Exam 3 Flashcards
What are the 3 types of pain
inflammatory, neuropathic, nociceptive
Inflammatory pain
cause by damage to tissue or inflammation of joints or by tumor cells
Neuropathic pain
caused by lesions or other damage to the nervous system (ex. carpal tunnel, brain damage from stroke)
Nociceptive pain
pain caused by activation of receptors in the skin called nocicpetors
Nociceptors
specialized cell receptors that respond to tissue damage or potential damage
What is the direct pathway model of pain? What evidence led researchers to question this model of pain perception?
This model says that pain occurs when specific nociceptor receptors in the skin are stimulated and send their signals directly from the skin to the brain. Researchers started questioning this when pain was noted to be affected by factors in addition to stimulation of the skin.
What is the gate control model of pain?
In this model there are additional pathways that influence the signals sent from the spinal cord to the brain. Nociceptors, mechanoreceptors, and central control impact the transmission cell that “creates” pain.
How do nociceptors impact the gate control model of pain?
They send excitatory signals to the transmission cell (causing pain). Excitatory signals from the neurons in the dorsal horn “open the gate” and increase the firing of the transmission cells (more pain).
Mechanoreceptors
specialized cell receptors that respond to non-painful tactile stimulation
How do mechanoreceptors impact the gate control model of pain?
When activity in the mechanoreceptors reach the dorsal horn inhibitory signals “close the gate” and decrease the firing of the transmission cells (less/no pain).
Central control
information related to cognitive functions such as expectation, attention, and distraction
How does central control impact the gate control model of pain?
Similar to mechanoreceptors, activity coming down from the brain also closes the gate and decreases transmission cell activity, thus decreasing pain.
Give an example of when expectation influenced pain
the placebo effect makes a patient expect some sort of medical relief, thus creating relief completely or partially. An interesting fact about placebos is that they can attach themselves to particular parts of the body (meaning your hand can be in pain while your foot is impacted by a placebo)
Give an example of when shifting attention influenced pain
not feeling pain until you see the blood, or playing a video game while changing the bandages of burn victims.
Give an example of when emotional distraction influenced pain
showing pictures of positive actions (playing sports) vs. negative actions (breaking a leg) impact the way a person feels as they stick their hand in a bucket of cold water.
Pain matrix
subcortical structors (hypothalamus, amygdala, thalamus, and areas of the cortex: somatosensory cortex/S1, anterior cingulate cortex/ACC, the prefrontal cortex/PFC, and the insula)
Describe the multimodal nature of pain
Pain is made up of both sensory (throbbing, dull, prickly) and emotional/affective (torturing, annoying, sickening) experiences
Pain
an unpleasant sensory and emotional experience
Opiods
chemicals such as opium and heroin that impact pain perception and attach themselves to receptor sites. These receptor sites are the same receptors that are activated by endorphines
Endorphines
endogenous (naturally occurring) morphine
Explain how people are impacted by watching other people being touched/hurt/etc.
Empathetic people are more likely to experience more pain while watching someone else in pain than people who are not classified as highly empathetic
What is the relation between heat and cold receptors–do we use the same receptors to sense both heat and cold?
We use thermo-receptors to feel temperature. They do not respond to anything other than temp. And there a different receptors for each. These receptors can feel radiant and touched temp.
Where are thermo-receptors located?
embedded in the epidermis and dermis
Where do the heat receptors project to? Where do the cold receptors project to?
Heat is projected to S1 and cold is projected to SII.
As the temperature increases, what happens to the response of a heat receptors? As the temperature decreases, what happens to the response of a cold receptors?
1) increase firing rate as temperature rises or falls ( at least to a certain extent)
2) continue to fire so long as high/low temperature remains
3) decreases firing rate as temperature decreased/increased
What is naloxone? How is it used in relation to pain?
A medical drug that is often injected into a person who has overdosed on heroin. It can almost immediately reverse the effects because it attached to the receptor sites that are usually occupied by heroin and blocks the action of the drug.
Describe the phantom limb phenomenon in relation to pain
People who have had a limb amputated can often feel as though the limb is still there, as well as, continue experiencing pain in the limb. Removal of pain nerves and cells does not affect the pain, thus informing us that pain is also mental.
What is a T-cell (pain section)?
A transmission cell affects pain, as in the increase of activity of a t-cell will result in more pain while a decrease in activity reduces pain.
Explain the mirror box treatment associated with phantom limb pain
placing your hand in a box with a mirror that gives the illusion that your other hand is in the box too is know to impact the pain associated with a clenched fist that an amputee might be feeling from their phantom limb. Having a realistic and “perfect” set up is necessary in creating the illusion.
