal).
Neuromuscular Junction at rest- calcium channels closed, ACh in synaptic vesicles, no Na+ diffusion, more negative charges inside sarcolemma, chemically-gated channels closed Neuromuscular junction active- calcium channels open, ACh in synaptic cleft, less negative charges inside sarcolemma, Na+ diffusion, chemically-gated channels open
Which of the following characteristics is similar between the sympathetic and parasympathetic branches for most neurons?
Neurotransmitter is secreted from the preganglionic neuron
How do the effects of chronic nicotine on nAChR expression differ from the predicted effects of a typical receptor agonist?
Nicotine causes up-regulation of nAChR.
Which type of acetylcholine receptor is present on postganglionic neurons, and which type is present on the target tissues in autonomic pathways?
Nicotinic on the postganglionic neurons and muscarinic on the target tissues
The somatic nervous system and the parasympathetic nervous system both release acetylcholine (ACh) onto their target tissues. Do you predict that this would indicate that these two pathways carry out the same effects? Why or why not?
No, because the receptors found on the target tissue for each pathway are different.
A patient has damage to one somatic motor neuron. What will this affect?
One motor unit
Muscarinic receptors are located on
Parasympathetic target organs
Bill contracts a viral disease that destroys cells in the anterior gray horns in his spinal cord. As a result, which of the following could you expect to happen in Bill?
Possible problems with moving his arms and problems with moving his legs
A patient is prescribed a muscarinic antagonist. This will inhibit signaling from which neurons?
Postganglionic parasympathetic
Which of the following cell types or structures can be found in both of the sympathetic and the parasympathetic nervous system?
Preganglionic neurons and chain ganglia
Which of the following would stop muscle contraction?
Pumping of calcium ions into the SR
The "rest and recovery" period, where the muscle restores depleted reserves, includes all of the following processes EXCEPT
Pyruvic acid is converted back to lactic acid
High capillary density, high myoglobin content, and high resistance to fatigue describe which of the following skeletal muscle types?
Red, slow oxidative muscle fibers
Inadequate calcium in the neuromuscular junction would directly affect which of the following processes?
Release of acetylcholine from the synaptic vesicles
Compared with skeletal and cardiac muscle, which of the following is not in smooth muscle? _________ in skeletal and cardiac muscle but not in smooth muscle.
Sarcomeres are
Which of the following statements best describes the pathology associated with periodic paralysis?
Skeletal muscles are plagued by being flaccid for short periods.
Which type(s) of muscle fiber is/are uninucleate?
Smooth and cardiac
Which of the following statements comparing smooth muscles to skeletal muscles is false?
Smooth muscles have more sarcoplasmic reticulum than skeletal muscles.
A type of voltage-gated ion channel located on the sarcolemma of the muscle fiber
Sodium channel
A neuron that delivers an action potential from the central nervous system to a skeletal muscle ________________.
Somatic motor neuron
Drag and drop each of the following events in their correct sequential order. Rank from earlier to latest. To rank items as equivalent, overlap them.
Somatic motor neuron delivers action potential——> acetylcholine is released from the axon terminal onto the motor endplate——> net Na+ influx through Nicotinic receptors——> muscle fiber depolarizes——> action potential travels down the T-tubule of the muscle fiber
Which of the following are components of the efferent nervous system?
Somatic motor neurons, parasympathetic neurons & sympathetic neurons.
Which of the following statements is true?
Some blood vessels contain alpha adrenergic receptors that cause vasoconstriction in the presence of epinephrine, whereas others have B2 adrenergic receptors that cause vasodilation in the presence of epinephrine
The division of the autonomic nervous system that prepares the body for intense levels of activity and stress is the __________________ division.
Sympathetic
The space between the axon terminal and junctional folds
Synaptic cleft
Membranous sac located in the axon terminal that contains neurotransmitter
Synaptic vesicle
A patient was exposed to a nerve gas during a chemical warfare attack. The nerve gas inhibited the enzyme acetylcholinesterase. What will happen to the amount of acetylcholine in the synaptic cleft, and how can this be treated?
The amount of acetylcholine will increase, treat with a cholinergic receptor antagonist.
How does the myosin head obtain the energy required for activation?
