M2-C2-L12 --> General Sensory System I

Front 1

Each somatosensory pathway consists of what three neurons?

Back 1

PRIMARY SENSORY NEURON - Ganglion Cell

SECONDARY SENSORY NEURON - Projection Cell

TERTIARY SENSORY NEURON - Thalamic Cell

Front 2

Each neuron of the somatosensory pathway contains what?

Back 2

Receptive field

Front 3

Describe the ganglion cell neuron.

Back 3

Unipolar with a receptor

Front 4

Describe the projection cell neuron.

Back 4

Axon decussates (projects from one side of CNS to the other side)

Front 5

Describe the thalamic cell neuron.

Back 5

Projects to the sensory cortex

Front 6

Define receptive field.

Back 6

Area of skin, when stimulated, either increases or decreases the firing rate of that cell.

Front 7

Each receptive field has what two regions?

Back 7

Excitatory center

Inhibitory surround

Front 8

What two components create the properties of lateral inhibition?

Back 8

Excitatory center

Inhibitory surround

Front 9

What does lateral inhibition increase?

Back 9

The signal to noise ratio, thus enhancing contrast between stimulated and unstimulated areas.

Front 10

Describe the size of receptive fields on various parts of the body.

Back 10

The larger receptive fields tend to be proximal, while the smaller receptive fields are more distal.

Front 11

Describe the innervation density on various parts of the body.

Back 11

The innervation density is proportional to the receptive field. Thus, greater innervation density is seen distally, while the lesser innervation density is seen proximally.

Front 12

Define receptors.

Back 12

Sensory terminal whose membrane responds to a stimulus by producing a local, graded, usually depolarizing potential (increased Na+ & K+ conductance)

Front 13

Action potentials are initiated by what?

Back 13

Threshold Receptor Potential

Front 14

For each receptor there is a unique what?

Back 14

Adequate stimulus

which will cause the receptor membrane to be depolarized.

Front 15

T/F - Adequate stimulus is the same for each type of receptor.

Back 15

False - Adequate stimulus is different for each type of receptor.

Front 16

What does the fact that each type of receptor has a different adequate stimulus mean?

Back 16

Implies that each receptor makes a unique contribution to somatic sensation.