Bio 212 Exam 4 Study Guide

What 3 ways do ions cross the plasma membranes efficiently?

1.) Flowing - flow along their electrochemical gradient through an ion channel - a protein that forms a pore in the membrane and allows a specific ion to diffuse along its gradient 2.) Carried - via a membrane cotransporter protein with another ion that diffuses along its electrochemical gradient 3.) Pumped - pumped against an electrochemical gradient by a membrane protein that hydrolyzes adenosin triphosphate (ATP)

What are the steps of releasing of a neurotransmitter?

1.) action potential arrives near synaptic cleft. 2.) voltage gated calcium channels open. calcium enters presynaptic cell. 3.) synaptic vesicles fuse with presynaptic membrane, then release neurotransmitter. 4.) ion channels in the postsynaptic membrane open when neurotransmitter binds; flow of ions causes change in postsynaptic cell potential. 5.) ion channels in the postsynaptic membrane then close as neurotransmitter is broken down or taken back up by presynaptic cell.

what is the ion ratio for the sodium/potassium pump?

3 sodium ions out of cell and 2 potassium ions in. It ensures that eventually the concentration of potassium is much higher on the inside of the plasma membrane than outside, while concentration of sodium is lower inside than out.

A skeletal muscle deprived of adequate ATP supplies will _____. A) enter a state where actin and myosin are unable to separate B) release all actin-myosin bonds C) immediately relax D) fire many more action potentials than usual and enter a state of "rigor" E) sequester all free calcium ions into the sarcoplasmic reticulum

A

During an action potential, why is there a positive feedback loop for the opening of sodium channels? A) To rapidly depolarize the membrane B) To rapidly repolarize the membrane C) To trigger the closing of potassium channels D) To quickly diminish the signal

A

How does myelination affect the propagation of an action potential? A) It speeds propagation because cations do not leak out of the membrane as they spread down the axon B) It slows down propagation because Na+ channels exist only at unmyelinated nodes (nodes of Ranvier). C) It speeds propagation by increasing electrochemical gradients favoring Na+ entry. D) It speeds propagation by increasing the density of voltage-gated channels.

A

If a sprinter began an endurance running program, which of the following would occur? A) Some fibers would develop a higher mitochondrial density. B) Some slow fibers would become fast fibers. C) Some fibers would develop a lower mitochondrial density. D) Some fast fibers would become slow fibers.

A

In muscle cells, myosin molecules continue moving along actin molecules as long as A) ATP is present and intracellular Ca2+ is high. B) ADP is present and tropomyosin is released from intracellular stores. C) ATP is present and troponin is not bound to Ca2+. D) ADP is present and intracellular acetylcholine is high.

A

The middle ear converts _____. A) air pressure waves to fluid pressure waves B) air pressure waves to nerve impulses C) pressure waves to hair cell movements D) fluid pressure waves to air pressure waves E) fluid pressure waves to nerve impulses

A

The perceived pitch of a sound depends on _____. A) which region of the basilar membrane was set in motion B) which part of the oval window produces waves in the cochlear fluid C) which part of the tympanic membrane is being vibrated by sound waves D) whether or not the listener has had training in music E) whether or not the sound moves the incus, malleus, and stapes

A

What is similar between endoskeletons and exoskeletons? A) Both attach to muscle to transmit muscle forces. B) Both are made up of chitin. C) Both are composed of calcium phosphate. D) Both occur on the inside of the organism.

A

What is the relationship between the size of brain area devoted to a body part and that body part? A) Proportionate to the sensitivity of the body part B) No relationship between the two C) Proportionate to the size of the actual body part D) It reflects an evolutionary relationship in which each body part with older traits has more space devoted to it.

A

What is the relative energy expense of galloping rather than trotting at 3.5 m/s? A) Trotting uses only 75 percent of the energy as galloping. B) Galloping is twice as costly energetically. C) Galloping is 400 times more efficient than trotting. D) Galloping is half as costly energetically.

A

Where on the figure do potassium channels begin to open up? A) At the peak of the depolarization phase B) At the base of the depolarization phase C) At the hyperpolarization phase D) During the resting potential

A

Which of the following is a muscular hydrostat? A) human tongue B) sponge spicule C) grasshopper leg D) lobster shell

A

Which of the following is the correct sequence that describes the excitation and contraction of a skeletal muscle fiber? 1. Tropomyosin shifts and unblocks the cross-bridge binding sites. 2. Calcium is released and binds to the troponin complex. 3. Transverse tubules depolarize the sarcoplasmic reticulum. 4. The thin filaments are ratcheted across the thick filaments by the heads of the myosin molecules using energy from ATP. 5. An action potential in a motor neuron causes the axon to release acetylcholine, which depolarizes the muscle cell membrane. A) 5 → 3 → 2 → 1 → 4 B) 2 → 1 → 3 → 5 → 4 C) 2 → 3 → 4 → 1 → 5 D) 1 → 2 → 3 → 4 → 5 E) 5 → 3 → 1 → 2 → 4

A

Why would the breast meat of a pigeon consist of dark meat? A) It is composed of slow muscle fibers. B) It is composed of intermediate muscle fibers. C) It is composed of smooth muscle. D) It is composed of fast muscle fibers.

A

If the flexor muscle of an antagonistic muscle group is injured, which of the following actions would the person have a problem performing? A) Kicking a ball B) Throwing a punch C) Doing a situp D) Doing a shoulder press E) None of the above

A The flexor is the muscle that pulls bones closer together, decreasing the joint angle between them. The abdominal muscles are paired with muscles in the lower back and contracting them decreases the angle between the spine and hips.

Johnny was playing hockey when he got hit in the head with a puck. When he woke up in the hospital he had a hard time producing any speech. Which of the following areas of the brain can you immediately determine is NOT responsible for Johnny's inability to speak? a. Occipital lobe b. Temporal lobe c. Cerebellum d. Frontal lobe e. I do not know

A The occipital lobe functions as the visual processing area of the brain and is not involved in speech production. It can therefore be immediately eliminated as the site of language-inhibiting brain damage. The other three options are all involved in language production in some way and if damaged, could affect speech production. The temporal lobe is involved in language comprehension and some memory functions. The frontal lobe allows for conscious higher order thoughts and is the site of Broca's area, which is linked to speech production. The cerebellum coordinates complex motor patterns, which is essential for the motor control of speech production.

Which of the following correctly outlines the steps of an Action Potential? a. Resting Potential - Graded Potential - Depolarization - Repolarization - Hyperpolarization b. Resting Potential - Depolarization - Graded Potential - Hyperpolarization - Repolarization c. Action Potential - Graded Potential - Hyperpolarization - Resting Potential - Repolarization d. Repolarization - Action Potential - Graded Potential - Hyperpolarization - Resting Potential e. I do not know

A Cells that are not currently communicating with other cells are usually in a state of equilibrium at a particular electrochemical gradient called the resting potential. At resting potential, cells are polarized with a more negative charge on the inside of the cell than on the outside. This polarization is maintained by various ion channels and pumps. Thus, the resting potential is the neutral phase of a cell and it can be considered the first step before an action potential occurs. When a cell is sufficiently stimulated, it can communicate with other cells via action potentials, which are rapid, temporary changes in the cell's membrane potential. Action potentials only occur if the cell is depolarized past a certain point. This initial depolarization can happen with a sufficiently large graded potential. Once the graded potential stimulates an action potential, the action potential occurs in three steps: further depolarization of the membrane so that the inside of the cell becomes positive, repolarization of the cell back towards a negative value, and hyperpolarization of the cell to an even more negative value than the resting potential. Following hyperpolarization, the cell then returns to the resting potential from which a new action potential could be triggered.

Gastrulation generates a body plan with three primary germ layers. Which of the following correctly describes the germ layer arrangement, moving from inside to outside? a. Endoderm, Mesoderm, Ectoderm b. Mesoderm, Endoderm, Ectoderm c. Ectoderm, Mesoderm, Endoderm d. Ectoderm, Endoderm, Mesoderm e. I do not know

A Endo refers to inner. Ecto refers to outer. Meso refers to middle. Endoderm is the inner germ layer. Ectoderm is the outer germ layer. Mesoderm is between the endoderm and ectoderm.

