Biology Ch35 Launchpad q's, BLY 122 Ch36 Launchpad, Chapter 37 Learning Curve
Which of the following statements about muscle contraction is false?
Actin and myosin filaments shorten during muscle contraction.
Which of the following statements about muscle proteins is false?
Actin filaments have globular heads.
Which of the following statements about hydrostatic skeletons is false?
Longitudinal muscle contractions increase the length of the body cavity.
Which of the following statements about muscles is correct?
Smooth muscles contract more slowly than skeletal muscles.
What happens during depolarization? Sodium ions flow into the cell. Potassium ions flow out of the cell. Potassium ions flow out of the cell AND sodium ions flow into the cell. The sodium/potassium pump protein reverses itself.
Sodium ions flow into the cell.
What role does ATP play in the cross-bridge cycle?
The binding of ATP to myosin causes myosin to detach from actin.
If all of the collagen were removed from a bone, how would the properties of that bone be altered?
The bone would be more brittle and easier to break.
The decision to initiate an action potential is made at the: cell body. axon hillock. synapse. dendrite.
axon hillock
An example of an involuntary response would be: secretion of saliva. sighing. heart rate. both secretion of saliva and heart rate.
both secretion of saliva and heart rate.
Which of the following organisms possesses a brain? flatworm earthworm squid both squid and earthworm
both squid and earthworm
Which of the following statements is true regarding the axial skeleton?
it is thought to have evolved before the appendicular skeleton.
An IPSP occurs when: ligand-gated chloride channels open. ligand-gated calcium channels open. both ligand- and voltage-gated chloride channels open. voltage-gated chloride channels open.
ligand-gated chloride channels open.
The signal to "rest and digest" comes from the: parasympathetic system. somatic system. peripheral system. sympathetic system.
parasympathetic system.
The action potential travels down: the synapse. both the dendrite and axon. the dendrite. the axon.
the axon
The release of neurotransmitter from the axon terminal is controlled by: voltage-gated sodium channels. voltage-gated potassium channels. voltage-gated calcium channels. voltage-gated chloride channels.
voltage-gated calcium channels.
A sample of muscle tissue shows large-diameter fibers that are white in color. Which of the following characteristics would also be associated with this tissue? A. high rates of ATP hydrolysis B. greater resistance to fatigue C. aerobic respiration D. abundant mitochondria E. All of the answer options are correct.
A. high rates of ATP hydrolysis
The five steps listed below are involved in excitation-contraction coupling. 1 - A wave of depolarization passes through the T-tubules. 2 - Ca2+ binds to and causes a conformational change in troponin. 3 - Tropomyosin moves to expose myosin-binding sites on the actin. 4 - Ca2+ is released from the sarcoplasmic reticulum. 5 - Cross-bridges form and produce a contraction. Which of the following lists the steps in the correct order of events?
1, 4, 2, 3, 5
Which of the following statements is true regarding axons and dendrites? In a neuron, axons typically receive signals and dendrites typically transmit or send signals. Neurons generally possess more axons than dendrites. The dendrite terminal is the site where neurotransmitters are released into the synaptic cleft. Action potentials travel along neuron axons. None of the answer options is true.
Action potentials travel along neuron axons.
Which of the following statements is false of animals?
All animals with exoskeletons or shells must molt in order to increase in size.
An action potential could be described as: the unit of information for a nerve cell. a rapid change in membrane potential. a consequence of passive transport across the plasma membrane. All of the answer options are correct.
All of the answer options are correct.
Cephalization is: -the development of a "head end" in an organism. -the concentration of sensory organs at one end of an animal. -the development of a brain. -All of the answer options are correct.
All of the answer options are correct.
The ability of a postsynaptic cell to respond to a neurotransmitter depends upon: an action potential in the presynaptic cell. release of neurotransmitter from the presynaptic cell. presence of receptors on the postsynaptic cell. All of the answer options are correct.
All of the answer options are correct.
The peripheral nervous system is composed of: sensory neurons. cranial nerves. spinal nerves. All of the answer options are correct.
