Deck 29: Nervous Systems

Question 1

The soma of a neuron contains the

A) synaptic vesicles.
B) nucleus.
C) dendrites.
D) axon hillock.
E) terminals.

Answer 1

nucleus.

Question 2

The glial cells of the nervous system

A) are electrically excitable.
B) provide electrical output to neurons.
C) are nourished by neurons.
D) provide electrical insulation.
E) receive input from the environment.

Answer 2

provide electrical insulation.

Question 3

Sensory neurons are different from motor neurons in that

A) sensory neurons carry information from enteroreceptors whereas motor neurons carry information from exteroreceptors.
B) motor neurons carry information away from the central nervous system whereas sensory neurons carry information towards the central nervous system.
C) sensory neurons function as efferent pathways whereas motor neurons function as afferent pathways.
D) motor neurons have long axons whereas the axons of sensory neurons are relatively short.
E) All the answers are correct.

Answer 3

motor neurons carry information away from the central nervous system whereas sensory neurons carry information towards the central nervous system.

Question 4

In a resting neuron

A) ion pumps actively transport Na⁺ to the outside of the membrane.
B) Na⁺ leaks through the membrane faster than any other ion.
C) the outside of the membrane is usually negative with respect to the inside.
D) the potential difference across the membrane is maintained by the diffusion of ions.
E) the membrane is more permeable to Na⁺ than to K⁺.

Question 5

In a nerve cell, as an action potential begins

A) ion pumps actively transport K⁺ to the outside of the cell.
B) K⁺ channels open and K⁺ leaves the cell.
C) Na⁺ channels open and Na⁺ leaves the cell.
D) K⁺ channels open and K⁺ enters the cell.
E) Na⁺ channels open and Na⁺ enters the cell.

Question 6

Energy in the form of ATP is required

A) to generate an action potential.
B) to propagate an action potential.
C) to maintain a nerve cell membrane at resting potential.
D) to transport K⁺ out of the cell.
E) All of the answers are correct.

Question 7

The period of reduced excitability in a nerve cell membrane following an action potential is called

A) hyperpolarisation.
B) inhibition.
C) the refractory period.
D) the saltatory period.
E) the resting period.

Question 8

After an action potential, the membrane returns to its resting potential when

A) Na⁺ channels open and Na⁺ flows out.
B) K⁺ channels open and K⁺ flows out.
C) Cl^- channels open and Cl^- flows in.
D) K⁺ channels open and K⁺ flows in and Na⁺ flows out.
E) the Na⁺-K⁺ pump is activated, transporting Na⁺ out and K⁺ in.

Question 9

The following events occur at the membrane of a nerve cell during the generation of an action potential:
1) The potential inside the cell is positive.
2) The potential inside the cell is negative.
3) The threshold potential is reached.
4) Voltage-dependent K⁺ channels open.
5) Voltage-dependent Na⁺ channels open.
Which of the following is a correct sequence for these events?

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

Question 10

A drug that deactivates the potassium channels in the membrane of a neuron would

A) make it easier to trigger action potentials in the neuron.
B) inhibit the conduction of action potentials along the neuron.
C) cause the membrane to hyperpolarise.
D) make it more difficult for the neuron to respond to repeated stimuli.
E) prevent depolarisation of the membrane.

Question 11

The speed of propagation of an action potential along an axon is increased by

A) a decrease in the insulation of the axon.
B) an increase in the length of the axon.
C) an increase in the diameter of the axon.
D) the number of Na⁺ channels in the axon.
E) a decrease in the concentration of Na⁺ ions inside the axon.

Question 12

After an action potential reaches a synaptic terminal, which of the following events would occur first?

A) Synaptic vesicles fusing with the cell membrane.
B) Membrane-bound Na⁺ channels opening.
C) Neurotransmitter binding to membrane-bound receptors.
D) Ca²⁺ entering the synaptic terminal.
E) Release of the transmitter into the synaptic cleft.

Question 13

The effect (excitatory or inhibitory) of a neurotransmitter on the postsynaptic neuron depends primarily on the

A) type of receptor on the postsynaptic membrane.
B) molecular structure of the neurotransmitter.
C) amount of neurotransmitter released.
D) permeability of the post-synaptic membrane.
E) number of receptors on the postsynaptic membrane.