The hair cells in the mammalian ear respond to pressure waves caused by sound. What kind of receptor are these hair cells and what happens to the membrane potential of the hair cell when a sound is perceived? a. Mechanoreceptors; they are depolarized, triggering an action potential b. Chemoreceptors; they are depolarized, triggering an action potential c. Chemoreceptors; they are hyperpolarized, triggering an action potential d. Mechanoreceptors; they are hyperpolarized, triggering an action potential e. I do not know

A Hair cells in the ear are mechanoreceptors because they respond to pressure waves that bend the stereocilia. When stereocilia are bent by the pressure wave, the hair cell depolarizes. This depolarization triggers an action potential that will be sent to the brain.

A drug increases the threshold potential of affected cells. What cell response would you expect to observe? drug_threshold a. The cell would signal less frequently than normal b. The cell's depolarization phase would be shorter than normal c. The cell's repolarization phase would be faster than normal d. The cell would no longer be functional e. I do not know

A If the threshold potential of a cell is increased, the likelihood of reaching it and triggering an action potential is decreased because a greater change in polarization is needed. This means the cell would signal less often than normal. Both the depolarization phase and repolarization phase would be the same length as normal because once the threshold potential is reached, the cell will repolarize at a certain voltage, usually around +40 mV. This concept can be visualized in the graph below.

Why is the muscle tense during rigor mortis? a. Lack of available ATP to relax the cross bridges b. Lack of available ADP to relax the cross bridges c. Abundance of ATP to contract the cross bridges d. Abundance of ADP to contract the cross bridges e. I do not know

A Rigor mortis occurs when muscle cells are locked in their contracted state, which on the molecular level occurs when myosin cannot release from actin. For myosin to release from actin, ATP needs to bind to the myosin head. In dead tissue, ATP is quickly used and cannot be regenerated, so the actin and myosin cross bridge becomes locked because there is no ATP available to release it.

The way that sound is received and processed in the ear could be likened to how a lipid-insoluble signal is received and processed by a cell. In this analogy, the behavior of the tympanic membrane in the outer ear is similar to __________, the behavior of the ossicles in the middle ear are comparable to __________, and the entire process of how changes in air pressure can be interpreted as sound is similar to __________. a. Signal reception; signal amplification; signal transduction b. Signal amplification; signal reception; signal transduction c. Signal transduction; signal amplification; signal reception d. Signal reception; signal transduction; signal amplification e. I do not know

A Sound waves enter the outer ear and cause the tympanic membrane to vibrate, which transfers the signal from the outer ear to the middle ear. This is similar to how a receptor protein binds to a signal and initiates signal transduction in the cell. The middle ear amplifies the sound waves through vibrations between the three ossicles, which is similar to the signal amplification that usually occurs in the cytosol of a cell. Finally, the entire process of how changes in air pressure can be converted into vibrations of the tympanic membrane and ossicles, then converted to vibrations in the fluid of the inner ear, and are eventually detected by mechanoreceptors that send neural signals to the brain is similar to the complicated path of signal transduction in the cell, which allows an extracellular ligand to eventually lead to changes in gene expression.

A disease targets the parasympathetic nervous system and inhibits the release of acetylcholine in the digestive system. What effect would you expect to see in the muscles in this area? a. A decrease in smooth muscle contraction b. An increase in smooth muscle contraction c. A decrease in skeletal muscle contraction d. An increase in skeletal muscle contraction e. I do not know

A The digestive system is composed of smooth muscle, which is unstriated, involuntary, and uninucleate. The parasympathetic nervous system allows the body to rest and digest. When it releases acetylcholine, the smooth muscle responds by increasing muscle contraction. If acetylcholine is inhibited, contraction would decrease, resulting in slower digestion.

Generally, which of the following tasks may be difficult for someone with severe damage to the left frontal lobe? a. Understanding and producing speech b. Nonverbal memories c. Facial recognition d. Processing visual cues e. I do not know

A The frontal lobe of the left cerebral hemisphere contains Broca's area, which is directly involved in producing speech, so of the four choices, this is the most likely capability to be affected. The temporal lobes on both sides of the brain are involved in memory, including nonverbal memories and facial recognition. Visual cues are processed in the occipital lobes.

The voltage-gated sodium (Na+) channels along the axon of a neuron have been damaged so that the inactivation gate is non-functional. Which of the following statements does not accurately describe the state of the neuron? a. The membrane potential will be extremely hyperpolarized b. The neuron will no longer have a refractory period c. The action potential will travel bi-directionally down the axon d. The membrane potential will remain above threshold e. I do not know

A The inactivation gate is what blocks more Na+ ions from entering the neuron after the action potential occurs. Once the inactivation gates close, the cell hyperpolarizes by opening the K+ channels. If the inactivation gate is damaged, then the refractory period will not occur and the cell will be unable to repolarize. The action potential will travel bi-directionally through the axon because of the diffusion of the ion movements in the cell which will continually trigger the Na+ channels that are unable to be inactivated. The membrane potential will remain depolarized in the neuron, causing the cell to remain above threshold.

The statocyst system is most like which of the following in mammals? a. Semicircular canals b. Cochlea c. Auditory nerve d. Basilar membrane e. I do not know

A The statocyst system can be found in crabs and is involved in detecting pressure changes caused by gravity. It consists of fluid-filled chambers and mechanoreceptors. This allows the crab to sense where it is in space and the orientation of its body. Similarly, semicircular canals are structures in the ears of mammals that are filled with fluid and have mechanoreceptors that can sense changes in body orientation as the fluid moves against the receptors.

PTC is a molecule that causes a bitter taste, but only in people who have a functional copy of the gene necessary to code for a protein that receives the molecule. Approximately 25% of Americans cannot sense the molecule. If it is evolutionarily advantageous to taste PTC and there was a similar protein-receptor and corresponding gene in squirrels, what would scientists expect to see in the squirrel population? a. Squirrels with the gene survive and reproduce more often b. Squirrels without the gene survive and reproduce more often c. Squirrels with the gene and squirrels without the gene survive and reproduce equally efficiently d. The effect of the gene cannot be predicted e. I do not know

A There are many genes devoted to detecting bitterness because the molecules that cause bitter tastes are found in many toxic plants. Animals that are better at detecting bitterness are more adaptive and produce more offspring than animals who are not able to do so.

If a drug prevents calcium ions from binding to troponin, what would be the result? a. Myosin head cannot bind to actin b. Myosin head cannot release from actin c. ATP cannot bind to a myosin head d. Nothing changes. Calcium is not involved in muscle contraction or relaxation e. I do not know

A Troponin and tropomyosin are proteins that form part of the thin filament in muscle cells. They work together to block sites on actin that would otherwise be able to bind to myosin and participate in muscle contraction. In order for contraction to occur, calcium ions bind to troponin, which then causes a conformation change that moves tropomyosin away from the myosin-binding sites. If calcium ions were unable to interact with troponin, there would be no way to move the tropomyosin away from the binding sites and myosin would be unable to bind to actin

Many human muscles are organized in antagonistic pairs, including the biceps brachii and the triceps brachii in the upper arm. If an individual flexes their forearm (bends their elbow), what is true about the state of the biceps and triceps muscles after this movement? a. The biceps would be contracted and the triceps would be relaxed b. The biceps would be relaxed and the triceps would be contracted c. Both the biceps and triceps would be relaxed d. Both the biceps and triceps would be contracted e. I do not know

A When the elbow bends and the forearm is flexed, the biceps muscle must contract (or shorten). Since the triceps is antagonistic to the biceps, the triceps will relax to compensate for the contraction of the biceps.

Positive feedback?

An occurrence of an event that makes the same vent more likely to recur. Ex: opening of sodium channels

A patient is hospitalized with muscle spasms caused by failure of back muscles to relax after contraction. Which of the following would be most likely to help? A) Depolarize the motor neurons to send an action potential to the muscle cells. B) Induce tropomycin and troponin to bind to the myosin binding sites on actin. C) Increase the amount of acetylcholine at the synapses between motor neurons and muscle cells. D) Inject calcium into the muscle cell, because it is not being released from the sarcoplasmic reticulum.