The energy comes from the hydrolysis of ATP.
Which is the fastest way that a skeletal muscle cell can generate ATP to power muscle contraction?
The high-energy phosphate on the creatine phosphate (phosphocreatine) is transferred to ADP creating more ATP.
How does the permanent depolarization of the skeletal muscle result in a flaccid (non-contracted) paralysis?
The muscle cell would not be able to depolarize a second time because the voltage-gated sodium channel never inactivates.
Why are some substances like nicotine difficult for users to stop using?
The nicotine in cigarettes enhances the reward pathways in the brain and the social aspects associated with smoking become pleasurable.
There is a high degree of overlap between the action potential and the contractile response in cardiac fibers. Why?
The overlap prevents summation of cardiac muscle contractions; it is critical that the heart have time to relax and fill with blood before the next contraction.
What structure is the functional unit of contraction in a skeletal muscle fiber?
The sarcomere {A sarcomere is a regular arrangement of thin and thick myofilaments that extends from one Z disc to the next. A myofibril consists of a series of sarcomeres.}
Which of the following statements about muscle contractions is (are) true?
The sarcomeres shorten during isometric and isotonic contractions
Which of the following statements is true?
The thin and thick filaments in smooth muscle have an oblique arrangement
Compare and contrast the voltage-gated sodium and potassium channels. What type of change in the cell is produced by ion movement through each type of channel?
The voltage-gated sodium channel opens in response to threshold voltage and allows sodium to enter the cell, thereby depolarizing the membrane potential and the potassium channel is also opened by threshold voltage and allows potassium to exit the cell, repolarizing or hyperpolarizing the membrane potential.
Which of these statements about smooth muscle is true?
There are two types: multi-unit, which lacks gap junctions, but has dense innervation; single-unit, which does have gap junctions, but sparse innervation.
Which of the following is NOT a similarity between somatic motor and autonomic pathways?
They all stimulate muscarinic receptors
End-plate potentials at the neuromuscular junction are similar to excitatory postsynaptic potentials in which of the following way(s)?
They are depolarizing.
How are cardiac muscle cells similar to smooth muscle cells?
They are electrically linked to one another.
Which of the following is (are) true about small motor units?
They tend to be recruited first during a contraction and they generate less tension than large motor units.
Sympathetic pathways originate in which regions of the spinal cord?
Thoracic and lumbar
Match the answers to the question. A. True only for the sympathetic division. B. True only for the parasympathetic division. C. True for both divisions The ganglion are found in a chain that runs close to the spinal cord or along the descending aorta
True only for the sympathetic division
To perform surgery with a minimum of pain for the patient and hassle for the surgeon, a patient may be administered a general anesthetic to prevent sensation and consciousness, as well as a paralytic agent to prevent reflexive muscle spasms. From what you have learned of motor control, which of the mechanisms below describes how a paralytic can prevent muscle contraction?
Virtually any drug that interferes with motor neuron activity at the neuromuscular junction could accomplish this.
Which of the following have a large muscle fiber diameter and a high force generating capacity?
White, fast glycolytic fibers
The motor end plate is
a folded area of muscle cell membrane with ACh receptors clustered at the top of each fold.
A motor unit consists of
a motor neuron and all of the myofibers innervated by it
Compared to skeletal muscle, contraction of smooth muscle cells is
a slower response to a stimulus and sustained without fatigue.
Neurotransmitter that stimulates skeletal muscle contraction
acetylcholine
The neurotransmitter that signals the contraction of skeletal muscle fibers is
acetylcholine
The major neurotransmitters/neurohormones of the autonomic nervous system are _________________.
acetylcholine, epinephrine, norepinephrine
Molecules common to both skeletal and smooth muscle crossbridge cycling include __________.
actin
Each myosin head has a binding site for
actin and ATP
A change in membrane voltage that travels down the T-tubule to cause opening of Ca2+ channels
action potential
Which of the following is an effect of the parasympathetic nervous system?
airway constriction
In the autonomic nervous system, acetylcholine is released by
all preganglionic sympathetic neurons, all preganglionic parasympathetic neurons, and all postganglionic parasympathetic neurons.
