Neurons

Question 1

purpose of nodes?

Answer 1

help conduct neural impulses more easily

Question 2

roles of astrocytes?

Answer 2

• form blood brain barrier
• embryonic development
• with other glial cells aid memory, thoughts and the immune system

Question 3

role of oligodendrocytes?

Answer 3

• makes myelin sheath

- releases chemicals to promote neural healing

Question 4

describe blood brain barrier

Answer 4

blood vessels wrapped by fatty coating; prevents large/polar/charged particles and pathogens from getting into bloodstream which serves the brain.

Question 5

describe graded potentials

Answer 5

aka postsynaptic potentials
can be excitatory or inhibitory
when signal meets threshold, action potential is stimulated.

Question 6

action potentials are all or nothing - describe

Answer 6

only activated if theshold is reached - and if so, occur at the same intensity

Question 7

action potentials are regenerative - explain

Answer 7

self perpetuating once it starts

continues down the axon

Question 8

what is the absolute refractory period

Answer 8

time after action potential when a new one can’t be stimulated - limits maximal firing rate of the neuron.

Question 9

describe resting potential

Answer 9

neuron is not stimulated.
slightly more negative chage inside the neuron than outside
-60millivolts

Question 10

describe action potential

Answer 10

positive ions flow into the neuron (depolarisation)
repolarisation: positive ions flow out of the neuron, so that the inside is more negative than it was initially, then it returns to norma;