All of them
Which of the following statements about the differences between exoskeletons and endoskeletons is correct?
An exoskeleton lies external to the body's soft tissues, whereas an endoskeleton lies internal to most of the body's soft tissues.
The olfactory nerve is made up of: A. chemosensitive hairs. B. axons of interneurons. C. axons of olfactory sensory neurons. D. dendrites of olfactory sensory neurons.
B. axons of interneurons.
Predict what would happen to a neuron's resting membrane potential if the number of sodium leak channels increased. A. The membrane potential would become more negative. B. The membrane potential would become slightly more negative. C. The membrane potential would become more positive. D. The membrane potential would remain the same due to the activity of the sodium-potassium pump.
C. The membrane potential would become more positive.
The cochlear branch of the vestibulocochlear nerve is made up of: A. bundles of hair cell bodies from the tectorial membrane. B. hair cell axons from the semicircular canal. C. hair cell axons from the basilar membrane. D. bundles of hair cell bodies from the basilar membrane.
C. hair cell axons from the basilar membrane.
Which of the following best outlines the evolution of a brain? A. nerve cord→ ganglia → brain B. nerve cord → interneuron → brain C. interneuron → ganglia → brain D. nerve cord → nerve net → brain
C. interneuron → ganglia → brain
Predict which type of channel is associated with ion transport in stereocilia. A. stretch-gated channel and voltage-gated channel B. ligand-gated channel C. stretch-gated channel D. voltage-gated channel
C. stretch-gated channel
Which of the following statements regarding smooth muscle versus striated muscle is false?
Calcium for skeletal muscle contraction enters the cell from the sarcoplasmic reticulum and through voltage-gated calcium channels in the plasma membrane, whereas the calcium for smooth muscle contraction enters the cell from the sarcoplasmic reticulum only.
Why is calcium necessary for muscle contraction?
Calcium is needed to activate troponin so that tropomyosin can be moved to expose the myosin-binding sites on the actin filament.
Which of the following is true for a nerve cell at rest? Channels allow for the movement of chloride into the cell. Channels allow for the movement of potassium out of the cell. Sodium ions are concentrated outside the cell. Channels allow for the movement of potassium out of the cell AND sodium ions are concentrated outside the cell.
Channels allow for the movement of potassium out of the cell AND sodium ions are concentrated outside the cell.
Aging can sometimes lead to an increase in the stiffness at the base of the basilar membrane. What affect would this have on a person's hearing? A. They would lose the ability to hear low-pitched sounds. B. They would not be able to distinguish the amplitude of a sound. C. They would only be able to hear loud sounds. D. They would lose the ability to hear high-pitched sounds.
D. They would lose the ability to hear high-pitched sounds.
Which of the following is a function of an exoskeleton?
Exoskeletons provide protection. Exoskeletons help reduce water loss in terrestrial species. Exoskeletons provide support. Exoskeletons provide a site for muscle attachment. (ALL OF THE ABOVE)
Animals with endoskeletons do not have any hydrostatic skeletal structures. Similarly, animals with exoskeletons do not have any hydrostatic components. Due to this, it could be said that every animal possesses a unique, singular skeleton that can (only) be classified as an endoskeleton, exoskeleton, or hydrostatic skeleton.
False
Which of the following statements is false according to twitch-fibers?
Fast-twitch fibers generate more force than slow-twitch fibers.
A young girl walking along the beach discovers a sea sponge washed up on the shore. She pokes it with her finger, and the animal twitches in response. As a result of the sea sponge's reaction to being prodded, the girl concludes that this animal has a brain. Is this conclusion correct? Yes, if an animal responds to any type of touch or sensory signal, the animal must have a brain where such a signal is processed. Yes, sea sponges are known to have brains; however, these structures are relatively simple compared to the brains of vertebrates. No, sea sponges possess paired ganglia that mediate their responses to touch or environmental changes (much like flatworms). No, sea sponges actually lack any type of nervous system—the reaction the girl observed is the result of a unique population of (non-neuronal) cells. None of the answer options is correct.
