Test Questions

Question 1

Ion leak channels
A) open when a chemical signal binds to its receptor
B) open in response to small voltage changes
C) allow substances to move into the cell but not out
D) all of the choices are correct
E) are responsible for the ion permeability of the resting plasma membrane

Answer 1

E) are responsible for the ion permeability of the resting plasma membrane

Question 2

An example of a properly functioning homeostatic response is
A) an increase in body temperature that results from exercise
B) the sun cause an increase in temperature in a stationary animal
C) an increase in body temperature results from shivering
D) none of the choices are correct
E) an increase in body temperature resulting from fever

Answer 2

C) an increase in body temperature results from shivering

Question 3

Which of the following is mismatched ?
A) autonomic nervous system - sympathetic and parasympathetic divisions
B) peripheral nervous system- spinal nerves
C) somatic nervous system- sensory division of PNS
D) peripheral nervous system- sensory (afferent) and motor (efferent ) divisions
E) central nervous system - brain

Answer 3

C) somatic nervous system- sensory division of PNS

Question 4

Which of the following are a primary function/functions of the brain stem?
A) executive functions like thinking, problem solving and movement
B) controlling heart and respiratory rate
C) smell, sound and formation/storage of memories
D) all of the choices are correct
E) coordinating and refining body movements

Answer 4

B) controlling heart and respiratory rate

Question 5

Multiple sclerosis (MS) is an autoimmune disorder. Patients with MS have:a) slowed (or failed) action potential conduction in neurons of the CNS and b) an increased leak of potassium through channels. What conditions could be related to each of these observations, respectively, in MS patients
A) smaller internal resistance, an increase in EPSPs
B) a small lambda length constant, a more positive membrane potential
C) loss of myelin, hyperpolarization
D) loss of myelin, depolarization
E) an increase in axonal diameter, depolarization

Answer 5

C) loss of myelin, hyperpolarization

Question 6

On a very cold day, President Synder waits for over an hour at the bus stop to catch a Greenie. Which structure helps President Synder’s body set and maintain a normal temperature; and in what way might this structure help her body thermoregulate in order to maintain homeostasis in the very cold weather?
A. Hypothalamus; increase the rate and depth of breathing
B. Hippocampus; stimulate skeletal muscles to rapidly contract (shiver)
C. Pons; decrease sweating to prevent heat loss through evaporation
D. Hypothalamus; constriction of blood vessels in the skin
E. Brain stem; stimulation of peripheral thermoreceptors in the skin

Answer 6

D. Hypothalamus; constriction of blood vessels in the skin

Question 7

Panic attacks and anxiety are common causes of hyperventilation. Hyperventilation ____
A. can lead to a homeostatic imbalance
B. can be an underlying cause of respiratory alkalosis
C. can lead to low carbon dioxide levels in the blood
D. Both A and B
E. A, B and C

Answer 7

E. A, B and C

Question 8

Mechanisms the body uses to help maintain an optimal internal environment include
A. Vasoconstriction
B. Shivering
C. Sweating
D. B and C only
E. All of the above

Answer 8

E. All of the above

Question 9

Antidiuretic hormone (ADH)
A. may be secreted when there is a significant increase in solute concentration in the ECF
B. is secreted by the posterior pituitary gland
C. increases urinary output
D. both A and B
E. A, B and C

Answer 9

D. both A and B

Question 10

This tissue is used primarily for support
A. Epithelial
B. Connective
C. Muscle
D. Columnar
E. Endothelial

Answer 10

B. Connective

Question 11

Most of the exchange surfaces in organs of multicellular animals are lined with
A. connective tissue.
B. smooth muscle cells.
C. neural tissue.
D. epithelial tissue.
E. adipose tissue.

Answer 11

D. epithelial tissue.

Question 12

If the drug, digitalis, acts to slow down the action of the sodium potassium pump, then sodium will
A. increase in the extracellular fluid
B. increase in the interior of cells
C. achieve equal concentrations inside and outside of the cell
D. passively move into the cell
E. all of the above

Answer 12

B. increase in the interior of cells

Question 13

Which of the following choices correctly summarizes the distribution of ions across the plasma membrane in a neuron at resting potential?
A. higher Na+ outside than inside, higher K+ inside than outside, various anions trapped inside
B. higher K+ outside than inside, higher Na+ inside than outside, various anions trapped outside
C. higher Na+ outside than inside, higher K+ inside than outside, various anions trapped outside
D. higher Na+ outside than inside, equal K+ inside and outside, various anions trapped inside
E. All of the above

Answer 13

A. higher Na+ outside than inside, higher K+ inside than outside, various anions trapped inside

Question 14

The absolute refractory period
A. limits how many action potentials can be produced during a given period of time
B. prevents an action potential from starting another action potential until it has concluded
C. is the period of time when a strong stimulus can initiate a second action potential
D. A and B only
E. A, B, and C

Answer 14

D. A and B only

Question 15

Which of the following is FALSE about λ (length constant) with regards to conduction velocity?
A. A larger length constant results in a greater conduction velocity.
B. With a larger length constant, the action potential doesn’t have to be regenerated as many times
C. The length constant, λ, is dependent on resistance
D. If you decrease the membrane resistance (rm), you will increase λ, which will increase conduction velocity.
E. If you increase the membrane resistance (rm), you will increase λ, which will increase conduction velocity.

Answer 15

D. If you decrease the membrane resistance (rm), you will increase λ, which will increase conduction velocity.

Question 16

The basis of the resting potential is:
A. Gradient of potassium (with more inside), gradient of sodium (with more outside) and a much greater number of sodium ungated (leak) channels
B. Gradient of potassium (with more outside), gradient of sodium (with more inside) and a much greater number of potassium ungated (leak) channels
C. Gradient of potassium (with more outside), gradient of sodium (with more inside) and a much greater number of sodium ungated (leak) channels
D. Gradient of potassium (with more inside), gradient of sodium (with more outside) and a much greater number of potassium ungated (leak) channels
E. Gradient of potassium (with more inside), gradient of sodium (with more inside) and many ungated sodium and potassium channels

Answer 16

D. Gradient of potassium (with more inside), gradient of sodium (with more outside) and a much greater number of potassium ungated (leak) channels

Question 17

Which of the following is a FALSE statement?
A. Metabotropic receptors are indirectly linked (through signal transduction mechanisms, often G proteins) to ion channels on the plasma membrane of the cell.
B. The size of a graded potential is related to the stimulus intensity or the amount of transmitter released
C. In the synapse, after a neurotransmitter has bound to its receptor, it can unbind from it and be taken up by the presynaptic terminal to be reused.
D. Temporal summation refers to the summation of EPSPs (or IPSPs) produced by the firing of different presynaptic neurons.
E. λ (lambda) indicates how far a current will spread along the inside of an axon and thereby influence the voltage along that distance.

