Human Phys Final

Absolute

The [A. absolute /B. relative] refractory period is a time when certain channels in an axon can notrespond to a graded potential no matter how large the depolarization.

Dura

The [A. dura/B. pia] mater is the meninges layer closest to the skull.

Amygdala

The [A. hippocampus /B. amygdala] is the area of the brain most closely associated with fear.

Amplitude

The all-or-none principle means that the [A. frequency/ B. amplitude] of an action potential is alwaysthe same for a given neuron

Adenohypophysis

The anterior pituitary is also known as the [A. adenohypophysis /B. neurohypophysis].

density of somatosensory receptors in that part

The area of the somatosensory cortex devoted to a specific body part is related to the [A.frequency that part is used/B. density of somatosensory receptors in that part].

hyper polarizes

A graded postsynaptic potential that moves the resting membrane potential farther away fromzero [A. depolarizes/B. hyperpolarizes] the neuron.

B

A lab technician has inadvertently substituted lithium (Li+) for sodium in a solution of saline foruse by students in neurophysiology labs. If a frog nerve was bathed in this solution, what wouldhappen upon stimulation of the nerve? [Assume channels are absolutely specific to ions discussed in class.] A. a depolarization phase will still occur as Li+ enters the cell B. a hyperpolarization phase will occur as K+ will still leave cell C. an action potential will still occur D. A and B E. A, B and C

Parietal

A major "sensory association" area of the brain resides in the [A. frontal/B. parietal] lobe.

two

A portal system is characterized by [A. one/B. two] capillary beds.

Depolarizes

A postsynaptic potential that moves the resting membrane potential closer to zero [A.hyperpolarizes/B. depolarizes] the neuron.

Language processing

A stroke in Wernicke's area would primarily effect [A. language processing/B. motor activity].

Receptive fields

A two-point discrimination test allows for the differentiation between [A. perceptual thresholds /B.receptive fields].

Presynaptic axo-axonic

A very potent form of inhibition can result from [A. presynaptic axo-axonic/B.postsynaptic axon to dendrite] events.

D

In a simple endocrine reflex, illustrated by the parathyroid cell, the endocrine cell is the A. sensor B. integration center C. target D. A and B E. A, B and C

hippocampus

An important structure in both learning and memory is the [A. hippocampus/ B. hypothalamus].

C

Arrange the following terms in correct order once an excitatory neurotransmitter binds to its receptor. 1. Ligand gated ion channel opens 2. Voltage gated-‐Ca2+ channels open 3. Trigger zone reaches threshold 4. Saltatory conduction occurs 5. A localized depolarization occurs 6. Voltage gated K+ channel opens 7. exocytosis A. 1, 2, 7, 3, 6, 5, 4 B. 3, 6, 5, 4, 1, 2, 7 C. 1, 5, 3, 6, 4, 2, 7 D. 1, 3, 5, 4, 6, 7, 2 E. 5, 3, 6, 4, 1, 2, 7

E C and D are the somatosensory cortex and the parietal lobe, which is used for sensory integration and perception

Based on the following diagram, which of the following statements is CORRECT. A. The areas labeled a and b are involved in somatic sensory processing. B. The areas labeled g & h are involved in somatic sensory processing. C. The areas labeled e & f are involved in somatic sensory processing. D. The areas labeled d & e are involved in somatic sensory processing. E. The areas labeled c & d are involved in somatic sensory processing.

A

Based on the following diagram, you would expect to find axons DESCENDING from the brain in A. e B. f C. g D. a E. c

B Hyper-polarization is when the membrane potential becomes more negative at a particular spot on the neuron's membrane, while depolarization is when the membrane potential becomes less negative (more positive).

Below is a recording trace from two different neurons [A and B] in culture, with each verticalline representing an action potential spike. At the inverted triangle each neuron was separately stimulated and stimulation lasted as long as the double-headed arrow. Based on this data, which of the following statements is TRUE? A. Neuron A was hyperpolarized and Neuron B was depolarized by the stimulus. B. Neuron A was depolarized, and Neuron B was hyperpolarized by the stimulus. C. Both neurons A and B have been depolarized by the stimulus. D. Both neurons A and B have been hyperpolarized by the stimulus. E. The stimulus did not affect either neuron as they have tonic activity.

