Lecture 4: Neuronal basis of Behaviour/Sensing the Environment

Question 1

What is a stimulus?
A) A type of receptor protein
B) A graded potential that causes depolarization
C) Energy from outside the cell that the cell can respond to
D) A structure that processes sensory information

Answer 1

Correct Answer: C) Energy from outside the cell that the cell can respond to

Question 2

What is the function of a sensory receptor cell?
A) To integrate sensory information into the brain
B) To convert stimulus energy into neural signals
C) To depolarize neurons without generating a receptor potential
D) To amplify sensory stimuli

Answer 2

Correct Answer: B) To convert stimulus energy into neural signals

Question 3

Which of the following best describes a sense organ?
A) A specialized cell that converts neural signals into sensory information
B) An anatomical structure specialized for a specific kind of stimulus
C) A receptor protein that detects external energy
D) A graded potential that triggers an action potential

Answer 3

Correct Answer: B) An anatomical structure specialized for a specific kind of stimulus

Question 4

Which of the following is TRUE about a receptor potential?
A) It is an all-or-none response.
B) It is a graded potential that occurs in response to a stimulus.
C) It directly triggers neurotransmitter release without depolarization.
D) It cannot trigger an action potential, even at high intensities.

Answer 4

Correct Answer: B) It is a graded potential that occurs in response to a stimulus.

Question 5

What is the role of a sensory neuron?
A) To process and amplify neural signals in the brain.
B) To act as the receptor protein and generate action potentials.
C) To directly sense stimuli without depolarization.
D) To maintain the resting potential in sensory systems.

Answer 5

Correct Answer: B) To act as the receptor protein and generate action potentials.

Question 6

Which of the following is an example of a receptor that uses sensory neurons?
A) Photoreceptors in the retina
B) Touch receptors in the fingertips
C) Olfactory receptors in the nasal cavity
D) Hair cells in the cochlea

Answer 6

Correct Answer: B) Touch receptors in the fingertips

Question 7

How does an epithelial sensory cell differ from a sensory neuron?
A) The epithelial sensory cell generates action potentials directly.
B) The epithelial sensory cell is separate from the afferent neuron.
C) The epithelial sensory cell does not release neurotransmitters.
D) The epithelial sensory cell does not generate receptor potentials.

Answer 7

Correct Answer: B) The epithelial sensory cell is separate from the afferent neuron.

Question 8

What is a defining feature of epithelial sensory cells?
A) They generate their own action potentials.
B) They synapse with afferent neurons to transmit signals.
C) They directly process sensory information without releasing neurotransmitters.
D) They are primarily found in the fingertips.

Answer 8

Correct Answer: B) They synapse with afferent neurons to transmit signals.

Question 9

What happens when a stimulus acts on the receptor protein of an epithelial sensory cell?
A) An action potential is immediately generated in the receptor cell.
B) A receptor potential is generated, leading to neurotransmitter release.
C) The receptor potential is transmitted directly to the CNS.
D) The sensory cell directly depolarizes the afferent neuron.

Answer 9

Correct Answer: B) A receptor potential is generated, leading to neurotransmitter release.

Question 10

Which of the following is an example of an epithelial sensory cell?
A) Touch receptors in the skin
B) Receptors for sound
C) Olfactory receptors
D) Pain receptors

Answer 10

Correct Answer: B) Receptors for sound

Question 11

Which of the following is TRUE about epithelial sensory cells?
A) They generate action potentials instead of receptor potentials.
B) They are a one-step process where the cell is the receptor and neuron.
C) They release neurotransmitters to activate afferent neurons.
D) They are not involved in any graded potentials.

Answer 11

Correct Answer: C) They release neurotransmitters to activate afferent neurons.

Question 12

Which of the following correctly matches the receptor type with the stimulus it detects?
A) Chemoreceptor - Electric currents
B) Mechanoreceptor - Pressure
C) Photoreceptor - Heat
D) Thermoreceptor - Light

Answer 12

Correct Answer: B) Mechanoreceptor - Pressure

Question 13

How does ionotropic transduction work?
A) A stimulus triggers the release of a second messenger.
B) A stimulus opens ion channels directly, allowing ions to flow in.
C) A stimulus binds to a G-protein coupled receptor (GPCR).
D) A stimulus inhibits ion flow through the membrane.

