Question 1

Doing push-ups often puts large amounts of pressure on your hand that you may not be used to feeling. In addition to holding your own body weight, your hands must sustain the force generated to push your body up from the ground, which compressed and stretches the skin. Which receptors are detecting this increased amount of pressure?

Accepted Answer

Merkel discs are responsible for detecting light touch and pressure, while Ruffini corpuscles are responsible for detecting stretch and sustained pressure. Therefore, both Merkel discs and Ruffini corpuscles would be responsible for detecting the increased pressure of push-ups.

Question 2

Second order neurons in pain pathways would have receptors for which neurotransmitters?

Accepted Answer

Glutamate and substance P are both neurotransmitters involved in pain pathways and are commonly found in second order neurons. Bradykinin and histamine are involved in pain signaling, but they typically act on first order neurons and do not have receptors on second order neurons.

Question 3

The dendrites of olfactory receptor cells are located in the

Accepted Answer

The olfactory receptor cells have dendrites located in the olfactory epithelium, which is a specialized tissue lining the nasal cavity. The glomeruli and olfactory bulb are located deeper in the nasal cavity and are involved in processing odor information. The olfactory gland is not directly involved in olfaction, but rather produces mucus that helps to trap odor molecules.

Question 4

Michael is an Iraq War veteran and lost one of his legs during his service to his country. Which of these is a possible explanation for him still being able to feel like his amputated foot itches?

Accepted Answer

When nerves are severed, the pain signals can still be sent to the brain, leading to phantom sensations. This is likely what Michael is experiencing with the itch sensation in his amputated foot, due to severed C fiber endings still existing in his amputated stump that may have originally existed in his foot. PTSD, while a possible factor for some individuals who have experienced trauma, is not necessarily the cause of Michael's phantom sensation in this case. A and D are incorrect because A fibers do not transmit the sensation of itch, and intact nerve endings cannot transmit signals from a foot that is no longer attached.

Question 5

Damage to third order somatosensory neurons would directly prevent transfer of information between which two brain regions, respectively?

Accepted Answer

Third order somatosensory neurons are responsible for carrying information from the thalamus to the primary somatosensory cortex. Therefore, damage to these neurons would prevent transfer of information between the thalamus and primary somatosensory cortex. Choices A, B, and C involve transfer of information between different regions, but not specifically between the thalamus and primary somatosensory cortex.

Question 6

A 65 year-old man visits the emergency room due to complaints about tight chest pain and numbness in his left arm. What is a likely cause for this pain, and at which point does this information converge onto the pain pathway for the chest?

Accepted Answer

The likely cause for the tight chest pain and numbness in the left arm is a heart attack, which is a result of damage to the heart muscle. The information about the pain in the chest would converge onto the pain pathway for the heart by second order neurons.

Question 7

You are in line at the grocery store and the cashier tells you that you need to pay $2.34 cents, so you reach into your pocket and count two dimes, two nickels and four pennies before pulling them all out and handing them to the cashier. Which area in your brain allowed you to count the coins correctly without seeing them?

Accepted Answer

The somatosensory association area processes information from the primary somatosensory cortex and allows for identification and recognition of objects based on touch and other somatic senses. In this case, counting the coins in your pocket without seeing them involves recognition through touch and proprioception, which would activate the somatosensory association area.

Question 8

Thermoreceptors have encapsulated nerve endings.

Accepted Answer

Thermoreceptors, which detect temperature changes, generally have free nerve endings rather than encapsulated endings. Encapsulated nerve endings are more characteristic of mechanoreceptors, which respond to mechanical pressure or distortion.

Question 9

A woman visits the ER because she has been experiencing ongoing neck and shoulder pain and no amount of sleep or therapeutic massages can relieve it. What is the most likely cause of her pain, and what is the type of pain that she is experiencing, respectively?

Accepted Answer

The answer of A woman visits the ER because she...