A

Below is the "GHK" equation at 37oC using ions K+, Na+ and Cl- (subscript 'o' is outside while 'i'is inside the cell). Given this equation which of the following is FALSE? A. Each of the "P" values is the membrane permeability of the given ion, most often given relative to Na+ ions. B. This equation basically says that a resting membrane potential depends on the electrochemical gradients of all permeable ions. C. The "61 log" is a short cut that already considers the temperature, the ideal gas constant(R) and Faraday's (F) constant, and yielding final units of mVolts. D. For Cl- ions, the ratio of ion concentration is 'in over out' (rather than out over in)because of its valency. E. If the P for Na+ and Cl- ions goes to zero, you effectively end up with the Nerstequation telling you the Vm will equal the equilibrium potential for K+ ions.

A the hypothalamus signals the anterior pituitary's release of its hormones through the hypophyseal portal system, or this little capillary bed. And then the hypothalamus also communicates with the posterior pituitary, and it does that through stimulation of nerves which run down that pituitary stalk right here.

Benefits to having a portal system between the hypothalamus and pituitary include A. allowing small amounts of upstream trophic hormones to be delivered directly to the cells of interest B. allowing small amounts of upstream regulatory hormones to be diluted in the generalcirculation before use C. provide regulatory feedback signals from downstream target that are not diluted in thegeneral circulation D. A and C E. B and C

D Example: (6 EPSPs x 6mV) - (2IPSPs x 5mV)

Compare the firing pattern between three 'typical textbook' neurons (A, B & C) based on thefollowing inputs at the trigger zone. [AP = action potential] Neuron A detects 6 EPSPs of 6 mV, and 2 IPSPs at 5 mV. Neuron B detects 5 EPSPs of 6 mV and 3 IPSPs of 4 mV Neuron C detects 7 EPSPs of 4 mV and 2 IPSP of 6 mV. A. all three neurons fire APs, with A more than B or C which have the same frequency. B. C will fire at high frequency while A and B will fire at low frequency, with B slightlymore than A. C. only A and B fire APs, with A firing at higher frequency than B D. A will fire at high frequency while B and C will fire at low frequency with B slightlymore than C. E. only B and C fire APs, with B firing at higher frequency than C, which barely fires asingle AP.

C The absolute refractory period refers to a period during the action potential. This is the time during which another stimulus given to the neuron (no matter how strong) will not lead to a second action potential. So in this case, there would be a lower frequency of action potentials

Compared to its normal condition, if you were to suddenly lengthen the absolute refractory period ofa neuron, A. you would increase the frequency of action potentials B. you would decrease the amplitude of its next action potentials C. you would decrease the frequency of action potentials D. you would increase the amplitude of its next action potentials E. B and C

E

Concerning sensory physiology, which of the following is TRUE? A. A phasic ON receptor detects the start of a touch and hyperpolarizes the membrane. B. To make it easier to perceive things, different modalities will converge onto the same secondary neuron. C. Convergence of axons onto a single secondary neuron tends to decrease the apparentsize of the receptive field. D. An "adequate" stimulus is the minimum amount of a stimulus required to activate asensory receptor. E. The receptive field of one type of sensory receptor may overlap with that of a sensory neuron detecting a different stimulus.

A

Consider a sensory neuron on your fingertip and its response to a stimulus (the square waves A orB). With stimulus A, a receptor potential is observed as shown below A with a peak height of 10 mV[the dashed line indicates threshold]. If this same neuron is given stimulus B, twice as big in bothdirections as shown by the arrows, what will the receptor potential look like? A. it will look almost identical to that shown for A except be twice as high (20 mV) and twice as long. B. it will look almost identical to that shown for A except be half as high (5 mV) and half aslong as shown for A. C. it will still peak at 20 mv when the stimulus first hits, rapidly go back down to baseline,and then re-peak at 20 mV as the stimulus stops, before going back down to baseline. D. it will peak at 10 mv when the stimulus first hits and rapidly go to back to baseline. E. it will peak at 20 mv when the stimulus first hits and rapidly go to back to baseline.

