4.5 How Neurons Communicate

Question 1

Neurons

Answer 1

• cell body (soma)
• nucleus: translates genetic codes
• axon and axon terminals: responsible to transmit info to other neurons
• dendrites: receives input from other neurons

Question 2

Glia

Answer 2

“glue”
- supporting cells (eg ensure neuron cells stay in place)
- provides support for efficiency communication
- helps remove cellular debris
help ensure for neurons to do their job effectively

Question 3

Blood-brain barrier

Answer 3

• glia forms tight connections w the blood vessels serving the NS
• prevents toxins circulating the blood from exiting into brain tissue where neurons could be harmed

Question 4

Myelin

Answer 4

wraps around axon => myeline sheath
- glia wraps around some axons to form myelin
- insulation that allows the transmission of neural signals to be faster

Question 5

what are the two effects on the receiving (post-synaptic) neuron? NTs and receptors

Answer 5

either excitation or inhibition

• excitatory effect: slightly depolarizes the post-synaptic neuron, increases likelihood that the neuron will reach the threshold and initiate an action potential
• inhibitory effect: opposite, hyperpolarizes, reducing likelihood of a.p

Question 6

Axon

Answer 6

usually responsible for transmitting info to other neurons

Question 7

Dendrites

Answer 7

a branch of a neuron
- receives input from other cells

Question 8

Cell body

Answer 8

large, central mass of the neuron
contains the nucleus

Question 9

when does a neuron fire an electrical impulse?

Answer 9

when a neuron is stimulated enough, it fires an electrical impulse => axon => neighboring neurons

1 signal to send
1 uniform strength and speed

Question 10

what can vary?

Answer 10

frequency / number of pulses
=> action potential

they are different to for the brain to decode which message it is

Question 11

voltage

Answer 11

measure of potential energy generated by separate charges (mV)

larger membrane potential = more difference in (+) and (-) areas

Question 12

current

Answer 12

flow of electricity from one point to another
=> related to voltage and resistance (R = cell membrane)

Question 13

neuron at rest

Answer 13

not processing info
=> the inside of the cell is more NEGATIVE

Question 14

polarized

Answer 14

negative membrane potential

Question 15

Sodium Potassium pump

Answer 15

pumps in 2K, 3Na out
=> creates a difference in concentration and charges
=> outside is more positively charged

Question 16

refractory period

Answer 16

prevent signals from travelling in both directions down the axon at once