Answer 17

D. Temporal summation refers to the summation of EPSPs (or IPSPs) produced by the firing of different presynaptic neurons.

Question 18

A neuron that conducts pain sensations to the central nervous system would be classified as a(n)
A. motor neuron.
B. sensory or afferent neuron.
C. efferent neuron.
D. association neuron.
E. interneuron.

Answer 18

B. sensory or afferent neuron.

Question 19

Which of the following choices correctly summarizes the ion types and directions of flow occurring in a neuron during repolarization?
A. Na+ flows inward, K+ concentrations inside do not change
B. Na+ flow ceases, K+ ions flow outward
C. K+ flow ceases, Na+ flows inward
D. K+ flows outward, Na+ flows inward
E. None of the above

Answer 19

B. Na+ flow ceases, K+ ions flow outward

Question 20

Choose the correct sequence of events that occur during neurotransmission at a chemical synapse.
1. Ligand gated ion channels open on the postsynaptic membrane
2. Voltage gated calcium channels open
3. Neurotransmitter binds to postsynaptic receptor
4. Action potential reaches the axon terminal of the presynaptic neurons
5. Neurotransmitter is released by exocytosis
A. 4,2,5,3,1
B. 4,5,3,1,2
C. 4,3,5, 2,1
D. 2,4,5,3,1
E. 2,5,4,3,1

Answer 20

A. 4,2,5,3,1

Question 21

Which of the following are glial cells in the CNS that are correctly matched with their function?
A. Satellite cells: help maintain ion concentrations in the interstitial fluid
B. Microglia: immune cells that respond to infection and inflammation
C. Schwann cells: form myelin sheaths
D. Astrocytes: produce CSF
E. All of the above

Answer 21

B. Microglia: immune cells that respond to infection and inflammation

Question 22

A synapse is a site where a neuron makes a communicating connection with another neuron or with an effector, such as a muscle fiber or gland. In the human brain, it is believed each neuron makes and receives synaptic contacts with about 1000 other neurons. Which of the following is NOT true with regard to synapses?
A. chemical synapses are faster than electrical synapses, but are not modulated as well as electrical synapses
B. electrical synapses enable synchronized electrical activity among populations of neurons.
C. neurotransmission at chemical synapses can be direct or indirect
D. electrical synapses occur in locations such as the pulp of a tooth where they contribute to the almost instant and intense pain we feel if the pulp is disturbed
E. all of the above are true

Answer 22

A. chemical synapses are faster than electrical synapses, but are not modulated as well as electrical synapses

Question 23

The shaker (Sh) gene, when mutated, causes a variety of atypical behaviors in the fruit fly, Drosophila melanogaster. It encodes for the shaker protein which functions as a voltage-gated potassium channel that mediates transmembrane potassium transport in excitable membranes. What component of neurotransmission is likely to be directly disrupted in a fruit fly that has a mutation in the Sh gene?
A. neurotransmitter reuptake
B. repolarization
C. synaptic vesicle fusion
D. depolarization
E. receptor potential generation

Answer 23

B. repolarization

Question 24

Neuronal activity is dependent on electrical currents. The relationship between three important components is shown by Ohm’s Law:
Current = Voltage
Resistance
Which of the following is true with regard to the neuron?
A. There is a difference in charge distribution at the plasma membrane. This difference is what gives rise to the membrane potential, and is measured in millivolts (or mV).
B. Current is generated when charged ions diffuse across the plasma membrane through open channels.
C. Voltage-sensitive ion channels open and close in response to changes in the membrane voltage Vm
D. The Goldman equation allows the prediction of membrane potential (Vm) when the membrane is permeable to more than one ion.
E. All of the above

Answer 24

E. All of the above

Question 25

This neurotransmitter is associated with behavior and cognition, voluntary movement, motivation and reward. Degeneration of neurons that produce it can lead to Parkinson’s disease.
A. Acetylcholine
B. Dopamine
C. Serotonin
D. Norepinephrine
E. Glutatmate

Answer 25

B. Dopamine

Question 26

Zoloft, Prozac and Paxil are examples of SSRI’s (selective serotonin reuptake inhibitors), a type of medication for the treatment of depression. SSRI’s block the reuptake of serotonin from the synapse such that the serotonin stays in the synapse for a longer period of time, prolonging its effects and elevating the mood of the patient. What is a potential side effect of these medications?
A. low blood pressure because serotonin relaxes smooth muscle in the walls of blood vessels, causing dilation
B. the reduced perception of pain because serotonin is released during pleasurable experiences
C. digestive system distress because serotonin also regulates intestinal movements
D. frequent urination, because serotonin stimulates the release of ADH (anti diuretic hormone)
E. ADHD because serotonin increases attention and mental focus

Answer 26

C. digestive system distress because serotonin also regulates intestinal movements

Question 27

. K + ions are nearly at their equilibrium distribution across a plasma membrane of a neuron at rest even though they are significantly more concentrated on one side. How is it possible for some molecules such as K+ to be at equilibrium across a biological membrane and yet not be at the same concentration on both sides?
A. The concentration of Na+ outside the membrane balances the concentration of K+ inside.
B. K+ responds to both components of the electrochemical gradient and will distribute accordingly.
C. Unless it’s during the repolarization stage of an action potential, no K+ ions can move across the membrane, so they remain more concentrated on one side of the cell.
D. The Na+/K+ pump continuously acts to pump K+ ions out of the
E. All of the above

Answer 27

B. K+ responds to both components of the electrochemical gradient and will distribute accordingly.

Question 28

Suppose that the electrochemical force for an anion X (known as X-) acts to move the anion out of the cell. If a neurotransmitter binding to its receptor opened channels for X- on the postsynaptic cell, then the response would
A. be an EPSP
B. be an IPSP
C. be stabilization of the membrane
D. not occur
E. be a hyperpolarizaton

Answer 28

A. be an EPSP

Question 29

Suppose that all the calcium could be removed from the extracellular fluid surrounding a neuron. Such removal would inhibit the ability of a neuron to
A. store calcium
B. degrade neurotransmitters
C. release neurotransmitters
D. directly inhibit the binding of a neurotransmitter to its receptor
E. none of the above

Answer 29

C. release neurotransmitters

Question 30

Which statement is False?
A. Mechanically gated channels can be found in sensory receptors
B. In a neuron at rest, it is primarily ungated (or leak) channels that are open
C. The sodium-potassium pump transports 2 Na+ to the inside of the cell and 3K+ to the outside.
D. The Nerst equation predicts the equilibrium potential (in mV) across the membrane of a cell for a singly charged ion
E. None of the above