A

Dexamethasone is a drug used to suppress the secretion of ACTH from the anterior pituitary gland. Two patients with hypersecretion of cortisol are given dexamethasone. Anika's cortisol secretion level falls to normal after the medication, but Bonnie's cortisol secretion remains elevated. Based on this data which statement(s) is/are CORRECT? A. Bonnie has primary hypercortisolism B. Anika has primary hypercortisolism C. Anika and Bonnie both have primary hypercortisolism D. Anika has primary hypocortisolism E. C and D

A

During an action potential the direction of ion flow depends on A. concentration and electrical gradients B. the cell's membrane potential (e.g. P values) C. voltage-‐gated Na+ or K+ channels D. the cell's permeability to each ion changing in a 'feedforward' process E. a change in passive channel activity

B Synergism occurs when two or more hormones combine to produce effects greater than the sum of their individual effects.

Epinephrine on its own increases blood glucose by 5m g/100m L and glucagon alone by 8m g/100m L. Ifboth hormones are present, blood glucose increases by 17m g/100m L. This is an example of a(n)________ hormone interaction. A. antagonistic B. synergistic C. short-‐loop D. long-‐loop E. permissive

A

If the resting axon's membrane becomes more permeable to potassium ions, A. it will take a stimulus of larger magnitude to initiate an action potential. B. the inside of the membrane will become more positively charged. C. the membrane will become depolarized. D. the hyperpolarization at the end of the action potential will not occur. E. the membrane will depolarize more rapidly.

B Typically, chloride flows through activated GABA receptors into the neurons causing hyperpolarization or shunting inhibition, and in turn inhibits action potential (AP) generation

Gamma-aminobutyric acid (GABA) is a major___ neurotransmitter and causes an influx of ____ions into a nerve cell. A. inhibitory ; sodium B. inhibitory ; chloride C. inhibitory ; calcium D. excitatory ; chloride E. excitatory ; sodium

inhibitory

Gamma-‐aminobutyric acid (GABA) is a potent [A. inhibitory /B. excitatory] neurotransmitter.

A

Grade potentials have all of the following properties EXCEPT: A. Have a specific threshold B. Hyperpolarizing C. Depolarizing D. Diminish over time E. Diminish over distance

D The basal ganglion are located in the midbrain, while the reticular formation are in the brainstem

Identify the one phrase that does NOT complete this sentence correctly: "The reticular formation ..." A. projects axons to almost every region of the brain. B. resides in the brain stem between various axon tracts. C. is a diffuse set of neuronal nuclei D. includes the basal ganglion E. has a major neuromodulatory role

D

In each tracing below, the solid line is a typical action potential, the dashed line is a Na+ ion conductance curve, and the dotted line is a K+ ion conductance curve. Which one (A to E) best represents the correct relationship of ion conductance to action potential? A. A B. B C. C D. D E. E

B. More frequent To know: Increasing stimulus strength causes a membrane to depolarize more frequently, thus increasing the frequency of signal transmission (action potentials).

In order to signal a stronger stimulus, action potentials become A. higher in amplitude B. more frequent C. longer-lasting D. A and B E. A and C

C Calcium causes vesicles to fuse with the presynaptic membrane and release neurotransmitter into the synaptic cleft

In synapses, calcium ions A. help form synaptic vesicles. B. stop the last action potential from occurring. C. cause fusion of synaptic vesicles. D. hyperpolarize the axon terminal. E. interfere with the action potential.

D

Inactivation of the sodium channel is possible because A. the extracellular concentration of sodium decreases. B. it is inactivated by the efflux of potassium ions. C. the activation gate becomes insensitive to stimuli. D. there is more than one gate that can close the channel. E. it is inactivated by the positive potential that develops during the action potential.

