Nervous System III - Sensory Physiology Flashcards
In a sensory unit, all receptors are ________
The same type
Opiate NTs act via what action?
Binding with opiate receptors on afferent pain-fibres to block transmission of pain signal
What type of pain can be felt in both superficial and deeper tissues and organs?
Slow pain
Sensation produced by slow pain fibres
Dull aching
_____ ________: age-related hearing loss
Neural presbycusis
An adequate stimulus for a given receptor involved a stimulus whose….?
Modality is specific to that receptor, and is the modality for which that receptor is most sensitive
Autonomic response to pain
Increase in BP and HR, epinephrine, blood glucose, sweating, and pupil dilation
Three components of sound
Pitch, loudness, timbre
Reactions to pain:
Pain sensation, autonomic responses, and emotional responses
Stimulus intensity is coded via…?
Frequency of APs and recruitment
Adaptation results in a ________‘d perception of stimulus
Decreased
The receptor function of signal transduction is the…?
The type of information that is being conveyed
Stereocilia of hair cells inter-connected via
Protein bridges
Transduction is defined as…?
Conversion of stimulus energy into electrical enegency
Loudness is coded by…?
Intensity coding; amplitude of wave coded in degree of deflection and resulting ion influx
Sensory receptors create a …… potential
Graded
Three ear ossicles (in order)
Stapes, incus, malleus
Population coding, aka________:
recruitment; stronger stimulus activates more receptors from the same or different afferent neurons
Perception is defined as…?
Conscious interpretation of external world
Response stimulus for 2 types of cold activated thermoreceptors
Also respond to menthol and eucalyptus oil; one responds to mustard oil, garlic, and cinnamon
Response stimulus for 4 types of heat activated thermoreceptors
2 are found in nociceptors and respond to temps above 42 degrees C; 1 responds to camphor (warming chemical); 1 responds to capcasin
Three types of nociceptors
Mechanical, thermal, polymodal
Audition: second order neuron synapses with third order neuron in ________
Medial geniculate nucleus of thalamus
Fibres in slow pain receptors
Unmyelinated c fibres
The modality of of signal transduction is the…?
energy form of stimulus
Hair cells synapse on afferent axons of CN ____
VIII
Pitch is coded for by…?
Location of deflection on the basilar membrane
Fibres in fast pain receptors
Myelinated a delta fibres
Coding of stimulus location is done by way of….
Receptive fields in somatic senses and vision (size of receptive field and degree of overlap) and lateral inhibition
Localization ability of fast pain fibres
Well localized
Gate-control theory of pain:
mechanical stimulation can suppress pain sensation by way of a-beta fibre from mechanoreceptor—exciting—> inhibitory interneuron —-inhibits—-> second-order neuron; suppresses pain signal from traveling up to brain
Receptor potentials are _____ potentials, caused by_______
Graded potentials; caused by the opening and closing of ion channels
_______ deafness caused by inadequate transduction of sound waves to electrical signals in inner ear
Sensorineural deafness
Localization ability of slow pain fibres
Poor localization
Law of specific nerve energies says that
Receptors show specificity to one modality
Adaptation is defined as…?
A decrease in amplitude of a receptor potential over time in presence of a constant stimulus
________ deafness is caused by damage to the neural pathway for sound
Central deafness
Characteristics of warm thermoreceptors
Free nerve endings, respond to temperatures 30-45 degrees C, increase frequency in temperature
Adaptation results in a corresponding decrease in _______ of AP
Frequency
The receptor potentials are defined as…?
The change in membrane potential in response to a stimulus acting on a sensory receptor
_______ deafness is caused by inadequate conduction of sound waves through external and/or middle ear
Conductive deafness
three types of opiate receptor NTs
Endorphins, enkephalins, and dynorphines
Sensation produced by fast pain fibres
Sharp pricking sensation
A sensory unit is defined as….?
A single afferent neuron plus all of the receptors associated with it
Audition: third-order neuron synapses in ________
Auditory cortex
Perception of pain is based on:
Past experiences
Opiate NT serve as?
Analgesics
Axons of hair cells make up ____ nerve
Cochlear nerve
Depolarization of hair cells caused by
Mechanical bending towards tall stereocilia
Hyperpolarization of hair cells caused by
Mechanical bending towards short steriocilia
Sound amplification in middle ear
sound waves strike tympanic membrane -> movement of ossicles (amplification) -> movement of oval window (amplification)
Information from the PNS to the CNS from the internal environment is called….?
Visceral afferent
Two point discrimination
Ability to perceive two points on skin
Definition of visceral pain:
Pain originating in internal organs, which has a sensation referred to the body surface
Two regions that help suppress transmission in pain pathways
Periqueductal gray matter and reticular formation
The CNS codes for stimulus type by…?
Receptor type activated, specific pathway activated, and occasionally by integration from different sensory systems
Mechanism of referred pain
2nd order neuron receives info from somatic afferents and visceral afferents, so based on history, the brain thinks pain signal is coming from somatic input
Cochlear nerve enters brainstem and synapses with….
Second-order neuron
Characteristics of cold receptors
Possible free nerve ending, respond to temps below 35 degrees C, increase frequency with decrease in temperature
Pain response comes from…?
A sensation produced by tissue damaging stimulus, or a stimulus that could potentially cause tissue damage
Auditory cortex has a _________ map
Frequency