Answer 30

C. The sodium-potassium pump transports 2 Na+ to the inside of the cell and 3K+ to the outside.

Question 31

Synapses can be classified as
A. axoaxonic
B. chemical
C. axodendritic
D. electrical
E. All of the above

Answer 31

E. All of the above

Question 32

What is Dr. Kuemerle’s favorite chemical equation?
A. CO2+H2O ⬄ H2CO3⬄HCO3- + H+
B. E=mc2
C. a2+b2=c2
D. 1+1=2
E. f=ma

Answer 32

A. CO2+H2O ⬄ H2CO3⬄HCO3- + H+

Question 33

Darlene Etienne suffered dehydration due to her entrapment after a major earthquake in Haiti. How might her body respond to dehydration in an attempt to restore homeostasis?
A. vasoconstriction of renal (kidney) circulation to reduce urinary water loss
B. release of ADH in response to an increase in the osmotic concentration (due to fluid moving into dehydrating cells)
C. vasoconstriction of blood vessels in the skin to reduce insensible water loss
D. A and B
E. A, B and C

Answer 33

E. A, B and C

Question 34

Ionic concentrations in the extracellular fluid are highly regulated to successfully maintain homeostasis. Over a hundred years ago, midwives performed an unusual test on the infants they delivered. They would lick the infant’s forehead. A salty taste meant the child was destined to die of a mysterious disease, that we now know is cystic fibrosis (CF). CF is usually caused by a mutation in CFTR (Cystic fibrosis transmembrane conductance regulator) which allows Cl- ions to move across epithelial cell membranes. Normally, when Cl- crosses a membrane, Na+ follows to preserve electrical neutrality. How might the disease, cystic fibrosis, disrupt the maintenance of normal homeostasis, making an infant’s forehead taste salty?
A. Under normal circumstances, the concentration of Cl- inside a given cell is much higher than the concentration outside the cell, so Cl- ions tend to move down their concentration gradient, from inside to cell to outside the cell. Due to the mutation, in infants with CF, Cl- ions cannot move from the cells into the sweat.
B. Infants with CF have a lot of mucus in their lungs, which directly causes them to sweat more.
C. As sweat moves toward the skin’s surface through sweat ducts, CTFR normally allows Cl- ions to move out of the sweat and back into epithelial cells. This process is disrupted in person with cystic fibrosis.
D. Both A and B
E. Both A and C

Answer 34

C. As sweat moves toward the skin’s surface through sweat ducts, CTFR normally allows Cl- ions to move out of the sweat and back into epithelial cells. This process is disrupted in person with cystic fibrosis.

Question 35

Epinephrine (also known as adrenaline) binds to different types of receptors. The binding of epinephrine to α-adrenergic receptors on the smooth muscle that surrounds blood vessels in the intestine causes these vessels to constrict. However, the binding of epinephrine to β-adrenergic receptors on smooth muscle that surrounds blood vessels to the skeletal muscles causes the blood vessels to dilate. When might blood vessels dilate in the body?
A. When the body is experiencing of active hyperemia
B. When the body needs to thermoregulate
C. When there is low blood pressure
D. A and B only
E. B and C only

Answer 35

D. A and B only

Question 36

Which of the following is correctly matched?
A. Blood: a type of connective tissue
B. Columnar epithelium: commonly found under the skin, and primarily functions to provide elasticity
C. Fibrous connective tissue: commonly found at the ends of long bones, nose and parts of airways
D. Epithelium: the thin layer of cells that line the interior of blood vessels
E. Cartilage: consists of osteocytes in a matrix of collagen and glycoproteins hardened with hydroxyapatite

Answer 36

A. Blood: a type of connective tissue

Question 37

6. The parasympathetic nervous system chiefly uses acetylcholine(ACh) as its neurotransmitter. Sarin, a colorless, odorless liquid is a potent organophosphate that is used in chemical warfare. As an inhibitor of acetylcholinesterase, sarin can cause excessive buildup of acetylcholine at the synapses where it is the neurotransmitter. Which of the following symptoms would most likely be occur in an individual with sarin poisoning?
   A. Increased urination, constriction of pupils, breathing difficulty (due to bronchiole constriction)
   B. Pupil dilation, decreased sweating, and increased urination
   C. Decreased urination, increased salivation, increased defecation (due to stimulation of intestinal activity)
   D. Decreased sweating, increased heart rate, increased salivation
   E. None of the above

Answer 37

A. Increased urination, constriction of pupils, breathing difficulty (due to bronchiole constriction)

Question 38

Hypercapnia refers to excessive carbon dioxide in the bloodstream. Excessive carbon dioxide in the blood__
A. can lead to respiratory acidosis
B. can stimulate the muscles of ventilation which would increase the rate and depth of breathing
C. can be caused by COPD
D. can be sensed by central chemoreceptors
E. all of the above

Answer 38

E. all of the above

Question 39

Spatial bypass of a countercurrent exchanger is found in the arm. In warm weather, the blood flowing into the arm returns to the core of the body through
A. veins that run adjacent to arteries
B. arteries that run adjacent to veins
C. veins lying near the surface of the arm
D. arteries lying near the surface of the arm
E. dilated superficial veins

Answer 39

C. veins lying near the surface of the arm

Question 40

Ed, our favorite med student, finally graduated from Medical School and started his residency. His first patient as a resident exhibited the following: nausea, reduced urinary output, BP at 102/60, pulse rate at 96, and reduced skin elasticity when performing a skin pinch test. He decided to administer an IV of 0.9% saline. Was this a good idea?
A. No. This will cause the patient’s red blood cells to burst since the solution in the IV is hyperosmotic to her blood.
B. No. Adding salt to the IV is comparable to drinking sea water. It will only dehydrate her further.
C. No. He should have delivered distilled water through the IV to rehydrate her as quickly as possible.
D. Yes. The 0.9% saline is hyposmotic to the blood and will cause water to move into her cells, effectively rehydrating her
E. Yes. The 0.9% saline solution is known as “Normal saline” and is isosmotic to the blood.