No, sea sponges actually lack any type of nervous system—the reaction the girl observed is the result of a unique population of (non-neuronal) cells.
Imagine that you are talking with one of your friends about your biology course. He states that the somatic nervous system is subdivided into sympathetic and parasympathetic components, and is responsible for involuntary responses. Is this statement correct? No, although the somatic nervous system controls involuntary responses, it is the autonomic nervous system that is subdivided into parasympathetic and sympathetic components. No, although the somatic nervous system does have both sympathetic and parasympathetic subdivisions, it is responsible for voluntary responses. Yes, this statement is correct. The somatic nervous system has both sympathetic and parasympathetic components and controls involuntary responses. No, the somatic nervous system is responsible for voluntary responses, and is not subdivided into sympathetic and parasympathetic components.
No, the somatic nervous system is responsible for voluntary responses, and is not subdivided into sympathetic and parasympathetic components.
A movie director asks his computer animation team to create a dragon with an exoskeleton, as such a skeleton will make it impervious to any attacks. Is this statement correct?
None of the answer options is correct.
The basic contractile unit of a muscle is called the:
Sarcomere
A researcher is comparing the size of sarcomeres in mice to that in elephants. What will he find?
Sarcomere size is relatively constant in vertebrates. As a result, mouse and elephant sarcomeres will likely be equal in size.
Which of the following statements is false of muscles?
Shortening a muscle prior to contraction reduces the energy consumption of that muscle.
Which of the following statements is true regarding cephalization? Cephalization first appeared in the last common ancestor of cnidarians and bilaterans; it is not the result of convergent evolution. The eyes of owls, the noses of bloodhounds, and the ears of bats could all be considered examples of cephalization (as each of these structures are associated with specific cranial ganglia and nerves). Although most predatory vertebrates demonstrate cephalization, herbivores and other prey animals do not (as cephalization is thought to have evolved specifically in predators). All multicellular organisms demonstrate cephalization, including both cnidarians and bilaterans. Cephalization was initially believed to have evolved to assist in "backward" motion, as many organisms possess sensory organs at both their anterior and posterior ends.
The eyes of owls, the noses of bloodhounds, and the ears of bats could all be considered examples of cephalization (as each of these structures are associated with specific cranial ganglia and nerves).
Smooth muscles can be activated by all of the following except:
The nervous system
When the longitudinal muscles within an earthworm segment contract, what effect does this have on the shape of the segment?
The segment will shorten and widen.
Imagine that a researcher is examining the positioning of synaptic clefts in adult mice. In one of his mice, he notices that synaptic clefts are about 100 nm wide. What can be said of this mouse? This is a normal or wild-type mouse; synaptic clefts are generally 100 to 500 nm wide. This is likely a mutant mouse (as synaptic clefts are typically 10 to 20 nm wide); however, as neurotransmitters function better over long distances, this mouse will respond quicker to stimuli. This is likely a mutant mouse (as synaptic clefts are typically 10 to 20 nm wide). Given that neurotransmitters act over short distances, this mouse may demonstrate delayed responses to stimuli, or no responses at all. This is likely a mutant mouse, as synaptic clefts directly connect the cytoplasm of presynaptic and postsynaptic cells (there is no space in between these cells). However, the width of this synaptic cleft will not affect the response of the mouse to stimuli. None of the answer options is correct because synaptic clefts have no relationship to the release of neurotransmitters or the transmission of action potentials.
This is likely a mutant mouse (as synaptic clefts are typically 10 to 20 nm wide). Given that neurotransmitters act over short distances, this mouse may demonstrate delayed responses to stimuli, or no responses at all.
Although animal nervous systems differ in complexity, their nerve cells are still remarkably similar. (T/F)
True
When compared to the leg muscles of an Olympic sprinter, the muscles of an Olympic marathoner would likely show a greater proportion of slow-twitch fibers.
