Lect 8 - Pain (Intro)

Question 1

4 Elementary Attributes of Stimulus

Answer 1

Modality
Intensity
Location
Duration

Question 2

Sensation

Answer 2

Sensory information that we are aware of

Question 3

Perception

Answer 3

Understanding of stimulus, CNS job

Question 4

Define: Law of specific nerve energies

Answer 4

A specific sensory receptor will respond to a specific modality

Photoreceptor responds to light

Question 5

Somatic Sensations

Answer 5

Tactile
Temperature
Proprioception: Stretch
Nociceptors: Pain

Question 6

What is the afferent-receptor configuration of Pain

Answer 6

Direct

Stimulus turns on an ion channel –> Triggers AP

Question 7

What is the afferent-receptor configuration of Light

Answer 7

Indirect

Stimulus acts on voltage gated Ca2+ which triggers release of neurotransmitters

Neurotransmitters activate receptor protein on separate afferent neuron

Question 8

What is a sensory unit

Answer 8

Collection of sensory receptors that are connected to the same afferent neuron

Question 9

What is a receptive field

Answer 9

Area that can be stimulated to cause an increase/decrease in activity of afferent

Question 10

Meissner Corpuscle

Answer 10

Tingling/Vibrations
Rapid Adaptation

Near the surface
Small Receptive Field

Looks like Small Ovals

Question 11

Pacinian Corpuscle

Answer 11

Tingling/Vibrations
Rapid Adaptation

Deep
Large Receptive Field

Looks like a Whorl

Question 12

Merkel Cells

Answer 12

Steady Pressure
Slow Adaptation

Near the surface
Small Receptive Field

Looks like Small Branches

Question 13

Ruffini Endings

Answer 13

Steady Pressure
Slow Adaptation

Deep
Large Receptive Field

Looks like a muscle

Question 14

Transduction

Answer 14

Stimulus is converted into electrical signal through ion channels

Ions flowing causes depolarization leading to action potential

Question 15

Intensity of action potential

Answer 15

Stronger stimulus will lead to larger change in receptor potential

Will lead to action potentials more often
(AP is more frequent instead of being literally bigger)

Question 16

Slowly Adapting

Answer 16

Stimulus triggers continuous AP until next stimulus

(Pressure)

Question 17

Rapidly Adapting

Answer 17

Stimulus triggers AP on, another stimulus will

(Vibrations)

Question 18

Population Coding

Answer 18

Multiple receptors on the same/different afferents

Stronger stimulus will trigger more afferents

Question 19

First Order Afferent

Answer 19

Peripheral to CNS

Question 20

Second Order Afferent

Answer 20

Spinal Cord / Brainstem to Cortex

Question 21

Third Order Afferent

Answer 21

Thalamus to Cortex

Question 22

How does CNS recognize stimulus

Answer 22

Specialized pathways are activated by stimulus,

Question 23

Stimulus Coding in Somatosensory System

Answer 23

Different modalities use different specialized pathways

Each pathway projects to a specific region in sensory cortex

Question 24

Size of target in somatosensory system

Answer 24

The larger it is the more nerves = More specific feeling

Question 25

Lower two point discrimination

Answer 25

Lots of nerve endings, feeling is very specific

Question 26

Different Kinds of Nociceptors

Answer 26

Mechanical Nociceptors Thermal Nociceptors Chemical Nociceptors Polymodal Nociceptors

Question 27

Chemical Nociceptors

Answer 27

Endogenous stimuli, chemical signals in body

Question 28

What are Nociceptors

Answer 28

Respond to extreme stimuli

Question 29

Are nociceptors affernts

Answer 29

No Afferents lead to different pathways Separates normal touch from pain

Question 30

TRP

Answer 30

Transient Receptor Potential Use cation channels Use different ligands to open channel

Question 31

Piezo Channel

Answer 31

Mechanical Force detected by Piezo1 Channel Allows in Ca2+ which activates AP and Inflammatory Responses