Answer 40

E. Yes. The 0.9% saline solution is known as “Normal saline” and is isosmotic to the blood.

Question 41

K+ ions are nearly at their equilibrium distribution across a plasma membrane of a neuron at rest even though they are significantly more concentrated on one side. How is it possible for some molecules such as K+ to be at equilibrium across a biological membrane and yet not be at the same concentration on both sides?
A. The concentration of Na+ outside the membrane balances the concentration of K+ inside.
B. K+ responds to both components of the electrochemical gradient and will distribute accordingly.
C. Unless it’s during the repolarization stage of an action potential, no K+ ions can move across the membrane, so they remain more concentrated on one side of the cell.
D. The Na+/K+ pump continuously acts to pump K+ ions out of the cell
E. All of the above contribute to this phenomenon

Answer 41

B. K+ responds to both components of the electrochemical gradient and will distribute accordingly.

Question 42

Which of the following are true during action potential transmission involving a chemical synapse?
A. action potentials in the presynaptic terminal cause voltage gated calcium channels to open
B. neurotransmitters can be taken up by the presynaptic terminal
C. neurotransmitters bind to voltage gated Na+ channels on the postsynaptic membrane
D. both A and B
E. both A and C

Answer 42

D. both A and B

Question 43

Recall that in a patient with hyperkalemia, the extracellular concentration of K+ is significantly increased. In a patient with hypernatremia, there is an elevation of the sodium concentration in the extracellular fluid. A major symptom of hypernatremia is thirst. Confusion may also occur due to brain cell shrinkage. Which of the following is (are) not true regarding sodium concentration?
A. The Goldman equation utilizes sodium concentrations to predict the equilibrium potential of Na+
B. Because a neuron is not very permeable to Na+ when at rest, a large increase in the extracellular sodium concentration will not likely significantly affect its resting membrane potential
C. Using the Nerst equation, knowledge of sodium concentrations in both the inside and outside of the cell is needed to predict the membrane potential
D. Both A and B
E. Both A and C

Answer 43

E. Both A and C

Question 44

Consider the diagram above. Note that axons contain Na+ channels and K+ channels that are both activated (opened) at membrane potentials that are more positive than threshold (for example, at -20mV some Na+ and K+ channels can both be in an open state). If this is the case, why do action potentials occur? That is, if both types of channels open at the same membrane potentials, and Na+ and K+ ions move down their own concentration gradients, wouldn’t the resulting movement of Na+ ions be offset by the opposite movement of K+ ions, resulting in no net change and thus, no action potential? Which of the following best explains this—that is, why action potentials occur even if both Na+ and K+ channels can open at the same membrane potential?

A. Regardless of the membrane potential, once threshold is reached, K+ ions enter the cell and Na+ ions exit the cell, giving rise to the depolarization and repolarization that generates an action potential.
B. K+ channels enter into an inactive state before they return to their closed state. This allows time for Na+ to rush into the cell before K+ leaves the cell, thereby generating an action potential.
C. Even though the channels may open at the same membrane potential, the speed with which channel open and closes differs. The Na+ channels open very rapidly, but the K+ channels are slower to open. The result is an initial flow of Na+ across the membrane, followed later by a flow of K+
D. Both A and B
E. Both B and C

Answer 44

C. Even though the channels may open at the same membrane potential, the speed with which channel open and closes differs. The Na+ channels open very rapidly, but the K+ channels are slower to open. The result is an initial flow of Na+ across the membrane, followed later by a flow of K+

Question 45

The absolute refractory period
A. Limits how many action potentials can be produced during a given period of time
B. Is the period of time when a strong stimulus can initiate a second action potential
C. Usually occurs during the hyperpolarization stage of the action potential
D. Both A and B
E. Both B and C

Answer 45

A. Limits how many action potentials can be produced during a given period of time

Question 46

Insecticides are substances used to kill insects. Pyrethrins are insecticides derived from chrysanthemum flowers. They are a mixture of six chemicals that are toxic to insects. Bees have been shown to be particularly sensitive to pyrethrin, with fatal doses as small as 0.02 micrograms. Due to this sensitivity and pollinator decline, pyrethrins are recommended to be applied at night to avoid typical pollinating hours. Pyrethrins function by disabling the inactivation gate of Na+ channels. In neurons poisoned with pyrethrins, what would you predict would happen to the membrane potential?
A. Na+ channels would proceed directly from the open to the closed state, which would cause the membrane potential to hyperpolarize thereby moving it closer to threshold.
B. The membrane potential would depolarize and stay depolarized, causing hyperexcitability
C. The membrane potential would become more negative, causing K+ ions to move out of the neuron
D. The membrane potential would enter the repolarization stage, since Na+ ions would not be able to flow through the channel
E. None of the above

Answer 46

B. The membrane potential would depolarize and stay depolarized, causing hyperexcitability

Question 47

Which of the following is a false statement?
A. Metabotropic receptors are indirectly linked (through signal transduction mechanisms, often G proteins) to ion channels on the plasma membrane of the cell.
B. The size of a graded potential is related to the stimulus intensity or the amount of transmitter released
C. In the synapse, after a neurotransmitter has bound to its receptor, it can unbind from it and be taken up by the presynaptic terminal to be reused.
D. Temporal summation refers to the summation of EPSPs (or IPSPs) produced by the firing of different presynaptic neurons.
E. λ (lambda) indicates how far a current will spread along the inside of an axon and thereby influence the voltage along that distance.

Answer 47

D. Temporal summation refers to the summation of EPSPs (or IPSPs) produced by the firing of different presynaptic neurons.

Question 48

Infantile spasms (IS) is a form of epilepsy characterized by: the onset seizures at four to eight months of age, deteriorating mental development, and a specific brain wave pattern on electroencephalography (EEG) testing called hypsarrhythmia. The seizures often look like a sudden bending forward of the body with stiffening of the arms and legs lasting for 1-2 seconds; some children arch their backs as they extend their arms and legs. One effective therapy for controlling this type of seizure is adrenocorticotrophic hormone (ACTH), which acts to increases blood brain barrier (BBB) integrity and enhance the binding of the neurotransmitter, GABA. If the seizures are caused by brain lesions (abnormal tissue), surgical removal of these lesions often results in improvement, although surgeons are careful not to remove the lateral ventricles (and the tissue near the ventricles) during surgery. Which of the following is a plausible explanation for the physiological basis underlying these treatments?
A. A leaky BBB may permit molecules that trigger action potentials into the brain, resulting in abnormal brain activity and seizures. Increasing BBB integrity would reduce this effect.
B. GABA is usually excitatory, and can compensate for the decreased brain activity that results from the surgical removal of brain tissue
C. Removing the abnormal tissue that causes irregular neuronal activity removes the causative factor; but because cells in the area of the ventricles make CSF, this particuar tissue should not be removed.
D. A and B only
E. A and C only

Answer 48

E. A and C only

Question 49

A few areas of the brain lack a functional blood brain barrier (BBB) because their capillaries have leaky endothelium like most of the rest of the body. One of these areas is in the region that initiates vomiting. Neurons in this region monitor the blood for possible toxic foreign substances, such as drugs. If they sense something harmful, they initiate the vomiting reflex to remove the contents of the digestive system and eliminate the ingested toxins. What region of the brain is responsible for the initiation of vomiting?
A. VTA
B. Thalamus
C. Hypothalamus
D. Motor cortex
E. None of the above

