SDL-7 Sensory Receptors Flashcards
It takes an average of _____ms to appreciate and react to an incoming stimulus.
0.250ms
_______________ are receptors that respond to stimuli arising from outside the body. May be divided into two subgroups:
I. Telereceptors
II. Contact receptors
Exteroreceptors
______________ are receptors that detect signals originating some distance from the receptor (e.g. light detected by the eye, sound by the ear, and chemicals by the nose).
Telereceptors
_____________ are receptors that detect signals impinging on the external skin such as touch, pressure, heat, and cold.
Contact receptors
_____________ are receptors that are sensitive to signals from within the body, such as viscera, blood vessels, etc.
Interoreceptors
_____________ are receptors that detect signals from somatic structures which contribute to our sense of orientation and movement of the body in space (e.g. angle of limbs).
Proprioceptors
A specific modality of stimulus that a receptor is highly sensitive to is referred to as the ______________.
Adequate stimulus or specific energy
The theory that receptors are highly sensitive to one specific modality of stimulus is known as the ____________ theory.
Specific nerve energy
The ___________ theory states that sensation results from differing patterns of action potentials produced in a single sensory fiber.
Pattern
The intensity of a stimulus is coded in a single nerve fiber by the (amplitude/frequency) of action potentials.
Frequency
Most neurons are spontaneously active even when an action potential is not present. This rate of spontaneous activity represents a set point and is referred to as ______________.
Background frequency
As the strength of a stimulus increases, receptors with (higher/lower) thresholds are recruited to the synapse.
Higher
The absolute intensity of a stimulus involves the _______________________ and ___________________________.
I. Firing frequency of receptor nerve fibers
II. Number of receptor fibers carrying the signal
The initial signal that depolarizes a membrane is the ______________.
Generator potential
TRP receptors are non-specific, but the inward driving force for (Na+/K+/Cl-) is greater than the others, resulting in membrane depolarization.
Na+
_____________ is either a decrease or complete cessation of response of a receptor to a continuing or repeated stimulus.
Adaptation
Receptors capable of completely adapting to a stimulus are (phasic/tonic) receptors.
Phasic
Receptors that continue their activity as long as the stimulus is present are (phasic/tonic) receptors.
Tonic
____________ refers to a decrease in reflex action or to a decrease in awareness of a continuing or repeated stimulus due to decreased responsiveness of central neurons.
Habituation
(T/F) Habituation involves changing the strength of associated synapses which results in altered afferent input.
True
The ____________ of a single neuron is the area of body from which stimulation influences the neuron’s discharge rate.
Receptive field
How is the two point discrimination test conducted?
Two point discrimination is done by touching the skin with one or two points and asking the subject to tell how many points were used. When the two points are less than a threshold distance apart, the subject will report feeling one point.
What is an example of the wide variety of two point discrimination thresholds in the body?
Two point discrimination threshold distance is about 1mm on the fingers, compared to about 40mm on the back.
The cell body of each primary somatosensory neuron is located in a (dorsal root/ventral root) ganglion of the ______________.
Dorsal root ganglion of the spinal cord