C11 21

Question 1

Neurotransmitter

Answer 1

Chemical messenger released by neurons that may, upon binding to receptors of neurons or effector cells, stimulate or inhibit those neurons or effector cells.

Question 2

Neuromodulator

Answer 2

Chemical messenger that doe not directly cause EPSPs or IPSPs, but instead affects the strength of synaptic transmission. Presynaptically a neuromod may influence the synthesis/release/degradation/reuptake of a neurotransmitter. Postsynaptically it may

Question 3

Indirect vs. Direct neurotransmitters

Answer 3

Direct: bind to and open ion channels (alter membrane potential) - ACh, amino acid groups. Indirect: promote broader, longer lasting effects by acting through second messenger molecules - Biogenic, neuropeptides, gases.

Question 4

Functional classes of neurotransmitters

Answer 4

Excitatory/inhibitory, Direct/indirect

Question 5

Neuronal pools

Answer 5

Functional groups of neurons that process and integrate information (pools are organized into circuits)

Question 6

Serial vs. parallel processing

Answer 6

Serial: input travels along one pathway to a specific destination. (spinal reflexes, sequential stimulation of circuit). Parallel: input travels along several different pathways to be integrated in different CNS regions. (inputs stimulate many pathways

Question 7

Reflexes

Answer 7

rapid, automatic responses to stimuli in which a particular stimulous always causes the same response.

Question 8

Neuronal circuit types

Answer 8

Diverging, converging, reverbating, parallel after discharge.

Question 9

Diverging circuit

Answer 9

Common in sensory and motor pathways. Characterized by an incoming fiber that triggers responses in ever-increasing numbers of fibers along the circuit. (muscle contraction, amplifying action)

Question 10

converging circuit

Answer 10

Common in sensory and motor pathway. Characterized by reception of input from many sources and funneling to a given circuit, resulting in strong stimulation of inhibition.

Question 11

Reverbating circuit

Answer 11

Characterized by feedback by axon collaterals to previous points in the pathway resulting in ongoing stimulation of the pathway. (feedback and renew themselves)

Question 12

Parallel after discharge circuit

Answer 12

Characterized by stimulation of several neurons arranged in parallel arrays by the stimulating neuron. May be involved in complex activities. (step on a tack, many