Answer 49

E. None of the above

Question 50

Neurons require a constant supply of oxygen and glucose to make ATP for the active transport of ions and neurotransmitters. Because of its high demand for oxygen, the brain receives about 15% of the blood pumped from the heart. If blood flow to the brain is interrupted, brain damage occurs after only a few minutes without oxygen. A stroke is a medical condition in which poor blood flow to the brain results in cell death. If a stroke is suspected, a patient is assessed in order to determine where the stroke may have occurred. An example of an assessment to assess whether balance and coordination are affected by having the patient slide his heel up and down the shin of his other leg, and repeat this on the other side, noting whether the patient has difficulty moving in a straight line. If a person were to fail this test, what brain region is likely most directly affected by the stroke?
A. Reticular formation
B. VTA
C. Cerebellum
D. Hypothalamus
E. None of the above

Answer 50

C. Cerebellum

Question 51

If the dorsal root of the spinal cord is cut, what function will be most directly disrupted?
A. Sensory function
B. Motor function
C. Memory function
D. Vision
E. None of the above

Answer 51

A. Sensory function

Question 52

Which of the following are glial cells in the CNS that are correctly matched with their function?
A. Satellite cells: help maintain ion concentrations in the interstitial fluid
B. Microglia: immune cells that respond to infection and inflammation
C. Schwann cells: form myelin sheaths
D. Astrocytes: produce CSF
E. All of the above

Answer 52

B. Microglia: immune cells that respond to infection and inflammation

Question 53

The nervous system has two major components: the CNS and the PNS, which are highly organized and interconnected. Which of the following statements is (are) true with regard to the nervous system?
A. The somatic system sends input to effectors in the afferent system
B. The spinal cord is a major component of the peripheral nervous system
C. Both the sympathetic and parasympathetic systems are subdivisions of the somatic system
D. Subdivisions of the efferent system include the somatic system and the autonomic system
E. Both A and B

Answer 53

D. Subdivisions of the efferent system include the somatic system and the autonomic system

Question 54

S.M., also sometimes referred to as SM-046, is a female patient first described in 1994 who has had exclusive and complete bilateral destruction of a particular region in her brain as consequence of an extremely rare genetic condition known as Urbach–Wiethe disease. S.M. is notable in that, because of this damage, she has little to no capacity to experience fear in her life, a characteristic which has resulted in her being dubbed by the media as the “woman with no fear”. What part of her brain was most likely destroyed?
A. Amygdala
B. Hypothalamus
C. VTA
D. Brocas’s area
E. Somatosensory cortex

Answer 54

A. Amygdala

Question 55

Symptoms of the mental illness, Schizophrenia, appear when dopamine levels in the brain are high. Thus schizophrenics are often treated with dopamine lowering drugs, such as Haldol. Haldol is a dopamine receptor antagonist. What problem might this cause?
A. The treatment may cause symptoms of Alzheimer’s Disease to occur.
B. Vision will likely be affected.
C. The treatment may cause symptoms of Parkinson’s Disease to occur
D. Vasodilation will likely occur
E. None of the above

Answer 55

C. The treatment may cause symptoms of Parkinson’s Disease to occur

Question 56

In our problem set on opioids, we learned that the brain can adjust to the overwhelming surges in dopamine (due to opioid abuse) by reducing the number of dopamine receptors. As a result, dopamine’s impact on the reward circuit of the brain in someone who abuses drugs can become abnormally low, and that person’s ability to experience any pleasure is reduced (compelling them to take more drugs). A somewhat analogous situation occurs in diabetic patients. Under normal circumstances, the only energy source for neurons is glucose (although during starvation, the brain can metabolize ketones produced by fat breakdown). By some estimates, the brain is responsible for about half the body’s glucose consumption. Diabetic patients have too much glucose in the blood. Sustained hyperglycemia causes the cells in the blood brain barrier to down regulate their glucose transporters. What potential effects are likely to result due to this situation?
A. A PET scan (that utilizes radioactive glucose) of a diabetic person under these circumstances would indicate impaired CNS activity.
B. In diabetics who are treated with insulin (to facilitate the transport of glucose into the cells and thus reduce their total blood glucose to normal levels), the cells in the brain will not be able to effectively take up the normal amount of glucose needed to sustain their normal activity.
C. Action potential firing and metabolic reactions in the neuron will increase to offset the lack of glucose
D. Both A and B
E. A, B and C

Answer 56

D. Both A and B

Question 57

Dr. Eric Kandel was awarded a Nobel prize for his work on memory. He elucidated the molecular basis for long term potentiation (LTP). Which of the following is the correct order of events that characterize early LTP?
1. the postsynaptic cell is depolarized due to an influx of Na+
2. Ca2+ enters the post-synaptic cell
3. glutamate binds to AMPA receptors
4. the post-synaptic cell inserts new AMPA receptors into its membrane
5. the Mg2+ block is removed from NMDA receptor channels

A. 1,3,4,2,5
B. 3,1,5,2,4
C. 5,3,2,4,1,
D. 1,2,3,5,4
E. None of the above

Answer 57

B. 3,1,5,2,4

Question 58

Acupuncture analgesia (AA), the technique of relieving pain by inserting and manipulating threadlike needles at key points in the body, has been practiced in China for more than 2000 years. The primary mechanism of AA’s action is thought to be that the needles activate specific afferent nerve fibers which cause analgesia by suppressing pain transmission through the use of particular neurotransmitters. In the body, which neurotransmitters usually block pain and which are generally used in pain transmission?
A. Block: nitrous oxide & endothelin; Transmit: endogenous opiods & dynorphins
B. Block: ADH & glycine; Transmit: L-Dopa & serotonin
C. Block: endorphins & enkephalins; Transmit: substance P & glutamate
D. Block: dopamine & GABA; Transmit: endorphins & endogenous opiods
E. None of the above

Answer 58

C. Block: endorphins & enkephalins; Transmit: substance P & glutamate

Question 59

The proprioceptive sense___
A. Utilizes proprioceptors to detect stimuli and transmit information to the CNS in order to monitor and maintain body and limb positions
B. Utilizes chemoreceptors on the steriocilia of hair cells to provide information about motion and orientation
C. Utilizes Golgi tendon organs that are located exclusively in the skeletal muscle to detect the position and the movement of the limbs
D. Utilizes mechanoreceptors such as: Pacinian corpuscles, Ruffini endings and free nerve endings that are found in the skin to detect light touch, deep pressure and vibration
E. None of the above

Answer 59

A. Utilizes proprioceptors to detect stimuli and transmit information to the CNS in order to monitor and maintain body and limb positions

Question 60

Mrs. B complained to her physician of bouts of dizziness. The physician asked her whether by “dizziness” she meant a feeling of lightheadedness, as if she were going to faint (a condition known as syncope) or a feeling that she or surrounding objects in the room were spinning around (a condition known as vertigo). Why is this distinction important in the differential diagnosis of her condition?
A. If it is vertigo, it could likely be due to a circulatory disorder (such as low blood pressure)
B. If it is syncope, is could likely be due to dysfunction of the vestibular apparatus (perhaps caused by a virus)
C. If it is syncope, it could likely be due to a circulatory disorder (such as low blood pressure)
D. Both A and B
E. None of the above

Answer 60

C. If it is syncope, it could likely be due to a circulatory disorder (such as low blood pressure)

Question 61

Which structure is not correctly matched?
A. oval window: vibrates in unison with movement of stapes (to which is attached)
B. scala tympani: contains endolymph and houses the organ of Corti
C. semicircular canal ampulla: detects rotational acceleration or deceleration
D. organ of Corti: rests on top of the basilar membrane and contains hair cells
E. tympanic membrane: separates external and middle ear; vibrates in synchrony with the sound waves that strike it.

