Deck 4: The Peripheral Nervous System

Question 1

Which of the following are NOT correctly paired?

A) chemoreceptor/oxygen concentration
B) mechanoreceptor/skeletal muscle stretch
C) nociceptor/light touch
D) photoreceptor/light

Answer 1

C

Question 2

Which afferent input does NOT reach the conscious level?

A) somatic sense
B) proprioceptive sense
C) visceral sense
D) a special sense

Answer 2

C

Question 3

Which statement concerning receptors is correct?

A) The larger the receptor potential, the greater the frequency of action potentials initiated in the afferent neuron.
B) Tonic receptors often exhibit an "off-response."
C) Phasic receptors are important in situations where maintained information about a stimulus is valuable.
D) Receptor adaptation results from nerve fatigue.

Answer 3

A

Question 4

What is astigmatism?

A) the bending of light at angulated surfaces
B) the nonuniform (uneven) curvature of the cornea, lens, or retina
C) a disorder of accommodation in which the lens cannot bring near objects in focus
D) a disorder of accommodation in which the lens cannot bring far objects in focus

Question 5

Which statement concerning polymodal nociceptors is correct?

A) They respond only to mechanical damage such as cutting, crushing, or pinching.
B) They transmit impulses along A-delta fibres.
C) They activate the slow pain pathway on stimulation.
D) They release prostaglandins.

Question 6

What is characteristic of fast pain?

A) poorly localized
B) occurs upon stimulation of polymodal nociceptors
C) impulses carried along myelinated A-delta fibres
D) produces dull aching sensation

Question 7

Which statement concerning receptors is correct?

A) They may be either a specialized ending of an afferent neuron or a special cell closely associated with the peripheral ending of an afferent neuron.
B) They are present for every modality in the environment.
C) When stimulated, they bring about opening of K+ channels in the efferent neuron membrane
D) Mechanical receptors are sensitive to varying amounts of heat

Question 8

Endorphins and enkephalins ______________.

A) are endogenous morphine-like substances
B) activate ascending pathways
C) stimulate the release of substance P by binding with opiate receptors
D) stimulate the release of bradykinin

Question 9

Which statement concerning pacinian corpuscles is correct?

A) They adapt rapidly as the pressure energy is dissipated.
B) They can detect temperature changes.
C) They are tonic receptors.
D) They do not display an "off-response."

Question 10

Which statement concerning receptors is correct?

A) They respond to various physical or chemical changes in their environment.
B) They carry impulses from the CNS.
C) They are found at the peripheral endings of efferent neurons.
D) They are found only in the somatic nervous system.

Question 11

In somatosensory pathways,where do first-order neurons usually synapse with second-order neurons?

A) dorsal root ganglia
B) anterior root ganglion
C) cerebellum
D) thalamus

Question 12

Destruction of which of the following can cause instant blindness in one eye?

A) optic nerve
B) optic tract
C) right half of optic chiasm
D) temporal lobe

Question 13

How is the slow pain pathway activated?

A) by stimulation of mechanical or thermal nociceptors
B) by stimulation of polymodal nociceptors
C) in the absence of tissue injury
D) by large and myelinated fibres

Question 14

Coding of sensory information may result from which action?

A) frequency of the stimuli
B) location of the stimuli
C) graded potential
D) spacial pattern coding

Question 15

Which receptors are rapidly adapting?

A) muscle stretch receptors
B) tonic receptors
C) phasic receptors
D) Ruffini nerve ending

Question 16

What is the conscious interpretation of external stimuli?

A) proprioceptive sensation
B) rising blood pressure
C) sensory perception
D) dilation of pupils

Question 17

Which statement concerning receptor potentials is correct?

A) They are usually repolarizations of receptors.
B) They are graded potentials.
C) They occur in neuronal cell bodies upon summation of presynaptic input.
D) They self-propagate along the efferent fibres.

Question 18

Which statement concerning phasic receptors is correct?

A) They respond to pain stimulus
B) They signal a change in stimulus intensity.
C) They are slowly adapting receptors.
D) muscle stretch receptors is an example

Question 19

Which statement concerning tonic receptors is correct?

A) They adapt rapidly.
B) They frequently exhibit an "off-response. "
C) They can measure the degree of joint flexion.
D) They signal a change in stimulus intensity.

Question 20

The smaller the receptive fields in a region,will result in what action?