B

A person able to hear only high-frequency sounds would probably have which of the following structural problems in the ear? A) The ear ossicles are abnormally thickened. B) The basilar membrane is stiffened along its entire length. C) The tympanum is damaged because of chronic ear infections. D) All of these problems could result in inability to detect low-frequency sound.

B

Depolarization of hair cells in the mammalian ear results from increases in intracellular concentrations of what ion? A) chloride B) potassium C) calcium D) sodium

B

How does summation operate in a post-synaptic cell? A) It adds up all of the previous action potentials and releases one of that value. B) Input from many cells is required for it to fire. C) Post-synaptic cells do not fire. D) Sodium ions are moved from one cell to the next in an additive way.

B

How would an abnormally large oval window in a mouse affect that animal's hearing? A) The mouse could detect noise at much lower volumes. B) Hearing ability would be reduced in comparison with normal mice. C) The mouse could detect noise in a much broader range of frequencies. D) Hearing is not affected by the size of the oval window.

B

How would hearing be affected by a punctured eardrum? A) Only low-pitched sound could be heard. B) Hearing loss would occur at all pitches. C) Only high-pitched sound could be heard. D) No noticeable impact to hearing would occur.

B

Motor neurons release the neurotransmitter acetylcholine (ACh) and acetylcholinesterase degrades ACh in the synapse. If a neurophysiologist applies onchidal (a naturally occurring acetylcholinesterase inhibitor produced by the mollusc Onchidella binneyi) to a synapse, what would you expect to happen? A) gradual loss of resting potential B) convulsions due to constant muscle stimulation C) paralysis of muscle tissue D) decrease in the frequency of action potentials E) no effect

B

The structure pictured in the figure is found in _____. A) smooth muscles and cardiac muscles B) cardiac muscles and skeletal muscles C) skeletal muscles and smooth muscles D) smooth muscles E) smooth muscles, skeletal muscles, and cardiac muscles

B

What might be a reason a soldier with an amputated arm might experience phantom limb pain? A) The experience is purely psychological. B) Sensory neurons previously associated with the limb fire action potentials associated with pain. C) The body develops proprioceptors to compensate for the missing limb. D) Sensory neurons previously associated with the limb are damaged.

B

What might occur to an animal with an untreated lesion on its brain stem? A) Reduced memory B) It would likely die. C) Reduced physical movements D) Reduced cognitive ability

B

What would occur if the uptake of calcium ions was blocked in the sarcoplasmic reticulum? A) Sustained muscle relaxation B) Sustained muscle contraction C) Quicker repolarization of cell membrane D) Blocked reuptake of acetylcholine

B

Both smooth and cardiac muscles are involuntary muscles that are controlled by the peripheral nervous system. One function smooth muscle has is to control the size of airways in the lungs by constricting to make them smaller or relaxing to make them larger. Recalling that the sympathetic nervous system controls the "fight-or-flight" response, what muscular responses would you expect to see when sympathetic neurons release norepinephrine and epinephrine to the lungs and heart? a. Increased smooth muscle contraction in the lungs and decreased cardiac muscle contraction b. Decreased smooth muscle contraction in the lungs and increased cardiac muscle contraction c. Increased contraction in both smooth muscle of the lungs and cardiac muscle d. Decreased contraction in both smooth muscle of the lungs and cardiac muscle e. I do not know

B Muscle cells respond differently to the same neurotransmitter depending on what receptors they have. When norepinephrine and epinephrine are released, smooth muscle contraction can decrease in some areas, which results in relaxed airways and slowed down digestion, among other things. However, in the presence of the same neurotransmitters, cardiac muscle has an opposite response, increasing contraction rate, in order to increase the amount of blood pumped throughout the body.

What is scanned when the retina is analyzed using a fundoscope? a. The point of the fovea b. The blood vessel patterns c. The neuronal patterns d. The depth of the retinal layers e. I do not know

B A fundoscope, or opthalmoscope, is shone into the eye through the pupil and used to detect the health of the retina in eye examinations. If you've ever been to the eye doctor, this is what they use when they shine a very bright light in your eye and sometimes they dilate your pupils before using it. The main structures that can be seen in fundoscopy are the blood vessels supplying the retina, the optic disc (where the optic nerve leaves the eye), and the macula lutea (the location of a large concentration of cones). Therefore, b is the best choice. The other characteristics in a, c, and d cannot be seen that well using the fundoscope.

The resting potential of a neuron is -70mV. You record a neuron with a membrane potential of -90mV. Which statement correctly describes the ion movement that is responsible for the increased negative potential? a. Excess Cl- moving out of the cell b. Excess K+ moving out of the cell c. Excess Na+ moving into the cell d. Excess K+ moving into the cell e. I do not know

B As K+ ions move out of the cell, the membrane potential repolarizes, or becomes more negative, because positive charges are moving out of the cell. If either excess K+ or Na+ ions moved into the cell, the membrane potential would depolarize (become closer to zero) because positively charged atoms would enter the cell. If excess Cl- ions moved out of the cell, it would have the same depolarizing effect on the cell as K+ and Na+ ions moving into the cell.

SSRIs, a common type of antidepressant drug, function by preventing the reabsorption of the neurotransmitter serotonin. This leads to a high concentration of serotonin in the synaptic cleft. Which of the following is a probable result of this drug? a. An increase in presynaptic neuron signaling b. An increase in postsynaptic neuron function c. A decrease in presynaptic neuron signaling d. A decrease in postsynaptic neuron function e. I do not know

B Because the neurotransmitter is in the synaptic cleft for a longer time, more serotonin molecules will bind to the receptors on the postsynaptic neuron. This would stimulate a response from the postsynaptic neuron.

The toxin carried by a venemous snake binds to and blocks the Ca2+ voltage-gated channels in neurons. If someone were bitten by this snake, which step in neural signaling would this interfere with? a. The propagation of an action potential down the axon b. The release of neurotransmitters into the synaptic cleft c. The reuptake of neurotransmitters into the presynaptic cell d. Neural signaling would be unaffected e. I do not know

B Ca2+ voltage-gated channels open in response to an action potential reaching the end of an axon. Ca2+ would then move into the cell, which would trigger the fusion of synaptic vesicles with the cell membrane and neurotransmitter would be released into the synaptic cleft. If the Ca2+ voltage-gated channels were blocked, Ca2+ would not be able to enter the cell and neurotransmitter could not be released.

Joey was given a sample of muscle but is unable to identify the muscle type. Joey was able to tell you that the sample appears striated with branches and intercalated discs. Based on this information, what type of muscle did the sample likely come from? a. Skeletal muscle b. Cardiac muscle c. Smooth muscle d. There is not enough information provided to identify the muscle type e. I do not know

B Cardiac muscle cells are striated, similar to skeletal muscles, but they can be distinguishes by their unique branching pattern and intercalated discs. Smooth muscle cells are not striated.

The states of the sodium and potassium voltage-gated channels can be classified as open, closed, or inactivated. These channels change between states as a neuron fires and recovers from an action potential. Which of the following statements correctly identifies the state of the sodium and potassium voltage-gated channels during and immediately following the peak of an action potential (position 3 in the diagram)? SP a. Sodium channels closed, potassium channels open b. Sodium channels inactivated, potassium channels open c. Sodium channels inactivated, potassium channels closed d. Sodium channels open, potassium channels open e. I do not know

B During the build-up to an action potential, sodium channels are open and potassium channels are closed. Once the action potential reaches its peak, the sodium channels inactivate (this is what accounts for the refractory period) and potassium channels open in order to repolarize the neuron.

A mutation is present in the gene coding for tropomyosin, so that the protein cannot be made. What would be the result in the muscle cells with this mutation? a. The myosin binding sites on actin would never be exposed b. The muscle cells would be able to contract without calcium ions present c. The muscle cells would only be able to contract when calcium ions are present d. The sarcoplasmic reticulum would be unable to release calcium ions in response to an action potential e. I do not know

B If tropomyosin is not present in the cell, then it would be unable to form a complex with troponin to cover up the myosin binding sites on actin. Since the binding sites would remain exposed, the muscle fiber would not have to rely on the presence of calcium to allow for a muscle contraction.