Answer 61

B. scala tympani: contains endolymph and houses the organ of Corti

Question 62

We read a case study about a man who had a bad cold and was on a long airplane flight that resulted in ear pain and poor hearing. His doctor prescribed a decongestant. Some patients, though, have a history of repeated middle ear infections that are accompanied by chronic fluid accumulation, and that cause hearing impairment. These patients often have tubes surgically placed in their ear. How does a middle ear infection interfere with hearing and how would tubes help resolve the problem?
A. The tubes provide an unobstructed passageway for the sound waves as they move through the endolymph that resides in the external auditory canal, enabling the sound to be clearly heard.
B. Fluid accumulation impedes the movement ear structures (such as the tympanic membrane, ossicles, and the oval window) in response to sound. Tubes drain the fluid.
C. The tubes are placed in each ear such that they bypass the ossicles and attach to the round window (which resides directly behind the stapes) thereby transmitting sound waves unimpeded and directly to the cochlea.
D. All of the above are ways that tubes are utilized to help resolve the problem
E. None of the above are ways that tubes are utilized to help resolve the problem

Answer 62

. Fluid accumulation impedes the movement ear structures (such as the tympanic membrane, ossicles, and the oval window) in response to sound. Tubes drain the fluid.

Question 63

Dr. Kuemerle’s grandmother had glaucoma and succumbed to total permanent blindness when she was in her fifties. Glaucoma is an often inherited condition that causes damage to the eyes due to increased intraocular pressure caused by high fluid pressure when the liquid (aqueous humor) in the front part of the eye doesn’t circulate properly. Normally, aqueous humor flows out of the eye through a spongy tissue called the trabecular meshwork into a drainage canal. If the canal gets blocked, liquid builds up, increasing pressure. Regarding the eye, which of the following is correct?
A. Vitreous chamber: located between the lens and the retina, contains a gelatinous substance that helps to refract light and hold the eye on place.
B. Choroid: the white, protective, outermost eye layer
C. During the process of accommodation, the lens flattens when viewing a nearby object.
D. Photopsin: the photoreceptive molecule in rods
E. During the process of phototransduction, when lights strikes retinal on rhodopsin, the rhodopsin becomes activated, which through a series of steps, causes Na+ channels on the rod cell membrane to open, resulting in a depolarization that leads to the production of action potentials in ganglion cells.

Answer 63

A. Vitreous chamber: located between the lens and the retina, contains a gelatinous substance that

Question 64

Congenital anosmia is a condition in which people are born with a lifelong inability to smell. Some people affected by congenital anosmia have mutations in the PROKR2 gene, which provides instructions for making a protein called prokineticin receptor 2. This receptor interacts with a protein called prokineticin 2 (produced from the PROK2 gene). Prokineticin 2 and its receptor play an important role in the development of olfactory neurons. These neurons are critical for the perception of odors.
Which of the following are true regarding olfaction?
A. The sensory receptors utilized in olfaction are mechanoreceptors
B. The medial olfactory area of the brain is primarily involved with the conscious perception of smell
C. As is the case with most neurons, olfactory receptor cells are permanent cells that are not regularly replaced.
D. The olfactory receptor cells have sensory hairs (or cilia) that protrude into the mucus of the nasal cavity.
E. The axons of olfactory receptive cells comprise the olfactory tract, which transmits information to various target regions in the brain so that the odor can be perceived.

Answer 64

D. The olfactory receptor cells have sensory hairs (or cilia) that protrude into the mucus of the nasal cavity.

Question 65

Why is your sense of smell reduced when you have a cold, even though the cold virus does not directly adversely affect the olfactory receptor cells?
A. Because odorants do not reach the receptor cells as readily when the mucous membranes lining the nasal passageways are swollen and excess mucus is present.
B. Because excess mucus blocks the binding of odorants to the receptors. As a result, no action potentials are transmitted to the thalamus and then to the olfactory areas of the cerebral cortex.
C. Because colds result in the build-up of fluids in the normally gelantinous cupula structure that surrounds hair cell steriocilia. This impedes their movement and thus the transmission of action potentials to the olfactory cortex.
D. Both A and B
E. A, B and C

Answer 65

A. Because odorants do not reach the receptor cells as readily when the mucous membranes lining the nasal passageways are swollen and excess mucus is present.

Question 66

Nyctalopia (night blindness) is a condition that makes it difficult or impossible to see in relatively low light. It most likely could be caused by
A. a lack of cones.
B. a lack of iodopsin.
C. a lack of rhodopsin.
D. too much vitamin A in the diet.
E. all of the above

Answer 66

C. a lack of rhodopsin.

Question 67

High frequency deafness can result from prolonged or frequent exposure to excessively loud noises which causes degeneration of the organ of corti at the ___________ of the _________
A. wide end (near the oval window); basilar membrane
B. narrow end (near the oval window); basilar membrane
C. wide end (near the round window); cochlea
D. thin end (near the round window); spiral organ
E. less stiff end (near the round window); basilar membrane

Answer 67

B. narrow end (near the oval window); basilar membrane

Question 68

Which of the following is NOT associated with the rod cell when light is absorbed by a photoreceptor cell
A. Na+ channels close
B. Glutamate stops being released (or its release is significantly decreased)
C. Phosphodiesterase is activated
D. Rhodopsin is activated
E. The loss of cGMP opens the Na+ channel

Answer 68

E. The loss of cGMP opens the Na+ channel

Question 69

Choose the arrangement that lists the correct order of events, starting with the photoreceptor cells in the resting, non-activated state.
1. bipolar cells depolarize
2. glutamate release from presynaptic terminals of photoreceptor cells decreases
3. light strikes photoreceptor cells
4. photoreceptor cells are depolarized
5. photoreceptor cell are hyperpolarized