Question 10

Suzanne sees her doctor and complains that she is able to feel the shapes of objects but is having difficulties recognizing objects just based on feel. For example, when she reaches into her backpack, she cannot tell the difference between an apple and a banana. The doctor orders a brain scan. Which area of Suzanne's brain is most likely to show a problem?

Accepted Answer

The somatosensory association area is responsible for integrating and interpreting sensory information from different parts of the body, including touch and proprioception (the sense of the body's position in space). It also plays an important role in object recognition through touch. Therefore, a problem in this area is likely to cause difficulty in recognizing objects based on feel. The other options (medulla, primary somatosensory cortex, and thalamus) are not specifically involved in object recognition through touch.

Question 11

What type of ion channel is involved in transduction of stimuli in a pacinian corpuscle?

Accepted Answer

Pacinian corpuscles are mechanoreceptors that respond to mechanical stimuli such as pressure and vibrations. Therefore, the ion channels involved in their transduction of stimuli are mechanically-gated ion channels.

Question 12

Which of the following area(s) of the body lack nociceptors?

Accepted Answer

The spinal cord lacks nociceptors, which are sensory receptors for pain. Other areas like bone, liver, and muscle do have nociceptors.

Question 13

Alain has an accident that damages somatosensory receptors in his right leg. As a result, he would have reduced activity in somatosensory neurons in the

Accepted Answer

The somatosensory receptors in Alain's right leg will send sensory information through the right dorsal column to the left primary somatosensory cortex. Therefore, the reduced activity would be observed in the right dorsal column and the left primary somatosensory cortex.

Question 14

Which of the following is NOT an example of an endogenous analgesic?

Accepted Answer

Bradykinin is not an endogenous analgesic. It is a peptide that can cause pain and inflammation. Dynorphin, enkephalin, and endorphin are all examples of endogenous analgesics, which are naturally occurring substances in the body that can reduce pain perception.

Question 15

Melissa develops a cyst in her spinal cord that damages her dorsal column pathway. This would alter Melissa's ability to perceive all of the following sensations, EXCEPT

Accepted Answer

The dorsal column pathway is responsible for relaying information related to touch, proprioception, and vibration. However, temperature sensation is carried by a different pathway called the spinothalamic pathway. Therefore, damage to the dorsal column pathway would not alter Melissa's ability to perceive temperature.

Question 16

A patient complains of loss of sensation in her right hand. An examination shows that she is unable to sense touch, vibration, finger position, heat or pain. A brain scan shows that the patient has a tumor in the _____ cerebral cortex.

Accepted Answer

The answer of A patient complains of loss of sensation...

Question 17

Phantom limb syndrome is a condition in which patients who have lost a body part, for example a limb, experience sensation in the missing limb. This condition appears to be due to reorganization and rewiring in the brain so that sensations are localized to the missing body part. Which part of the brain is most likely being reorganized?

Accepted Answer

The primary somatosensory cortex is responsible for processing information about touch, pain, temperature, and proprioception (awareness of body position). It receives input from sensory neurons in the body and creates a map of the body’s surface on the cortex. In phantom limb syndrome, the area of the somatosensory cortex that corresponds to the missing limb is rewired to respond to input from nearby areas, leading to sensations in the missing limb.

Question 18

Transient receptor potential channels can transduce temperature, pain and gustatory stimuli.

Accepted Answer

Transient receptor potential (TRP) channels are a family of ion channels that transduce various sensory stimuli, including temperature, pain, and taste.

Question 19

Which receptors underlie sensations of vibration?

Accepted Answer

Meissner and Pacinian corpuscles are both mechanoreceptors that respond to vibrations. Meissner corpuscles detect low-frequency vibrations (up to 50 Hz) while Pacinian corpuscles detect high-frequency vibrations (above 50 Hz).

Question 20

Fast pain is transmitted by sensory neurons with what type of fibers?

Accepted Answer

Fast pain is transmitted by sensory neurons with A-delta fibers.

Quiz 9: Sensory Systems