True
What class of membrane-transport protein is associated with triggering an action potential? a sodium/potassium symporter a ligand-gated ion channel a voltage-gated ion channel a pump protein
a voltage-gated ion channel
4. At any given point along the length of the gill lamella, how does the pO2 of the blood flowing through the blood vessels in the lamella compare to the pO2 of the water flowing over the gill lamella? a. The pO2 of the blood is lower than the pO2 of the water. b. The pO2 of the blood is higher than the pO2 of the water. c. The partial pressure of oxygen in the blood is equal to the pO2 of the water. d. The pO2 of the blood is variable and cannot be compared to the pO2 of the water. e. The pO2 of the blood never exceeds 50% of the pO2 of the water.
a. The pO2 of the blood is lower than the pO2 of the water.
38. Why are muscles always associated with some type of skeleton? a. The skeleton transmits the force generated by the muscles. b. The skeleton is always necessary to support the body against gravity. c. The skeleton provides a storage area for calcium ions used by muscle. d. The skeleton is necessary for animals to grow. e. All the answer options are correct.
a. The skeleton transmits the force generated by the muscles.
26. An animal with a hydrostatic skeleton such as an earthworm can elongate its segments (which is how it moves forward) by a. contracting circular (circumferential) muscles and pushing the fluid-filled body cavity forward. b. contracting cartilage muscles, which pushes the fluid-filled body cavity forward. c. contracting longitudinal muscles, which puts pressure on the hydrostatic skeleton and pushes the fluid-filled body cavity forward. d. contracting extensors and flexors against the joints of the exoskeleton.
a. contracting circular (circumferential) muscles and pushing the fluid-filled body cavity forward.
8. A neuron may receive multiple stimuli from the same sensory neuron over a very short period of time. The firing rate of the receiving neuron is proportional to the number of signals received from the sensory neuron. Which of the following is this an example of? a. temporal summation b. spatial summation c. action potential d. hyperpolarization
a. temporal summation
The term saltatory propagation refers to the: involvement of ions such as sodium and potassium in production of the action potential. ability of an action potential to "jump" from one node of Ranvier to the next. tendency of an action potential to move in one direction. All of the answer options are correct.
ability of an action potential to "jump" from one node of Ranvier to the next.
Which of the following is not an advantage of cephalization? ability to quickly produce a suitable behavioral response to stimuli ability to better detect and capture prey ability to sense stimuli from the environment toward which an organism is moving ability to receive sensory information
ability to receive sensory information
Where on a neuron would you expect to find myelin? at the synapse round the dendrites at the axon hillock along the axon
along the axon
Body functions such as heart rate, blood flow, and digestion are controlled by the: somatic nervous system. autonomic nervous system. automatic nervous system. sympathetic nervous system.
autonomic nervous system.
15. There is a venom made by certain marine snails that blocks voltage-gated calcium channels. If this toxin were applied to the experimental preparation of neurons, an action potential initiated in a presynaptic axon, what do you expect will happen? a. The action potential in the presynaptic neuron will be blocked all along the length of that neuron's axon. b. The action potential along the presynaptic axon will be normal, but synaptic vesicles will not release neurotransmitter. c. Neurotransmitter will bind to their receptors, but second messenger actions will be prevented. d. Synaptic vesicles will release neurotransmitter but the neurotransmitter will be blocked from reaching receptors.
b. The action potential along the presynaptic axon will be normal, but synaptic vesicles will not release neurotransmitter.
When you are running on a treadmill at Ping Center, the respiratory control center in your brainstem increases your breathing rate to restore Po2 and Pco2 levels in your tissues to their resting levels. It does so because sensory receptors in the brainstem detect changes in the blood and cerebrospinal fluid. The principal change that these neurons sense is: a. a drop in Po2 b. a rise in Pco2 c. a rise in pH d. a drop in HCO3-
b. a rise in Pco2
10. During long-term potentiation the release of the neurotransmitter glutamate triggers the opening of sodium and calcium channels in the postsynaptic cell, increasing ion flow. What type of channel is responsible for this increase in ion flow? a. voltage-gated ion channel b. ligand-gated ion channel c. light-gated ion channel d. pump protein
b. ligand-gated ion channel
3. During inhalation the diaphragm contracts and moves downward. What effect does this have on the pressure in alveoli in the lungs? a. pressure in the alveoli increases to values higher than atmospheric pressure b. pressure in the alveoli decreases to values lower than atmospheric pressure c. pressure in the alveoli does not change.