A

Lateral inhibition A. increases the contrast between neighboring receptive fields B. increases the amplitude of the receptor potential C. increase the frequency of action potentials originating from the primary sensoryneuron. D. A and B E. A, B and C

white

Myelinated axons are found in the [A. grey /B. white] matter.

C

Neural networks allow flexible outputs. Here, neuron Q innervates three target cells (A, B and C),with neuron "S" acting as an inhibitory and "W" as an excitatory, axon-axonic connection, each asshown. Targets A, B and C can be differentially activated depending on which of these threeneurons are firing. But what activation pattern listed below can NOT occur? A. all three targets can be activated. B. target B and C can be activated, while simultaneously hyperactivating C. C. only target B can be activated on its own. D. all three targets can be activated, while simultaneously hyperactivating C. E. only targets B and C can be activated.

E it is caused by voltage dependent calcium channels

Neuronal function is tightly linked to the kind of channel being used. Which of the following isNOT correctly matched? A. action potential ; voltage gated channel B. IPSP ; ligand gated channel C. EPSP ; ligand gated channel D. resting membrane potential ; passive channel E. synaptic vesicle release ; passive channel.

strong noxious stimuli

Nocireceptors respond to [A. strong noxious stimuli/B. gentle touch].

myelinated

Saltatory conduction is characteristic of [A. unmyelinated/B. myelinate] axons.

C CRH is the releasing hormone of ACTH, so you are more likely to find ACTH in the blood rather than CRH

Of the following hormones, which one is the least likely to be detected in a normal blood sample taken from a person's arm? A. Vasopressin B. TSH C. CRH D. ACTH E. Prolactin

Prolactin

Of these anterior pituitary hormones, [A. ACTH /B. Prolactin] has a nonendocrine target.

C

Optogenetics is a new tool that uses light to activate different kinds of ion channels. This is allowing researchers to activate or inhibit a neuron simply by turning a 'blue' light on. Which ONE of the following conditions will NOT initiate action potentials in a neuron when exposed to light? A. Activation of a light-sensitive Na+ channel in the initial segment. B. Activation of a light-sensitive Na+ channel in dendrites branches. C. Activation of a light-sensitive Na+ channel in the axon terminal. D. Activation of a light-sensitive Na+ channel at a Node of Ranvier. E. None they will initiate an action potential.

A

Ouabain, a specific inhibitor of the Na+-‐K+ ATPase, is applied to a neuron. The next action potential that fires after ouabain application will appear ____. A. the same as normal B. larger than normal C. smaller than normal D. No action potential will fire after ouabain is applied. E. Can not tell from information given

A A preprohormone is the precursor protein to one or more prohormones, which are in turn precursors to peptide hormones.

Peptide hormones A. are derived from a preprohormone translated on a ribosome attached to the ER. B. are digested into small peptides in the cytosol and then pumped into vesicles. C. are secreted as prohormones that are processed into a mature hormone in theblood D. are secreted into the blood after being attached to cholesterol. E. are derived from amino acids such as tyrosine or tryptophan.

Preprohormone

Peptide hormones are characterized by the presence of an ER signal sequence in its [A.prohormone/B. preprohomrone] state.

D

Referred pain A. is the perception of pain in the arm for example, even though it originates froman internal organ. B. is thought to occur as neurons from an organ converge on the secondary neurons used to process information from the skin. C. is thought to occur as neurons from an organ converge on the thalamic neurons that are connected to skin receptors. D. A and B E. A and C

B

Steroid hormones A. can only travel in the blood as a soluble ligand B. are derivatives of cholesterol that diffuse out of a cell after synthesis. C. are exocytosed from the cell after being processed in the Golgi. D. are synthesized on ribosomes attached to the ER E. must bind to a cell surface receptor to activate nuclear transcription.

A

Tetrodotoxin is a toxin that blocks voltage-‐gated sodium channels. What effect does this substancehave on the function of neurons? A. The neuron is not able to propagate action potentials. B. Action potentials lack a repolarization phase. C. Neurons depolarize more rapidly. D. The resting membrane potential would hyperpolarize. E. The absolute refractory period is shorter than normal.