A. 1,2,3,4,5
B. 2,4,3,5,1
C. 3,4,2,5,1,
D. 4,3,5,2,1,
E. 5,3,4,1,2

Answer 69

D. 4,3,5,2,1,

Question 70

Which of the following is true regarding “off center” bipolar cells?
A. They generally have ionotrophic channels that permit the flow of Na+ into the cell
B. They can hyperpolarize or depolarize, depending on conditions
C. They can form synapses with rods, cones and/or horizontal cells
D. All of the above
E. None of the above

Answer 70

D. All of the above

Question 71

As a stereocilium on hair cells in the organ of corti bends, ______ channel gates open, causing a ______.
A. Na+, depolarization
B. K+, depolarization
C. Cl- , hyperpolarization
D. Ca2+, depolarization
E. K+ leak, IPSP

Answer 71

B. K+, depolarization

Question 72

Macular degeneration is the leading cause of blindness in the Western Hemisphere. This condition is characterized by the loss of photoreceptors in the macula (also called the macula lutea) in association with advancing age. The macula___
A. consists of the area immediately surrounding the fovea
B. is involved with high acuity vision
C. is located in the retina
D. Both A and B
E. A, B and C

Answer 72

E. A, B and C

Question 73

Choose the arrangement that lists the correct order of events when a sound is heard.
1. The steriocilia on the hair cells bend
2. The ossicles vibrate
3. The tympanic membrane vibrates due to sound waves
4. Vibrations cause the fluid in the cochlea to move
5. Graded potentials are generated

A. 3,2,1,4,5
B. 2,3,4,5,1
C. 3,2,4,1,5
D. 2,1,5,3,4
E. 4,3,2,1,5

Answer 73

C. 3,2,4,1,5

Question 74

Glutamate has various roles in the body. When a photoreceptor cell located in the receptive field center is in the dark, glutamate released from it ______
A. ultimately causes the firing of an on center ganglion cell to be increased
B. ultimately causes the firing of an off center ganglion cell to be decreased
C. causes on center bipolar cells to be depolarized, which then causes on center ganglion cells firing to increase
D. causes on center bipolar cells to become hyperpolarized and off center bipolar cells to become depolarized
E. None of the above

Answer 74

D. causes on center bipolar cells to become hyperpolarized and off center bipolar cells to become depolarized

Question 75

Which of the following is true regarding gustation?
A. During the gustatory process, odorants bind to receptors on sensory cells
B. Humans are most sensitive to bitter tastants
C. Each taste receptor cell expresses only one type of receptor protein
D. Both A and B
E. Both B and C

Answer 75

B. Humans are most sensitive to bitter tastants

Question 76

Which of the following is (are) characteristic(s) of a skeletal muscle?
A. autorhythmic
B. control can be both by voluntary and involuntary (reflexes) input
C. contains fasiculi, blood vessels, muscle fibers
D. Both A and B
E. Both B and C

Answer 76

E. Both B and C

Question 77

Sarcomeres_____ ; and sarcolemma ____
A. are delimited by M lines; refers to the plasma membrane of a muscle fiber
B. are the basic contractile unit of a muscle fiber; refers to the cytoplasm of the muscle fiber
C. are found in myofibrils; refers to the plasma membrane of a muscle fiber
D. Both B and C
E. None of the above

Answer 77

C. are found in myofibrils; refers to the plasma membrane of a muscle fiber

Question 78

Homeostasis has become the central unifying concept of physiology and is defined as a self-regulating process by which an organism can maintain internal stability while adjusting to changing conditions. During heart failure, there is a decrease in cardiac output that the body will try to compensate for. Since cardiac output = heart rate*stroke volume, what is an expected response of the body?
A. Activation of the sympathetic nervous system to increase heart rate and contractility
B. Activation of parasympathetic nervous system to increase heart rate and contractility
C. Decreased production of ADH to decrease water retention
D. Increased temperature set point
E. None of the above

Answer 78

. Activation of the sympathetic nervous system to increase heart rate and contractility

Question 79

Why is it important to maintain a constant body temperature?
A. So that we don’t get cold
B. To stop the multiplication of bacteria in the body
C. So that we have enough energy to move
D. to maintain the optimum temperature for enzymes and biochemical reactions in the body
E. Only A and B

Answer 79

D. to maintain the optimum temperature for enzymes and biochemical reactions in the body

Question 80

An explorer is adventuring through Antarctica (a very cold environment). What would be the expected change in his peripheral blood vessels?
A. No change
B. Vasodilation
C. Vasoconstriction
D. Decrease in heartrate and therefore a lower pulse in the peripheral blood vessels
E. All of the above

Answer 80

C. Vasoconstriction

Question 81

Orthostatic hypotension (also known as postural hypotension) is a form of low blood pressure that happens when standing after sitting or lying down. Orthostatic hypotension can cause dizziness or lightheadedness and possibly fainting. Which type of receptors primarily monitor sudden changes in blood pressure and buffer these changes to prevent excessive fluctuations (rise or fall) in blood pressure?
A. Nociceptors
B. Thermoreceptors
C. Baroreceptors
D. Both A and C
E. Both B and C

Answer 81

. Baroreceptors

Question 82

Kussmaul breathing is a deep and fast breathing pattern often associated with severe metabolic acidosis, particularly diabetic ketoacidosis (DKA) but also kidney failure. To restore homeostasis during acidosis, which of the following may occur?
A. Central chemoreceptors would detect and increase in CO2
B. Carotid and aortic chemoreceptors would detect an increase in H+
C. Action potentials would be sent to respiratory control centers in the medulla
D. Muscles of ventilation would increase the rate and depth of breathing
E. All of the above

Answer 82

E. All of the above

Question 83

Myasthenia gravis is a chronic autoimmune, neuromuscular disease that causes weakness in the skeletal muscles that worsens after periods of activity and improves after periods of rest. In myasthenia gravis, antibodies (immune proteins produced by the body’s immune system) block, alter, or destroy the receptors for acetylcholine at the neuromuscular junction, which prevents the muscle from contracting. This is most often caused by antibodies to the acetylcholine receptor itself. The most serious complications of myasthenia gravis is a myasthenia crisis. This is a condition of extreme muscle weakness, particularly of the diaphragm and chest muscles that support breathing. Breathing may become shallow or ineffective. If a person has the inability to ventilate adequately, it can lead to
A. Increased blood carbon dioxide
B. Decreased pH
C. Respiratory acidosis
D. A and B only
E. A, B and C

Answer 83

E. A, B and C

Question 84

Which of the following statements is false regarding temperature homeostasis in the body?
A. Changes in skin temperature are detected by peripheral thermoreceptors
B. Sweating and shivering are mechanisms that the body uses to regulate body temperature
C. Changes in core temperature are detected by central chemoreceptors located in the hippocampus
D. Countercurrent exchange ensures gradients that facilitate the maximal amount of heat retention
E. Animals with feathers or fur can fluff up their feathers or fur as the temperature gets colder to increase insulation.