b. pressure in the alveoli decreases to values lower than atmospheric pressure
Whether a neurotransmitter has an inhibitory or excitatory effect on a postsynaptic cell depends on a. the type of neurotransmitter b. the nature of the postsynaptic receptor and channel c. the concentration of neurotransmitter in the synaptic cleft
b. the nature of the postsynaptic receptor and channel
4. The steps necessary for hearing include (1) amplification of sound waves, (2) transfer of sound vibrations to fluid pressure waves, and (3) mechanoreception by hair cells of the cochlea. How are the sound vibrations transferred to fluid pressure waves? a. by the bones of the middle ear b. through the oval window c. by the tympanic membrane d. by the action of the vestibular system
b. through the oval window
Why is a reflex arc so fast? because the afferent and efferent cells are in the spinal cord because the axons are shorter because all the neurons involved are myelinated because there are fewer cells involved in the network
because the afferent and efferent cells are in the spinal cord
Why does an action potential travel in one direction down an axon? because voltage-gated sodium channels cannot immediately reopen because it needs to reach the synapse to trigger release of neurotransmitter because voltage-gated potassium channels remain open longer because the diffusion of charge can only occur in one direction
because voltage-gated sodium channels cannot immediately reopen
What cellular component of a sensory neuron would account for its specialization in response to physical or chemical cues? the phospholipid composition of its plasma membrane both the shape of the cell and the proteins in its cytosol or membrane the proteins present in its cytosol or on its plasma membrane the shape of the neuron
both the shape of the cell and the proteins in its cytosol or membrane
What are the nodes of Ranvier? the point of communication between an axon terminal and a muscle cell the population of voltage-gated sodium channels located at the axon hillock breaks in the myelination along an axon branch points along an axon
breaks in the myelination along an axon
13. The action potential is produced by a combination of an influx of sodium ions and an efflux of potassium ions. Since these ions carry similar charge and are moving in opposite directions, why doesn't this movement during the action potential cause them to simply cancel each other out so that there is no change in the membrane potential? a. Action potentials are all-or-none. b. The Na+/K+ ATPase pumps 3 Na+ out for every 2 K+ in c. The opening of voltage-gated K+ channels is delayed compared to the opening of voltage-gated Na+ channels. d. The opening of voltage-gated K+ channels requires ATP.
c. The opening of voltage-gated K+ channels is delayed compared to the opening of voltage-gated Na+ channels.
12. Which of the following is a key determinant of whether a neurotransmitter produces an EPSP or an IPSP? a. EPSPs are produced by ion channel receptors; IPSPs are produced by G-protein linked receptors b. IPSPs are produced by negatively charged neurotransmitters and EPSPs produced by positively charged neurotransmitters c. Whether the response is an EPSP or an IPSP is a function of the ion channel controlled by the postsynaptic receptor. d. Whether the response is an EPSP or an IPSP depends on whether the neurotransmitter is a peptide or a amine.
c. Whether the response is an EPSP or an IPSP is a function of the ion channel controlled by the postsynaptic receptor.
Smooth muscle cells are activated when Ca2+ binds to:
calmodulin.
Striated muscles include:
cardiac muscle and skeletal muscle.
Approximately how many nerve cells does a human have? a. 10 million b. 100 million c. 10 billion d. 100 billion e. We do not have a good estimate.
d. 100 billion
23. Which of the following is true of astrocytes? Select all correct choices. a. They are a specific type of glial cell. b. They surround blood vessels in the brain. c. They contribute to the blood-brain barrier. d. All of above
d. All of above
The ability to alter the connections between neurons is known as: a. long-term memory. b. synaptic plasticity. c. long-term potentiation. d. All of the answer options are correct.
d. All of the answer options are correct.