Answer 13

Correct Answer: B) A stimulus opens ion channels directly, allowing ions to flow in.

Question 14

What is the main difference between ionotropic and metabotropic transduction?
A) Ionotropic transduction requires second messengers, while metabotropic transduction is direct.
B) Ionotropic transduction uses direct action to open channels, while metabotropic transduction relies on signaling cascades.
C) Metabotropic transduction involves direct ion flow, while ionotropic transduction does not.
D) Both processes rely entirely on G-protein coupled receptors.

Answer 14

Correct Answer: B) Ionotropic transduction uses direct action to open channels, while metabotropic transduction relies on signaling cascades.

Question 15

What is the primary function of sensory receptors?
A) To generate unique action potentials for different types of stimuli
B) To convert stimuli into action potentials in afferent neurons
C) To interpret stimuli directly in the sensory organ
D) To amplify the strength of all stimuli

Answer 15

Correct Answer: B) To convert stimuli into action potentials in afferent neurons

Question 16

Which of the following is TRUE about action potentials?
A) Each action potential encodes a specific type of stimulus.
B) Action potentials are identical and represent changes in membrane potential.
C) Action potentials differ in shape depending on the intensity of the stimulus.
D) Action potentials are not involved in sensory systems.

Answer 16

Correct Answer: B) Action potentials are identical and represent changes in membrane potential.

Question 17

What must receptor cells encode to allow the brain to interpret stimuli?
A) Frequency, polarity, and stimulus shape
B) Modality, intensity, location, and duration
C) Amplitude, speed, and polarity of the stimulus
D) Type, volume, and wavelength of the stimulus

Answer 17

Correct Answer: B) Modality, intensity, location, and duration

Question 18

How does the brain differentiate between a loud noise and a soft noise?
A) By analyzing the amplitude of the action potential
B) By interpreting the intensity of the signal encoded by receptor cells
C) By changing the polarity of the action potential
D) By detecting differences in action potential shapes

Answer 18

Correct Answer: B) By interpreting the intensity of the signal encoded by receptor cells

Question 19

Which of the following best describes “modality” as encoded by receptor cells?
A) The frequency of the action potentials
B) The location of the stimulus on the body
C) The type of stimulus (e.g., light vs. touch)
D) The duration of the stimulus

Answer 19

Correct Answer: C) The type of stimulus (e.g., light vs. touch)

Question 20

What is the labeled-line principle?
A) The idea that all sensory signals are interpreted in the same region of the brain.
B) The concept that different receptor types activate specific axons, which synapse in designated brain regions.
C) The idea that sensory cells can activate multiple afferent neurons simultaneously.
D) The principle that all sensory modalities share the same receptor type.

Answer 20

Correct Answer: B) The concept that different receptor types activate specific axons, which synapse in designated brain regions.

Question 21

Which of the following sensory modalities relies on true sensory neurons that connect directly to the CNS?
A) Taste and light
B) Light and sound
C) Touch and smell
D) Sound and taste

Answer 21

Correct Answer: C) Touch and smell

Question 22

How does the brain interpret the type of stimulus detected?
A) By the frequency of action potentials in sensory neurons.
B) By the type of receptor and the specific line activated in the brain.
C) By the strength of the membrane potential in sensory cells.
D) By the duration of the action potential signal.

Answer 22

Correct Answer: B) By the type of receptor and the specific line activated in the brain.

Question 23

What distinguishes taste, light, and sound from touch and smell in terms of sensory cell structure?
A) Taste, light, and sound use sensory neurons, while touch and smell use epithelial sensory cells.
B) Taste, light, and sound use epithelial sensory cells that synapse with afferent neurons, while touch and smell use true sensory neurons.
C) Touch and smell do not connect to the CNS directly.
D) Taste, light, and sound do not use afferent neurons to send signals to the brain.

Answer 23

Correct Answer: B) Taste, light, and sound use epithelial sensory cells that synapse with afferent neurons, while touch and smell use true sensory neurons.