E

The CNS must distinguish which of the following properties of a sensory stimulus? A. nature or type B. duration C. location D. intensity E. all of the above

E

The diagram below depicts a cell with a negative resting membrane potential. Ion X is distributed such that it is ten times more concentrated inside than outside of the cell. Ion Y has an equal concentration on each side of the membrane. Based on this diagram which statement below is correct? A. Both electrical and chemical gradients tend to move Y into the cell. B. Both electrical and chemical gradients tend to move X out of the cell. C. For Y, the chemical gradient tends to force Y out of the cell but this is counteracted by the electrical gradient. D. For X, the chemical gradient tends to force X into the cell but this is counteracted by the electrical gradient pushing X out of the cell. E. For X, the chemical gradient tends to force X out of the cell but this is counteracted by the electrical gradient keeping X in the cell.

A and C

The diagram below illustrates a sensory neuron that is touched as indicated by the square wave andblock arrow. Points along the axon (A, B & C) are indicated by the small arrowheads pointed up,with A being the trigger zone. Based on diagram, which of the following statements is/are TRUE? A. Touch intensity is encoded by the amplitude of a receptor potential at or before A. B. At B, the intensity of touch is encoded by the amplitude of the action potentials. C. At C, the intensity of touch is encoded as a frequency of action potentials. D. A and B E. A and C

E 1. Stimulus starts the rapid change in voltage or action potential. In patch-clamp mode, sufficient current must be administered to the cell in order to raise the voltage above the threshold voltage to start membrane depolarization. 2. Depolarization is caused by a rapid rise in membrane potential opening of sodium channels in the cellular membrane, resulting in a large influx of sodium ions. 3. Membrane Repolarization results from rapid sodium channel inactivation as well as a large efflux of potassium ions resulting from activated potassium channels. 4. Hyper-polarization is a lowered membrane potential caused by the efflux of potassium ions and closing of the potassium channels. 5. Resting state is when membrane potential returns to the resting voltage that occurred before the stimulus occurred.

The diagram below is an action potential of a "typical neuron" of the textbook. Based on thisdiagram which statement below is TRUE? A. At C, the voltage dependent sodium channel is in the closed position. B. The resting membrane potential is at A and voltage dependent sodium channels are open. C. The shape at F occurs as too much K+ ions enter the cell. D. At D, the membrane potential is considered to be hyperpolarized. E. At E, the voltage dependent sodium channel is in an inactivated state, and voltagedependent K+ channels are open.

A Which is located above the diencephalon

The diencephalon includes all of the following EXCEPT: A. Cingulate gyrus B. Hypothalamus C. Pituitary D. Pineal gland E. Thalamus

D

The diencephalon is composed of all of the following EXCEPT: A. thalamus B. pituitary C. pineal gland D. amygdala E. hypothalamus

E

The equilibrium potential of a given ion across a membrane is A. a function of the concentration of that ion on the inside of the cell. B. the potential at which the membrane potential is zero. C. the potential at which there is no net movement of all permeable ions across themembrane. D. the potential difference across a membrane that creates the electrical gradientmoving ions into a neuron. E. the potential at which there is no net movement of that ion across the membrane.

A

The following diagram of the hypothalamus-‐pituitary axis shows two neurons (A & B) with axonprojections as indicated, and a third cell C. Which of the following statements is CORRECT? A. Neuron A could produce ADH and secrete it into general circulation in theposterior pituitary. B. Neuron A could produce prolactin releasing factor (PRF) which then regulatescell C's secretion of prolactin into general circulation. C. Cell C, an endocrine cell, could produce very large amounts of oxytocin thatenters general circulation in the anterior pituitary. D. Neuron B could produce vasopressin and release it into the portal system whereit then enters general circulation in the posterior pituitary. E. Neuron B could make TRH which in turn regulates cell C's secretion of ACTHinto general circulation.

