Psychology Chapter on Senses and Thresholds

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Questions and Answers

What distinguishes conscious senses from unconscious senses?

Conscious senses are processed in the spinal cord.

Conscious senses do not include pain perception.

Conscious senses have their highest centers in the cerebral cortex. (correct)

Conscious senses are perceived without awareness.

Which of the following is an example of an unconscious sense?

Temperature

Chemoreceptors (correct)

Touch

Hearing

What is defined as the absolute threshold?

The maximum level of stimulus required to activate a sense.

The average level of stimulus that can be perceived.

The smallest detectable difference between two stimuli.

The absolute minimum stimulus needed to activate a sense. (correct)

What is the discriminative threshold?

The minimal difference between two stimuli that can be perceived as distinct. Signup and view all the answers

Which example relates to the spatial discriminative threshold?

Two points touching the skin that could be perceived as separate. Signup and view all the answers

Which statement concerning absolute thresholds is correct?

An absolute threshold can vary depending on the individual's sensitivity. Signup and view all the answers

Which of the following is NOT a conscious sense?

Baroreceptors Signup and view all the answers

What is an example of a stimulus that might activate the absolute threshold for hearing?

A sound at 0 dB. Signup and view all the answers

What is the primary cause of Meniere’s disease?

Decreased Endolymph removal Signup and view all the answers

What happens to the hair cell's stereocilia when the Stapes moves into the Oval window?

They are bent towards the shortest stereocilia Signup and view all the answers

Which of the following describes the potential of Endolymph?

+80 mV Signup and view all the answers

What is the result when pressure in the Scala Vestibuli is greater than in the Scala Tympani?

Sound waves travel into the Scala Vestibuli Signup and view all the answers

How does potassium (K+) enter the hair cells during sound transmission?

Via Mechanosensitive K+ channels Signup and view all the answers

What condition results when there is a viral infection affecting the endolymph?

Meniere’s disease Signup and view all the answers

What ion influx occurs in hair cells due to the opening of voltage-gated channels after stereocilia movement?

Ca2+ Signup and view all the answers

What is the K+ concentration in the endolymph surrounding hair cells?

150 mM/L Signup and view all the answers

What conclusion can be drawn if a person hears noise equally from both ears during Weber's Test?

There is no auditory loss in either ear. Signup and view all the answers

Which statement best describes a possible implication of lateralization to one ear during Weber's Test?

The ear perceiving noise worse may have sensorineural loss. Signup and view all the answers

What is the reason for the ear that hears better to indicate conductive hearing loss?

Air conduction issues make that ear more sensitive to bone conduction. Signup and view all the answers

What is the purpose of performing Rinne's test following a negative Weber's test?

To differentiate between sensorineural and conductive hearing loss. Signup and view all the answers

If a person fails the Rinne's test, what can be inferred?

They definitely have conductive hearing loss in that ear. Signup and view all the answers

Which of the following is NOT a reason for sensorineural hearing loss in the ear that perceives noise worse?

Issues with hair cell sensitivity to air vibrations. Signup and view all the answers

What occurs during Weber's test if sound lateralizes to the left ear?

Rinne's test must be conducted on the left ear. Signup and view all the answers

Which conclusion about a person who has not heard noise equally during Weber's test is accurate?

It is unclear without additional testing. Signup and view all the answers

What happens to the medial rectus muscle when the left eye mechanism is activated during a right head turn?

It relaxes to allow leftward eye movement. Signup and view all the answers

Which nerve is activated when turning the head to the right to move the left eye leftward?

Contralateral abducens nerve. Signup and view all the answers

What is the primary mechanism responsible for the depolarization of nociceptive receptor cells?

Na+ influx via mechanosensitive channels. Signup and view all the answers

What initiates the action of nociceptive receptors?

Mechanical pressure. Signup and view all the answers

What happens to the bipolar OFF cell during light conditions?

It undergoes hyperpolarization. Signup and view all the answers

What type of receptor is activated in a bipolar ON cell in dark conditions?

Metabotropic receptor Signup and view all the answers

Which component involves relaxation of the lateral rectus muscle on the ipsilateral side during head movement?

Inhibition of ipsilateral abducens nucleus. Signup and view all the answers

Which statement describes the response of the ganglionar OFF cell to peripheral illumination?

It produces a high frequency of action potentials. Signup and view all the answers

In the vestibulo-ocular reflex, what is the function of the contralateral oculomotor nerve during head movement?

It relaxes the medial rectus muscle. Signup and view all the answers

During phototransduction in light conditions, how is the Na+ influx affected in a bipolar ON cell?

Inhibition of Na+ channels occurs. Signup and view all the answers

Which type of nerve fibers are associated with primary pain responses?

A-delta fibers. Signup and view all the answers

What is the role of free nerve endings in the pain reception process?

They detect mechanical pressure and temperature. Signup and view all the answers

What occurs in the receptive field center of a ganglionar OFF cell when light is fully present?

It leads to no action potential generation. Signup and view all the answers

What triggers the hyperpolarization in a bipolar ON cell under light conditions?