Drugs to treat asthma attacks might include __________.
alpha agonists and beta agonists
The A band contains
an area of partial overlap between thick and thin filaments
The disease known as myasthenia gravis produces an unusually rapid onset of fatigue and weakness in certain muscle groups due to
autoimmune destruction of the ACh receptors of motor neurons
Which of the following best describes the direction and function of efferent signals?
away from the central nervous system, cause motor effects in glands or muscles
Activation of _______________ adrenergic receptors raises the concentration of cAMP in effector cells.
beta 1 and beta 2
What triggers contraction in smooth muscle?
calcium binds to calmodulin
When myosin is bound to actin during the crossbridge cycle __________.
calcium is bound to the troponin complex and myosin is in its high-energy form
In which type of muscle is the function of gap junctions of the greatest importance in maintaining life?
cardiac
The autonomic nervous system innervates
cardiac muscle, blood vessels, and adipose tissue
Both alpha-bungarotoxin and curare are chemical agents that bind to the same neurotransmitter receptor, but only curare binds reversibly. Which of the locations listed would not be a location for this receptor?
cardiac muscle, smooth muscle, and glands
The binding of acetylcholine to its receptor at the neuromuscular junction causes the opening of a
channel for both Na+ and K+.
The generation of a smooth, steady, maximum tension contraction by a muscle fiber, with no evidence of relaxation, due to very rapid stimulation of the muscle fiber is known as ________________.
complete (or fused) tetanus
During skeletal muscle contraction, thick and thin filaments bind together forming
crossbridges
During complete tetanus
cytosolic calcium levels are high enough to saturate all the troponin molecules, action potential frequency is higher than the fused muscle twitch frequency, and action potential frequency is higher than the fused muscle twitch frequency
What is the type of chemical reaction used to rebuild ADP into ATP?
dehydration synthesis
The cause of skeletal muscle fatigue during extended submaximal exercise is primarily a(n)
depletion of glycogen stores
The disease myasthenia gravis is caused by
destruction of acetylcholine receptors.
The latent period is due to the time it takes for
excitation-contraction coupling
During a prolonged bout of continuous exercise (longer than 30 minutes), ATP stores are replenished by
fatty acids in the bloodstream
A toxin that prevents the release of acetylcholine at the neuromuscular junction would cause __________.
flaccid paralysis of skeletal muscles
The force generated by a muscle depends directly or indirectly on the
force generated by individual muscle fibers, number of muscle fibers contracting, and number of active crossbridges formed
Muscle fibers can obtain energy from ______________ when the oxygen supply for catabolism is too slow to meet the ATP demands of heavy exercise.
glucose that is metabolized to lactic acid
Which of the following processes produces molecules of ATP and has two pyruvic acid molecules as end products?
glycolysis
The somatic nervous system differs from the parasympathetic nervous system in that
it is mostly under voluntary control and the efferent pathway consists of only a single motor neuron
The burning sensation that is felt in muscles during exercise is due to the buildup of
lactic acid
As the load on a muscle increases, which of the following also increase(s)?
latent period
Sympathetic preganglionic neurons emerge from the ______________ portion of the spinal cord.
lumbar and thoracic
An area of muscle fiber membrane that is in close association with the axon terminal of the motor neuron, contain receptors for acetylcholine
motor end plate
Somatic motor neurons in the spinal cord control all of the following muscles, except those that
move the face
What type of drug would decrease heart rate?
muscarinic agonist
The neurotransmitter that controls skeletal muscle causes which of the following?
muscle contraction
Which of the following structures is/are necessary to initiate the muscle action potential?
muscle fiber, acetylcholine, ACh receptor-channels, motor neuron, motor end plate
A toxin that inhibits acetylcholinesterase at the neuromuscular junction would cause __________.
muscle spasms and respiratory failure
The functional unit within a muscle fiber is called a sarcomere. Which of the following does not make up part of the sarcomere?
myofibril
Thick filaments are made up of
myosin
Both alpha-bungarotoxin and curare are chemical agents that bind to the same neurotransmitter receptor, but only curare binds reversibly. Which receptor type is involved?
nicotinic acetylcholine receptor
Curare produces skeletal muscle paralysis because it is a(n) __________.
nicotinic cholinergic antagonist
An important difference between single-unit and multiunit smooth muscle is the
numerous gap junctions in single-unit smooth muscle, which allow many cells to work together as a sheet.