Some animals, such as owls and cats, are able to see much more easily in the dark. This is partly due to a higher number of __________ cells compared to humans. a. Ganglion b. Rod c. Cone d. Bipolar e. I do not know

B Rods are sensitive in dim light but do not process color. An excess number of rods enable nocturnal animals to collect as much light as possible and see in what we perceive as complete darkness.

During an examination, ophthalmologists will sometimes dilate patients' eyes in order to view the retina in the back of the eye. Which of the following is a possible mechanism of dilating drops? The drops: a. Cause the cornea to contract b. Inhibit the ability of the iris to expand c. Cause the retina to enlarge d. Inhibit the ability of the lens to stretch e. I do not know

B The amount of light coming into the pupil is regulated by the iris. The iris has two sets of smooth muscles, and depending on which set contracts, the pupil is dilated or constricted. In order to see through to the back of the eye, the pupil needs to remain dilated, even when a bright light is shone into it. Dilating drops inhibit the activity of the smooth muscle group that would normally cause the iris to expand and the pupil to constrict. This would allow more light in to the eye to visualize the retina and optic nerve.

A farmer is worried that his cattle may be infected with BSE (Bovine Spongiform Encephalopathy) and wants them to be tested. What would be the least invasive measure he could use and what would be the observed result if the cattle were infected with BSE? a. Perform a brain biopsy where you would observe protein build-up and neurodegeneration b. Perform an electroretinography where you would observe decreased retinal thickness c. Perform an electroretinography where you would observe protein build-up in the retina d. There is no way to measure whether or not the cows are infected; you have to wait until they start showing behavioral symptoms of the disease e. I do not know

B The electroretinography has been shown to be a significantly good predictor of cattle who are infected with BSE. This method of diagnostics is also much less invasive than a brain biopsy.

Which of the following correctly pairs anatomy with function with respect to the human brain? a. Cerebrum - relay sensory information and control homeostasis b. Cerebellum - coordinate complex motor patterns c. Diencephalon - divided into two hemispheres and makes up bulk of the brain d. Brain Stem - involved in conscious thought and memory e. I do not know

B The following describes the functions of the cerebrum, diencephalon, and brain stem: The cerebrum is involved in conscious thought and memory; structurally, it is divided into two hemispheres and makes up the bulk of the brain. The diencephalon relays sensory information and controls homeostasis. The brain stem regulates cardiovascular, digestive, and other involuntary functions.

Many prion diseases are linked to which type of change in the protein, causing it to become infectious? a. A primary structure change - amino acid change b. A secondary structure change - mis-folding of the protein into sheets or helices c. A tertiary structure change - breaking of bonds between the amino acid R-groups d. A quaternary structure change - faulty interactions between subunits of the protein e. I do not know

B The formation of the infectious prion protein is due to a propagation of a misfolded protein that accumulates in the nervous system. Typically these folding changes will result in a protein changing from an alpha-helix to a beta sheet or vice versa.

Researchers have learned about the brain by studying the effects of brain damage in different patients. These lesion studies suggest that: a. The effect of damage cannot be predicted because function is spread across the brain randomly b. Specific areas of the brain perform specific functions c. Brain damage can only be assessed postmortem d. There is no effect unless the corpus callosum is severed e. I do not know

B Using lesion studies, researchers observed the effects of damage and extrapolated information about what that area of the brain controlled. One example discussed in the book was the example of Phineas Gage, who survived an iron rod entering his frontal lobe. After his accident, his personality and emotions changed dramatically, suggesting that the frontal lobe is in charge of those functions.

When Jane bumps her elbow, she rubs it to dull the pain. This tells us that touch-sensing neurons and pain-sensing neurons are interacting. Which of the following best describes what is happening to the nerves in Jane's elbow? a. Pain neurons are producing IPSPs on Touch neurons b. Touch neurons are producing IPSPs on Pain neurons c. Pain neurons are producing EPSPs on Touch neurons d. Touch neurons are producing EPSPs on Pain neurons e. I do not know

B When Jane bumps her elbow, pain-sensing neurons send signals to her central nervous system that are interpreted as a sharp pain. Because the rubbing her elbow dulls the pain, we can infer that the neurons sensing the touch of her hand are counter-acting the signal of pain being sent by her pain-sensing neurons. This would have to be done via IPSPs (inhibitory postsynaptic potentials), because they cause a change in the postsynaptic cell (pain cell) that makes it more negative. By making the postsynaptic cells more negative, it makes it harder for the cell to reach the threshold value that would stimulate an action potential, so less pain signals would reach Jane's central nervous system. An EPSP (excitatory postsynaptic potential) has the opposite effect of an IPSP. It would make the membrane potential of the pain-sensing neurons more positive and therefore it would be easier to stimulate action potentials.

Neurotransmitters are dispersed in packets called vesicles. We find a drug which prevents calcium ions from interacting with vesicles inside the neuron. What can we expect to observe? a. More vesicles would be released b. Fewer vesicles would be released c. Neurotransmitter levels in the presynaptic cell would be reduced d. Calcium doesn't interact with vesicles, so the neuron functions normally e. I do not know

B When an action potential reaches the end of an axon, voltage-gated ion channels are opened to allow Ca2+ to enter the presynaptic cell. These calcium ions increase the concentration of calcium in the axon, which signals vesicles containing neurotransmitter to fuse with the presynaptic membrane and release the neurotransmitter in the synaptic cleft. Therefore, if calcium cannot interact with the vesicles, it would be unable to signal the fusion of the vesicles with the membrane and fewer vesicles would be released.

Why are action potentials propagated in one direction?

Because upstream sodium channels, in the direction of the cell body, are in the refractory state.

A muscle that swings two long bones in an arc toward each other is a ______, and an example is the ______. A) extensor; quadriceps B) extensor; hamstring muscle C) flexor; hamstring muscle D) flexor; quadriceps

C

All skeletal muscle fibers are _____. A) smooth and under involuntary control B) smooth and operate independently of other skeletal muscle fibers C) striated and under voluntary control D) striated and electrically coupled to neighboring fibers E) smooth and under voluntary control

C

Cardiac muscle cells are both _____. A) smooth and under involuntary control B) striated and under voluntary control C) striated and interconnected by intercalated disks D) striated and operate independently of other cardiac cells E) smooth and under voluntary control

C

Considering that sounds and odors both trigger changes in the patterns of action potentials from sensory cells, how does the brain perceive which sense is which when the action potentials reach the brain? A) Mechanoreception is not consciously perceived by the brain, whereas chemoreception is. B) Chemoreception is not consciously perceived by the brain, whereas mechanoreception is. C) The axons from different sensory neurons go to different areas of the brain. D) The action potentials stimulated by sounds are different in size and shape from those stimulated by an odor.

C

In terms of signaling, what is most significant about action potentials? A) The magnitude B) The number of partial action potentials C) The frequency D) The number of phases

C

Mechanoreceptors that react to changes in pressure are part of the _____. A) human sense of smell B) pain receptors in birds C) lateral line systems in fish D) human sense of taste E) eyes in arthropods

C

Predict the effect on heart rate of a drug that activates sympathetic nervous system activity. A) decrease heart rate B) heart rate would be without changes C) increase heart rate

C

The depolarization phase of an action potential is characterized by _____. A) active transport of sodium out of the cell B) active transport of sodium into the cell C) diffusion of sodium into the cell D) diffusion of sodium out of the cell

C

What would occur if neurons simultaneously stimulated both the biceps and triceps muscles to contract? A) The forearm would move towards the body. B) The forearm would alternate moving toward and away from the body. C) The forearm would not move. D) The forearm would move away from the body.

C

Which of the following is critical to the function of most exoskeletons, endoskeletons, and hydrostatic skeletons? A) Muscles attach to each of these types of skeleton via tendons. B) Segments of the body or limbs are extended when paired muscles relax in unison. C) Muscles interact with the skeleton in antagonistic groups. D) Muscles extend joints by pushing skeletal elements.

