What are the two kinds of deafness and what is wrong in each?
Conducive or middle ear deafness:
cant conduct sound from the outside
loss of hair cells that transduce
What cues do we use for sound localizaon?
Interaural level diﬀerence (ILD): how loud at which ear
Interaural Time Delay (ITD): when did it arrive at which ear
CHAPTER ELEVEN STUDY QUESTIONS
The vesbular organ has three semicircular canals that have otoliths and jelly-like ﬂuid.
Using these, how do we detect the direcon of lt and the amount of acceleraon of
Directs compensatory movements of eye and helps maintain balance
What is moon sickness caused by?
Inner ears, eyes, skin, muscles get confused
The Somatosensory system is one of our mechanical senses.
What is it detecng?
Discriminave touch, deep pressure, cold, warmth, pain, itch, ckle, posion and
movement of the joints
What are three primary kinds of somatosensory receptors? What ion is used to trigger
an acon potenal? In what organ are they located? Hint: it is your largest organ…
Pain (nociceptors) , touch (tacle) , temperature (thermal)
In order for us to sense all of the diﬀerent aspects of touch, we not only need diﬀerent
kinds of receptors, but those receptors have to have special properes. Understand
these concepts and be familiar with the charts:
1. Receptors are tuned to certain types of touch
2. Have varying
Large vs. small recepve ﬁelds
at diﬀerent rates
Slowly Adapng (SA) vs. Fast Adapng (FA)
The somatosensory informaon below the neck goes into the CNS via the
31 spinal nerves and each is associated with a dermatome. Areas of the
face are not innervated by the spinal nerves but instead by cranial nerves.
refers to the skin area connected to or innervated by a
single sensory spinal nerve and each spinal nerve has a sensory
component and a motor component and connects to a limited area of the
The informaon going into the spinal cord makes its way to the brain and is processed
through some structures.
What are they?
Pain and touch have diﬀerent aﬀerent pathways.
Does touch informaon ascend up
the spine on the ipsilateral side or the contralateral side?
What about pain and
temperature informaon? Since we know they both
are contralateral, they
both cross over at some point, but where/when?
As soon as they enter the spine or
when they get to the spinal medullary juncon?
DC/ML- touch informaon, crosses over at medulla
STT-pain, crosses over instantly at spinal chord
Don’t forget our friend, the homunculus for somatosensory input to the cortex as it
responds to diﬀerent areas of the body.
Shows us: 1. How much cortex is devoted to an area of the body 2. That neighboring
regions of the body are nearby each other in the cortex
What neurotransmier is involved in mild pain? What about more intense pain?
neurotransmier can be used to “gate” or minimize pain?
Mild pain: glutamate
Intense pain: glutamate and substance P
“gate”: opioid receptors
There are both sensory and emoonal aspects to pain and each one smulates a
diﬀerent part of the cortex.
What part of the cortex is involved for each?
Emoonal: hypothalamus, amygdala, & cingulate cortex
We have many drugs for pain management. What are placebos and nocebos and how
do they work? How does capsaicin work? Where do cannabinoids work? Does morphine
work for thinner axons (dull pain) or thicker axons (sharp pain)?
: drug or other procedure with no pharamacological eﬀect; decreases pain by
percepon by decreasing the brain’s emoonal response to pain percepon, not the
sensaon itself; decreases response in cingulate cortex but not in the somatosensory
: chemicals related to marijuana that block pain; act mainly in ther
periphery of the brain
: inhibits thinner axons (dull pain)
: releases substance P faster than cells can resynthesize it, so burning
sensaon, followed by decreased pain, also damages free nerve endings, another way to
“close the gate for the pain message”
Damaged or inﬂamed ssue releases histamine, NGF, other chemicals and those
chemicals help repair damage, but they also increase the number of Na+ gates in nearby
receptors, including free-nerve endings, so magnify acvaon of those receptors so can
cause more pain. Non-steroidal an-inﬂammatory drugs (NSAIDs) block release of those