test 1

Question 1

ways to classify neurons (3 ways)

Answer 1

1. direction
   - afferent/sensory - start in periphery and terminate in CNS
   - efferent/motor - start in CNS and terminate in periphery
   - interneuron - begin and end in CNS
2. # of poles
   • multipolar - most neurons
   • bipolar - soma with two poles in opp. directions
   • unipolar - one long process with soma off to side
     uni/bi tend to be afferent/sensory
3. circuit
   - projection - project from one brain region to distant nervous system region (tend to be larger with long axons)
   - local - found within local /cortical region (tend to be smaller with short axons)

Question 2

types of glial cells (3)

Answer 2

1. oligodendroglial cell - asymmetrical; forms myelin sheath around axons in CNS
2. schwann cells - asymmetrical; forms myelin sheath around PNS; aid in nerve regeneration
3. astrocyte - star-shaped; symmetrical; aids in transfer of nutrients (ex glucose); cell eating (phagocytosis); take up excess K+ for cell to maintain homeostasis; make up blood brain barrier;
   microglia - immune cells for the brain; cell eating (phagocytosis)

Question 3

what maintains RMP

Answer 3

1. permeability
2. driving force (diffusion and electrical gradient)
3. Na+/K+ pump

Question 4

what is the threshold of activation

Answer 4

-55mV

Question 5

what causes depolarization to trigger AP

Answer 5

the EPSPs adding together from time and space

Question 6

where is AP triggered

Answer 6

usually in axon hillock aka “trigger zone”

Question 7

why doesn’t it get up to 55mV

Answer 7

delayed opening of K+ voltage gated channels so K+ rushes OUT at same time of Na+ voltage gated channels so Na+ can no longer come IN

Question 8

what is the process by which a neurotransmitter is sent down the axon to another cell

Answer 8

exocytosis

Question 9

how does myelin speed up AP

Answer 9

acts as insulator which makes the path of least resistance be through the axon rather than out the sides