4. Neurons tend to differ in their (select all correct choices): a. function. b. size and shape. c. number of extensions d. all of above
d. all of above
Vertebrate skeletal muscle is a. under the control of the sympathetic nervous system. b. under control of the parasympathetic nervous system. c. dually controlled by sympathetic and parasympathetic neurons. d. dually controlled by the autonomic and somatic nervous systems. e. under control of the somatic, and not the autonomic nervous system.
d. dually controlled by the autonomic and somatic nervous systems.
In a neuron, what creates the concentration gradient favoring the outflow of K+? a. ligand-gated Na+/K+ channels b. voltage-gated K+ channels c. leakage K+ channels d. the Na+/K+ ATPase e. voltage-gated Na+ channels
d. the Na+/K+ ATPase
Which part of a neuron is associated with receiving information? axon cell body synapse dendrite
dendrite
Predict which of the following scenarios would be most likely to result in an action potential. dendrites: high-frequency IPSP; cell body: low-frequency EPSP dendrites: high-frequency EPSP; cell body: high-frequency IPSP dendrites: low-frequency IPSP; cell body: high-frequency EPSP dendrites: low-frequency EPSP; cell body: high-frequency IPSP
dendrites: low-frequency IPSP; cell body: high-frequency EPSP
Which set of steps best accounts for the role of the axon hillock in nerve cell activity? threshold, action potential, refractory period, summation depolarization, summation, threshold, action potential threshold, refractory period, depolarization, action potential summation, refractory period, threshold, action potential
depolarization, summation, threshold, action potential
. You join an expedition to climb K2 in the Himalayas at 28,350 ft. Some maniacs in your climbing team want to attempt it without using supplemental oxygen. At 21,000 ft, two of the maniacs get very sick and very flaky. They see an image of Frank Zapa ion the summit and are just TOO happy. Why has this happened? a. The percent atmospheric oxygen is higher at 21,000 ft, and they are suffering from oxygen toxicity. b. The accumulation of CO2 in their bloodstream accounts for the visions and euphoria. c. They must have taken drugs, because PO2 and P CO2 is the same at sea level and at 21,000 ft. d. The percent atmospheric oxygen has dropped far below the 21% at sea level and this causes decreased PO2, causing hypoxia in the brain. e. Oxygen remains 21% of the atmospheric gas, but atmospheric pressure is less, causing low PO2 and symptoms of hypoxia.
e. Oxygen remains 21% of the atmospheric gas, but atmospheric pressure is less, causing low PO2 and symptoms of hypoxia.
2. Which of the following would you find in the lumen (inner open space) of the transverse tubule (T-tubule) of vertebrate skeletal muscle? a. extracellular fluid b. cytoplasm c. actin d. myosin e. sarcoplasmic reticulum
e. sarcoplasmic reticulum
What class of neurons in the central nervous system sends commands to muscles? afferent neurons efferent neurons interneurons peripheral neurons
efferent neurons
Predict which of the following types of synapse would be associated with the fastest reflex arc. chemical synapse with inhibitory neurotransmitters electrical synapse chemical synapse with excitatory neurotransmitters chemical synapse with neuropeptides
electrical synapse
An embryologist is looking at a cross-section of a mouse embryo. She notices that flanking either side of the neural tube (the rudiment of the spinal chord) are eggplant-shaped structures that contain many cell bodies. These structures are most likely: ganglia. nerve cords. nerves. myelin sheaths. axon hillocks.
ganglia
An astrocyte is a type of: glial cell. interneuron. motor neuron. sensory neuron.
glial cell
A sample of muscle tissue shows large-diameter fibers that are white in color. Which of the following characteristics would also be associated with this tissue?
high rates of ATP hydrolysis
Which of the following ions does not contribute to information flow in a nervous system? hydrogen potassium calcium chloride
hydrogen
Which of the following best outlines the evolution of a brain? nerve cord→ ganglia → brain interneuron → ganglia → brain nerve cord → interneuron → brain nerve cord → nerve net → brain
interneuron → ganglia → brain
Which of the following is not a correct pairing of structure and function?
motor endplate: region of the motor neuron axon that releases acetylcholine
Sensory neurons are involved in all of the following except: vision. taste. movement. hearing.
movement
The earliest nervous system likely resembled a: ganglia. nerve cord. simple brain and nerve cord. nerve net.
nerve net.