Question 14

The mammalian vasculature is regulated by which neurotransmitter(s)?

A) Adrenaline
B) Noradrenaline
C) Acetylcholine
D) Adrenaline and noradrenaline
E) Adrenaline, noradrenaline and acetylcholine

Question 15

The organisation of neurons into ganglia seems to be associated with the evolution of

A) bilateral symmetry.
B) metameric segmentation.
C) complex behaviour.
D) nerve nets.
E) autocrine receptors.

Question 16

The largest part of the human brain is the

A) cerebellar cortex.
B) thalamus.
C) corpus callosum.
D) cerebral cortex.
E) cerebellum.

Question 17

Which of the following is NOT found in the central grey region of the spinal cord?

A) Nerve cell bodies
B) Dendrites
C) Initial parts of axons and synaptic inputs
D) Areas of sensory connections
E) Axons that pass up and down the cord

Question 18

Which of the following is found in invertebrate but not vertebrate nervous systems?

A) Segmental ganglion
B) Dorsal root ganglion.
C) Suboesophageal ganglion
D) Encephalisation
E) Optic ganglion

Question 19

The neurons of all animal nervous systems are typically organised into specific patterns known as

A) nerve nets.
B) neural circuits.
C) reflex arcs.
D) ganglia.
E) peripheral nervous system.

Question 20

In a squid, which of the following behaviours would involve the highest degree of input from higher brain centres?

A) The tentacles shoot forward to grasp a small fish and then withdraw it to the mouth.
B) An extended tentacle suddenly contracts in immediate response to a tactile stimulus.
C) The rate of the regular in and out movements of the mantle, that ventilate the gills, increases in response to a decrease in the oxygen concentration of the surrounding water.
D) A sudden forceful contraction of the mantle muscles expels water through the siphon, propelling the animal backwards, away from a predator.
E) The release of ink in response to fear.

Question 21

Mechanical stimulation of a Mauthner neuron, in fish, results in a stereotyped escape response. Within milliseconds, contraction of particular trunk muscles and other muscles in the fin, jaw and operculum, cause an abrupt body turn away from the stimulus, positioning the fish to accelerate away. This behaviour is an example of a

A) rhythmically generated pattern modified by conscious input.
B) consciously generated pattern modified by a rhythmic pattern generator.
C) monosynaptic reflex.
D) polysynaptic reflex.
E) response to adrenaline release.

Question 22

The pigment-cup eye of a flatworm can

A) recognise patterns.
B) form a clear image of an object.
C) focus light onto a layer of photopigment.
D) detect the direction of a light source.
E) form images that are subsequently combined physically.

Question 23

Simple eyes of vertebrates differ from compound eyes of invertebrates in that

A) they have a single lens.
B) they can form an image.
C) they focus light.
D) the final image is constructed by the nervous system.
E) some detect polarised light.

Question 24

In the vertebrate ear, the role of the tympanum is to

A) distinguish soundwaves of different frequencies.
B) conduct and amplify soundwaves.
C) collect and concentrate soundwaves.
D) concentrate sound waves to a small area.
E) convert soundwaves into electrical impulses.

Question 25

In the cochlea of the ear, soundwaves run up the

A) auditory ossicles.
B) scala tympani.
C) pinna.
D) tectorial membrane.
E) scala vestibuli.

Question 26

When pain is felt, it is thought that nerve endings are stimulated by

A) activation of stretch receptors.
B) the deformation of Pacinian corpuscles.
C) adrenaline released in response to the damage.
D) chemicals released by damaged or irritated tissue.
E) the release of endorphins.

Question 27

Which receptors have Pacinian corpuscles at the end of the sensory axon?

A) Chemoreceptors
B) Mechanoreceptors
C) Photoreceptors
D) Enteroreceptors
E) Exteroreceptors

Question 28

In a 'flight or fight' response, the increase in frequency and strength of the heartbeat is controlled by

A) thyroid hormones.
B) the hypothalamus.
C) the autonomic nervous system.
D) the somatic nervous system.
E) the sympathetic nervous system.

Question 29

Which division of the nervous system can still function when all neural connections with the central nervous system are severed?

A) Sympathetic nervous system.
B) Parasympathetic nervous system.
C) Enteric nervous system.
D) No division can function without the central nervous system.
E) Somatic nervous system.

