NEUROBIO EXAM 3

Light adaptation at the photoreceptor cell is mediated by what mechanism

It is mediated by a decrease of intracellular calcium concentration

Light adaptation in the retina is achieved by which two mechanisms?

• A. Activation of Ca?*/calmodulin-dependent protein kinase Il in photoreceptor and surround antagonism from horizontal cells to the center cone cell

• B. Decreasing intracellular calcium concentration in photoreceptor and surround antagonism from bipolar cells to the center cone cell

• C. Decreasing intracellular calcium concentration in photoreceptor and surround antagonism from horizontal cells to the center cone cell

• D. Activation of Ca2+/calmodulin-dependent protein kinase Il in photoreceptor and surround antagonism from bipolar cells to the center cone cell

• E. Decreasing intracellular CAMP concentration in photoreceptor and surround antagonism from bipolar cells to the center cone cell

Decreasing intracellular calcium concentration in the photoreceptor and surround antagonism from horizonal cells to center cone cell

Which of the following steps does NOT occur during phototransduction?

A. Opening of cGMP-gated ion channels

B. Reduced concentration of cMP

C. Activation of transducin

D. Absorption of a photon of light by 11-cis retinal to convert to all-trans retinal

E. Activation of phosphodiesterase

A. Opening of the cGMP-gated ion channels

What is phototransduction

This is when light is converted to electrical signals

Which of the following correctly matches rods and cones with their properties?

• A. Rods: more effective light adaptation; cones: high convergence (15-30:1 to ganglion cell)

• B. Rods: high visual acuity; cones: mediate color vision

• C. Rods: low sensitivity to light; cones: saturate to high illumination

• D. Rods: activated in scotopic vision; cones: contain three types of photopigments (S, M, L)

• E. Rods: very high density in the fovea, especially in foveola; cones: activated in photopic vision

Rods: activated in scotopic vision ; cones: contain three types of photopigment (S,M,L)

A scientist who is working on a cure for hearing loss develops a chemical compound that can bind to the auditory hair cell MET channel. Would you expect this drug to be effective? Why?

A. Yes, it would induce a second messenger cascade that will hold MET channels open longer

B. Yes, it would increase the flow of cations into the hair cell

C. No, the MET channel can only be altered by mechanical means

D. Yes, it would open the MET channel without sound stimuli

E. No, it would decrease the flow of cations into the hair cell

No, the MET channel can only be altered by mechanical means

Which of the following statements about sensory transduction by auditory hair cells is correct?

1. A. Displacement of the hair bundle parallel to the plane of bilateral symmetry stretches or compresses the tip links, leading to opening or closing of mechanoelectrical transducer (MET) channels

2. B. Bending of the hair bundle toward the tallest stereocilia produces hyperpolarization

3. C. Depolarized hair cells release serotonin as their neurotransmitter

4. D. Opening of the MET channels elicits action potentials in the hair cell

5. E. None of the statements about sensory transduction by auditory hair cells are correct

Displacement of the hair bundle parallel to the plane of bilateral symmetry stretches or compresses the tip links, leading to opening or closing of MET channels

How does the ionic composition of endolymph differ from most extracellular fluids?

• A. K+-poor and Nat-rich

B. Kt-rich and Nat-poor

c. Caz+-poor and Nat-poor

D. Kt-rich and Nat-rich

E. Caz*-poor and Nat-rich

K+ rich and Na+ poor

Tonotopy refers to?

• A. The point-for-point correspondence of an area of the body to a specific point on the primary somatosensory cortex

B. Spatial arrangement of where sounds of different frequencies are processed in the different regions of the auditory system

C. The mapping of visual input from the retina to other CNS neurons in the visual system

D. Individual pyriform cortical cells are broadly tuned to different odors in the olfactory system

E. Central vestibular processing is multisensory nature and vestibular inputs are integrated with inputs from other sensory systems

Spatial arrangement where sounds of different frequencies are processed in different regions of the auditory system

Shake or turn the head to right results in?

A. Depolarization of hair cells only in the right horizontal canal and no displacement of hair bundles of hair cells in the left horizontal canal

B. Hyperpolarization of hair cells in both right and left horizontal canals

C. Depolarization of hair cells in both right and left horizontal canals

D. Depolarization of hair cells in the left horizontal canal and hyperpolarization of hair cells in the right horizontal canal

E. Depolarization of hair cells in the right horizontal canal and hyperpolarization of hair cells in the left horizontal canal

Depolarization of the hair cells in the right horizontal canal and hyper polarization of hair cells in the left horizontal canal

How is firing in the vestibular nerve expected to change as a child rides a carousel?

A. Increased firing during acceleration, baseline firing during the ride, and decreased firing during deceleration

B. Decreased firing during acceleration, baseline firing during the ride, and increased firing during deceleration

C. The firing rate would increase during acceleration, then decrease below baseline while at 40 mph

D. Decreased firing while the child is in motion

E. Increased firing while the child is in motion

Increased firing during acceleration, baseline firing during the ride, and decreased firing during deceleration

What would most likely happen if a monkey does not have otoconia?

A. Increased sensitivity to head movements

B. Decreased sensation of rotational head movements

C. Cannot stabilize gaze

D. Decreased sensation of only vertical head movements

E. Decreased sensation of linear head movements

Decreased sensation of linear head movements

Which of the following statements regarding the vestibular system is NOT correct?