A motor unit consists of
one neuron and all the skeletal muscle fibers it controls.
Skeletal muscle fibers with the greatest endurance rely on ___________ for energy.
oxidative phosphorylation
A neuron that receives an action potential from another neuron and then delivers that action potential to a smooth muscle __________________.
postganglionic autonomic neuron
Which has its cell body in the ganglion?
postganglionic neuron
A neuron that delivers an action potential from the central nervous system to another neuron in the peripheral nervous system ________________.
preganglionic autonomic neuron
Molecules that are more likely to be found in higher concentrations in a fast glycolytic fiber include
pyruvate to lactic acid
The function of transverse tubules is to
rapidly conduct action potentials to the interior of the muscle fiber.
An increase in the force generated by a muscle is achieved by the __________ of more motor units.
recruitment
Skeletal muscles with the most endurance (resistance to fatigue) are _____________ in color.
red
What immediately follows hydrolysis at ATP during muscle contraction?
rotation of the myosin head to the cocked position
Striated muscles are so-called because of a repeating pattern of light and dark bands. One repeating unit of the banding pattern is called a
sarcomere
Effector tissue of the somatic motor division is __________.
skeletal muscle
If a person has a genetic disorder that caused him/her to not produce norepinephrine, which type of tissue would be affected the least?
skeletal muscle
Which muscle fiber type experiences slow-wave potentials?
smooth muscle
Which type of muscle is subject to the greatest diversity of hormonal control?
smooth muscle
In which types of muscle does myosin have an ATPase activity?
smooth, cardiac, skeletal
What are the ions directly associated with all forms of periodic paralysis due to the fact that the channels for these ions are defective?
sodium and calcium
A single neuron is stimulated at the central nervous system; this signal travels all the way to the target tissue, where the neurotransmitter acetylcholine is released onto the target tissue. The acetylcholine binds to a nicotinic receptor to induce skeletal muscle contraction. These steps describe the function of which branch of the efferent nervous system?
somatic
CNS areas that are involved in the control of autonomic functions include the __________.
spinal cord, hypothalamus, and pons
When a muscle is stimulated at a high frequency such that the twitches build on each other, _________________ is observed.
summation
Match the response with the type of chemical. A. Sympathetic agonist B. Parasympathetic agonist Pupil dilation
sympathetic agonist
During strenuous exercise, which of the following are likely to be more active?
sympathetic nervous system; somatic nervous system
Skeletal muscle cells are usually attached to bone by
tendons
The amount of force a muscle can generate depends on
the number of sarcomeres in parallel, the length of individual sarcomeres, and the cross-sectional diameter of the muscle fiber
Which of the following statements best describes the neuromuscular junction?
the point of synapse between a motor neuron and the muscle fiber that it innervates
Similarities between autonomic neuroeffector synapses and the neuromuscular junction include
the presence of enzymes such as acetylcholinesterase or monoamine oxidase and the requirement for calcium to produce transmitter release
If a somatic motor neuron fires an action potential, then ________.
the response is always excitatory
When the arrival of an action potential at the muscle cell membrane triggers the release of calcium from the sarcoplasmic reticulum, this process does not go on indefinitely because __________.
the rising concentration of cytosolic calcium triggers the closure of calcium channels in the sarcoplasmic reticulum
Muscle tension decreases at short muscle lengths because
the thin filaments at opposite ends of the sarcomere overlap and the Z lines come into contact with the thick filaments
After the myosin ATPase hydrolyzes ATP into ADP + Pi, __________.
the two products stay attached to the myosin head, the myosin head is cocked and binds to a different G-actin molecule, ready for the power stroke
Synapses between postganglionic neurons and effector organs are different from other synapses in that
there are no distinct postsynaptic sites on the effector organs and transmitter is released from several areas on the postganglionic axon
The Troponin complex in thin filaments can bind
tropomyosin, calcium, and actin
Which type of muscle fiber has a large quantity of glycogen and mainly uses glycolysis to synthesize ATP?
white fast twitch fibers