Question 24

How is stimulus intensity encoded by action potentials?
A) By the amplitude of each action potential
B) By the frequency of action potentials
C) By the shape of the action potential
D) By the location of the receptor

Answer 24

Correct Answer: B) By the frequency of action potentials

Question 25

What does the dynamic range of a receptor refer to? A) The ability of a receptor to adapt to changes in temperature B) The sensitivity range between the receptor's threshold and saturation point C) The amount of time a receptor can detect a stimulus D) The maximum number of receptors activated at once

Answer 25

Correct Answer: B) The sensitivity range between the receptor's threshold and saturation point

Question 26

What happens when a receptor reaches saturation? A) It increases the frequency of action potentials indefinitely. B) It stops responding to any additional stimulus intensity. C) It changes its dynamic range to adapt to stronger signals. D) It sends signals to recruit other receptors.

Answer 26

Correct Answer: B) It stops responding to any additional stimulus intensity.

Question 27

Why can't a single receptor detect all possible stimulus intensities? A) It can only encode stimuli through changes in amplitude. B) Its dynamic range is limited to specific thresholds. C) It does not generate action potentials for weak stimuli. D) It only encodes information about stimulus location.

Answer 27

Correct Answer: B) Its dynamic range is limited to specific thresholds.

Question 28

What is range fractionation? A) The ability of a single receptor to detect all stimulus intensities. B) The division of the dynamic range among multiple receptor types, each tuned to a narrow range. C) The increase in receptor sensitivity as stimulus intensity decreases. D) The process by which receptors reduce their response to continuous stimulation.

Answer 28

Correct Answer: B) The division of the dynamic range among multiple receptor types, each tuned to a narrow range.

Question 29

Which of the following best describes how range fractionation increases dynamic range? A) A single receptor type adapts to cover the entire range of stimulus intensities. B) Different receptors are specialized to respond to overlapping ranges of stimulus intensity. C) Each receptor type alternates between sensitivity to bright and dim stimuli. D) Receptors use amplification to detect weak signals over a wide range.

Answer 29

Correct Answer: B) Different receptors are specialized to respond to overlapping ranges of stimulus intensity.

Question 30

What activates mechanoreceptors? A) Changes in temperature B) Stretch or distortion of the plasma membrane C) Binding of light-sensitive proteins D) Detection of chemical gradients

Answer 30

Correct Answer: B) Stretch or distortion of the plasma membrane

Question 31

Which of the following is NOT an example of mechanoreception? A) Tactile receptors detecting touch and pressure B) Baroreceptors monitoring pressure in blood vessels C) Photoreceptors detecting light intensity D) Proprioceptors monitoring body position E) B, C & D

Answer 31

E)

Question 31

Where are tactile receptors primarily located? A) Inside blood vessels B) Embedded in the skin C) In the digestive tract D) Surrounding muscle spindles

Answer 31

B)

Question 32

What is the primary function of proprioceptors? A) Detecting pressure in the cardiovascular system B) Monitoring the position of the body (e.g., muscle spindles) C) Sensing touch and vibrations on the skin D) Detecting chemical changes in the environment

Answer 32

B)

Question 33

Which type of mechanoreceptor detects pressure in blood vessels and organs? A) Proprioceptors B) Photoreceptors C) Tactile receptors D) Baroreceptors

Answer 33

Correct Answer: D) Baroreceptors

Question 34

Which tactile receptor is responsible for detecting pain and itch? A) Merkel's disks B) Ruffini corpuscles C) Free nerve endings D) Pacinian corpuscles

Answer 34

c)

Question 35

What is the function of Merkel's disks? A) Detecting pressure and vibration B) Monitoring movements across the skin C) Sensing touch and pressure, including sensitivity to Braille D) Detecting pain and itch

Answer 35

Correct Answer: C) Sensing touch and pressure, including sensitivity to Braille

Question 36

Which receptor is most sensitive to pressure and vibration, such as the sensation of a vibrating phone in your pocket? A) Ruffini corpuscles B) Merkel's disks C) Pacinian corpuscles D) Root hair plexus