B

The following is a cartoon of a sensory neuron being touched. At left a stimulus is represented bythe black box and the response, action potentials, shown as vertical lines. This sensory neuron isthen touched in one of five patterns shown (grey) with a possible firing pattern shown by thevertical lines. Which of these firing patterns is/are CORRECT? A. A, C, D and E B. A, C and D C. A and C D. B E. E

D

The following is a flow chart of an endocrine pathway much like that seen in your textbook. The'upper brain' talks to neurons (Y) which secrete CRH (black circles). A second hormone (triangles) issecreted in response to CRH which then regulates secretion of a third hormone (star) from a targetcell (W). Blood vessels are indicated by A, B & C. Based on this diagram and explanation, which ofthe following is FALSE? A. The portal system, here A, carries CRH to the anterior pituitary. B. The cell W releases cortisol. C. The triangle hormone is ACTH secreted from endocrine cells in the anterior pituitary. D. The star shaped hormone initiates positive feedback signals to Y and Z. E. none, they are all correct.

C Vasopressin (ADH) and Oxytocin secreted from the posterior pituitary

The following is a partial diagram of the hypothalamus-pituitary axis, and the projections of twoneurons is provide. Based on this diagram, which of the following statements is CORRECT? A. Cell B could make prolactin releasing factor (PRF) which in turn regulates secretion ofgrowth hormone from cell C via the arterial blood flow. B. Neuron B could produce oxytocin and secrete it into the anterior pituitary. C. Neuron A could produce vasopressin and secrete it into the posterior pituitary. D. Neuron A could produce ADH and secrete it into the Portal System to stimulate cell C. E. Cell B could make dopamine which in turn regulates secretion of TSH from cell C viathe portal system.

B

The following is from your textbook and shows a major reflex loop associated with thehypothalamuss pituitary axis. Based on this flow chart, which of the following is NOT correct? A. X is a trophic factor released by the hypothalamus B. Y is the hormone oxytocin. C. Y is a hormone released directly into the blood, D. The endocrine cell, E, receives factor X via the portal system. E. All of the above are correct.

B

The graph below shows the plasma concentration of ACTH in normal people and three other groups of people (A-C). Based on this graph, which group(s) is/are most likely experiencing primary hypocortisolism? A. group A B. group B C. group C D. groups A and C E. groups B and C

C

The main differences between the modes of action of peptide hormones and steroid hormones are: A. Peptide hormones bind to intracellular receptors whereas steroid hormones most often bind to receptors on the cell surface. B. There is no difference: both act by binding to receptors on the cell surface. C. Peptide hormones bind to receptors on the cell surface whereas steroid hormones mostoften bind to intracellular receptors. D. Peptide hormones bind to receptors on the cell surface whereas steroid hormones actas second messengers. E. Peptide hormones bind to receptors in the nucleus whereas steroid hormones mostoften bind to receptors in the cytosol.

Brain stem

The oldest and most primitive region of the brain is the [A. cerebrum /B. brain stem].

B

The site where an individual neuron most often integrates information is A. the axon terminal B. the trigger zone C. the dendrites D. the chemical synapse E. the cell body

convergence

The pattern of synaptic connectivity where a large number of presynaptic neurons provide inputto a single postsynaptic neuron, is known as [A. convergence/ B. divergence].

Steroid

The rate limiting step for [A. peptide/B. steroid] hormone secretion is activation of its syntheticenzyme.

C

The somatosensory cortex A. alters sensory information into movement B. clusters all sensory information together to create a map of our external surroundings. C. clusters all of the somatosensory information from one region of the body (say fingertip) into one area of the cortex. D. sends axons down into the spinal cord that synapse with motor neurons E. lies immediately in front of the central sulcus

Absolute

The time during which an excitable membrane cannot respond to further stimulation regardless of thestimulus strength is the [A. absolute/ B. relative] refractory period.

depends on the type of receptor it activates

The type of action of a neurotransmitter [A. depends on the type of receptor it activates/B. is alwaysthe same].

Antagonistic

Two hormones that have opposite affects on a target are [A. synergistic/B. antagonistic].

