Lecture 14: Sensory Physiology

Question 1

What two things do sensory information provide us with

Answer 1

1) Information from environment

2) Information about ourselves

Question 2

What are the 3 senses

Answer 2

1) Conscious
2) Unconscious
3) Receptors

Question 3

Define the two senses in Consciousness

Answer 3

1) Special senses = the 5 main senses

2) Somatic senses: Touch temp, pain, itch all within the somatosensory cortex of the parietal lobe

Question 4

What are the two unconscious senses

Answer 4

1) Somatic (muscle tension

2) Visceral senses (involving organs)

Question 5

Proprioception can be what two senses

Answer 5

Conscious or unconscious

Question 6

In neuroscience a receptor can refer to what

Answer 6

a) A protein that binds a ligand

b) A structure that detects sensory information

Question 7

What are the 5 general properties of sensory systems

Answer 7

1) Receptors are most sensitive to certain forms of energy and stimuli
2) Sensory transduction converts stimuli to graded potentials
3) Sensory neurons have receptive fields
4) The CNS integrates sensory information
5) Coding and processing distinguish stimulus properties

Question 8

What is modality

Answer 8

Refers to what is perceived after a stimulus (form of stimuli)

Question 9

What are the 4 main modality detected by sensory receptors

Answer 9

1) Heat
2) Light
3) Mechanical energy
4) Chemical stimuli/ligands

Question 10

What are the 3 general structural forms of sensory receptors and describe each

Answer 10

1) Simple : free nerve endings
2) Complex = Nerve endings ensheathed in non-neuronal accessory cells
3) Special: nerve ending creates a synapse with a specialized transducer cell

Question 11

Transduction process involves changes in what

Answer 11

membrane potentials of sensory neurons

Question 12

Receptor threshold refers to what

Answer 12

the minimum amount/intensity of a stimulus required for activation of a specific receptor

Question 13

What is the cause of large secondary receptive fields

Answer 13

convergence

Question 14

the more convergence there is for a secondary sensory neuron, the _____ the receptive field will become

Answer 14

Larger

Question 15

What will be perceived if 2 stimuli fall within the same receptive field

Answer 15

only 1 will be percieved

Question 16

Acuity means

Answer 16

the degree of sensitivity

Question 17

Describe the relationship between the amount of space in the somatosensory cortex and the sensitive of the body part

Answer 17

More area for one body part = more sensitive

Question 18

Perceptual threshold is

Answer 18

the level of stimulus required in order to be consciously aware

Question 19

Coding and processing is a ___ level of processing that occurs where

Answer 19

Higher; CNS

Question 20

Define modality

Answer 20

the form of a stimulus

Question 21

Why does Phantom Limb Syndrome occur

Answer 21

Experience pain in a missing limb due to previously associated cortical neurons inappropriately activating in response to activities of neighbouring areas or secondary neurons in spinal cords

Question 22

What is the difference between tonic and phasic receptors?

Answer 22

Tonic = slow=adapting

Phasic = fast-adapting

Question 23

Coding refers to what

Answer 23

the propertites of the action potentials generated in sensory neurons

Question 24

What are the types and functions of the skin mechanoreceptors

Answer 24

1) Free Never Endings = detects pain and itch
2) Meissner Corpuscles = light touch
3) Merkel Discs = steady pressure, texture
4) Ruffini Endings = Stretch, Tension
5) Pacinian corpuscles = deep pressure/vibrations

Question 25

Temperature receptors are ___ channels found on what

Answer 25

ion channels found on free nerve endings

Question 26

When do nociceptors activate in response to temperature?

Answer 26

Above 45 degrees C

Question 27

What is the reason we feel pain or heat after an injury

Answer 27

the release of arachidonic Acid

Question 28

Are there more cold receptors or warm receptors

Answer 28

cold

Question 29

Transient Receptor Potential (TRP) channels are

Answer 29

cation channels used to initiate action potentials for thermoreceptors

Question 30

Where are nociceptors found

Answer 30

Free nerve endings

Question 31

What type of axons deliver fast, sharp pain and what type delivers slow, intense pain and whats a difference between them?

Answer 31

fast = a-beta and a-delta

slow = c-fibers

Fast have myelinated slow doesnt

Question 32

Pain killers are often known as what kind of drugs

Answer 32

Analgesic

Question 33

Itch is perceived when

Answer 33

activation of a certain type of C-Fibre in the skin

Question 34

Capsaicin activates what

Answer 34

Warm receptors

Question 35

Chemoreceptors respond to what

Answer 35

chemical ligands that bind to the receptor smell and taste

Question 36

Ipsilateral refers to what

Answer 36

the same side

Question 37

Define Labeled line Coding

Answer 37

The association of a receptor with a specific sensation

Question 38

What are the four main kinds of modality

Answer 38

1) Touch
2) Proprioception
3) Temp
4) Nociception

Question 39

When do warm receptors kick in

Answer 39

37-45 Degrees S

Question 40

What type of ion channels do warm receptors primarily involve

Answer 40

TRPV1

Question 41

Define Proprioception

Answer 41

Awareness of body or limb location and orientation within space