Answer 36

Correct Answer: C) Pacinian corpuscles

Question 37

What is the primary role of Ruffini corpuscles? A) Detecting movements across the surface of the skin B) Monitoring stretching and position in connective tissue, skin, and joints C) Sensing pain and itch D) Detecting vibration and deep pressure

Answer 37

Correct Answer: B) Monitoring stretching and position in connective tissue, skin, and joints

Question 38

Which tactile receptor detects movements across the surface of the skin, such as when an insect lands on you? A) Merkel's disks B) Root hair plexus C) Ruffini corpuscles D) Free nerve endings

Answer 38

Correct Answer: B) Root hair plexus

Question 39

What defines a receptive field? A) The ability of a receptor to detect high-intensity stimuli B) The area of the body where a stimulus affects the activity of a specific afferent neuron C) The ability of sensory neurons to adapt to continuous stimuli D) The range of intensities a receptor can detect

Answer 39

Correct Answer: B) The area of the body where a stimulus affects the activity of a specific afferent neuron

Question 40

Which of the following tactile receptors is associated with large receptive fields and low precision? A) Merkel's disks B) Free nerve endings C) Pacinian corpuscles D) Root hair plexus

Answer 40

Correct Answer: C) Pacinian corpuscles

Question 41

What is the purpose of lateral inhibition in sensory processing? A) To increase the size of receptive fields B) To improve precision by defining boundaries between neurons C) To allow all neurons to fire simultaneously D) To adapt to continuous stimuli over time

Answer 41

Correct Answer: B) To improve precision by defining boundaries between neurons

Question 42

What is the primary purpose of lateral inhibition? A) To increase the intensity of weaker stimuli B) To focus on the strongest stimulus and suppress weaker, surrounding stimuli C) To allow all neurons to equally transmit signals to the brain D) To amplify the signals of peripheral neurons

Answer 42

Correct Answer: B) To focus on the strongest stimulus and suppress weaker, surrounding stimuli

Question 43

In the lateral inhibition process, what happens to the signals from neurons A and C when neuron B receives a strong stimulus? A) They are amplified to match the intensity of neuron B. B) They are blocked by interneurons releasing inhibitory neurotransmitters. C) They are transmitted equally alongside neuron B’s signal. D) They are converted into excitatory signals to support neuron B.

Answer 43

Correct Answer: B) They are blocked by interneurons releasing inhibitory neurotransmitters.

Question 44

Which of the following best describes the role of interneurons in lateral inhibition? A) They amplify the action potentials of the strongest stimulus. B) They prevent neurotransmitter release from the strongest neuron. C) They release inhibitory neurotransmitters to block weaker signals from surrounding neurons. D) They synapse with sensory neurons to transmit weak signals to the brain.

Answer 44

Correct Answer: C) They release inhibitory neurotransmitters to block weaker signals from surrounding neurons.

Question 45

Explain the process of lateral inhibition and its significance in sensory processing. Include how interneurons and surrounding neurons contribute to this process.

Answer 45

Lateral inhibition enhances sensory precision by allowing the brain to focus on the strongest stimulus while suppressing weaker, surrounding stimuli. When a strong stimulus activates a central neuron (e.g., neuron B), interneurons release inhibitory neurotransmitters onto neighboring neurons (e.g., neurons A and C). This reduces the signals from surrounding neurons, ensuring that the brain primarily receives input from the strongest stimulus. This mechanism helps the brain accurately identify the precise location of the stimulus and improves contrast in sensory perception.

Question 46

Which of the following statements about tonic receptors is TRUE? A) They depolarize only at the beginning of a stimulus. B) They encode the duration of a stimulus and adapt slowly. C) They are examples of phasic receptors. D) They are not involved in detecting sustained stimuli like touch or pressure.

Answer 46

b

Question 47

What is the primary characteristic of phasic receptors? A) They fire action potentials continuously as long as the stimulus is present. B) They adapt slowly to prolonged stimuli. C) They depolarize only at the onset or offset of a stimulus. D) They are responsible for encoding stimulus intensity over time.