A) smaller the density of receptors in the region
B) greater the acuity in the region
C) less cortical space allotted for sensory reception from the region
D) lesser the sensitivity to stimuli

Question 21

Which statement concerning the lens of the eye is correct?

A) It has convex surfaces.
B) It is stronger when it is flatter.
C) It contributes most extensively to the eye's total refractive ability.
D) Its stronger lens must be used for distant sources.

Question 22

Which statement is NOT correct about slow pain?

A) It is carried by large, myelinated A-delta fibres.
B) It is poorly localized.
C) It occurs by the stimulation of polymodal nociceptors.
D) It occurs for a longer time than fast pain.

Question 23

Which statement concerning the retina is correct?

A) It is the middle layer of the eye.
B) It contains the photoreceptors.
C) It becomes specialized anteriorly to form the cornea.
D) It secretes the aqueous humour.

Question 24

What is the first structure to intercept light as it enters the eye?

A) aqueous humour
B) cornea
C) lens
D) retina

Question 25

When does natural analgesia occur?

A) when endogenous opiates bind to P-substance
B) when endogenous opiates bind to receptors on afferent pain fibres
C) when the anterior gray horn is stimulated
D) when C fibres are stimulated

Question 26

Which statement is correct of hyperopia?

A) The eyeball is too short or the lens is too weak.
B) A near object is focused in front of the retina, even with accommodation.
C) A far source of light is focused on the surface of the retina.
D) The eyeball is too rounded.

Question 27

What must happen for accommodation to occur?

A) The shape of the cornea must be changed.
B) The shape of the lens must be changed.
C) The ciliary muscle is relaxed for near vision.
D) The ciliary muscle is contracted for distant vision.

Question 28

Which structure contributes the most to the total refractive ability of the eye?

A) lens
B) cornea
C) ciliary muscle
D) retina

Question 29

Which statement concerning fovea is correct?

A) It is located in the exact centre of the retina.
B) It contains a greater abundance of rods than cones.
C) It is the point on the retina at which the optic nerve leaves and blood vessels pass through.
D) It has fairly high acuity.

Question 30

What is the role of glutamate in the pain pathways?

A) binds to AMPA receptors on dorsal horn cells
B) results in numbness of damaged tissue
C) causes P-substance release
D) major inhibitory neurotransmitter

Question 31

Which statement concerning the choroids is correct?

A) It contains rods and cones.
B) It is a fluid within the eye.
C) It is also known as the blind spot.
D) It is the middle layer of the eyeball.

Question 32

Which statement concerning the blind spot is correct?

A) It is the point on the retina at which the optic nerve leaves and blood vessels pass through.
B) It contains high concentrations of rods or cones.
C) It is in the exact centre of the retina.
D) It contains high concentration of cones but no rods.

Question 33

What helps reduce internal reflection (scattering of light within the eye)?

A) sclera
B) choroid
C) blind spot
D) lens

Question 34

The circular muscle of the iris __________________.

A) contracts in response to bright light to produce pupillary constriction
B) is innervated by the sympathetic nervous system
C) contracts to slacken the suspensory ligaments and increase the strength of the lens during accommodation
D) is under voluntary control

Question 35

What happens during accommodation for near vision?

A) The ciliary muscle relaxes.
B) The lens becomes more concave.
C) The suspensory ligaments become less taut.
D) Both ciliary muscle must relax and lens more concave

Question 36

Which statement concerning myopia is correct?

A) The curvature of the lens is uneven.
B) A near source of light is focused on the retina without accommodation.
C) A convex lens is used to correct the condition.
D) The images from the two eyes are not fused within the cortex.

Question 37

Which neuromodulator is NOT capable of binding to opiate receptors in the analgesic pathways?

A) bradykinin
B) dynorphin
C) endogenous opiates
D) endorphins

Question 38

Which statement is correct for rhodopsin?

A) It is the photopigment found in the red cones.
B) It consists of an opsin and retinene.
C) It is most highly concentrated in the fovea.
D) It is slowly broken down in the absence of light.

Question 39

What happens when light passes from one medium to a medium of a different density?

A) It is refracted and bends at specific angles.
B) It travels faster.
C) It changes wavelengths.
D) It gradually disappears.

Question 40

What normally controls the amount of light entering the eye?

A) ciliary muscle
B) suspensory ligaments
C) iris
D) cornea

Question 41

What happens in light adaptation?