C

Which of the following parts of the brain is involved in coordination of motor patterns? A) diencephalon B) brain stem C) cerebellum D) cerebrum

C

Why is memory thought to involve changes in particular synapses? A) When researchers stimulated certain neurons electrically, individuals replayed memories. B) People who lack short-term memory have specific deficits in synapses within the brain regions responsible for memory. C) In some systems, an increased release of neurotransmitters occurs after learning takes place. D) In some systems, the type of neurotransmitter released at the synapse changes after learning takes place.

C

In Dr. Greenlee's findings, what was true about the retinas of cows after exposure? a. The retinas were unchanged b. The retinas were noticeably thicker c. The retinas were noticeably thinner d. The retinas were porous and damaged e. I do not know

C Bovine spongiform encephalopathy (BSE) is a type of prion disease, in which misfolded proteins accumulate in the central nervous system. Dr. Greenlee's team is trying to detect BSE in cows as early as possible through examination of the retina, because the retina is one of the most accessible parts of the central nervous system and is therefore relatively easy to examine. Dr. Greenlee's team found several changes in the retinal function and morphology of cows with BSE, including a significant thinning of the retina relative to healthy cows.

A marine animal able to detect miniscule movements of other animals in the area most likely has a highly sensitive __________ sensory system. a. Olfactory b. Thermoreception c. Electroreception d. Magnetoreception e. I do not know

C Nerves and muscles in animals give off weak electrical impulses that can be detected by animals that can sense electric fields. Many fish use electroreception to detect prey or predators since water is a good conductor of electrical impulses.

After a long winter, spring promises longer days with more sun and warmer weather. One day, you walk outside and feel the heat of the sun and think that it would be a great day for a run. When thinking about the nervous system, the __________ allows you to sense the sunlight and the __________ allows you to go for a run. a. Afferent division; sympathetic nervous system b. Efferent division; parasympathetic nervous system c. Afferent division; somatic nervous system d. Efferent division; autonomic nervous system e. I do not know

C The peripheral nervous system can be divided into afferent and efferent divisions. The afferent division monitors conditions inside and outside of the body, transmitting information to the central nervous system. The afferent division would allow you to tell that the sun is shining and it is warm outside. The efferent division sends signals from the central nervous system to the peripheral nervous system. It can be divided into the somatic nervous system and the autonomic nervous system. The somatic nervous system controls voluntary moments, such as running. The autonomic nervous system controls involuntary, internal processes.

Would you expect to see a difference in the ratio of fast twitch and slow twitch skeletal muscle fibers in a sprinter after they spent a year training for the Olympics? a. Yes, the sprinter would have more fast twitch muscle fibers (converted from slow twitch fibers) after training because they would allow the sprinter to run faster b. Yes, the sprinter should have more slow twitch fibers (converted from fast twitch fibers) after training because they would allow a greater endurance during aerobic exercise c. No, the sprinter should have the same ratio of slow twitch and fast twitch fibers after training because this ratio is genetically determined and one type cannot be converted into the other type d. No, the sprinter should have the same ratio of slow and fast twitch fibers after training because it takes much longer than a year to convert one type of fiber to the other type e. I do not know

C Although skeletal muscle fibers can increase in efficiency through training--by increasing the density of blood vessels, mitochondria, and myoglobin--they cannot be converted from fast twitch to slow twitch or vice versa. The ratio of fast twitch to slow twitch muscles can vary from person to person, but within a person this ratio is genetically determined.

Why are Alzheimer's disease and Parkinson's disease considered to be prion-like diseases? a. They can be spread to other organisms through direct contact, like prion diseases b. They are only seen in elderly individuals, which is when prion diseases are most commonly observed in humans c. They deal with misfolded protein accumulation causing neurodegeneration, which is characteristic of prion diseases d. Scientists believe that Alzheimer's disease and Parkinson's disease are caused by the exact same proteins that act as infectious agents in prion diseases e. I do not know

C Alzheimer's disease is characterized by plaque build-up due to the misfolded amyloid-beta in the brain causing neurodegeneration. Parkinson's disease is characterized by misfolded alpha-synuclein protein that causes neurodegeneration in specific areas of the brain. The characteristic that both of these diseases have in common is that they all deal with misfolded proteins accumulating in some areas of the brain, resulting in neurodegeneration.

In the video we watched in class, what are researchers in Australia looking for in patients who took the plant extract supplement? a. Flourescence indicating healthy retinal neurons b. Flourescence indicating the presence of alpha synuclein c. Flourescence indicating the presence of amyloid beta plaques d. Flourescence indicating the presence of macular degeneration e. I do not know

C Amyloid beta plaques are proteins that become folded into the wrong shape and are involved specifically in Alzheimer's disease. Amyloid beta plaques contain a cross-beta sheet structure that can be detected using fluorescence when patients ingest a plant substance containing cumin. This test allows doctors to diagnose a patient with Alzheimer's disease up to 17 years before the patient shows any symptoms.

Which of the following steps is associated with the Repolarization point in the Action Potential sequence? a. Opening of Na+ Channels and closing of Ca++ Channels b. Opening of Ca++ Channels and closing of K+ Channels c. Closing of Na+ Channels and opening of K+ Channels d. Closing of Ca++ Channels and opening of Na+ Channels e. I do not know

C During depolarization, Na+ voltage-gated ion channels are open and the influx of sodium ions into the cell causes it to become positively charged. When the cell repolarizes, it becomes more negative. This is accomplished by shutting the Na+ voltage-gated channels to prevent further positive charge entering the cell and opening K+ voltage-gated channels. The concentration of K+ is much greater in the cell than outside of it, so potassium ions flow out of the cell when the channels are open, which allows the cell to become more negative.

Which of the following statements about excitatory postsynaptic potentials (EPSPs) and inhibitory postsynaptic potentials (IPSPs) is NOT correct? a. They are graded potentials, not all-or-none events b. They can be induced by neurotransmitters c. They are long lasting because action potentials don't always occur d. Summation refers to the additive nature of EPSPs and IPSPs e. I do not know

C EPSPs and IPSPs are not long lasting because the neurotransmitters inducing them do not bind irreversibly to the receptors and channels located on the postsynaptic cell. Since the neurotransmitters are either destroyed or endocytosed back into the presynaptic neuron they are typically short lived.

Which of the following is not true about the sliding filament model of muscle contraction? a. The thin and thick filaments slide past one another during contraction b. The length of the sarcomere shortens during contraction c. The thin (actin) filaments shorten during contraction because they are attached to a Z disk d. The thick (myosin) filaments interact with the thin (actin) filaments using their head subunit e. I do not know

C Even though the thin filaments are bound to the z disk on one end, the filament does not change length during contraction. Instead, the length of the sarcomere shortens when the thick (myosin) filaments pull the thin (actin) filaments toward the mid-line of the sarcomere.

Allison went to the dentist and had to get a cavity filled. Her dentist used lidocaine to numb Allison's mouth during the procedure but the numbness faded after a few hours. Using the information that lidocaine temporarily blocks voltage-gated Na+ channels from opening, you can infer that lidocaine induces anesthesia (temporary loss of sensation) by temporarily: a. Preventing hyperpolarization of the postsynaptic cell b. Causing neurotransmitters to remain in the synaptic cleft for a longer period of time c. Blocking action potentials from forming in the postsynaptic cell d. Causing a decrease in neurotransmitter release from the presynaptic cell e. I do not know

C If voltage-gated Na+ channels are blocked from opening, then the postsynaptic cells will not be able to sufficiently depolarize for an action potential to form. This means that the signal will not be propagated in the postsynaptic cell.

Which of the following is not a method of how learning and memory occur? a. Molecular and structural changes to synapses b. Changes to gene expression c. Production of amyloid plaques d. Neurogenesis e. I do not know

C Learning and memory have been shown to involve changes in the synapse (with experiments on the sea slug Aplysia), the formation of new neurons through neurogenesis (with experiments on song birds), and long-term memory is even involved in changes in gene expression. In contrast, the production of amyloid plaques around neurons is actually associated with memory loss and neurodegenerative disorders, such as Alzheimer's.