Answer 47

C

Question 48

Which receptor type is an example of a tonic receptor? A) Pacinian corpuscles B) Merkel’s discs C) Root hair plexus D) Ruffini corpuscles

Answer 48

Answer: B

Question 49

What is the role of Pacinian corpuscles in sensory perception? A) Detecting light touch and pressure over time B) Detecting pressure and vibration with rapid adaptation C) Encoding the duration of sustained stimuli D) Monitoring the position of body parts in space

Answer 49

Answer: B

Question 50

How do phasic receptors differ from tonic receptors? A) Phasic receptors encode stimulus intensity, while tonic receptors encode stimulus duration. B) Phasic receptors depolarize continuously, while tonic receptors only respond at the onset of a stimulus. C) Phasic receptors adapt rapidly to stimuli, while tonic receptors adapt slowly. D) Phasic receptors are examples of Merkel’s discs, while tonic receptors are Pacinian corpuscles.

Answer 50

Answer: C

Question 51

What is the primary characteristic of Pacinian corpuscles? A) They are tonic receptors that detect sustained pressure. B) They are extremely phasic receptors that respond to changes in pressure and vibration. C) They are located superficially in the skin for detecting light touch. D) They adapt slowly and encode stimulus duration.

Answer 51

Answer: B

Question 52

Where are Pacinian corpuscles located, and what surrounds their dendrites? A) Superficially in the epidermis; surrounded by Merkel’s discs. B) Deep within the skin; surrounded by layers of Schwann cells and viscous gel. C) In the connective tissue of joints; surrounded by free nerve endings. D) In the hair follicles; surrounded by the root hair plexus.

Answer 52

b

Question 53

Why are Pacinian corpuscles described as "extreme phasic receptors"? A) They respond continuously to constant pressure stimuli. B) They respond only at the onset and release of a stimulus. C) They detect light touch and adapt slowly to sustained stimuli. D) They produce graded potentials instead of action potentials.

Answer 53

B

Question 54

How do Pacinian corpuscles generate an action potential? A) By encoding sustained pressure over time. B) By depolarizing in response to compression and again upon release of the stimulus. C) By releasing neurotransmitters upon constant stimulation. D) By being activated through lateral inhibition.

Answer 54

Answer: B

Question 55

What is sensory adaptation? A) The increase in action potential frequency with continuous stimulation. B) The maintenance of action potential frequency regardless of stimulus intensity. C) The decline in action potential frequency even if the stimulus is maintained. D) The complete cessation of sensory input during continuous stimulation.

Answer 55

Answer: C

Question 56

Why is sensory adaptation important for wild animals? A) It helps them respond immediately to all stimuli without filtering. B) It allows them to ignore constant, unimportant stimuli and focus on novel sensations. C) It increases sensitivity to unchanging environmental factors. D) It eliminates the need for phasic receptors.

Answer 56

b

Question 57

What is the primary function of hair cells in vertebrates? A) Detecting temperature changes in the environment. B) Providing information on balance and orientation. C) Generating motor signals for movement. D) Acting as photoreceptors in vision.

Answer 57

B

Question 58

Where are hair cells primarily used in vertebrates? A) Digestive systems. B) Auditory systems (hearing). C) Visual systems. D) Olfactory systems.

Answer 58

Answer: B

Question 59

Which of the following is NOT true about hair cells? A) They are a major class of mechanoreceptors. B) They transduce mechanical stimuli into electrical signals. C) They are found in all insects and vertebrates. D) They are evolutionarily ancient and found in many vertebrate groups.

Answer 59

c

Question 60

Which structure in hair cells is organized in increasing length and connected via tip links? A) Kinocilium B) Stereocilia C) Actin fibers D) Synaptic connections

Answer 60

B

Question 61

What is the role of the kinocilium in hair cells? A) It releases neurotransmitters. B) It is linked to accessory structures that respond to stimuli. C) It generates action potentials directly. D) It acts as a receptor for chemical signals.

Answer 61

Answer: B

Question 62

Which of the following best describes a hair cell? A) A type of neuron specialized for detecting sound and balance stimuli. B) A muscle cell involved in mechanical movement. C) An epithelial sensory cell that detects mechanical stimuli and releases neurotransmitters. D) A connective tissue cell responsible for structural support in sensory organs.

Answer 62

Correct Answer: C) An epithelial sensory cell that detects mechanical stimuli and releases neurotransmitters.