A) Rhodopsin levels increase in rods.
B) Rhodopsin levels decrease in rods.
C) Cones become inactive.
D) Rhodopsin levels increase in rods and cones become inactive.

Question 42

Which statement is correct for Rods?

A) They are less sensitive to light than cones.
B) They have low acuity.
C) They provide vision in shades of gray.
D) They have both low acuity and provide vision in shades of gray.

Question 43

What is characteristic of presbyopia?

A) the lack of a cone type
B) pronounced visual difficulty in the early teenage years
C) a reduction in accommodative ability as a result of a loss of lens elasticity
D) retinal damage

Question 44

What relays incoming visual information to the appropriate cortical tissue?

A) colliculi
B) lateral geniculate nuclei
C) hypothalamus.
D) thalamus and hypothalamus

Question 45

What happens during dark adaptation?

A) Photopigments are gradually regenerated.
B) Rhodopsin is rapidly broken down.
C) The cones for gray vision are stimulated more than the cones for colour vision.
D) The sensitivity of the photoreceptors is reduced so that the image appears dim.

Question 46

Which statement concerning colour vision is correct?

A) It is accomplished by rods at night and cones during the day.
B) It depends on the three cone types' various ratios of stimulation in response to different wavelengths of light.
C) It is usually lost in vitamin A deficiency.
D) It depends on activation of a specific cone for each visible colour.

Question 47

Which one of the following is an anterior specialization of the choroid layer?

A) aqueous humour
B) ciliary body
C) cornea
D) lens

Question 48

Which structure is associated with hearing?

A) ampulla
B) cochlea
C) cupula
D) cristae

Question 49

In the visual pathway,which statement is true? ___________________________.

A) The fibres from the lateral halves of both retinas cross at the optic chiasm.
B) The optic nerve carries information from the lateral half of one retina and the medial half of the other retina.
C) The optic nerve carries information from both the lateral half and the medial half of the retina of the same eye.
D) The optic nerve carries information from the medial half of one retina and the lateral half of the other retina.

Question 50

What is the proper sequence of retinal processing?

A) rods and cones, ganglion cells, bipolar cells
B) rods and cones, bipolar cells, ganglion cells
C) ganglion cells, bipolar cells, rods and cones
D) ganglion cells, rods and cones, bipolar cells

Question 51

What are the three types of cones?

A) black, red, and white
B) blue, green, and red
C) blue, green, and white
D) green, orange, and yellow

Question 52

What does NOT occur in a photoreceptor during exposure to light?

A) membrane hyperpolarization
B) closure of Na+ channels in the outer segment
C) increased transmitter release from the synaptic terminal
D) decrease in cyclic GMP in the outer segment

Question 53

Which statement is correct for cones?

A) They are most abundant in the periphery of the retina.
B) They are more numerous than rods.
C) They have high sensitivity to light.
D) They are responsible for colour vision.

Question 54

Why do cones have higher acuity than rods?

A) Cones respond more to dim light.
B) There are three types of cones.
C) There is little convergence in the cone pathways within the retina.
D) There are more cones than rods.

Question 55

Which statement concerning cones is NOT correct?

A) Cones are used for day vision.
B) Cones are very sensitive to light.
C) Cones exhibit high acuity.
D) Cones are concentrated in the fovea.

Question 56

What does vitamin A deficiency cause?

A) poor night vision
B) astigmatism
C) presbyopia
D) colour blindness

Question 57

Which activities occur in the presence of light within the phototransduction pathway?

A) Ganglion cells produce action potentials.
B) cGMP levels are high in receptors.
C) Bipolar cells produce graded potentials.
D) Sodium channels open in receptors.

Question 58

What condition is caused by uneven curvatures in the lens?

A) astigmatism
B) myopia
C) presbyopia
D) hyperopia

Question 59

Which statement is correct for the optic tracts?

A) They carry information from the lateral half of the retina on the same side and the medial half of the retina on the opposite side.
B) They carry information from the lateral halves of both retinas.
C) They carry information from the medial halves of both retinas.
D) They carry information from the lateral half of the retina on the opposite side and the medial half of the retina on the same side.

Question 60

What does the middle layer of the retina contain?

A) bipolar neurons
B) convex cells
C) ganglion cells
D) rods and cones

Question 61

In which order does the vibrational stimulus normally pass through the middle ear ossicles?