Which of the following statements are true regarding sea anemones? Because sea anemones are "simple" organisms, these animals only possess motor neurons; sensory neurons or interneurons are never found in sea anemones. Although sea anemones possess "net-like" nervous systems, these animals have brains located at their bases (near where they would attach to rocks). Sponges—not sea anemones—possess what is considered to be the "simplest" nervous system found in animals. Although sea anemones lack definitive brains, they do possess ganglia that serve a similar function as the paired ganglia of flatworms. None of the answer options is correct.
none
The permeability of a nerve cell membrane depends upon the: number of receptor proteins present. number of open channels. concentration of cholesterol present in the bilayer. concentration of pump proteins.
number of open channels.
Myelination of neurons in the brain is the product of: Schwann cells. astrocytes. oligodendrocytes. both Schwann cells and oligodendrites.
oligodendrocytes.
Imagine that you travel back in time 600 million years and are looking at marine organisms. What types of skeletons would you observe in these creatures?
only hydrostatic skeletons and exoskeletons
Suppose that when the doorbell rings your cat's pupils dilate and she runs under the couch. When you reach under the couch to grab the cat, you also notice that her heart rate has increased. Which responses in your cat are the result of her autonomic nervous system? the dilation of her pupils the movement of her limb muscles as she runs under the couch her increased heart rate only the dilation of her pupils and her increased heart rate All of these responses are due to the autonomic nervous system.
only the dilation of her pupils and her increased heart rate
Inhibition of the flexor muscle during the knee-jerk reflex is an example of: negative feedback. homeostasis. reciprocal inhibition. All of the answer options are correct.
reciprocal inhibition.
The role of an interneuron is to: relay information from sensory to motor neurons. stimulate a muscle to contract. maintain homeostasis. convey information from the internal environment of an organism.
relay information from sensory to motor neurons.
In vertebrates, the location of spinal cord damage determines the region of the body that is impaired. This is a product of: organization of efferent neurons. localization of spinal ganglia. segmentation of the spinal cord. organization of spinal nerves.
segmentation of the spinal cord.
Which ion is present at higher concentration outside a neuron at rest? potassium sodium chloride calcium
sodium
Which ion is present at higher concentration outside a neuron at rest? sodium potassium chloride calcium
sodium
Which of the following types of organisms lacks a nervous system? sponges sea anemone spiders squid
sponges
Which of the following would result in tetanus?
stimulating the muscle fiber so frequently that it cannot relax at all
The afferent neuron in the knee-jerk reflex is the: extensor muscle motor neuron. stretch receptor sensory neuron. spinal interneuron. flexor muscle motor neuron.
stretch receptor sensory neuron.
The movement of potassium out of a resting neuron is a consequence of: the electrical gradient across the membrane. the high concentration of potassium inside the cell. the presence of potassium leak channels in the membrane. the high concentration of potassium inside the cell AND the presence of potassium leak channels in the membrane.
the high concentration of potassium inside the cell AND the presence of potassium leak channels in the membrane.
The power stroke describes:
the pivoting of the myosin head, which causes actin and myosin to slide relative to each other.
Imagine that a researcher has dissected out a single muscle bundle from a triceps muscle biopsy. She sections this bundle and stains it for a variety of muscle-associated proteins. After this staining, when she zooms in on a sarcomere, she notices that a certain protein always dots the periphery of the thin filaments. This protein is most likely:
tropomyosin.
The initial depolarization associated with the action potential is the consequence of the opening of _________________ at the axon hillock. voltage-gated sodium channels voltage-gated calcium channels voltage-gated potassium channels voltage-gated chloride channels
voltage-gated sodium channels