Question 63

What happens when hair cells bend toward the kinocilium? A) The cell hyperpolarizes, decreasing the frequency of action potentials in the sensory axon. B) The cell depolarizes, increasing the frequency of action potentials in the sensory axon. C) The cell remains at resting potential, with no change in action potential frequency. D) The cell depolarizes, but the frequency of action potentials decreases.

Answer 63

Correct Answer: B) The cell depolarizes, increasing the frequency of action potentials in the sensory axon.

Question 64

What occurs when hair cells bend away from the kinocilium? A) The cell depolarizes, increasing intracellular voltage. B) The cell hyperpolarizes, reducing the frequency of action potentials. C) The cell maintains its resting membrane potential. D) The cell hyperpolarizes, increasing the frequency of action potentials.

Answer 64

Correct Answer: B) The cell hyperpolarizes, reducing the frequency of action potentials.

Question 65

What determines whether a hair cell depolarizes or hyperpolarizes? A) The presence of neurotransmitters in the synaptic cleft. B) The strength of the mechanical stimulus. C) The direction of hair cell bending relative to the kinocilium. D) The frequency of action potentials in the afferent neuron.

Answer 65

C

Question 66

Which ion is primarily responsible for depolarization in hair cells? A) Sodium (Na⁺) B) Potassium (K⁺) C) Calcium (Ca²⁺) D) Chloride (Cl⁻)

Answer 66

Correct Answer: B) Potassium (K⁺)

Question 67

What happens when hair cells bend toward the kinocilium? A) Voltage-gated Ca²⁺ channels close. B) Potassium (K⁺) exits the cell. C) More potassium (K⁺) enters the cell. D) Neurotransmitter release decreases.

Answer 67

Correct Answer: C) More potassium (K⁺) enters the cell.

Question 68

Why does potassium (K⁺) enter hair cells instead of leaving, as in most neurons? A) The extracellular fluid in the inner ear is rich in K⁺. B) Potassium channels are closed in hair cells. C) Sodium-potassium pumps are inactive in hair cells. D) The intracellular concentration of K⁺ is higher than extracellular concentration.

Answer 68

Correct Answer: A) The extracellular fluid in the inner ear is rich in K⁺.

Question 69

What is the effect of increased neurotransmitter release at the synapse of a hair cell? A) Decrease in action potential frequency. B) No change in action potential frequency. C) Increase in action potential frequency in the sensory neuron. D) Hyperpolarization of the sensory neuron.

Answer 69

c

Question 70

What happens when the hair cell bends away from the kinocilium? A) Potassium (K⁺) ion channels open, causing depolarization. B) Potassium (K⁺) ion channels close, causing hyperpolarization. C) Calcium (Ca²⁺) ion channels open, increasing neurotransmitter release. D) Neurotransmitter release increases, leading to more action potentials.

Answer 70

Correct Answer: B) Potassium (K⁺) ion channels close, causing hyperpolarization.

Question 71

What is the consequence of fewer neurotransmitters being released by the hair cell? A) The primary afferent neuron fires more action potentials. B) The hair cell enters a state of depolarization. C) The primary afferent neuron fires fewer action potentials. D) The potassium (K⁺) channels reopen to restore activity.

Answer 71

c

Question 72

What is the primary function of tip links in hair cells? A) To transmit electrical signals to adjacent cells. B) To connect stereocilia and mechanically open/close ion channels. C) To anchor the kinocilium to the stereocilia. D) To release neurotransmitters into the synaptic cleft.

Answer 72

Correct Answer: B) To connect stereocilia and mechanically open/close ion channels.

Question 73

Tip links are primarily composed of: A) Actin filaments and kinocilium. B) Myosin and mechanosensitive ion channels. C) Proteins that join adjacent stereocilia. D) Voltage-gated calcium channels.

Answer 73

Correct Answer: C) Proteins that join adjacent stereocilia.

Question 74

How do tip links contribute to mechanical signal transduction in hair cells? A) By depolarizing adjacent neurons directly. B) By acting as springs to physically open/close ion channels. C) By amplifying electrical signals within the cell. D) By stabilizing the stereocilia during mechanical movement.

