6.5 NEURONS AND SYNAPSES

Question 1

ESSENTIAL IDEA

Answer 1

neurons transmit the message, synapses modulate the message

Question 2

NERVOUS SYSTEM IS COMPOSED OF

Answer 2

neurons

Question 3

NEURONS

Answer 3

cells that carry electrical impulses

Question 4

TYPICAL MOTOR NEURON DIAGRAM

Answer 4

https://image.slidesharecdn.com/biok6-160301001800/95/bioknowledgy-presentation-on-65-neurons-and-synapses-4-638.jpg?cb=1457771602

Question 5

SYNAPSE

Answer 5

junction between neurons and between neurons and receptor or effector cells

Question 6

NERVE IMPULSES

Answer 6

action potentials propagated along the axon of neurons

Question 7

NERVE IMPULSE IS A RESULT OF

Answer 7

a change in concentration of Na and K ions across the membranes of the neuron

depo/ repolarisation= action potential

Question 8

RESTING POTENTIAL

Answer 8

the electrical potential across the plasma membrane of a cell that is not conducting an impulse

Question 9

ACTION POTENTIAL

Answer 9

the reversal (depolarisation) and restoration (repolarisation) of the electrical potential across a plasma membrane as a nerve impulse passes along a neuron

Question 10

EXPLIN HOW A NERVE IMPULSE PASSES ALONG A NON- MYELINATED NEURON

Answer 10

action potential activates voltage gated Na channels

Na ions rush to axons

potential increases

if it increases beyond threshold, more Na channels open

axon depolarises, stimulating adjacent sections

K channels open, K rushes out

potential is reduced (repolarisation)

refractory period ensures one way conduction of action potential;

Na-K pump returns axon section to resting potential

Question 11

SYNAPTIC TRANSMISSION

Answer 11

the chemical impulse is converted to a chemical neurotransmitter

Question 12

WHY IS SYNAPTIC TRANSMISSION NEEDED?

Answer 12

at the dendritic end of the nerve cell, each dendrite collects the nerve impulse from the terminal end of a different nerve cell

the impulse needs to jump across a small gap- the synapse

by synaptic transmission

Question 13

PRE SYNAPTIC DIAGRAM

Answer 13

https://image.slidesharecdn.com/biok6-160301001800/95/bioknowledgy-presentation-on-65-neurons-and-synapses-19-638.jpg?cb=1457771602

Question 14

SUMMARY OF SYNAPTIC TRANSMISSION

Answer 14

https://image.slidesharecdn.com/biok6-160301001800/95/bioknowledgy-presentation-on-65-neurons-and-synapses-20-638.jpg?cb=1457771602

Question 15

EXPLAIN THE PRINCIPLES OF SYNAPTIC TRANSMISSION

Answer 15

nerve impulse travels to end of presynaptic neuron

triggers influx of Ca

causes synaptic vesicle to fuse with membrane

release neurotransmitter M into synaptic cleft

NT diffuses across channel

NT binds to receptor on post synaptic neuron

depolarisation

NT degraded

Ca pumped back into synaptic cleft by A.T

Question 16

METHODS OF MEMBRANE TRANSPORT IN NERVES AND SYNAPSES 4

Answer 16

active transport

simple diffusion

facilitated diffusion

vesicle transport

Question 17

METHODS OF MEMBRANE TRANSPORT IN NERVES AND SYNAPSES

A.T

Answer 17

Na-K pump resets resting potential in the axon following nerve impulse

re-uptake of NT to the pre-synaptic neuron following synaptic transmission

removal of Ca from pre-synaptic neuron following synaptic transmission

Question 18

METHODS OF MEMBRANE TRANSPORT IN NERVES AND SYNAPSES

SIMPLE DIFFUSION

Answer 18

diffusion of NT across synaptic cleft

diffusion of K ions out of axon in resting potential

Question 19

METHODS OF MEMBRANE TRANSPORT IN NERVES AND SYNAPSES

FACILITATED DIFFUSION

Answer 19

opening the voltage-gated Na and K channels in action potential

opening of voltage gated Ca channels at pre-synaptic terminal

Na channels activated at post synaptic terminal to propagated AP

Question 20

METHODS OF MEMBRANE TRANSPORT IN NERVES AND SYNAPSES

VESICLE TRANSPORT

Answer 20

influx of Ca activates vesicle of NT

exocytosis of NT from pre synaptic neuron to synaptic cleft

Question 21

ACETYLCHOLINE

Answer 21

neurotransmitter used in many synapses through the nervous system

Question 22

ACETYLCHOLINE INTERFERENCE CONSEQUENCES

Answer 22

paralysis

convultions

Question 23

BINDING OF NEONICOTINOID PESTICIDES IN INSECTS

Answer 23

binds to acetylcholine

blocking of synaptic transmission at cholinergic synapses