A) incus to the malleus to the stapes
B) incus to the stapes to the incus
C) malleus to the incus to the stapes
D) malleus to the stapes to the incus

Question 62

Which statement is correct for the semicircular canals?

A) They detect the position of the head relative to gravity.
B) They detect rotational or angular acceleration or deceleration of the head.
C) They contain otoliths.
D) They are responsible for static equilibrium.

Question 63

Which statement is correct for the ossicular system of the ear?

A) It serves to keep the pressure on the two sides of the tympanic membrane equal.
B) It increases the pressure of vibration as it transfers the sound wave from air in the outer ear to fluid in the inner ear.
C) It assists in determining whether a sound comes from the front or rear.
D) It is part of the vestibular apparatus.

Question 64

Which structure is NOT found inside the cochlear duct?

A) basilar membrane
B) endolymph
C) oval window
D) organ of Corti

Question 65

Which type of sensory input is NOT integrated into the sense of equilibrium?

A) cutaneous
B) proprioceptive
C) vestibular
D) visual

Question 66

The human ear is most sensitive to sound frequencies within which range?

A) 0-20,000 cycles per second
B) 10-100,000 cycles per second
C) 20-20,000 cycles per second
D) 1,000-4,000 cycles per second

Question 67

How are high- and low-frequency sounds discriminated?

A) low frequencies producing stronger vibrations
B) high frequencies producing larger action potentials
C) the middle ear bones vibrating more vigorously for low frequencies
D) low frequencies deflecting the basilar membrane at a greater distance from the oval window

Question 68

What happens in response to movement of the oval window?

A) Pressure waves occur in the scala vestibuli.
B) A portion of oval window vibrates.
C) Certain hair cell receptors in the ossicles become excited.
D) The eardrum vibrates.

Question 69

Which abnormality could give rise to sensorineural deafness?

A) rupture of the tympanic membrane
B) disease or injury in the organ of Corti
C) restriction of ossicular movement because of adhesions between the bones
D) damage to the occipital lobes of the cortex

Question 70

What does fluid movement in the cochlea cause?

A) displacement of the oval window, which dissipates pressure
B) deflection of the tympanic membrane
C) the hairs of the receptor cells of the organ of Corti to be bent as they are moved in relation to the tectorial membrane
D) displacement of the ear tube

Question 71

Which of the following is NOT involved in sending a vibrational signal to the inner ear?

A) external auditory meatus
B) eustachian tube
C) malleus
D) stapes

Question 72

Where does the actual conversion of sound vibrations to nerve impulses occur?

A) eardrum
B) eustachian tube
C) cochlea
D) oval window

Question 73

Which statement concerning the tympanic membrane is correct?

A) It vibrates when struck by sound waves.
B) It contains the organ of Corti.
C) It produces ear wax.
D) It is connected to the stapes.

Question 74

Which statement concerning the oval window is correct?

A) It attaches to the malleus.
B) It transfers the sound wave from the external ear to the middle ear.
C) It is reflexively tightened in response to loud sounds to diminish transmission of these sounds to the inner ear.
D) It attaches to the stapes and transfers the sound wave from the middle ear to the inner ear.

Question 75

Where are the hair cells for hearing located?

A) cochlea
B) eustachian tube
C) saccule
D) utricle

Question 76

Which statement about sound waves is NOT correct?

A) They are produced by a disturbance pattern in air molecules.
B) They gradually dissipate as they travel from the original sound source.
C) The human ear can detect sound waves between 20 and 20,000 cycles per second.
D) The average human ear is most sensitive to sound waves with frequencies between 5,000 and 10,000 cycles per second.

Question 77

What happens when there is deflection of the basilar membrane?

A) it activates the receptors of the organ of Corti
B) it occurs in response to movements of ossicles
C) it results from displacement of the round window
D) it results from displacement of tympanic membrane

Question 78

The pitch of a sound is based on what?____________________.

A) it is determined by the frequency of vibrations of air molecules
B) it depends on the amplitude of the waves
C) it is measured in units of decibels
D) it depends on the shapes of the ossicles

Question 79

What does transmission of sound through the middle ear result in?

A) amplification of the pressure vibrations
B) stimulation of middle ear receptor cells
C) opening of the eustachian tube
D) increased firing rate in sensory axons associated with the tympanic membrane

Question 80

In which structure do sound waves first pass?

A) cochlear duct
B) scala media
C) scala tympani
D) scala vestibuli