Answer 74

b

Question 75

Which structure in the vestibular system is responsible for detecting angular acceleration? A) Utricle B) Saccule C) Semicircular canals D) Cochlea

Answer 75

Answer: C) Semicircular canals

Question 76

What is the function of the otoliths in the vestibular sac? A) Detect angular acceleration B) Detect changes in sound frequency C) Add weight to the gelatinous matrix and help detect acceleration D) Transmit vibrations to the cochlea

Answer 76

Answer: C) Add weight to the gelatinous matrix and help detect acceleration

Question 77

What are the two systems relied upon by the vestibular system to detect balance and equilibrium? A) Cochlea and Otolith organs B) Otolith organs and Semicircular canals C) Semicircular canals and Auditory ossicles D) Cochlea and Semicircular canals

Answer 77

Answer: B) Otolith organs and Semicircular canals

Question 78

Which part of the vestibular system detects changes in position relative to gravity? A) Semicircular canals B) Utricle and Saccule C) Cochlea D) Ampulla

Answer 78

Answer: B) Utricle and Saccule

Question 79

What is the primary function of the ampulla in the semicircular canals? A) Detect linear acceleration B) Detect angular acceleration and rotational movements C) Amplify sound waves for hearing D) Detect changes in pressure

Answer 79

Answer: B) Detect angular acceleration and rotational movements

Question 80

What is the result of backward acceleration on hair cell activity? A. Increased neurotransmitter release and higher action potential frequency. B. Decreased neurotransmitter release and lower action potential frequency. C. No change in neurotransmitter release or action potentials. D. Random activation of mechanoreceptors unrelated to movement.

Answer 80

B

Question 81

What role do the otoliths play in sensing movement? A. Generate action potentials directly. B. Add weight to the gelatinous layer, enabling the detection of acceleration. C. Protect the hair cells from overstimulation. D. Trigger the release of neurotransmitters independent of movement.

Answer 81

b

Question 82

What structure is located at the base of each semicircular canal and plays a key role in detecting angular acceleration? A. Otoliths B. Macula C. Ampulla D. Cochlea

Answer 82

C) ampulla

Question 83

What is the neuromast composed of in the semicircular canal system? A. Otoliths and hair cells B. Cupula and otoliths C. Hair cells and cupula D. Macula and ampulla .

Answer 83

Answer: C. Hair cells and cupula

Question 84

What occurs when fluid moves the stereocilia away from the kinocilium? A. Hyperpolarization occurs, decreasing action potential frequency. B. Depolarization occurs, increasing action potential frequency. C. Action potential frequency remains unchanged. D. The hair cells release neurotransmitters continuously.

Answer 84

Answer: A. Hyperpolarization occurs, decreasing action potential frequency.

Question 85

When the head rotates to the left, what occurs in the left semicircular canal? A. Hair cells are pushed away from the kinocilium, decreasing action potentials. B. Hair cells are pushed toward the kinocilium, increasing action potentials. C. Hair cells are not affected by head rotation. D. Action potential frequency remains unchanged.

Answer 85

Answer: B. Hair cells are pushed toward the kinocilium, increasing action potentials.

Question 86

What is the state of the hair cells at rest in the semicircular canals? A. Completely inactive, with no action potentials fired. B. Partially active, with a baseline level of action potentials fired. C. Fully activated, with maximum action potentials fired. D. Continuously hyperpolarized.

Answer 86

b

Question 87

What happens to action potential frequency when the head accelerates to the right? A. Action potential frequency decreases on the right and increases on the left. B. Action potential frequency increases on the right and decreases on the left. C. Both sides show no change in action potential frequency. D. Action potential frequency is completely inhibited on both sides.

Answer 87

Answer: A. Action potential frequency decreases on the right and increases on the left.

Question 88

Which structure in the semicircular canal plays a key role in detecting angular acceleration? A. Otoliths B. Ampulla with gelatinous cupula C. Macula D. Basilar membrane

Answer 88

b

Question 89

What is the primary function of the middle ear? A. To amplify sound waves before they reach the cochlea. B. To convert sound waves into electrical signals. C. To transmit light signals to the brain. D. To detect angular acceleration.

