Class 2: Sensation

Question 1

Sensation

Answer 1

Conscious or nonconscious awareness of external stimuli

Question 2

Sensory impulses relayed to spinal cord:

Answer 2

Spinal reflexes

Question 3

Sensory impulses relayed to lower brain stem:

Answer 3

Autonomic, nonconscious responses (change in heartrate, respiration)

Question 4

Sensory impulses relayed to cerebral cortex

Answer 4

Perception

Question 5

Perception

Answer 5

Conscious awareness and interpretation of sensation.

Localization, memory

Question 6

Sensory modality

Answer 6

The property by which we distinguish one sensation from another

Ex. Light, touch, hot/cold, smell

Question 7

Where are the baroreceptors

Answer 7

Carotid artery, aortic arch

Question 8

Two classes of sensory modalities

Answer 8

General and special

Question 9

Special senses

Answer 9

Small, taste, vision, hearing, and equilibrium.

Each have their own unique sensory receptor cells

Question 10

General senses

Answer 10

Somatic (tactile, thermal, pain, proprioceptive)

Visceral

Question 11

Process of sensation

Answer 11

1. stimulation of receptor
2. transduction
3. generation of impulse
4. integration

Question 12

Transduction

Answer 12

The conversion of one form of energy to another. In the case of the body, the conversion is always into electrical energy.

Question 13

General Sensory Receptors

Answer 13

AKA somatic receptors

Unspecialized free nerve endings
Pain, tickle, itch, temperature

Question 14

Structural Classification of sensory receptors:

Answer 14

1. free nerve endings of first order neurons
2. encapsulated nerve endings of first order neurons
3. separate cells that synapse with first order neurons

Question 15

Free nerve endings

Answer 15

Bare dendrites, lacking any structural specialization

Question 16

Encapsulated nerve endings

Answer 16

Receptors for some somatic senses (pressure, vibration, deep touch)

Question 17

Classification of sensory receptors by stimuli detected:

Answer 17

Mechanoreceptors
Thermoreceptors
Nociceptors
Chemoreceptors
Photoreceptors
Etc.

Question 18

Mechanoreceptors

Answer 18

Direct pressure or stretch
Touch, pressure, vibration, hearing, proprioception, equilibrium and BP

Includes stretching of blood vessels and internal organs.

Muscle spindle stretch receptors (plus mechanoreceptors in joints, tendons, ligaments) affect posture and movement.

Question 19

Nociceptors

Answer 19

Detect noxious stimuli.

Intense mechanical deformation, heat, inflammatory chemicals, etc.

Question 20

Hyperalgesia

Answer 20

Heightened pain reaction; occurs in response to previous painful stimuli.

Question 21

Stimulation-produced analgesia

Answer 21

Descending pathway inhibits transmission of pain signal

Question 22

Referred pain

Answer 22

Both visceral and somatic afferent use of same interneuron –> excitation of one can lead to excitation of the other

Question 23

Chemoreceptors

Answer 23

Detect chemicals in mouth, nose, and bodily fluids.

Taste, smell, changes in arterial O2, osmolarity, blood CO, blood glucose, pH, etc.

Question 24

Rod

Answer 24

Photoreceptor that responds to low light

Question 25

Cone

Answer 25

Photoreceptor that responds to bright light

Green, red, and blue sensitive

Question 26

Ampullae of Lorenzini

Answer 26

Sensory receptor sensitive primarily to electric fields, but also salinity, and temperature.

In humans only found in Aquaman. Otherwise mostly in cartilaginous fish (like sharks).

Question 27

Baroreceptors

Answer 27

Respond to pressure and stretch in walls of blood vessels.

In carotid artery and aortic arch

Special type of mechanoreceptor

Question 28

Hydroreceptors

Answer 28

Respond to changes in humidity. Cockroaches have ‘em. We don’t.

Question 29

Electromagnetic receptors

Answer 29

Respond to electromagnetic waves. Pigeons?

Question 30

How to classify sensory receptors

Answer 30

1. By structure (free nerve ending, encapsulated nerve ending, specialized receptor cells)
2. By stimuli (mechano, chemo, thermo, noci, photceptors, etc)
3. Receptor location

Question 31

Generator potential

Answer 31

A type of graded potential generated by general sense receptors and olfactory receptors.

When large enough, triggers potential in first-order neuron

Question 32

Receptor potential

Answer 32

A type of graded potential generated by separate sensory receptors (vision, hearing, equilibrium, taste)

Trigger release of NT, which trigger post-synaptic potential in first order neuron.

Amplitude varies with intensity of stimulus.

Question 33

First Order Neuron

Answer 33

PNS –> CNS

Question 34

Second Order Neuron

Answer 34

Medulla (or wherever) –> Thalamus

Question 35

Third Order Neuron

Answer 35

Thalamus –> Target cortices

Question 36

Sensory receptors classified by location

Answer 36

Exteroreceptors
Interoreceptors
Proprioceptors

Question 37

Exteroreceptors

Answer 37

Near surface of body.
Receive external stimuli
Hearing, vision, taste, touch, smell, pressure, pain, vibration and temperature

Question 38

Interoreceptors

Answer 38

Monitor internal environment
Blood pressure, viscera
Mostly not conscious, except for pressure and pain

Question 39

Proprioceptors

Answer 39

In muscles, tendons, joints and inner ear.

Sense body position and movement

Question 40

Adaptation

Answer 40

The tendency for the generator or receptor potential to decrease in amplitude during maintained, constant stimulus.

Rapid or slowly (tonic) adapting

Question 41

Tonic adaptors

Answer 41

Slowly adapting sensory receptors. Continue to trigger nerve impulses as long as stimulus persists.

Pain, proprioception, chemical composition of blood

Question 42

Phasic adaptors

Answer 42

Rapidly adapting sensory receptros. Specialized for signalling change in stimulus.

Pressure, touch, smell. Pacinian corpuscle (vibration)