Chapter 11 Flashcards
Merkels DIsc
texture and fine detail
give a more sustained response
Meissners Corpuscle
for texture and fine detail
- closer to surface
- responds with brief burst of impulses
Pacinian Corpuscle and Ruffian Endings
deeper in skin layer
- detect stretch of the skin and the perception of the shape of grasped object
Temperature Receptors
all members of the transient receptor potential family of protein ion channels
Thermal Pain Receptors
hurts because of the extreme temperature
- also a type of TRP receptors
Chemical Pain. Receptors
wide range of chemical irritants
- includes spicy things
Mechanical Pain Receptors
- exist but cannot tell us what they are
- like being punched
Vestibular Sense
- helps us maintain balance
- provides information about head position and movement
- maintained by fluid-filled vestibular organ of inner ear
Proprioception
senses movement, action, and location
Skin senses
senses conditions at the body surface
Vestibular System
senses body positions at the body surface
Semiciruclar annals
3 of them
- arranged in different orientations
- helps us respond to head movements in the three different directions
- position of our head
Utricle and Saccule
monitor head and position in terms of gravity
INtroceptive System
senses states of our internal organs
Cupula
tuffs of hair cells within it
- as they move and bend, it gives us information about positions
- speed at which they bend tells us at the speed in which the head is moving
- bend tells us which was the head is bending
- can only tell when your head accelerates not decelerates
Vestibular Nuclei, Cerebellum, Cortex (PIV)
receives information from the vestibular system
Parietal Insular Vestibular Cortex
receives information from the vestibular system
Dermatome
a segment of the body served by a single spinal nerve
- informs us what spinal nerve serves what portion of the bodies senses
Somatosensory Cortex
the projection area for the body sense neurons
- located in the parietal lobes just behind the primary motor cortex and the central sulcus
How Body Sense Information get to the Somatosensory Cortex?
enter spinal cord via spinal nerves or straight to the brain if it’s via a cranial nerve, then crosses over the midline in the medulla and travels to the thalamus
Somatotopic Map
representation of the body in the somatosensory cortex, with adjacent body parts represented in adjacent parts of the cortex
Somatosensory Cortex
four areas, each contains a somatotopic map of the body
Secondary Somato
integrates information from both sides of the body
- neurones in this area responsive to stimuli that have acquired meaning
- sends connections to the part of the temporal lobe that includes the hippocampus, and the the posterior parietal cortex
Movement to the Secondary Somatosensory Cortex
information passed from the thalamus to two subareas, extract some information, pass to two other areas which process info and pass the the secondary somatosensory cortex
Hippocampus
forms somatosensory memories
Posterior Parietal Cortex
association area that brings together the body senses, vision, and audition
- finally able to label what we are sensing
- neurons fire before and during movement to pass on information to frontal areas that trigger movements
Body Integrity Identity Disorder
condition where individuals with no apparent brain damage or disorder are convinced their limb foes not belong to them
- when the limb is touched, their is no response in the superior parietal areas
- skin conductance response to stimulation is doubled in that limb suggesting intense emotion about the limb but still no perception
Out of Body Experience
an illusion where the individual hallucinates seeing their body from another location
Fast Pain Pathway
- red lines, myelinated
- registers localized pain and relays it to the cortex in a fraction of a second
Slow
conveys the less localized, longer-lasting, aching, or burning pain
- C fibres are slower
Alpha (A) Delta Fibers
myelinated so thicker and faster
- for fast pathway
- go up into the somatosensory areas
Pain neurons immediately pass over at the
spinal cord
C Fibres
for the slow pathway
- unmylinated so slower
- go to the midbrain and thalamus
SUbstance P
neuropeptide that increases pain sensitivity
- so any future pain feels more intense
Glutamate
released for mild pain and eventually substance P is released in the spinal cord and enhance sensitivity
Nonsteroid Anti-Inflammitory (NSAID)
decreases swelling in tissues
Opiates
stimulates opiate receptors, blocks pain messages in CNS
COX-2 INhibitor (selective NSAID)
decreased inflammation
Acetaminophen
blocks pain signals in CNS
Endorphins
neurochemicals that function as neurotransmitters and hormones
- act at opiate receptors in nervous system
- only works under highly specific conditions
inescapable pain, must really activate it, life or death
- naloxone eliminates that analgesia induced by inescapable shock but the milder analgesia that follows escapable shock
Analgesia
pain relieving
Gate Control Theory
pressure signals arriving in the brain trigger an inhibitory message that travels back down the spinal cord, where it close a neural ‘gate’ in the pain pathway
- where we believe endorphins are acting
Periaqueductal Gray (PAG)
a brain stem structure surrounding the cerebral ventricles with a large number of endorphin synapses
- women have less opiate receptors here than men so they need more drugs to relieve pain
- there are cannabinoid receptors here
Endorphins
- stop the ascending pathway
- inhibit the release of substance P
Origins of Endorphin Activation
cingulate cortex or amygdala
Congenital Analgesia
insensitivity to pain
- rare and dangerous
- linked to mutations in the SCN94, PRDM12. and NGFB genes as well as elevated natural opioid levels in the cerebrospinal fluid
- do have pain but don’t feel it as intensely
Inflammatory Soup
an array of signalling molecules released when the body is in pain, which includes histamine, proteins, lipids, neurotransmitters, and cytokines
Chronic Pain
pain that lasts after healing occurs
- severity of injury does not determine likelihood of chronic pain
- depression is strongly related to chronic pain
- strength of functional connectivity between nucleus accumbent and frontal cortex predicts chronic back pain; suggest emotional connection between injury and chronic pain
SCN9A, COMT, 6 variations of Glucocorticoid Gene
genes associated with chronic pain
Phantom Pain
Nervous System Changes during Chronic Pain
- pain pathways more sensitive
- new connections between peripheral neurones in spinal cord; increase sensitivity
- normal spinal inhibitory mechanisms depressed
Brain Changes to Chronic Pain
- brain-stem pathways more responsive
- increase prefrontal cortex, anterior cingulate cortex, and insult activation
- more somatosensory cortex devoted to painful areas
- grey matter lost proportionately to the amount and duration of pain
