1QQ#17 for 10:30 Correct the inaccurate statements. 1.Taste receptors cells produce action potentials. 2.The adequate stimulus for free nerve endings.

1QQ#17 for 10:30Correct the inaccurate statements.

1. Taste receptors cells produce action potentials.2. The adequate stimulus for free nerve endings

surrounding a hair root is tissue damage.3. The intensity of a stimulus is proportional to the

amplitude of the action potentials it causes.4. At supra-threshold stimulus applied to center of

a receptive field of a first order sensory neuron will generate a higher frequency of action potentials than the same stimulus applied to the edge of that neuron’s receptive field.

Convergence and two-point discrimination test

What about amount of overlap? How might that affect our ability to spatially resolve a stimulus?

Fig. 07.08Receptive fields often overlap – how might the neural circuit enhance differences and thus spatial discrimination?

Spatial discrimination is enhanced by lateral inhibition• Lateral inhibition involves near neighbors that inhibit each other• Lateral projections inhibit via NTs and IPSPs

Fig. 07.11

Relative timing of stimuli

• Receptors show different state of temporal adaptation (Shouldn’t that be “acclimation”, Dr Davis?)

• Tonic vs. phasic– Tonic receptors show little adaptation and continue to

transmit signals as long as there is a stimulus

– Phasic receptors show a high level of adaptation and will decrease their responsiveness to a steady stimulus

Polymodal Sensory Neurons and Referred Pain

Topographic maps

• The bizarre cases of people missing limbs and appendages?

Muscle PhysiologyChapter 9

Characteristics: Location, cell shape, nuclei per cell, innervation, connections to adjacent myofibers, arrangement of actin and myosin, regulation of cross bridges, sources of Ca++, response to injury, twitch duration, etc.

Different types of muscles for different tasks!

S 1

S 2