Sensory Receptors and Sensory Transduction Flashcards
Mechanical displacement
Mechanoreceptors
Temperature change
Thermoreceptors
Tissue damage
alerted to this and associate it with pain
Nociceptors Pain
Chemicals
Food (salty, spicy, bitter, etc.) (on tongue)
smells (nose) (tequila, hand sanitizer)
Chemoreceptors
Light
photons
photoreceptors
cells that detect stimuli and produce receptor potentials
sensory receptors
monitoring within the body
Interoceptors
respond to changes in position of the body or its parts
proprioceptors
respond to stimuli that arise outside the body
Exteroceptors
the type of stimulus to which a receptor is most sensitive
what most easily stimulates a receptor
Adequate stimulus
area in the periphery where application of an adequate stimulus will cause a receptor to respond
Receptive fields
can stimuli stimulate other receptors?
yes, seeing light when punched in the eye (mechanical force of the punch can push on receptors so hard that a flash of light is seen) (sound in oval window should go down cochlea to stimulate that side but if it is loud enough or an extra window in canal, it will stimulate vestib side causing nystagmus)
what are special senses
Hearing (audition) & Balance
* Vision
* Olfaction
* Taste (gustatory sensations)
layers or a thin capsule
Encapsulated
free nerve endings or accessory structures
nonencapsulated
examples of cutaneous receptors
encapsulated and nonencapsulated
what are inner hair cells?
specialized mechanoreceptors
6 prominent types of mechanoreceptors in skin and subcutaneous tissues
Encapsulated—Pacinian corpuscle, Meissner corpuscle, Ruffini ending
– Nonecapsulated –Hair receptors, Merkel endings, free nerve endings
encapsulated
Detect muscle length
muscle spindles
Important Receptors in
Muscles and Joints
Many free nerve endings—function unknown
Muscle spindles - muscles
GTOs
Joint receptors - in joints
encapsulated and similar to Ruffini endings
Detect muscle tension
golgi tendon organs
Free nerve endings and others similar to receptors found in the skin
Respond to joint position and movement
joint receptors
all proprioceptors in joints, tendons, and muscles
Muscle spindles - muscles
GTOs
Joint receptors - in joints
how proprioception relates to as and vs?
helps keep our balance
Variety of receptors
Less is known about these
Mostly free nerve endings
Acting mostly at the subconscious level through visceral reflexes
visceral receptors
if bladder is full
blood vessels dilate or constrict
at organ level
visceral receptors
cells that detect types of stimuli and generate Receptor Potentials
Sensory receptor
inside of the cell about ______ more negative than outside
65 to 70 mv
electrical difference/change/firing
Potential
If a threshold of change is reached
then an Action Potentials will be generated to travel along an axon
opposite charges
attract
same charges
repel
If opposite charges are physically separated
Energy is expended and work is performed to keep them separate
If the charges are released, the charges come together (move) returning energy to the system
“Separated charge is potential electrical energy”
why do we need charge to not be at 0?
need cells to have extracellular fluid ready for receptor potential and action potential and equal status with all ions wouldn’t cause any activity and we would be dead
Elongated doughnut shapes
Ions can pass through the central pore
selectively permeable
ion channels
Ions of the Cellular Milieu
K+ Potassium
Na+ Sodium
Cl- Chloride
Ca++ Calcium
A- Anions
At rest ____ leaks into the cell and ____ leaks out
Na+ , K+
The sodium-potassium pump counterbalances this leakage moving
3 Na+ out and 2 K+ in (3:2 ratio)
Na+/K+ ATPase pump
active/uses energy
Maintains and re-establishes the resting membrane potential (balance necessary)
Other pumps exist too for
Ca++ and Cl-
Explain receptor potential process
Local (non-propogated), graded (amplitude modulated) change in the electrochemical balance
The beginning of encoding sensory information
Changes the stimulus into an electrochemical change that the nervous system uses to transmit and understand the sensory input
If threshold is reached, for example shifting the potential from -70 mv to -45 mv
Action Potentials begin to fire/travel along the neuron
Communication across synapses
Carried to a destination for an action or processing
The receptor returns to its resting potential
what is amplitude modulation
amount of stim = amount of change
what is encoded?
Type of stimulus (what is it’s nature or modality) (characteristic)
Location
Strength/intensity
Duration (onset and offset)
Frequency and rate
RP is AM
AP is FM
where it came from, what type of stimulus it was, where in brain it goes
type of stimulus
each receptor has modality of what it picks up - from that receptor to brain to perceive that stimulus)
skin receptor on hand picking up touch, neurons tell brain it is touch based on the receptor it came from
if it was pain receptor, will perceive it as pain
if light to retina, perceive as light
mode is picked up by the type of receptor
stimulating wrong thing - hard punch to eye and seeing light ex.
like a category - brain knows what it is because of where it came from and stimulated
inner ear receptor - hearing
pacinian corpusal - touch
location
where in the body then mapped to a place in the CNS (receptive fields)
knows because of mapping in brain
HAL
left hand goes to right side and goes to HAL’s hand and brain knows it was a bug on the L hand
strength
AM for RP and sensitivity of the receptor (some more sensitive some only responding to strong stimuli)
amp modulated
more volt change in receptor stronger the stimulus
Duration
Duration = duration (and some special responses such as only at the onset0
some neurons respond differently when gets to CNS, PSTH (onset, primary like, offset, choppers, pausers) and picking up these things
Freq/rate
daptation to sustained stimuli
because we have receptors while stim is there, tapping vs vibrating tuning fork on hand
can pick up
once rp starts ap and carries the distance it goes to CNS, it isn’t amp modulated it goes to frequency modulated
slower for softer
faster for stronger
RP
AM
AP
FM
what happens with encoding
anything that we need to know about ext environ and sensations has to be binary coded into RP strong enough or not? got AP and fast or slow moving?
where it is coming from and what receptor is picking it up
