chapter 12

Locate the lateral spinothalamic tract in the following illustration.

(medial part of the inferior end)

A 55-year-old male undergoes a neurological exam that indicates loss of pain and temperature sensitivity, vibratory sense, and proprioception in both his legs. These symptoms could be due to which of the following speculations?

A tumor in the postcentral gyrus

Mechanoreceptors: (select all that apply)

Are part of general sensation Are widely distributed throughout the body

Sensation of sharp, acute pain are most likely transmitted along which of the following fibers?

A∂ fibers

Match the following receptor types to their sensory modality:

Baroreceptors=Pressure Proprioceptors=Body position Nociceptors=Pain Tactile receptors= touch

Which fiber type has the slowest conduction velocity to the CNS?

C

Free nerve endings: (select all that apply)

Can detect temperature Are polymodal

Mechanoreceptors detect:

Changes in the cell membrane Cell damage

Adaptation to a sensory stimulus produces

Decreased sensation when a stimulus is constantly applied

Why was the patient unable to feel her feet?

Diabetic neuropathy had destroyed the nerves over time

Visceral organs have more pain receptors than anywhere else in the body.

False

Match the following mechanoreceptors with their property (slow or fast adapting).

Free nerve endings=Slow Merkel cells=Slow Meissner's corpuscles=Rapid Krause's corpuscles=Rapid Ruffini corpuscles= Slow Pacinian corpuscles= Rapid

What is likely wrong with the patient?

He has no functional nociceptors

Visceral pain:

Is poorly localized

Which of the following are found within mucous membranes?

Krause's corpuscles

The edges of structures are emphasized by ________.

Lateral inhibition

A patient suffering from severe pain in his right leg undergoes ventrolateral cordotomy. Which specific tract is targeted by the neurosurgeon to offer relief of pain in this patient?

Left lateral spinothalamic tract

Loss of proprioceptive sensation in a patient with damage to the dorsal column is ______________ the loss of pain sensation in the same patient.

Less than

Nociceptors can detect which of the following stimuli?

Mechanical Thermal Chemical

Which of the following receptors become activated by the presence of a physical force?

Mechanoreceptor

Match the sensory receptor to the stimulus it detects.

Mechanoreceptor = body position Osmoreceptors= Solute concentration of fluids Thermoreceptor=Changes in temperature Nociceptor= Cell damage

Which of the following detect can detect vibrations?

Meissner's corpuscles

Which of the following sensory receptors are the encapsulated receptors that are found just beneath the epidermis in the dermal papillae in the non-hairy parts of the skin such as the lips and the finger tips?

Meissner's corpuscles

The distinct characteristic that makes one sensation different from others is called its:

Modality

The distinct characteristic that makes one sensation different from others is called:

Modality

Sensory receptors use which of the following as they respond to a stimulus?

Modality Location Intensity Duration

Which of the following two types of sensory receptors are free nerve endings?

Nociceptors and thermoreceptors

Referred pain:

Occurs when pain is perceived in an area outside of where the cell damage occurred

The process by which sensory information is interpreted in a meaningful form is known as _________.

Perception

The cell bodies of the first-order neurons in the anterolateral spinothalamic pathway are located in the:

Posterior root ganglia.

Which of the following sensations are relayed via the dorsal column pathway?

Proprioception Touch Vibration

Touch and pressure are sensed by the following receptors except one. Identify the receptor that is not associated with touch and pressure sensation.

Ruffini corpuscles

Which of the following neurons connect the spinal cord to the thalamus in the anterolateral pathway?

Second-order neuron

The simplest sensory receptors are

Sensory nerve endings of unipolar neurons

Arrange the following structures in the sensory pathway in the correct order.

Sensory receptor Dorsal root ganglion Dorsal root Thalamus Cerebral cortex

Which of the following channels open at temperatures above 34°C? Select all that apply.

TRPV1 TRPV2 TRPV3

Pacinian corpuscles are examples of:

Tactile receptors

Sensory adaption refers to

The limitations on the ability of a sensory neuron to respond to a stimulus

Which of the following statements regarding the determination of the intensity of the stimulus is true?

The magnitude of receptor potentials increases with increasing stimulus intensity. The frequency of action potentials increases with increasing stimulus intensity.

The second order neuron in an ascending sensory pathway is found _________.

Within the spinal cord or brainstem

The medial lemniscus is part of the ________.

dorsal pathway

If there is a logarithmic relationship between stimulus intensity and action potential frequency in sensory neurons, how much will the action potential rate increase if the stimulus intensity increases by 100?

it will double

The smallest sensory receptive fields are found in the fingertips and _______

lips

Muscle spindles are:

proprioceptors

A 67-year-old woman is in the doctor's office complaining of numbness on the left side of her body. She also has difficulty moving her left arm and her left leg. Further tests at the doctor's office reveal that she is unable to distinguish between a coin and a paper clip using her left hand when her eyes are closed and cannot feel vibrations of a tuning fork. Pinpricking resulted in duller pain on the left side than the right. Two days after her doctor's visit, she called the doctor's office with burning pain on the left side even with gentle touching. The doctor is suspecting a lesion along one of the sensory pathways. Determine which location of the pathway the problem is occurring at:

the thalamus