Answer 84

C. Changes in core temperature are detected by central chemoreceptors located in the hippocampus

Question 85

Dogs are all about movement; they love walking, running, jumping, wagging their tails, and more. All of this highlights the importance of their nervous system. Canine Degenerative Myelopathy (DM) mainly affects German Shepherds. DM is a disease affecting the spinal cord, resulting in slowly progressive hind limb weakness and paralysis. The symptoms result from degeneration of the white matter of the spinal cord. The spinal cord
A. contains afferent axons in the ventral root
B. is a part of the Peripheral Nervous System
C. contains efferent axons in the dorsal root
D. does not have meninges, white matter or grey matter (these are only found in the brain)
E. none of the above

Answer 85

E. none of the above

Question 86

Glioblastoma is an aggressive type of cancer that can occur in the brain or spinal cord. It is the most common brain malignancy and is almost always lethal. Glioblastoma forms from cells called astrocytes. Which of the following is true regarding astrocytes?
A. They are phagocytic cells that ingest and break down pathogens and waste products in the CNS
B. They are found in the PNS where they cover the surfaces of blood vessels and are used for structural support and to help maintain ion concentrations in the interstitial fluid surrounding them.
C. They produce cerebrospinal fluid
D. They form myelin sheaths in CNS
E. None of the above

Answer 86

E. None of the above

Question 87

This neurotransmitter is an agonist of specific chloride channels. It allows negatively charged Cl- ions into the postsynaptic cell. What is it?
A. Glutamate
B. Noradrenaline
C. GABA
D. Acetylcholine
E. None of the above

Answer 87

C. GABA

Question 88

Walther Hermann Nernst was a German chemist known for his work in thermodynamics, physical chemistry, electrochemistry, and solid state physics. His formulation of the Nernst heat theorem helped pave the way for the third law of thermodynamics, for which he won the 1920 Nobel Prize in Chemistry. He is also known for developing the Nernst equation in 1887. Which of the following would the Nernst equation predict?
A. the equilibrium potential (in mV) across the membrane of a cell for a singly charged positive ion.
B. that when the inside of the membrane is 90mV more negative than the outside, K+ is at equilibrium.
C. the membrane potential at which the voltage gradient of a particular ion balances the concentration gradient for the ion such that there is no net flow of ion through channel
D. A and C only
E. A, B and C

Answer 88

E. A, B and C

Question 89

Which of the following is true regarding potassium channels in neurons?
A. They can open and close in response to changes in the membrane voltage.
B. They can be ungated
C. In a resting neuron, voltage gated K+ channels are open.
D. A and B only
E. A, B and C

Answer 89

. A and B only

Question 90

Epilepsy is a disorder in which the balance between cerebral excitability and inhibition is tipped toward uncontrolled excitability. When a sufficient number of neurons synchronously depolarize and generate action potentials, a seizure begins. The hallmark of this synchronous discharge of neurons in the epileptic focus is the PDS, which is a large and sustained depolarization of the neuron. During a seizure, the epileptic neurons undergo a prolonged depolarization with continuous bursts of action potentials without an intervening repolarization. This is very uncharacteristic of normal action potentials. Which of the following (is) are not characteristics of normal action potentials?
A. They have refractory periods
B. A larger stimulus increases their magnitude (size)
C. They go through a period of hyperpolarization
D. They propagate
E. Both B and C

Answer 90

B. A larger stimulus increases their magnitude (size)

Question 91

If we apply 180mV to a specific region of an axon, what is an approximate expected voltage at about 3 lambda length constants away?
A. ~90mV
B. ~5 mV
C. ~20mV
D. ~180mV
E. None of the above

Answer 91

. ~5 mV

Question 92

Which of the following is (are) false with regard to the lambda length constant?
A. It is a characteristic length on which the voltage across a membrane decays.
B. If a neuron has a larger lambda length constant, threshold can be reached further down an axon each time the action potential is generated.
C. Increasing the resistance of the membrane will decrease the lambda length constant and thus the conduction velocity
D. Both A and B
E. Both B and C

Answer 92

C. Increasing the resistance of the membrane will decrease the lambda length constant and thus the conduction velocity

Question 93

Clostridium tetani is a bacterium that produces a toxin known as tetanospasmin. Tetanospasmin prevents Ca2+-dependent release of an inhibitory neurotransmitter from CNS neurons, resulting in unopposed excitation of spinal neurons and muscle contraction. From the list below, which neurotransmitters are frequently inhibitory?
A. Acetylcholine
B. GABA and glycine
C. Glutamate
D. Dopamine
E. All of the above

Answer 93

B. GABA and glycine

Question 94

Which of the following is matched incorrectly?
A. Serotonin: derived from tyrosine
B. Substance P: pain perception
C. Dopamine: motivation and reward
D. Acetylcholine: involved in Alzheimer’s Disease
E. Endorphins: reduce the perception of pain

Answer 94

A. Serotonin: derived from tyrosine

Question 95

Which system(s) transmit information to the smooth muscles and glands?
A. afferent system
B. sympathetic division of the autonomic system
C. parasympathetic division of the autonomic system
D. A and B
E. B and C

Answer 95

E. B and C

Question 96

Why are action potentials usually conducted in one direction?
A. because ions can flow along the axon in only one direction
B. because the axon hillock has a higher membrane potential than the terminals of the axon
C. because voltage gated Na+ channels are inactivated during the refractory period
D. because the voltage gated channels for both Na+ and K+ open only in one direction.
E. because all neurons have identical shapes and structure

Answer 96

C. because voltage gated Na+ channels are inactivated during the refractory period

Question 97

Suppose a cell’s membrane potential shifts from -70mV to -50mV. What changes in the cell’s permeability to K+ or Na + could cause this shift?
A. A decrease in permeability to K+
B. An increase in permeability to Na+
C. No change in permeability to Na+ accompanied by an increase in permeability to K+
D. Both A and B
E. A, B and C

Answer 97

D. Both A and B

Question 98

You are conducting an experiment in which you are able to depolarized neurons (and bring their membrane potential to threshold) in the ventral tegmental area (VTA) in the brain of your research subject. What effect would you expect?
A. Neurons would release dopamine
B. Dorsal parts of the body would be stimulated
C. Your research subject would likely experience positive or pleasurable sensations
D. Both A and B
E. Both A and C

Answer 98

E. Both A and C

Question 99

Huntington’s disease (HD) is an inherited disorder that results in the death of brain cells. The most characteristic initial physical symptoms are jerky, random, and uncontrollable movements called chorea. HD affects the whole brain, but certain areas are more vulnerable than others. The most prominent early effects are likely in
A. Broca’s area
B. the basal ganglia
C. the reticular formation
D. the amygdala
E. the corpus callosum

Answer 99

B. the basal ganglia