Physioreview50(Sensory System)

Front 1

What is a sensory receptor?

Back 1

Specialized cell that transduce environmental signals into neural ones.

Front 2

What types of cells are usually sensory receptors?

Back 2

Epithelial cells and neurons

Front 3

What is a receptive field?

Back 3

Area on the body that changes the firing rate of its sensory neuron when stimulated.

Front 4

What is the field called if it increases the firing rate?

Back 4

Excitatory

Front 5

What is the field called if it decreases the firing rate?

Back 5

Inhibitory

Front 6

How are sensory neurons classified?

Back 6

By diameter(roman numerals 1-1V) and conduction velocity (A and C)

Front 7

What types of fibers are generally classified by their conduction velocity?

Back 7

Sensory nerve fibers

Front 8

Give the relative size of the following sensory neuron classifications:
1
11
111
1V

Back 8

1= largest
11= medium
111= small
1V= smallest

Front 9

Give the relative conduction velocity of the following sensory neuron classifications.
A-alpha
A-beta
A-gamma
C

Back 9

A-alpha=fastest
A-beta=medium
A-gamma=medium
C-slowest

Front 10

Describe what occurs in sensory transduction.

Back 10

1. Stimulus acts on sensory receptor
2. Sensory receptor opens ion channels
3. Change in membrane potential
4. Receptor potential generated
5. Inward, depolarizing the cell

Front 11

What direction does the current usually flow when sensory receptor channels open?

Back 11

Inward, depolarizing the cell

Front 12

What is an exception to this flow direction?

Back 12

Photoreceptors: stimulation decreases inward current and hyperpolarizes the membrane

Front 13

What effect does size of the stimulus have on the receptor potential generated?

Back 13

Larger stimuli create larger receptor potentials(graded potential)

Front 14

What types of adaptation do sensory receptors exhibit?

Back 14

Tonic(slow) and phasic(rapid)

Front 15

Which type detects onset and offset of a stimulus?

Back 15

Phasic

Front 16

What type responds repetitively to prolonged stimuli?

Back 16

Tonic

Front 17

What type detects steady stimuli?

Back 17

Tonic

Front 18

What happens to action potential frequency in phasic receptors with constant stimulation?

Back 18

Decreases

Front 19

What is the location of first and second order neurons?

Back 19

First- Dorsal root or spinal cord ganglia
Second- Spinal cord or brain stem

Third- Thalamus(relay nucei)
Fourth- Cerebral cortex

Front 20

At what level does sensory information cross the midline?

Back 20

Relay nucleus

Front 21

What sensations are perceived by the somatosensory system?

Back 21

Touch
Movement
Temperature
Pain

Front 22

What pathways does the somatosensory system use?

Back 22

Dorsal column system and anterolateral system

Front 23

What sensations are detected by the dorsal column system?

Back 23

Fine touch
Pressure
Two point discrimination
Vibration
Proprioception

Front 24

What sensations are detected by the anterolateral system?

Back 24

Temperature
Pain
Light touch

Front 25

What type of nerve fiber is prevalent in the:
Dorsal column system
Anterolateral system

Back 25

Dorsal-Group 11
Anterolateral- groups 111/1V

Front 26

What path does sensory information take in the dorsal column system?

Back 26

1. Receptors with cell bodies in the dorsal root receive stimulus
2. Signal ascends to the nucleus gracilis and nucleus cuneatus in the medulla
3. Signal crosses the midline and enters contralateral thalamus
4. Signal sent to somatosensory cortex

Front 27

What path does sensory information take in the anterolateral system?

Back 27

1. Stimulus received by receptors in the periphery
2. Signal crosses the midline and enters the enterolateral quadrant of the spinal cord
3. Signal ascends to contralateral thalamus
4. Signal sent to somatosensory cortex

Front 28

What is another name for the sensory cortex?

Back 28

Sensory homunculus

Front 29

What are the types of mechanoreceptors that detect touch and pressure?

Back 29

Meissner's corpuscles
Merkel's disc
Pacinian corpuscle
Ruffini's scorpuscle

Front 30

What sensation is encoded by the following mechanoreceptors:
Meissner's corp
Merkel's disc
Pacinian corp
Ruffini's corp

Back 30

Meissners corpuscle- velocity
Merkels's- location
Pacinian- Vibration and tapping
Ruffini's corp- pressure

Front 31

Which types of mechanoreceptors demonstrate phasic adaptation?

Back 31

Meissner's and Pacinian's corp

Front 32

Which types of mechanoreceptors demonstrate tonic adaptation?

Back 32

Merkel's disc and Ruffini's corpuscles

Front 33

What is nociception?

Back 33

Detection and perception of noxious stimuli(pain)

Front 34

Where are pain receptors located?

Back 34

Skin
Muscle
Viscera

Front 35

What types of receptors detect pain?

Back 35

No, specialized receptors, instead pain is detected by free nerve endings.

Front 36

How is visceral pain perceived by the body?

Back 36

Referred to the skin in dermatomal fashion

Front 37

What fibers carry fast pain signals?

Back 37

Group 111

Front 38

What fibers carry slow pain signals?

Back 38

C fibers

Front 39

What type of pain has rapid onset and offset?

Back 39

Fast pain

Front 40

What type of pain is poorly localized?

Back 40

Slow pain

Front 41

Opiates inhibit the release of what neurotransmitter for nociception?

Back 41

Substance P