Which of the following statements is true about prion disease? a. Prions are contagious and can be spread through air particles b. Prion diseases only result from ingesting infected meat c. Prion diseases are typically fatal d. Prions are still a mystery to the scientific community so this question cannot be answered e. I do not know

C Many of the classic prion diseases, such as Creutzfeldt-Jakob disease (which is seen in humans), are fatal diseases and cause neurodegeneration leading to death. Prion diseases are not transmitted through air particles and are considered not contagious through normal human contact. They have been shown to be transmitted between humans, however, through medical injections or ingestion. Kuru (a prion disease) was a result of eating infected brain meat. Prion diseases are also likely caused by other infectious agents, which have not yet been identified.

Multiple sclerosis is a disease that affects the nervous system. One of the drugs used to treat the muscle spasms of multiple sclerosis activates the receptors of a specific neurotransmitter. This drug is likely to act on __________. a. The presynaptic cell b. The neurotransmitter released by the presynaptic cell c. The postsynaptic cell d. There is not enough information to determine the answer e. I do not know

C Neurotransmitter receptors are found on the postsynaptic cell across the synaptic cleft from the presynaptic cell. Since the drug in question deals with the receptor rather than the neurotransmitter it can be inferred that it is acting on the postsynaptic cell.

Which of the following describes the receptors that respond to painful stimuli? a. Mechanoreceptors b. Thermoreceptors c. Nociceptors d. Chemoreceptors e. I do not know

C Nociceptors detect harmful stimuli, which includes pain. Mechanoreceptors respond to pressure and other types of distortion. Thermoreceptors detect changes in temperature. Chemoreceptors respond to specific molecules, or chemicals.

Which of the following does not characterize slow muscle fibers? a. Abundance of myoglobin b. Slowly oxidize ATP c. Rapidly oxidize ATP d. High concentration of mitochondria e. I do not know

C Slow muscle fibers are a type of skeletal muscle fiber that contract relatively slowly but can work for a long time without tiring. They contract slowly because they hydrolyze ATP relatively slowly. They fatigue slowly because ATP is conserved in the muscle through the slow hydrolysis, but also because slow muscle fibers can generate ATP at a steady rate through aerobic respiration. This can be done due to the high concentration of mitochondria and high concentration of oxygen (supplied by myoglobin) that is necessary for aerobic respiration. (See Ch. 9 for a review on aerobic respiration.)

While you are stretching after a workout, you feel a pain in your leg and notice your muscle twitching occasionally. Which of the following tissues did you most likely injure? a. Ligament b. Cartilage c. Tendon d. Bone e. I do not know

C Tendons connect muscles to bone. If a muscle is over-stretched during physical activity, the connecting tendon may be stretched or torn as a result. Ligaments connect bone to bone and could be injured during an improper movement of a joint.

Some animals are adapted to be able to hear a wider range of sound waves than humans, such as infrasound or ultrasound. Which part of the ear is most likely adapted to be able to process these different wavelengths? a. Outer ear b. Middle ear c. Inner ear d. The ear would not have noticeable differences e. I do not know

C The basilar membrane in the inner ear has different sections that respond to different frequencies of sound. The part of the membrane that is stiffer responds to high-frequency sounds and the part that is more flexible responds to low-frequency sounds. Animals that are able to detect ultrasound would have a modified basilar membrane in the stiffer region that is better able to detect high frequency sounds and animals that are able to detect infrasound would have a longer basilar membrane with a larger area of the flexible region to detect low frequency sounds.

A procedure that has been performed on patients with severe epilepsy, a disease that causes seizures, is to remove small portions of affected brain tissue or in extreme cases, cut the brain so the two hemispheres cannot communicate. If a patient had an extremely severe case and required that the two hemispheres be disconnected, which of the following brain structures would be lesioned (cut)? a. Brain stem b. Cerebellum c. Corpus Callosum d. Diencephalon e. I do not know

C The corpus callosum is responsible for communication between the right and left hemispheres of the brain. The brainstem is responsible for autonomic control of the heart, lungs and digestive system. The cerebellum is responsible for coordination of complex movements. The diencephalon is responsible for controlling homeostasis.

Which of the following is the correct order of how sound is transmitted from the external environment to the auditory nerve in the mammalian ear? a. Tympanic membrane, ear ossicles, cochlea, oval window, ear canal b. Tympanic membrane, oval window, cochlea, ear canal, ear ossicles c. Ear canal, tympanic membrane, ear ossicles, oval window, cochlea d. Ear canal, tympanic membrane, cochlea, ear ossicles, oval window e. I do not know

C The sound waves enter the ear through the ear canal and reach the tympanic membrane first, causing it to vibrate. The vibration of the tympanic membrane will then cause the ear ossicles in the middle ear to vibrate. The ear ossicles amplify the vibration and pass it on to the oval window, which creates waves in the fluid-filled inner ear. In the inner ear, these waves pass through the cochlea and are detected by hair cells. Finally, the axons of the hair cells send signals to the auditory nerve.

What are potassium leak channels?

Channels that allow potassium to leak out of the cell for equilibrium potential.

Neurotransmitters

Chemical messengers that transmit info from one neuron to another neuron, or from a neuron to a target cell in a muscle or gland.

Action potentials are only propagated "downstream" (away from the cell body) because A) sodium ions only move upstream along the inside of the cell membrane. B) potassium channels upstream are refractory to action potentials. C) sodium ions only move downstream along the inside of the cell membrane. D) sodium channels upstream are refractory to action potentials.

D

Deafness caused by loud sounds often results from damage to which receptor cells? A) thermoreceptors B) electroreceptors C) chemoreceptors D) mechanoreceptors E) nociceptors

D

If a neurotransmitter opens an ion channel allowing chloride ions to leave the cell, what is the consequence? A) The cell remains static. B) More neurotransmitters are created. C) The neuron is being repolarized. D) The neuron is more likely to reach an action potential.

D

In a neuron, what creates the electrochemical gradient favoring the outflow of K+ when the cell is at rest? A) voltage-gated K+ channels B) voltage-gated Na+ channels C) ligand-gated Na+/K+ channels D) Na+/K+-ATPase

D

In a relaxed skeletal muscle _____. A) calcium is released from the sarcoplasmic reticulum B) sarcomeres are at their shortest length C) thick and thin filaments overlap to the greatest extent possible D) the Z lines are farthest apart

D

R. McNeill Alexander discovered that the arch of the human foot operates like a spring during running. Predict how a runner's oxygen consumption would change if a runner wore shoes that prevented the arches from changing shape. Part A Explain your reasoning. A) The oxygen consumption of the runner would not change. B) The oxygen consumption of the runner would decrease. C) The oxygen consumption of the runner would first decrease, than -- increase. D) The oxygen consumption of the runner would increase.

