Chapter 13

Question 1

PNS

Answer 1

outside Brain/Spinal cord

Question 2

PNS: Include Sensory receptors

Answer 2

– Peripheral nerves
– Associated ganglia
– Motor endings

Question 3

PNS

Answer 3

Provides links to/from the external environment

Question 4

Classification of Sensory Receptor: Location

Answer 4

Exteroceptors – near or at body surface; touch, pain,
pressure, temperature receptors in skin
– Interoceptors – visceral receptors, monitor chemical, tissue, and temperature stimuli
– Proprioceptors – constantly “advise” the brain and cerebellum of movements

Question 5

Sensory Receptor: Classified by stimulus:

Answer 5

Thermoreceptors, chemoreceptors, mechanoreceptors, nociceptors, photoreceptors

Question 6

Classified by structural complexity:

Answer 6

Simple (unencapsulated or encapsulated)
– Complex – special senses

Question 7

Sensory Receptors: monitor your world!

Answer 7

Structures specialized to respond to stimuli
* Activation of receptors = Depolarizations that trigger impulses to the CNS
* Sensory Integration: From Sensation to Perception

Question 8

Sensation

Answer 8

(you become aware of-Thalamus) to

Question 9

Perception

Answer 9

(Interpretation/understanding-Cortex)

Question 10

Sensation to Perception:

Answer 10

Survival
Sensation
Perception

Question 11

Sensation to Perception: Survival

Answer 11

Depends upon Sensation/Perception

Question 12

Sensation to Perception: Sensation

Answer 12

awareness of changes in the internal and external environment

Question 13

Sensation to Perception: Perception

Answer 13

conscious interpretation of those stimuli occurring in Cortex

Question 14

3 main levels of neural integration in the somatosensory system are

Answer 14

Receptor level – Sensory receptors
– Circuit level – Ascending pathways (“wiring” pathway)
– Perceptual level – Neuronal circuits in the Cerebral cortex

Question 15

Specificity

Answer 15

Receptor for that particular stimulus energy

Question 16

Receptive field

Answer 16

must be stimulated (the smaller the field = more accurate localization)

Question 17

converted

Answer 17

Stimulus energy converted into graded potential

Question 18

Tonic Receptors

Answer 18

(Equilibrium): always on, alterations in frequency

Question 19

Phasic Receptors:

Answer 19

normally “off” (Touch)/Report a change

Question 20

Adaptation

Answer 20

occurs when sensory receptors are subjected to an unchanging stimulus

Question 21

Adaptation

Answer 21

Receptor membranes become less responsive
– Receptor potentials decline in frequency/stop
– Pain receptors DO NOT adapt
– Slowly adapt/Not at all: Merkel’s discs, Ruffini’s
corpuscles, and Interoceptors that respond to chemical levels in the blood
Adapt Quickly: Pressure/Touch/Smell adapt quickly

Question 22

Thalamus projects fibers to

Answer 22

–Somatosensory cortex
– Sensory association areas

Question 23

Processing at the Perceptual Level

Answer 23

Brain interprets the activity of a specific receptor ALWAYS the same based on where it went (occipital lobe interprets visual signals)
* The result is an internal, conscious image of the
stimulus

Question 24

Projection:

Answer 24

brain refers sensations to their usual point of stimulation

Question 25

Main Aspects of Sensory Perception

Answer 25

* Perceptual detection – detecting that a stimulus has occurred * Magnitude estimation – how intense a stimulus is (frequency of APs) * Spatial discrimination –identifying the site or pattern of the stimulus – 2 Point discriminations test – Varies depending on site (Tongue- 5mm/Back - 50mm)

Question 26

Feature abstraction

Answer 26

used to identify a substance that has specific texture or shape

Question 27

Quality discrimination

Answer 27

the ability to identify submodalities of a sensation (e.g., sweet or sour tastes)

Question 28

Pattern recognition

Answer 28

ability to recognize patterns in stimuli (e.g., melody, familiar face)

Question 29

Regeneration of Nerve Fibers: Steps

Answer 29

1.The axon becomes fragmented at the injury site 2.Macrophages cleanse out the dead axon distal to the injury 3.Axon sprouts or grow through the regeneration tube 4.The axon regenerates and new myelin sheath