Question 30

An important difference between the sympathetic and the parasympathetic divisions of the autonomic nervous system is that

A) they are connected to different regions of the central nervous system.
B) they innervate different organs.
C) sympathetic nerves are under voluntary control whereas parasympathetic nerves are involuntary.
D) parasympathetic nerves are motor nerves whereas sympathetic nerves are sensory.
E) the sympathetic nerves control cardiovascular activity while the parasympathetic nerves control body metabolism.

Question 31

Motor neurons

A) detect signals from the external environment.
B) monitor blood pressure.
C) receive information from muscle cells to initiate a response.
D) control the activity of several glands.
E) require enteroreceptors and exteroreceptors for function.

Question 32

The cerebral cortex is concerned with

A) the processing of sensory information.
B) the control of movement.
C) memory.
D) emotional responses.
E) All of these functions.

Question 33

Cognitive brain functions such as formulation of speech, is localised in which area of the brain?

A) The thalamus.
B) The temporal lobe.
C) The left frontal lobe in Broca's area.
D) The pons.
E) The pineal gland.

Question 34

Many autonomic pathways are tonically active, which means

A) animals have strong avoidance behaviour to painful stimuli.
B) special neural networks control the automatic function of many internal organs.
C) the complex reflex circuits of the enteric nervous system is embedded in the walls of the digestive system.
D) that some groups of autonomic neurons fire action potentials continually and so control the level of activity of the organ they innervate.
E) autonomic neurons have axons which project to peripheral ganglia to control activity.

Question 35

Opiates suppress pain by

A) mimicking the action of peptide transmitters in the central nervous system.
B) inhibiting the transmission of information from the brain to the spinal cord.
C) binding to chemoreceptors and controlling cellular secretions involved in pain detection.
D) inhibiting the signal carried from the site of the pain to the brain.
E) stimulating the release of steroid signalling hormones which override the pain receptors.

Question 36

Glial cells

A) guide neuronal development and repair.
B) provide electrical insulation for neurons.
C) provide mechanical and nutrient support for neurons.
D) maintain the extracellular environment of neurons.
E) All options listed here are correct.

Question 37

Sensory neurons are sometimes referred to as

A) afferent neurons.
B) efferent neurons.
C) effectors.
D) affectors.
E) All options listed here are incorrect.

Question 38

What would happen to a neuron's electrochemical gradient if the plasma membrane became strongly permeable to Na⁺?

A) The voltage difference across the neuronal membrane would decrease.
B) The voltage difference across the neuronal membrane would increase slightly.
C) The voltage difference across the neuronal membrane would be unchanged.
D) The voltage difference across the neuronal membrane would increase significantly.
E) The neuronal membrane would become unstably polarised.

Question 39

An increase in the voltage difference across the plasma membrane causes it to become

A) excited, increasing Brownian motion.
B) degraded, due to denaturation of transmembrane proteins.
C) relaxed, facilitating ion transport.
D) hyperpolarised.
E) hypopolarised.

Question 40

Mosquitos are capable of detecting humans from significant distances, primarily by detecting CO₂ emissions. This would be an example of

A) mechanoreception.
B) chemotaxis.
C) chemoreception.
D) chemotropism.
E) mechanoflux.

Question 41

Elasmobranchs have electroreceptors known as

A) opaque internal amplitris.
B) nodules of Rovemina.
C) islets of Dyssius.
D) these phrases are all just plain gibberish.
E) ampullae of Lorenzini.

Question 42

Which organism has the most complex neural circuitry?

A) Drosophila melanogaster
B) Procambrus (crayfish)
C) Locusta (Orthopteran)
D) Mus musculus (mouse)
E) Helix (Gastropod)

Question 43

A first year student is spending her lunchtime at the bar. After several drinks, her balance and eye-hand coordination are noticeably impaired and all thoughts of attending her afternoon lab have been abolished. Which region of her brain is being most affected by the alcohol she has consumed?

A) Brain stem
B) Frontal lobe
C) Cerebellum
D) Parietal lobe
E) Central sulcus

Question 44

What is the factor in the evolution of neuronal membranes that limits the physical distance over which electrical information integration can occur?

A) Cranio-electroconductivity
B) The hormonal output of neurons.
C) The energy level of the neuronal electrochemical gradient
D) The electrical properties of neuronal membranes
E) The distance of environmental input signalling from external receptors