D

Research on the amnesiac patient Henry Gustav Molaison revealed the critical role of what brain region in learning and memory? A) brain stem B) diencephalon C) cerebellum D) cerebrum

D

The hydrostatic skeleton of the earthworm allows it to move around in its environment by _____. A) swimming with its setae B) walking on its limbs C) alternating contractions and relaxations of its flagella D) using peristaltic contractions of its circular and longitudinal muscles E) crawling with its feet

D

The transduction of sound waves into action potentials takes place _____. A) within the tectorial membrane as it is stimulated by the hair cells B) as the basilar membrane becomes more permeable to sodium ions and depolarizes, initiating an action potential in a sensory neuron C) as the basilar membrane vibrates at different frequencies in response to the varying volume of sounds D) when hair cells are bent against the tectorial membrane, causing them to depolarize and release neurotransmitter that stimulates sensory neurons E) within the middle ear as the vibrations are amplified by the malleus, incus, and stapes

D

What is a key mechanism behind learning and memory? A) An increased response of the parasympathetic nervous system B) Fewer connections between neurons C) Alterations to brain structure D) Changes in the number, sensitivity, and placement of synapses

D

Which of the following structures shortens when a muscle contracts? A) thick filaments B) the Z disk C) thin filaments D) sarcomeres

D

Most animals minimize the cost of movement by choosing different gaits at different speeds. Apply this idea to a student who is running late to class. In order to avoid running, the student speed-walks across campus at an unnaturally quick pace. Which of the following results would you expect to see if the student's oxygen consumption was measured? a. The student uses more energy speed-walking than he would have if he ran b. The student uses more energy speed-walking than he would have if he walked at a normal pace c. The student uses the same amount of energy speed walking as he would have if he walked at a normal pace d. Both A and B are possible e. I do not know

D In order to minimize energy cost during locomotion, many animals alter their gait at different speeds. For humans, we consider walking and running two different gaits. There is an optimum speed for each gait and outside of that speed, energy use increases. In this question, if forced to walk faster than the optimum speed, it may require even more energy than if you run, despite the idea that running uses more energy. This can be observed in the table below, adapted from McArdle (2000). Week_14_Img_17.png

During Jack's soccer game, he experienced a painful cramp in his calf muscle and had to be taken off the field. What was likely happening at the molecular level in his calf muscle during the cramp? a. An excess amount of ATP was causing ATP to be continually bound to the myosin head b. ATP was unable to hydrolyze to ADP and inorganic phosphate and therefore the power stroke could not occur c. ADP was unable to be released from the myosin head d. ATP was sufficiently depleted so that the myosin heads were "stuck" to the actin and unable to release e. I do not know

D ATP is required for the myosin head to release from the actin filament. Without ATP, the cross-bridge is maintained between the myosin and actin filaments, which causes a prolonged contraction of the muscle, also known as a cramp. Once Jack's ATP levels are able to reach normal levels in his muscle cells he will experience relief from the cramp.

A toxin damages the dendrites of a neuron. What would happen to that neuron's signaling? a. The cell's ability to receive and pass on signals would be unaffected b. The cell's ability to receive signals would be unaffected, but its ability to pass on signals would be greatly reduced c. The cell would be completely unable to receive or pass on signals d. The cell's ability to receive signals would be greatly reduced, and therefore it would pass on fewer signals to other cells e. I do not know

D Axons can synapse and pass signals on to both dendrites and cell bodies. Many of the synapses are located on the dendrites, so dendrites play a large role in collecting electrical signals from other neurons. If the dendrites are damaged, the cell's ability to receive signals would be greatly reduced, but some signals would still be received through the synapses on the cell body. If only the axon of the neuron was damaged, choice B would be the correct answer.

When a muscle is at rest, Ca++ ions are concentrated within the spaces of the: a. Actin filaments b. Myosin filaments c. Z line d. Sarcoplasmic reticulum e. I do not know

D Calcium ions are necessary for muscle contraction because they bind to the troponin-tropomyosin complex and remove it from the myosin-binding sites on actin. Therefore, when the muscle is at rest, the calcium ions have to be in a separate region of the cell from the sarcomeres, which contain the actin and myosin filaments and the Z lines (Z discs). The Ca2+ ions are stored in the sarcoplasmic reticulum, which is a specialized form of smooth endoplasmic reticulum. When the muscle cell receives a signal from the central nervous system, action potentials reach the interior of the cell via specialized pockets of cell membrane, called T tubules. These action potentials trigger Ca2+ channels to open and calcium ions can then reach the sarcomeres and allow contraction.

Which of the following skeletal systems does not have antagonistic muscle groups? a. Hydrostatic skeletons b. Endoskeletons c. Exoskeletons d. None of the above e. I do not know

D Each of the skeletal systems uses paired, antagonistic muscle groups to enable movement. Hydrostatic skeletons use circumferential and longitudinal muscles to change the pressure of internal fluid and the shape of body segments. Endoskeletal and exoskeletal organisms use flexor-extensor muscle pairs to change the angle of joints, rather than the size of body parts themselves.

Despite the plethora of different foods available to us every day, scientists have simplified the sensation of taste down to four "basic tastes"-- salty, sour, bitter, and sweet. Which of the following best explains how it is possible that many different foods can result in the same taste sensation? a. Some chemoreceptors have a small number of receptor proteins that can bind to many different types of similar molecules, resulting in the same cell response b. All foods have the same basic molecules that produce the taste sensations c. Chemoreceptors can have many different receptor proteins for binding to different molecules, so a variety of molecules can stimulate the same chemoreceptor d. Both A and C are correct e. I do not know

D For bitterness, it is common for one taste cell to have many different receptor proteins on its plasma membrane so it can be depolarized by many different types of molecules. This is the condition described by choice c. For sweetness, many sugars are able to bind to the same kinds of receptor proteins on a chemoreceptor, which triggers an action potential within the cell. This is the condition described by choice a.

Consider the difference between cellular-level experiments and experiments on the brain as a whole. Lesion studies are similar to __________ experiments and electrical stimulation studies are similar to __________ experiments. a. Both are similar to loss-of-function experiments b. Both are similar to gain-of-function experiments c. Gain-of-function; Loss-of-function d. Loss-of-function; Gain-of-function e. I do not know

D Lesion studies observe what happens when something in the brain is not able to function properly, similarly to a loss-of-function experiment. The area of brain that is damaged is similar to the knocked-out gene. Electrical stimulation studies are similar to gain-of-function experiments because the researcher is adding stimulation to an area of the brain to observe the response.

Muscle contraction is caused by: a. The shortening of the actin filament b. The shortening of the myosin filament c. The actin filament pulling on the myosin filament d. The myosin filament pulling on the actin filament e. I do not know

D Muscle contraction occurs when the myosin heads of the thick filament bind to the actin contained in the thin filaments within a sarcomere, which is a functional unit of thick and thin filaments. Once this happens, the position of the myosin head can pivot through interaction with ATP and ADP. This positional change of the myosin head causes the thick filament (myosin) to pull on the thin filament (actin) and causes the filaments to slide past one another. In this way, the sarcomere can shorten, while the lengths of the thick and thin filaments stay the same.

Glial cells are responsible for providing nerve cells with a myelin sheath, which is a covering that wraps around the axon of a neuron. What is the primary benefit of having a myelinated axon? a. It gives the glial cells a job b. It makes the axons bigger, so they can do their job more efficiently c. It allows the sodium and potassium channels to be spread out along the length of the axon d. It allows the action potentials to move down the axon more efficiently by "jumping" to unmyelinated regions e. I do not know

D Myelination acts as insulation for a neuron, preventing unnecessary leaking of the ions across the axonal membrane. Myelinated axons have unmyelinated regions known as Nodes of Ranvier. These nodes are areas of concentrated sodium and potassium channels. By having specific areas for the channels, the action potential is able to "jump" from node to node down the axon to propagate the action potential. This allows the action potential to travel more quickly and efficiently, especially when the signal must be transmitted down a long axon.

Alpha-Bungarotoxin (a component of the venom of the Taiwanese banded krait) is highly toxic because it binds competitively to a receptor on the postsynaptic cell at neuromuscular junctions, resulting in paralysis. Which process is directly disrupted by alpha-Bungarotoxin? a. The release of neurotransmitter b. The opening of voltage-gated Na+ channels c. The membrane potential on the postsynaptic cell d. Chemical transmission across the synapse e. I do not know

D Signals are passed from a nerve cell to a muscle cell at the neuromuscular junction. This junction consists of a synapse, which is where the presynaptic cell (nerve cell) releases a chemical signal that crosses a small gap (synaptic cleft) between cells that can then bind to receptors on the postsynaptic cell. If the postsynaptic receptors are blocked by alpha-Bungarotoxin, this would directly interfere with the chemical signal being passed from the presynaptic cell to the postsynaptic cell. Because it only interferes with the postsynaptic cell, the answer could not be "a". And while blocking the chemical transmission would affect signal propagation in the postsynaptic cell and therefore the processes in "b" and "c" would likely be disrupted by the toxin, they would both be indirect effects resulting from the direct interruption of the process described by "d".