Inactivation of metabotropic receptors. Signup and view all the answers

What is the main reason for action potential frequency being low in ganglionar OFF cells under full illumination?

Halted neurotransmitter production. Signup and view all the answers

What is the ionic transport mechanism in bipolar OFF cells during dark conditions?

Na+ influx due to open channels. Signup and view all the answers

What effect does the activation of ionotropic receptors have on the neurotransmitter response in bipolar OFF cells?

Neurotransmitter release increase. Signup and view all the answers

In the bipolars' bipolar ON cells during dark conditions, what is the impact of metabotropic receptor activation on Na+ channels?

They block Na+ influx. Signup and view all the answers

Study Notes

Conscious vs Unconscious Senses

Conscious senses are perceived consciously, include hearing, pain, temperature, touch, pressure, taste, and smell.
Unconscious senses are not perceived consciously, include chemoreceptors and baroreceptors.
Baroreceptors detect blood pressure and carbon dioxide levels.

Absolute vs Discriminative Threshold

Absolute Threshold is the minimum stimulus needed to activate a sense.
Discriminative Threshold is the minimum difference between two stimuli that can be perceived as different.
Three types of discriminative thresholds are
- Spatial Discriminative Threshold: Minimum distance between two stimuli that can be perceived as two distinct points.
- Temporal Discriminative Threshold: Minimum time difference between two stimuli that can be perceived as two distinct events.
- Intensity Discriminative Threshold: Minimum difference in intensity between two stimuli that can be perceived as two distinct intensities.

Phototransduction in Bipolar Cells

Bipolar OFF Cells are sign-conserving.
Bipolar ON Cells are sign-inverting.
Bipolar OFF Cells respond to a lack of neurotransmitter in light conditions.
Bipolar ON Cells respond to the presence of neurotransmitter in dark conditions.

Phototransduction in Ganglionar Cells

Ganglionar OFF cells are sign-conserving.
Ganglionar OFF Cells respond to the presence of neurotransmitter in dark conditions.
Ganglionar ON Cells respond to a lack of neurotransmitter in light conditions.
Receptive Fields are areas of photoreceptors connected to one bipolar and ganglionar cell.
- The center of the receptive field is connected to the ganglionar cell.
- The periphery of the receptive field is connected to horizontal bipolar cells, which are not connected to the ganglionar cell.

Weber's Test

Weber's test is used to assess hearing loss.
A tuning fork is placed on the forehead.
Normal air conduction and bone conduction in both ears will result in the sound being heard equally in both ears.
Air conduction greater than bone conduction will also indicate normal hearing.
If the sound is not heard equally in both ears, there is either conductive hearing loss in the ear that hears the sound better or sensorineural hearing loss in the ear that hears the sound worse.

Rinne's Test

Rinne's test is used to determine the type of hearing loss: conductive or sensorineural.
It is performed by placing a tuning fork on the mastoid bone and then in front of the ear.
A positive Rinne's test indicates that air conduction is better than bone conduction, which is normal.
A negative Rinne's test indicates that bone conduction is better than air conduction, which is a sign of conductive hearing loss.

Endolymph

Endolymph is a fluid in the inner ear.
It has a high potassium concentration (150 mM/L) and a positive potential (+80 mV).
Meniere's disease is characterized by decreased endolymph removal from the inner ear.
Symptoms include vertigo, sensorineural hearing loss, and tinnitus.

Sound Transmission Through Inner Ear

Stapes movement against the oval window creates shock waves that travel into the scala vestibuli, increasing pressure in the scala vestibuli and causing the basilar membrane to move down.
As the pressure increases, the tectorial membrane moves inwards and the hair cell stereocilia are bent towards the shortest one.
This closes mechanosensitive K+ channels and reduces K+ influx.
The pressure then decreases, causing the basilar membrane to move back up.

Vestibulo-Ocular Reflex (VOR)

The VOR ensures a stable visual world during head movements.
If the head is turned to the right, the left eye will move to the left, and the right eye will move to the right.
This is achieved by:
- Excitation of contralateral abducens nucleus: This causes the lateral rectus muscle on the contralateral side of the movement to contract.
- Excitation of ipsilateral oculomotor nucleus: This causes the medial rectus muscle on the ipsilateral side of the movement to contract.
- Inhibition of ipsilateral abducens nucleus: This causes the lateral rectus muscle on the ipsilateral side of the movement to relax.
- Inhibition of contralateral oculomotor nucleus: This causes the medial rectus muscle on the contralateral side of the movement to relax.

Pain Perception

Pain perception is a complex process involving different types of receptors, neurons, and brain regions.
Free nerve endings are specialized sensory receptors that respond to mechanical pressure, temperature, and chemicals.
These receptors are found in the skin, muscles, and internal organs.
When these receptors are activated, they generate electrical impulses that travel along sensory neurons to the spinal cord and then to the brain.
The brain then interprets these signals as pain.

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Description

Explore the distinctions between conscious and unconscious senses, including the mechanisms of baroreceptors and chemoreceptors. Learn about absolute and discriminative thresholds, and discover the various types of discriminative thresholds that aid perception. This quiz will deepen your understanding of sensory processing in psychology.