Medial lemniscal pathway to the brain
large, fast fibers that are associated with kinesthesis (limb position) and touch. This pathway projects to S1
Spinothalamic pathway to the brain
smaller, slower fibers that are associated with pain and temperature. This pathway projects to S1.
Large-diameter fibers (L-fibers)
are associated with high thresholds and sharp bursts of pain because they adapt more quickly than the slow fibers (meaning they slow back down after the pain starts). They respond to heat and pressure. Mechanoreceptors
Small-diameter fibers (S-fibers)
are associated with duller, throbbing, and long-lasting pain. They respond to heat, pressure, cold, and noxious chemicals. Nociceptors
What are some of the functions of the odor perception?
not in book
What is the difference between the detection threshold and the recognition threshold?
The odor detection threshold is the lowest concentration of a certain odor compound that is perceivable by the human sense of smell. Odor recognition threshold?
What are some factors that need to be taken into account when measuring the detection threshold and the difference threshold?
not in book
How well can people identify odors? What is the role of memory in odor recognition?
When we have trouble identifying odors, this trouble results not from deficiency in our olfactory system, but the inability to retrieve the odor’s name from our memory
Olfactory Receptor Neurons
There are 350 different types of ORNs in the mucosa in humans and there are about 10,000 of each type (aka millions of ORNs. They are responsible for “coding” each smell molecule that comes in.
Glomeruli
small structures in the olfactory bulb that receive signals from similar olfactory receptor neurons. One function of each glomerulus is to collect information about a small group of odorants.
Olfactory receptors
a protein string that responds to odor stimuli
Olfactory bulb
the structure that receives signals directly from the olfactory receptors. The olfactory bulb contains glomeruli, which receive these signals from the receptors.
What is calcium imaging in regards to odor recognition?
When an olfactory receptor responds, the concentration of calcium ions increases inside the ORN. Calcium images involves soaking olfactory neurons in a chemical that causes the ORN to fluoresce with a green glow when exposed to UV light. Increased calcium decreases the glow.
Odorant’s recognition profile
The pattern of activation for each odorant, indicating which ORNs are activated by the odorant
What is optical imaging in regards to odor recognition?
can be used to measure the activity of large areas of the olfactory bulb by measuring how much red light is reflected from the olfactory bulb. The area of the brain that has been activated will produce less red light.
Chemotopic map in olfactory
the pattern of activation in he olfactory system in which chemicals with different properties create a “map” of activation based on these properties. Also called Odor Map.
How have optical imaging and the 2-deoxyglucose technique been used to determine a chemotopic map on the olfactory bulb?
These imaging techniques show that certain smells are associated with certain firings from specific groups ORN’s thus allowing us to map particular areas associated with different smells.
Perceptual map in olfactory
A map of different odor experiences arranged on the olfactory bulb. However, we are not to this point yet (and don’t know if it is even possible)
What are the main structures in the olfactory system past the olfactory bulb?
1) the piriform cortex, which is the primary olfactory area
2) the orbitofrontal cortex, which is the secondary olfactory area
How are odors represented in the piriform cortex and how is it different from the olfactory bulb?
orderly activation pattern in the olfactory bulb no longer exists in the piriform cortex. Activity associated with a single chemical is spread out over a large area, which large spaces between active neurons.
What is it like when smelling something for the first time?
This can be compared to creating a new memory. You smell something and the ORNs are alerted, once you smell something again a connection between these ORNs may be present, and then after multiple encounters with the smell you may have the ability to recognize the odor.
Retronasal route
The opening from the oral cavity, through the nasal pharynx, into the nasal cavity. This route is the basis for the way smell combines with taste to create flavor.
Nasal pharynx
A passageway that connects the mouth cavity and the nasal cavity
Flavor
the combination of taste and smell
Give an example of when expectations about taste impacted taste judgements and brain response
Wine tasting based on the price of wine impacts your judgement of the taste; however, wine that has not been labeled with price is not
Give an example of when satiety impacted flavor
Food appears to have a better taste when you are hungry vs when you are full
What is the Proust effect?
the connection between taste and olfaction associated with the recall of a memory. There is a little hard evidence supporting this claim; however, we know it is true.
Can newborns taste?
Yes, we know this because of facial expressions. We also know that during pregnancy and during breast-feeding, a baby is influenced by the health choices that the mother makes.
Across-fiber patterns
the pattern of nerve firing that stimulus causes across a number if neurons. Also referred to as distributed coding.
Amiloride
a substance that blocks the flow of sodium into taste receptors
Amygdala
a subcortical structure that is involved in emotional responding and in processing olfactory signals
Anosmia
loss of the ability to smell due to injury or infection
Bimodal neuron
a neuron that responds to stimuli associated with more than one sense.