A. Central vestibular processing is multisensory nature and vestibular inputs are integrated with other sensory inputs in the central nervous system

B. The semicircular canals sense static tilts and linear accelerations of the head and the otolith organs sense rotational accelerations of the head

C. In the otolith organs, a specialized area called the striola divides the hair cells into two populations with opposing hair bundle polarities

D. The sensory epithelium of the otolith organs is called macula and the sensory epithelium of the semicircular canals is called crista

E. The peripheral components of the vestibular system formed by the interconnected chambers are called the vestibular labyrinth

The semicircular canals sense static tilts and linear accelerations of the head and the otolith organs sense rotational accelerations of the head.

What type of movement do the saccule and utricle respond to, respectively?

A. Vertical; rotational

B. Vertical; horizontal

C. Rotational; vertical

D. Horizontal; vertical

Vertical; horizontal

Due to the vestibulo-ocular reflex, which muscles contract when the head moves to the right?

A. Left lateral rectus and right medial rectus

B. Left lateral rectus and left medial rectus

C. Right lateral rectus and left medial rectus

D. Right lateral rectus and right medial rectus

E. Left lateral rectus and right lateral rectus

Left lateral rectus and right medial rectus

What purposes do the vestibulocervical (VCR) and vestibulospinal reflexes (VSR) serve, resepctively?

• A. Stabilizing gaze; Stabilizing head

• B. Stabilizing gaze; Stabilizing posture

• Stabilizing posture; Stabilizing gaze

• Stabilizing head; Stabilizing posture

Stabilizing head; stabilizing posture

What is the most direct path that light information travels on its way to the optic nerve?

1. Photoreceptor cell; bipolar cell; ganglion cell; optic nerve

2. Photoreceptor cell; ganglion cell; bipolar cell; optic nerve

3. C. Bipolar cell; photoreceptor cell; ganglion cell; optic nerve

4. D. Bipolar cell; ganglion cell; photoreceptor cell; optic nerve

1. Photoreceptor cell; bipolar cell; ganglion cell; optic nerve

Applying a drug that increases GMP levels in photoreceptors would cause which effect on a photoreceptor's response to a photon of LIGHT?

A. An intensified depolarization from normali

B. An attenuated depolarization from normal

C. An intensified hyperpolarization from normal

D. An attenuated hyperpolarization from normal

E. There would be no effect

An attenuated hyper-polarization from normal

How would an OFF-center neuron's firing rate change when a light was turned on, and then turned off?

• A. Increase, decrease

• B. No change, decrease

• C. Decrease, increase

• D. No change, increase

Decrease; increase

Which of the following sensory receptors does NOT use a G protein-coupled receptor for sensory transduction?

A. Umami taste cell

B. Olfactory receptor neuron

C. Photoreceptor

D. Sweet taste cell

E. Auditory hair cell

Auditory hair cell

How is olfactory information processed by mitral cells and pyriform cortical neurons?

1. Both mitral and pyriform cortical neurons are broadly tuned

2. Both mitral cells and pyriform cortical neurons are highly selective to a particular odorant

3. Mitral cells are broadly tuned but pyriform cortical neurons are highly selective to a particular odorant

4. Mitral cells use a spare coding mechanism and pyriform cortical neurons are broadly tuned

5. Both mitral cells and pyriform cortical neurons use a spare coding mechanism

Mitral cells use a spare coding mechanism and pyriform cortical neurons are broadly tuned

Listed below are the various components of the odor transduction process:

1. Golf G-protein

2. Voltage gated sodium channel

3. Calcium-activated chloride channel

4. CAMP-gated ion channel

5. Adenylyl cyclase III

Which of the following is the correct order in which these components are activated?

• A. 5; 1; 4; 3; 2

• B. 1; 5; 4; 3; 2

• C. 5; 4; 1; 3; 2

• D. 1; 5; 4; 2; 3

• E. 2; 1; 5; 4; 3

1;5;4;3;2

Which of the following cells belong to CNS?

• A. Taste cells

• B. ORN

• C. Photoreceptor

• D. olfactory receptor neurons

• E. Hair cells

Photoreceptor

Which of the tastes need TRPM5 channel in the sensory transduction?

A. Sweet, and sour

B. Sweet, sour and umami

C. Bitter and salt

D. Bitter, sweet and umami

E. sweet, salt, umami

Bitter, sweet, umami

Which of the following sensory systems does not relay through thalamus?

1. Olfactory system

2. visual system

3. c. vestibular system

4. D. auditory system

5. E. taste system

Olfactory system

One function of the retinal pigment epithelium is to regenerate photopigment molecules after they have been exposed to light.

A. True

B. False

True

Salty and sour tastes directly use ion channels to initiate sensory transduction.

1. True

2. False

True

Cochlear and vestibular hair cells are depolarized mainly by the inflow of sodium ions.

1. True

2. False

False

Tectorial membranes can act as a spectral decomposer to decompose a sound stimulus to its frequency components.

1. True

2. False

False

Auditory nerve fibers terminated to the apical end of the cochlea response to high frequency sounds and fibers related to the basal end response to low frequency sounds

• A. True

B. False

False