Answer 89

Answer: A. To amplify sound waves before they reach the cochlea.

Question 90

What type of environment is the middle ear compared to the inner ear? A. Both are fluid-filled. B. The middle ear is air-filled, while the inner ear is fluid-filled. C. The middle ear is fluid-filled, while the inner ear is air-filled. D. Both are air-filled.

Answer 90

b

Question 91

What structure transmits vibrations from the tympanic membrane to the oval window? A. Semicircular canals B. Cochlea C. Ossicles (malleus, incus, stapes) D. Round window

Answer 91

c

Question 92

Where are sound stimuli transduced into electrical signals? A. Tympanic membrane B. Oval window C. Cochlea D. Semicircular canals

Answer 92

Answer: C. Cochlea

Question 93

Which membrane supports the hair cells in the cochlea? A) Tectorial membrane B) Basilar membrane C) Tympanic membrane D) Oval window

Answer 93

b

Question 94

What is the function of the tectorial membrane in the organ of Corti? A) It transduces sound vibrations into electrical signals. B) It anchors the hair cells and helps displace their stereocilia during vibration. C) It transfers sound waves from the middle ear to the inner ear. D) It converts chemical signals into mechanical movement.

Answer 94

Answer: B) It anchors the hair cells and helps displace their stereocilia during vibration.

Question 95

What happens when the basilar membrane vibrates? A) Hair cells embedded in the tectorial membrane depolarize or hyperpolarize. B) Fluid flows out of the cochlea into the middle ear. C) The tympanic membrane vibrates in response. D) Sound waves are blocked from entering the cochlea.

Answer 95

Answer: A) Hair cells embedded in the tectorial membrane depolarize or hyperpolarize.

Question 96

The hair cells responsible for hearing are located in which structure? A) Semicircular canals B) Organ of Corti C) Otolith organs D) Tympanic membrane

Answer 96

Answer: B) Organ of Corti

Question 97

Which part of the basilar membrane detects high-frequency sounds? A) The apical end, which is wide and flexible B) The basal end, which is narrow and stiff C) The entire membrane detects high frequencies equally D) The middle section, where stiffness is moderate

Answer 97

Answer: B) The basal end, which is narrow and stiff

Question 98

Which part of the basilar membrane detects low-frequency sounds? A) The apical end, which is wide and flexible B) The basal end, which is narrow and stiff C) The middle section of the membrane D) The entire membrane detects low frequencies equally

Answer 98

Answer: A) The apical end, which is wide and flexible

Question 99

What is the main function of the lateral line system in fish? A) Detecting pressure changes in the inner ear B) Detecting motion of water and nearby objects C) Detecting high-frequency sounds in aquatic environments D) Balancing the fish during swimming

Answer 99

Answer: B) Detecting motion of water and nearby objects

Question 100

How do hair cells in the lateral line system detect motion? A) They amplify water pressure. B) Fluid enters through surface pores, bends the stereocilia, and generates action potentials. C) They respond to electric fields generated by nearby objects. D) They are directly connected to the central nervous system for signal transmission.

Answer 100

Answer: B) Fluid enters through surface pores, bends the stereocilia, and generates action potentials.

Question 101

Which group of animals uses electroreceptors to detect small electric fields? A) Teleosts (bony fish) B) Amphibians C) Cartilaginous fish D) Birds

Answer 101

Answer: C) Cartilaginous fish

Question 102

What type of cells do monotremes use for detecting electric fields? A) Hair cells with tip links B) Bipolar cells C) Mechanoreceptors in the skin D) Ciliated epithelial cells

Answer 102

Answer: B) Bipolar cells

Question 103

What is the purpose of the electric organ in the elephant nosed fish? A) To generate light in murky waters B) To create an electric current for navigation and object detection C) To produce sound waves for communication D) To generate heat in cold environments

Answer 103

Answer: B) To create an electric current for navigation and object detection

Question 104

What type of electroreception is used by the elephant nosed fish? A) Passive electroreception B) Active electroreception C) Vibrational electroreception D) Acoustic electroreception

Answer 104

Answer: B) Active electroreception