Lecture 14 Questions UNFINISHED Flashcards
what makes a sense a “special sense”?
- specialized transducer cell forms a synapse with sensory neuron
- requires 2 cells
list four of each (Special senses?)
- Vision
- Hearing
- Taste
- Smell
- Balance
? Ask
define receptor in two ways
The word receptor has two meanings in
neuroscience
1. A protein that binds a ligand
2. A structure that detects sensory info
what’s the difference between a special sense receptor, a complex receptor and
a simple receptor?
• Simple – Free nerve endings – Ex. pH, O2, temp
• Complex – Nerve ending ensheathed in non-neuronal accessory cells/tissue – Ex. Vibration,
• Special Senses – Specialized transducer cell forms a synapse with sensory neuron – Ex. Smell, vision
what is modality?
the nature of a stimulus
- a type of stimulus is a modality
- light stimulus for ex
list the four main kinds
Modalities detected by “receptors”
- Chemoreceptor
- Mechanoreceptor
- Thermoreceptor
- Photoreceptor
differentiate between adequate stimulus and intensity using the following
words: preferred, magnitude, graded potential, frequency, amount of neurotransmitter released.
• The adequate stimulus is the preferred type of stimulus for a receptor
• The intensity of the stimulus is encoded by the magnitude of the graded
potential produced
Where is the trigger zone for a primary sensory neuron?
axon hillock??
Ask
match the following with “tonic” or “phasic”
(A) parameters that are constantly monitored
(B) parameter that are usually ignored unless they are changing
(A) tonic ?
(B) phasic ?
What is accommodation?
even though a stimulus is present for a long period of time - we only see APs at the very beginning here (AKA phasic receptors)
what is a receptive field?
Defined as region of space in which the presence of a
stimulus will alter the firing of a sensory neuron
consider two areas of skin, one with little convergence onto secondary sensory neurons, one with extensive convergence.
Which will have the highest acuity? Which will have the largest receptive field. Explain (careful, this is tricky)
the MORE convergence of primary sensory neurons onto secondary neurons the LARGER the receptive field & the LOWER the acuity
therefore,
- the one with LITTLE convergence will have the HIGHEST acuity
- the one with EXTENSIVE convergence will have the LARGEST receptive field
?ask to make sure
what’s the difference between a primary receptive field, and a secondary receptive field.
Primary receptive field: somatic sensory & visual neurons are activate by stimuli that fall within a specific physical area known as the neuron’s receptive field ??
- the region within which a sensory neuron can sense a stimuli
Secondary receptive field: when multiple primary sensory neurons converge on a single secondary sensory neuron, their individual receptive fields merge into a single, large SECONDARY receptive field
ASK?
If there is extensive convergence, do you expect a smaller or larger representation on the somatosensory cortex?
larger ?? ask
what’s the difference between a receptor threshold and perceptual threshold?
- the MINIMUM stimulus to activate a receptor is the RECEPTOR THRESHOLD
Ex: minimum intensity of light in order to cause a change in the release of N.T. - Perceptual threshold: level of stimulus necessary to be AWARE of particular sensation
Ex: sitting outside when there is a light breeze moving hairs on skin b/c its not surpassing your perpectual threshold - but if you turn on tv & watch documentary on spides then the smallest breeze that might move those hairs your gonna swat out b/c your perceptive threshold has changed & now you are hyperaware of the movement of any of those hair cells
- When you enter a heightened state of arousal, then your perceptual threshold for certain stimuli can change
Dr Frankenstein has discovered labeled line processing of sensory
information. He decided to conduct an experiment to remove Merkel
Receptors in the skin of the fingertips and transplant photoreceptors in their
place. What do you expect the result to be?
A) The patient will “see” with their fingertips.
B) The patient will get the sensation of stretching skin when exposed to
light.
C) The patient will get the sensation of steady pressure or texture
sensation when exposed to light.
D) The patient will get the sensation of flutter or stroking when exposed
to light.
E) The patient will get the sensation of heat when exposed to light.
E?
What is a phantom limb?
one type of the phantom limb pain reported by amputees occurs when secondary sensory neurons in the spinal cord become hyperactive, resulting in the sensation of pain in a limb that is no longer there
explain how lateral inhibition can influence perception using the following
words: primary neurons, greatest stimulus strength, inhibits neighbours, enhanced perception
- lateral inhibition enhances contrast & makes a stimulus easier to perceive
- the responses of primary sensory neurons A, B, & C are proportional to the intensity of the stimulus in each receptor field
- secondary neuron B inhibits secondary neurons A & C, creating greater contrast b/t B & its neighbours
give the submodality (i.e. stretch, vibration etc), and location in the skin (deep ve superficial) for each of the following: free nerve ending, Meissner corpuscles, pacinian corpuscules, Rufinni corpuscules, Merkel receptors
ASK ????
what is the structure of temperature receptors?
Temperature receptors are ion channels
– Mint activates cold receptors (ion channels opened by cold
temperatures)
– Capsaicin activates warm receptors (ion channels opened by
warm/hot temperatures)
– Family of ion channels called TRP channels
- All temp receptors are found on free nerve endings
- More cold receptors than warm receptors.
- Cold: activated below body temp
- Warm: 37 to 45 °C
- Pain: Above 45 °C
what is the anatomical basis of fast pain and slow pain?
different types of axons (= fibres) carry pain info
- Medium diameter myelinated (A-beta) (=fast pain)
- Small myelinated (A-delta) (=fast pain)
- Small UNmyelinated (C-fibres) (=slow pain)