A The Nernst equation only considers one ion at a time. The Goldman-Hodgkin-Katz equation essentially combines the Nernst equations for multiple ions to calculate a membrane potential (Vm; V is for voltage) based on these ions' intracellular and extracellular concentrations and the membrane's permeability to these ions.

What does the Goldman-‐Hodgkin-‐Katz equation take into account that the Nernst equation doesNOT? A. the permeability of the ions B. the temperature of the system C. the electrical charge of the ions D. the size of the ions E. the solubility of the ions

D

What effect does hyperkalemia, an increase in extracellular plasma K+ concentration, have on the resting membrane potential of neurons? A. Less K+ leaves the cell so membrane potential becomes less negative. B. Membrane becomes hyperpolarized. C. Shifts it closer to threshold so the neuron is more likely to depolarize. D. A and C E. A, B and C

B

What happens if the threshold of the voltage gated Ca2+ channel changes from -‐55 mV (i.e.normal) to -‐60 mV? Compared to normal neurons, in this altered condition A. less neurotransmitter will be released per arriving action potential. B. more neurotransmitter will be released per arriving action potential. C. a presynaptic neuron would need to be excited to a greater level to activate apostsynaptic neuron to expected levels. D. this change in threshold is not sufficient to cause any change in actvity. E. the presynaptic terminal will hyperpolarize with incoming Action Potentials.

B

What happens if the threshold of voltage gated Ca2 + channels changes from say a normal -55 mV to-50 mV? Compared to normal neuron connections A. more neurotransmitter will be released per arriving action potential. B. a presynaptic neuron would need to be excited to a greater level to activate a post-synaptic neuron to expected levels. C. the presynaptic terminal will hyperpolarized as more calcium moves into the neuron D. at the initial segment of the presynaptic neuron, you will change the normal relationshipbetween graded potentials and action potentials. E. the post-synaptic neuron will now hyperpolarize in response to presynaptic activity.

D

What is the purpose of the blood-brain barrier? A. keep glucose levels high within the brain. B. cushion the brain during physical impact. C. keep neurohormones levels high within the brain. D. protect the brain from harmful substances in the blood. E. keep oxygen levels high within the brain.

A The corpus callosum is the largest white matter structure in the brain, consisting of 200-250 million contralateral axonal projections and the major commissural pathway connecting the hemispheres of the human brain.

Which of the following can NOT be considered the grey matter of the CNS. A. Corpus collosum B. Ventral horn C. Dorsal horn D. Basal ganglion E. The six layers of the cortex

E

Which of the following could be responsible for a receptor adapting to a stimulus? A. K+ channel closing B. Na+ channel closing C. K+ channel opening D. A and B E. B and C

Schwann cell Schwann cells are part of the Peripheral Nervous System (PNS) while the others are a part of the Central Nervous System (CNS).

Which of the following does NOT belong within this list? A. ependymal cell B. Schwann cell C. oligodendricyte D. microglia E. astrocyte

E

Which of the following does NOT influence the time it would take for a nerve impulse to be conveyed by a particular neuron? A. presence or absence of nodes of Ranvier B. presence or absence of a myelin sheath C. diameter of the axon D. length of the axon E. whether axon is sensory or motor

E

Which of the following is NOT matched correctly? A. mechanically-gated channels ; receptor potential of somatic sensory neuron B. ligand gated channels ; graded potentials at dendrites of neurons C. passive channels ; resting membrane potential of all cells D. voltage gated channels ; action potentials of all neurons E. none, they are all correct

B

Which of the following is TRUE? A. Cerebral spinal fluid is more similar to plasma than to interstitial fluid. B. Cerebral spinal fluid is produced by ependymal cells lining the ventricles. C. The cerebral spinal fluid is returned to general circulation through the bloodbrain barrier. D. The blood brain barrier involves gap junctions between the endothelial cells ofthe capillaries. E. The ventricles are filled with blood.

C Arachnoid villi act as one-way valves for the flow of CSF into venous blood, and hydrostatic pressure is the main stimulus that causes these valves to open.