You go to a dubstep concert and are exposed to a large amount of low frequencies. Which portion of the basilar membrane would you expect to respond? a. The stiff, narrow portion b. The flexible, narrow portion c. The stiff, wide portion d. The flexible, wide portion e. I do not know

D The basilar membrane is located in the cochlea and involved in detecting sound through vibrating. As sounds are transmitted to the inner ear via pressure waves, the different frequencies of those pressure waves cause different portions of the basilar membrane to vibrate. The basilar membrane is stiff and narrow near the oval window, where pressure waves first enter the cochlea, and the membrane becomes wider and more flexible as it coils away from the oval window. High frequency sounds cause the stiff and narrow portion of the basilar membrane to vibrate and low frequencies affect the wide and flexible portion.

Which of the following is not part of the central nervous system? a. Brain b. Brain stem c. Spinal cord d. Motor neuron e. I do not know

D The central nervous system consists of the brain (of which the brain stem is part) and the spinal cord. Any components of the nervous system outside of the brain and spinal cord are part of the peripheral nervous system. This includes motor neurons, which are nerve cells that send signals from the central nervous system to effector cells in other parts of the body.

Which of the following is correctly matched? a. Actin -- major component of the thick filament b. Myosin -- major component of thin filaments c. Tropomyosin -- calcium binding protein of skeletal muscle d. Troponin -- interferes with the binding of myosin to actin e. I do not know

D The following would be correct matches for actin, myosin, and tropomyosin: Actin -- major component of thin filaments Myosin -- major component of thick filaments Tropomyosin -- interferes with the binding of myosin to actin (along with troponin)

Both mammals and fish can detect pressure changes using mechanoreceptors. The mammalian ear can detect pressure changes in the air, while some fish have a lateral line system that can detect pressure waves in water. Which of the following statements is NOT true concerning the function of these two structures? a. They both utilize hair cells b. Pressure changes are sensed when stereocilia bend in both structures c. In the mammalian ear, pressure waves are perceived as sound d. In the lateral line system, pressure waves are perceived as sound e. I do not know

D The lateral line system in fish contains stereocilia and hair cells but does not perceive the pressure changes in water as sound. The lateral line system is instead used to perceive movement of other organisms and allows the fish to locate prey, mates, and predators.

If you were at a concert and the pianist played a very high-pitched note, which part of your basilar membrane would vibrate in response? a. The wide, stiff part of the basilar membrane that vibrates at low frequencies b. The narrow, flexible part of the basilar membrane that vibrates at low frequencies c. The wide, flexible part of the basilar membrane that vibrates at high frequencies d. The narrow, stiff part of the basilar membrane that vibrates at high frequencies e. I do not know

D The narrow part of the basilar membrane at the beginning of the cochlea is very stiff and therefore is only stimulated by high frequencies. The end of the basilar membrane is much wider and more flexible, which enables it to respond to lower frequencies. In this case, you heard a high frequency noise, so the narrow, stiff part of the basilar membrane would respond.

You are vacationing playing in the ocean when other people on the beach begin to yell "SHARK," so you sprint out of the water and realize that your heart is racing. What branch of your nervous system was responsible for causing your heart to race when the people began yelling? (pick the best answer). a. Central nervous system b. Somatic nervous system c. Parasympathetic nervous system d. Sympathetic nervous system e. I do not know

D The sympathetic nervous system is a branch of the peripheral and autonomic nervous systems. The sympathetic nervous system is responsible for the activation of the "flight or fight" response. This response causes an increase in heart rate, among many other physiological responses, which can be triggered by perceived danger.

Among these choices, the most energetically efficient locomotion per unit mass is likely _____. A) flying by a 100-gram bird B) running by a 50-gram rodent C) running by a 40-kilogram ungulate D) swimming by a 10-gram minnow (bony fish) E) swimming by a 100-kilogram tuna (bony fish)

E

How does the ear allow humans to distinguish the volume of different sounds? A) Louder sounds induce a lower frequency of action potentials than do softer sounds. B) Louder sounds cause larger action potentials than do softer sounds. C) Louder sounds cause larger action potentials than do softer sounds, and louder sounds induce a higher frequency of action potentials than do softer sounds. D) Louder sounds cause smaller action potentials than do softer sounds. E) Louder sounds induce a higher frequency of action potentials than do softer sounds.

E

In the digestive system, peristalsis is _____. A) voluntary control of the rectal sphincters regulating defecation B) a process of fat emulsification in the small intestine C) the transport of nutrients to the liver through the hepatic portal vessel D) a common cause of loss of appetite, fatigue, and dehydration E) smooth muscle contractions that move food along the esophagus

E

What is part of the Peripheral Nervous system (PNS)?

Everything else in the body that isn't the brain, spinal cord, or brain stem

what are changes in the postsynaptic cell that bring the membrane potential closer to threshold called? that make the membrane potential more negative?

Excitatory postsynaptic potentials (EPSPs) Inhibitory postsynaptic potentials (IPSPs)

What are a large number of neurons aggregated into clusters called?

Ganglia

Summation

If several EPSPs occur close together in a space or time, they sum and make the neuron more likely to reach threshold and fire an action potential. the additive nature of postsynaptic potentials is the summation

In a neuron, what atoms are mostly consisted inside the cell? what are mostly consisted out?

Inside - low concentrations of sodium and chloride. High concentrations of potassium Outside - High concentrations of sodium and chloride. Low concentrations of potassium.

What are voltage-gated channels?

Membrane proteins that open and close in response to changes in membrane voltage. The shape of the channel, and thus its ability to admit ions, changes in response to the charges present at the inside of the membrane. They are either open or closed

What divisions are in the autonomic nervous system?

Parasympathetic division - digestion, rest, conserve or restore energy. sympathetic division - prepare organs for stressful "fight or flight" situations. speed up heart rate, stimulate release of glucose from liver, and inhibit action by digestive organs.

What does the sensory, afferent system do?

Sends information from the body (PNS) to the brain (CNS)

What does the Motor, Efferent system do?

Sends the information from the CNS to the body (PNS)

What does S.A.M.E. stand for?

Sensory. Afferent. Motor. Efferent. or Sensory Away Motor Effer(To)

What is the afferent division divided up into? (system)

The autonomic nervous system, which controls internal processes such as digestion and heart rate.

What is part of the Central Nervous System (CNS)?

The brain, spinal cord, and brain stem

What happens when a neurotransmitter binds to a ligand gated ion channel in the postsynaptic membrane?

The channel opens and admits a flow of ions along an electrochemical gradient.

Neurogenesis

The formation of new neurons

What is the efferent division divided up into? (system)

The somatic nervous system, which controls voluntary movements

Potassium channels open quickly or with a delay after depolarization?

With a delay

ligand

a molecule that binds to a specific site on a receptor molecule. Many neurotransmitters are ligands that bind to receptors called ligand gated channels.

What does the cerebellum do?

coordinates complex motor patterns.

what are oligodendrocytes and schwann cells collectively together called?

glia

What does the autonomic nervous system carry out?

involuntary responses which are not under conscious control. smooth muscle, cardiac muscle, and glands serve as the effectors.

What do the ends of axons contain?

numerous sac-like structures called synaptic vesicles.

Neurotoxins?

poisons that affect neuron function - often resulting in convulsions, paralysis, or unconsciousness. They come from sources as diverse as venomous snakes and foxglove plants.

What is the "sending" cell? the "receiving" cell?

presynaptic neuron Postsynaptic neuron

What does the diencephalon do?

relays sensory info to the cerebrum and controls homeostasis

What are sensory neurons?

sensory cells that carry info to the brain and spinal cord

What does the size of an EPSP or IPSP depend on?

the amount of neurotransmitter that is released at the synapse at a given time.

what does the brain stem do?

the automomic center for regulating cardiovascular, digestive, and other involuntary functions.

what does the cerebrum do?

the bulk of the human brain which is associated with conscious thought and memory.

What happens in myelin degenertes?

the transmission of electrical signals slows considerably. The autoimmune disease multiple sclerosis (MS) develops when the immune system mistakenly targets the oligodendrocytes that make up the myelin sheath in the CNS.

What does the somatic nervous system carry out?

voluntary responses, which are under conscious control. skeletal muscles serve as the effectors.