Fitz

Question 1

sensory transduction

Answer 1

unique multistep physiological process common to all sensory systems

stimulus energy (electromagnetic, mechanical, or chemical) is converted into electrical potentials for interpretation by the nervous system

Question 2

What are the two types of receptors?

Answer 2

Primary afferent (somatosensory, olfactory)–peice of membrane has receptor proteins

“special senses” receptor–releases NT onto primary afferent neuron (auditory, visual)

Question 3

Receptive field

Answer 3

spacial region where a stimulus will produce a response (dendrites define region)

can overlap (redundancy)

size/shape/properties can vary

Question 4

Sensory unit

Answer 4

primary afferent + receptors that define its receptive field

Question 5

Adequate stimulus

Answer 5

receptors respond to one form of energy more than another (electromagnetic, mechanical, chemical)

receptors respond to narrow range of energy

Question 6

Stimulus intensity is encoded in two ways…

Answer 6

1) frequency coding – the firing rate of sensory neurons increases with increased intensity. Increasing the # of APs will increase intensity.
2) population coding – where the number of primary afferents responding increases (also called recruitment). One neuron responds “best” (i.e. lowest threshold) and adjacent neurons respond next (recruitment)

Question 7

Adaptation

Answer 7

the process by which a response of a receptor to a constant stimulus declines over time

If the adaptation in receptor potential occurs slowly, the response is called tonic;

if rapid adaption, called **phasic **

Question 8

acuity

Answer 8

the ability to localize a stimulus

determined by receptive field size and receptor density within a field

Question 9

Lateral Inhibition

Answer 9

CNS process to resove conflict of location

application of a stimulus to the center of the receptive field excites a central neuron, but a stimulus applied near the edge inhibits it

Question 10

Somatosensation

Answer 10

process conveying information regarding the body surface and its interaction with the environment.

It can be subdivided into mechanoreception (discriminative touch), thermosensation, and nociception.

Even among these submodalities, receptors are specialized to transduce specific stimuli, and have very different receptive field sizes and speeds of adaptation.

Question 11

Thermoreceptive proteins

Answer 11

A) Cold (5-35C & >45C–paradoxial cold (menthol)

B) Warm (30-45C–capsaicin)

receptor proteins are coupled directly to channel

Question 12

Mechanicoreceptors

Answer 12

difformation of membrane opens these ion channels

Question 13

Nociceptor proteins

Answer 13

channel opens with capsaicin, heat >45C, and H+

componds sensitizing the receptor proteins–> lower threshold for activating channel: 5HT, ATP, Bradykinin, prostagladins (THIS IS HOW NSAIDs work!)

Question 14

Pain

Answer 14

preception –arrising from nociceptive sensations

multiple pathways

varies among individuals

highly modifiable by emotions and past experiences

3 Types: acute nociceptive (fast/sharp (Adelta fibers), well localized and slow (achy) (C fibers)), inflammatory pain (damage to receptors or sensitization), neuropathic pain (complex, pheripheral central reorganization of pathways–no stimulus)

Question 15

chronic pain syndroms

Answer 15

outlast primary cause;

inflammatory pain and neuropathic pain

tends to be refractive to drugs