Which of the following is TRUE? A. Cerebral spinal fluid is more similar to plasma than to interstitual fluid. B. The blood brain barrier involves gap junctions between the endothelial cells of thecapillaries. C. The cerebral spinal fluid drains back to the systemic circulation via arachnoid villi D. The ventricles are filled with blood. E. Cerebral spinal fluid is produced by ependymal cells of arachnoid villi.

E

Which of the following statements about the somatosensory system is FALSE? A. Special connective tissue endings are often used by a sensory neuron to help detect a particular kind of stimulus. B. Tonic and phasic receptors send separate information about the duration of a stimulus. C. Sensory modalities start as separate information lines and remain so all the way to the somatosensory cortex. D. The receptive field of different types of sensory receptors often overlap within a given skin region. E. An adequate stimulus is the amount of stimulus required to initiate a receptor potential.

C

Which of the following statements is FALSE? A. A neuronal reflex, but not an endocrine reflex, requires an afferent pathway. B. Neural and endocrine reflexes both require an integration center. C. A neuronal reflex never regulates an endocrine reflex. D. Some endocrine gland cells sense the stimulus directly. E. A neuronal reflex requires an effector neuron.

C a type of sensory-nerve ending in the subcutaneous tissues of human fingers. Ruffini's corpuscles are believed to mediate sensations of skin stretch, motion detection, and hand and finger position.

Which one of the following is most likely to respond to a stretch of the skin?A. Merkel receptor B. free nerve endings C. Ruffini corpuscle D. Pacinian corpuscle E. Meissner's corpuscle

A The answer is partially correct. It does relay and modify information but it goes to the cerebrum, not the cerebellum

Which pairing is FALSE? A. Thalamus ; relays and modifies information going to and from the cerebellum B. Medulla oblongata ; contains control centers for blood pressure and breathing C. Midbrain ; relays signals for auditory and visual reflexes D. Cerebellum ; coordinates execution of movement E. Hypothalamus ; contains integrating centers for homeostasis

A. Lateral inhibition enhances the contrast between stronger and weaker touch signals. Stronger signals (at the point of contact) inhibit neighboring cells to a greater degree than weaker signals (peripheral to the point of contact). This activity allows the brain to determine the exact point of contact. Axoaxonic synapses modulate neuronal transmission by either inhibiting or facilitating depolarization at the presynaptic membrane. Dendrodendritic synapses appear to be unique in their ability to transmit in either direction, allowing for reciprocal effects.

Which phrase does NOT complete the following correctly? "During lateral inhibition of touchreceptors, ... " A. axo-axonic connections are used between primary neurons to cancel each other out inproportion to the amount they have been activated. B. secondary neurons must have a level of tonic activity. C. the net effect is to highlight which receptor was touched the most. D. each primary sensory neuron will fire action potentials in proportion to the amount oftouch received. E. neighboring secondary neurons attempt to cancel each other out in proportion to theamount they have been activated.

B

You learnt about inhibitory axo-‐axonic connections that alter the activity of a specific pre-‐synapticterminal. This is shown below as neuron "I" talks to a presynaptic terminal (x) of neuron M.Neuron M controls two targets -‐ Ta and Tb. While M talks to Tb, a third neuron, E, provides anexcitatory axo-‐axonic connection, to the presynaptic terminal (y) communicating with Tb. Giventhis network, which of the statements below is INCORRECT? A. If M and I fire, Tb would exhibit activity. B. All three neurons, M, E and I need to fire for E to enhance activity of 'y.' C. Activation of either E or I alone will not affect activity in Ta or Tb. D. Both neurons M and E need to fire for E to enhance activity of 'y. 'E. If only M fires, activity in both Ta and Tb is observed.

Primary

[A. Primary/B. Secondary] pathologies occur if the last endocrine gland in a reflex pathway isaffected.

Phasic

[A. Tonic/B. Phasic] receptors rapidly adapt as they respond mostly to a change in stimulus.

True

[A. True /B. False] All spinal nerves contain both afferent and efferent axons.

True

[A. True/ B. False] Temporal summation refers to the ability of two or more graded potentials toelicit an action potential if they occur within a short enough time interval.